[PATCH v14 00/25] Drivers for Gunyah hypervisor

[PATCH v14 00/25] Drivers for Gunyah hypervisor

[Elliot Berman]

Gunyah is a Type-1 hypervisor independent of any
high-level OS kernel, and runs in a higher CPU privilege level. It does
not depend on any lower-privileged OS kernel/code for its core
functionality. This increases its security and can support a much smaller
trusted computing base than a Type-2 hypervisor.

Gunyah is an open source hypervisor. The source repo is available at
https://github.com/quic/gunyah-hypervisor.

The diagram below shows the architecture.

::

         VM A                    VM B
     +-----+ +-----+  | +-----+ +-----+ +-----+
     |     | |     |  | |     | |     | |     |
 EL0 | APP | | APP |  | | APP | | APP | | APP |
     |     | |     |  | |     | |     | |     |
     +-----+ +-----+  | +-----+ +-----+ +-----+
 ---------------------|-------------------------
     +--------------+ | +----------------------+
     |              | | |                      |
 EL1 | Linux Kernel | | |Linux kernel/Other OS |   ...
     |              | | |                      |
     +--------------+ | +----------------------+
 --------hvc/smc------|------hvc/smc------------
     +----------------------------------------+
     |                                        |
 EL2 |            Gunyah Hypervisor           |
     |                                        |
     +----------------------------------------+

Gunyah provides these following features.

- Threads and Scheduling: The scheduler schedules virtual CPUs (VCPUs) on
physical CPUs and enables time-sharing of the CPUs.
- Memory Management: Gunyah tracks memory ownership and use of all memory
under its control. Memory partitioning between VMs is a fundamental
security feature.
- Interrupt Virtualization: All interrupts are handled in the hypervisor
and routed to the assigned VM.
- Inter-VM Communication: There are several different mechanisms provided
for communicating between VMs.
- Device Virtualization: Para-virtualization of devices is supported using
inter-VM communication. Low level system features and devices such as
interrupt controllers are supported with emulation where required.

This series adds the basic framework for detecting that Linux is running
under Gunyah as a virtual machine, communication with the Gunyah Resource
Manager, and a sample virtual machine manager capable of launching virtual machines.

The series relies on two other patches posted separately:
 - https://lore.kernel.org/all/20230213181832.3489174-1-quic_eberman@quicinc.com/
 - https://lore.kernel.org/all/20230213232537.2040976-2-quic_eberman@quicinc.com/


Changes in v14:
 - Coding/cosmetic tweaks suggested by Alex
 - Mark IRQs as wake-up capable

Changes in v13: https://lore.kernel.org/all/20230509204801.2824351-1-quic_eberman@quicinc.com/
 - Tweaks to message queue driver to address race condition between IRQ and mailbox registration
 - Allow removal of VM functions by function-specific comparison -- specifically to allow
   removing irqfd by label only and not requiring original FD to be provided.

Changes in v12: https://lore.kernel.org/all/20230424231558.70911-1-quic_eberman@quicinc.com/
 - Stylistic/cosmetic tweaks suggested by Alex
 - Remove patch "virt: gunyah: Identify hypervisor version" and squash the
   check that we're running under a reasonable Gunyah hypervisor into RM driver
 - Refactor platform hooks into a separate module per suggestion from Srini
 - GFP_KERNEL_ACCOUNT and account_locked_vm() for page pinning
 - enum-ify related constants

Changes in v11: https://lore.kernel.org/all/20230304010632.2127470-1-quic_eberman@quicinc.com/
 - Rename struct gh_vm_dtb_config:gpa -> guest_phys_addr & overflow checks for this
 - More docstrings throughout
 - Make resp_buf and resp_buf_size optional
 - Replace deprecated idr with xarray
 - Refconting on misc device instead of RM's platform device
 - Renaming variables, structs, etc. from gunyah_ -> gh_
 - Drop removal of user mem regions
 - Drop mem_lend functionality; to converge with restricted_memfd later

Changes in v10: https://lore.kernel.org/all/20230214211229.3239350-1-quic_eberman@quicinc.com/
 - Fix bisectability (end result of series is same, --fixups applied to wrong commits)
 - Convert GH_ERROR_* and GH_RM_ERROR_* to enums
 - Correct race condition between allocating/freeing user memory
 - Replace offsetof with struct_size
 - Series-wide renaming of functions to be more consistent
 - VM shutdown & restart support added in vCPU and VM Manager patches
 - Convert VM function name (string) to type (number)
 - Convert VM function argument to value (which could be a pointer) to remove memory wastage for arguments
 - Remove defensive checks of hypervisor correctness
 - Clean ups to ioeventfd as suggested by Srivatsa

Changes in v9: https://lore.kernel.org/all/20230120224627.4053418-1-quic_eberman@quicinc.com/
 - Refactor Gunyah API flags to be exposed as feature flags at kernel level
 - Move mbox client cleanup into gunyah_msgq_remove()
 - Simplify gh_rm_call return value and response payload
 - Missing clean-up/error handling/little endian fixes as suggested by Srivatsa and Alex in v8 series

Changes in v8: https://lore.kernel.org/all/20221219225850.2397345-1-quic_eberman@quicinc.com/
 - Treat VM manager as a library of RM
 - Add patches 21-28 as RFC to support proxy-scheduled vCPUs and necessary bits to support virtio
   from Gunyah userspace

Changes in v7: https://lore.kernel.org/all/20221121140009.2353512-1-quic_eberman@quicinc.com/
 - Refactor to remove gunyah RM bus
 - Refactor allow multiple RM device instances
 - Bump UAPI to start at 0x0
 - Refactor QCOM SCM's platform hooks to allow CONFIG_QCOM_SCM=Y/CONFIG_GUNYAH=M combinations

Changes in v6: https://lore.kernel.org/all/20221026185846.3983888-1-quic_eberman@quicinc.com/
 - *Replace gunyah-console with gunyah VM Manager*
 - Move include/asm-generic/gunyah.h into include/linux/gunyah.h
 - s/gunyah_msgq/gh_msgq/
 - Minor tweaks and documentation tidying based on comments from Jiri, Greg, Arnd, Dmitry, and Bagas.

Changes in v5: https://lore.kernel.org/all/20221011000840.289033-1-quic_eberman@quicinc.com/
 - Dropped sysfs nodes
 - Switch from aux bus to Gunyah RM bus for the subdevices
 - Cleaning up RM console

Changes in v4: https://lore.kernel.org/all/20220928195633.2348848-1-quic_eberman@quicinc.com/
 - Tidied up documentation throughout based on questions/feedback received
 - Switched message queue implementation to use mailboxes
 - Renamed "gunyah_device" as "gunyah_resource"

Changes in v3: https://lore.kernel.org/all/20220811214107.1074343-1-quic_eberman@quicinc.com/
 - /Maintained/Supported/ in MAINTAINERS
 - Tidied up documentation throughout based on questions/feedback received
 - Moved hypercalls into arch/arm64/gunyah/; following hyper-v's implementation
 - Drop opaque typedefs
 - Move sysfs nodes under /sys/hypervisor/gunyah/
 - Moved Gunyah console driver to drivers/tty/
 - Reworked gh_device design to drop the Gunyah bus.

Changes in v2: https://lore.kernel.org/all/20220801211240.597859-1-quic_eberman@quicinc.com/
 - DT bindings clean up
 - Switch hypercalls to follow SMCCC 

v1: https://lore.kernel.org/all/20220223233729.1571114-1-quic_eberman@quicinc.com/

Elliot Berman (25):
  docs: gunyah: Introduce Gunyah Hypervisor
  dt-bindings: Add binding for gunyah hypervisor
  gunyah: Common types and error codes for Gunyah hypercalls
  virt: gunyah: Add hypercalls to identify Gunyah
  virt: gunyah: msgq: Add hypercalls to send and receive messages
  mailbox: Add Gunyah message queue mailbox
  gunyah: rsc_mgr: Add resource manager RPC core
  gunyah: rsc_mgr: Add VM lifecycle RPC
  gunyah: vm_mgr: Introduce basic VM Manager
  gunyah: rsc_mgr: Add RPC for sharing memory
  gunyah: vm_mgr: Add/remove user memory regions
  gunyah: vm_mgr: Add ioctls to support basic non-proxy VM boot
  samples: Add sample userspace Gunyah VM Manager
  gunyah: rsc_mgr: Add platform ops on mem_lend/mem_reclaim
  virt: gunyah: Add Qualcomm Gunyah platform ops
  docs: gunyah: Document Gunyah VM Manager
  virt: gunyah: Translate gh_rm_hyp_resource into gunyah_resource
  gunyah: vm_mgr: Add framework for VM Functions
  virt: gunyah: Add resource tickets
  virt: gunyah: Add IO handlers
  virt: gunyah: Add proxy-scheduled vCPUs
  virt: gunyah: Add hypercalls for sending doorbell
  virt: gunyah: Add irqfd interface
  virt: gunyah: Add ioeventfd
  MAINTAINERS: Add Gunyah hypervisor drivers section

 .../bindings/firmware/gunyah-hypervisor.yaml  |  82 ++
 .../userspace-api/ioctl/ioctl-number.rst      |   1 +
 Documentation/virt/gunyah/index.rst           | 114 +++
 Documentation/virt/gunyah/message-queue.rst   |  71 ++
 Documentation/virt/gunyah/vm-manager.rst      | 143 +++
 Documentation/virt/index.rst                  |   1 +
 MAINTAINERS                                   |  13 +
 arch/arm64/Kbuild                             |   1 +
 arch/arm64/gunyah/Makefile                    |   3 +
 arch/arm64/gunyah/gunyah_hypercall.c          | 142 +++
 arch/arm64/include/asm/gunyah.h               |  24 +
 drivers/mailbox/Makefile                      |   2 +
 drivers/mailbox/gunyah-msgq.c                 | 219 +++++
 drivers/virt/Kconfig                          |   2 +
 drivers/virt/Makefile                         |   1 +
 drivers/virt/gunyah/Kconfig                   |  59 ++
 drivers/virt/gunyah/Makefile                  |  11 +
 drivers/virt/gunyah/gunyah_ioeventfd.c        | 130 +++
 drivers/virt/gunyah/gunyah_irqfd.c            | 180 ++++
 drivers/virt/gunyah/gunyah_platform_hooks.c   |  80 ++
 drivers/virt/gunyah/gunyah_qcom.c             | 153 +++
 drivers/virt/gunyah/gunyah_vcpu.c             | 470 +++++++++
 drivers/virt/gunyah/rsc_mgr.c                 | 909 ++++++++++++++++++
 drivers/virt/gunyah/rsc_mgr.h                 |  19 +
 drivers/virt/gunyah/rsc_mgr_rpc.c             | 500 ++++++++++
 drivers/virt/gunyah/vm_mgr.c                  | 791 +++++++++++++++
 drivers/virt/gunyah/vm_mgr.h                  |  70 ++
 drivers/virt/gunyah/vm_mgr_mm.c               | 252 +++++
 include/linux/gunyah.h                        | 207 ++++
 include/linux/gunyah_rsc_mgr.h                | 162 ++++
 include/linux/gunyah_vm_mgr.h                 | 153 +++
 include/uapi/linux/gunyah.h                   | 293 ++++++
 samples/Kconfig                               |  10 +
 samples/Makefile                              |   1 +
 samples/gunyah/.gitignore                     |   2 +
 samples/gunyah/Makefile                       |   6 +
 samples/gunyah/gunyah_vmm.c                   | 266 +++++
 samples/gunyah/sample_vm.dts                  |  68 ++
 38 files changed, 5611 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/firmware/gunyah-hypervisor.yaml
 create mode 100644 Documentation/virt/gunyah/index.rst
 create mode 100644 Documentation/virt/gunyah/message-queue.rst
 create mode 100644 Documentation/virt/gunyah/vm-manager.rst
 create mode 100644 arch/arm64/gunyah/Makefile
 create mode 100644 arch/arm64/gunyah/gunyah_hypercall.c
 create mode 100644 arch/arm64/include/asm/gunyah.h
 create mode 100644 drivers/mailbox/gunyah-msgq.c
 create mode 100644 drivers/virt/gunyah/Kconfig
 create mode 100644 drivers/virt/gunyah/Makefile
 create mode 100644 drivers/virt/gunyah/gunyah_ioeventfd.c
 create mode 100644 drivers/virt/gunyah/gunyah_irqfd.c
 create mode 100644 drivers/virt/gunyah/gunyah_platform_hooks.c
 create mode 100644 drivers/virt/gunyah/gunyah_qcom.c
 create mode 100644 drivers/virt/gunyah/gunyah_vcpu.c
 create mode 100644 drivers/virt/gunyah/rsc_mgr.c
 create mode 100644 drivers/virt/gunyah/rsc_mgr.h
 create mode 100644 drivers/virt/gunyah/rsc_mgr_rpc.c
 create mode 100644 drivers/virt/gunyah/vm_mgr.c
 create mode 100644 drivers/virt/gunyah/vm_mgr.h
 create mode 100644 drivers/virt/gunyah/vm_mgr_mm.c
 create mode 100644 include/linux/gunyah.h
 create mode 100644 include/linux/gunyah_rsc_mgr.h
 create mode 100644 include/linux/gunyah_vm_mgr.h
 create mode 100644 include/uapi/linux/gunyah.h
 create mode 100644 samples/gunyah/.gitignore
 create mode 100644 samples/gunyah/Makefile
 create mode 100644 samples/gunyah/gunyah_vmm.c
 create mode 100644 samples/gunyah/sample_vm.dts


base-commit: 858fd168a95c5b9669aac8db6c14a9aeab446375
-- 
2.40.0

[PATCH v14 01/25] docs: gunyah: Introduce Gunyah Hypervisor

[Elliot Berman]

Gunyah is an open-source Type-1 hypervisor developed by Qualcomm. It
does not depend on any lower-privileged OS/kernel code for its core
functionality. This increases its security and can support a smaller
trusted computing based when compared to Type-2 hypervisors.

Add documentation describing the Gunyah hypervisor and the main
components of the Gunyah hypervisor which are of interest to Linux
virtualization development.

Reviewed-by: Bagas Sanjaya <bagasdotme@gmail.com>
Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
---
 Documentation/virt/gunyah/index.rst         | 113 ++++++++++++++++++++
 Documentation/virt/gunyah/message-queue.rst |  63 +++++++++++
 Documentation/virt/index.rst                |   1 +
 3 files changed, 177 insertions(+)
 create mode 100644 Documentation/virt/gunyah/index.rst
 create mode 100644 Documentation/virt/gunyah/message-queue.rst

diff --git a/Documentation/virt/gunyah/index.rst b/Documentation/virt/gunyah/index.rst
new file mode 100644
index 0000000000000..74aa345e0a144
--- /dev/null
+++ b/Documentation/virt/gunyah/index.rst
@@ -0,0 +1,113 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+=================
+Gunyah Hypervisor
+=================
+
+.. toctree::
+   :maxdepth: 1
+
+   message-queue
+
+Gunyah is a Type-1 hypervisor which is independent of any OS kernel, and runs in
+a higher CPU privilege level. It does not depend on any lower-privileged operating system
+for its core functionality. This increases its security and can support a much smaller
+trusted computing base than a Type-2 hypervisor.
+
+Gunyah is an open source hypervisor. The source repo is available at
+https://github.com/quic/gunyah-hypervisor.
+
+Gunyah provides these following features.
+
+- Scheduling:
+
+  A scheduler for virtual CPUs (vCPUs) on physical CPUs enables time-sharing
+  of the CPUs. Gunyah supports two models of scheduling:
+
+    1. "Behind the back" scheduling in which Gunyah hypervisor schedules vCPUS on its own.
+    2. "Proxy" scheduling in which a delegated VM can donate part of one of its vCPU slice
+       to another VM's vCPU via a hypercall.
+
+- Memory Management:
+
+  APIs handling memory, abstracted as objects, limiting direct use of physical
+  addresses. Memory ownership and usage tracking of all memory under its control.
+  Memory partitioning between VMs is a fundamental security feature.
+
+- Interrupt Virtualization:
+
+  Uses CPU hardware interrupt virtualization capabilities. Interrupts are handled
+  in the hypervisor and routed to the assigned VM.
+
+- Inter-VM Communication:
+
+  There are several different mechanisms provided for communicating between VMs.
+
+- Virtual platform:
+
+  Architectural devices such as interrupt controllers and CPU timers are directly provided
+  by the hypervisor as well as core virtual platform devices and system APIs such as ARM PSCI.
+
+- Device Virtualization:
+
+  Para-virtualization of devices is supported using inter-VM communication.
+
+Architectures supported
+=======================
+AArch64 with a GIC
+
+Resources and Capabilities
+==========================
+
+Some services or resources provided by the Gunyah hypervisor are described to a virtual machine by
+capability IDs. For instance, inter-VM communication is performed with doorbells and message queues.
+Gunyah allows access to manipulate that doorbell via the capability ID. These resources are
+described in Linux as a struct gh_resource.
+
+High level management of these resources is performed by the resource manager VM. RM informs a
+guest VM about resources it can access through either the device tree or via guest-initiated RPC.
+
+For each virtual machine, Gunyah maintains a table of resources which can be accessed by that VM.
+An entry in this table is called a "capability" and VMs can only access resources via this
+capability table. Hence, virtual Gunyah resources are referenced by a "capability IDs" and not
+"resource IDs". If 2 VMs have access to the same resource, they might not be using the same
+capability ID to access that resource since the capability tables are independent per VM.
+
+Resource Manager
+================
+
+The resource manager (RM) is a privileged application VM supporting the Gunyah Hypervisor.
+It provides policy enforcement aspects of the virtualization system. The resource manager can
+be treated as an extension of the Hypervisor but is separated to its own partition to ensure
+that the hypervisor layer itself remains small and secure and to maintain a separation of policy
+and mechanism in the platform. RM runs at arm64 NS-EL1 similar to other virtual machines.
+
+Communication with the resource manager from each guest VM happens with message-queue.rst. Details
+about the specific messages can be found in drivers/virt/gunyah/rsc_mgr.c
+
+::
+
+  +-------+   +--------+   +--------+
+  |  RM   |   |  VM_A  |   |  VM_B  |
+  +-.-.-.-+   +---.----+   +---.----+
+    | |           |            |
+  +-.-.-----------.------------.----+
+  | | \==========/             |    |
+  |  \========================/     |
+  |            Gunyah               |
+  +---------------------------------+
+
+The source for the resource manager is available at https://github.com/quic/gunyah-resource-manager.
+
+The resource manager provides the following features:
+
+- VM lifecycle management: allocating a VM, starting VMs, destruction of VMs
+- VM access control policy, including memory sharing and lending
+- Interrupt routing configuration
+- Forwarding of system-level events (e.g. VM shutdown) to owner VM
+
+When booting a virtual machine which uses a devicetree such as Linux, resource manager overlays a
+/hypervisor node. This node can let Linux know it is running as a Gunyah guest VM,
+how to communicate with resource manager, and basic description and capabilities of
+this VM. See Documentation/devicetree/bindings/firmware/gunyah-hypervisor.yaml for a description
+of this node.
diff --git a/Documentation/virt/gunyah/message-queue.rst b/Documentation/virt/gunyah/message-queue.rst
new file mode 100644
index 0000000000000..b352918ae54b4
--- /dev/null
+++ b/Documentation/virt/gunyah/message-queue.rst
@@ -0,0 +1,63 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+Message Queues
+==============
+Message queue is a simple low-capacity IPC channel between two VMs. It is
+intended for sending small control and configuration messages. Each message
+queue is unidirectional, so a full-duplex IPC channel requires a pair of queues.
+
+Messages can be up to 240 bytes in length. Longer messages require a further
+protocol on top of the message queue messages themselves. For instance, communication
+with the resource manager adds a header field for sending longer messages via multiple
+message fragments.
+
+The diagram below shows how message queue works. A typical configuration involves
+2 message queues. Message queue 1 allows VM_A to send messages to VM_B. Message
+queue 2 allows VM_B to send messages to VM_A.
+
+1. VM_A sends a message of up to 240 bytes in length. It raises a hypercall
+   with the message to inform the hypervisor to add the message to
+   message queue 1's queue. The hypervisor copies memory into the internal
+   message queue representation; the memory doesn't need to be shared between
+   VM_A and VM_B.
+
+2. Gunyah raises the corresponding interrupt for VM_B (Rx vIRQ) when any of
+   these happens:
+
+   a. gh_msgq_send() has PUSH flag. Queue is immediately flushed. This is the typical case.
+   b. Explicility with gh_msgq_push command from VM_A.
+   c. Message queue has reached a threshold depth.
+
+3. VM_B calls gh_msgq_recv() and Gunyah copies message to requested buffer.
+
+4. Gunyah buffers messages in the queue. If the queue became full when VM_A added a message,
+   the return values for gh_msgq_send() include a flag that indicates the queue is full.
+   Once VM_B receives the message and, thus, there is space in the queue, Gunyah
+   will raise the Tx vIRQ on VM_A to indicate it can continue sending messages.
+
+For VM_B to send a message to VM_A, the process is identical, except that hypercalls
+reference message queue 2's capability ID. Each message queue has its own independent
+vIRQ: two TX message queues will have two vIRQs (and two capability IDs).
+
+::
+
+      +---------------+         +-----------------+         +---------------+
+      |      VM_A     |         |Gunyah hypervisor|         |      VM_B     |
+      |               |         |                 |         |               |
+      |               |         |                 |         |               |
+      |               |   Tx    |                 |         |               |
+      |               |-------->|                 | Rx vIRQ |               |
+      |gh_msgq_send() | Tx vIRQ |Message queue 1  |-------->|gh_msgq_recv() |
+      |               |<------- |                 |         |               |
+      |               |         |                 |         |               |
+      | Message Queue |         |                 |         | Message Queue |
+      | driver        |         |                 |         | driver        |
+      |               |         |                 |         |               |
+      |               |         |                 |         |               |
+      |               |         |                 |   Tx    |               |
+      |               | Rx vIRQ |                 |<--------|               |
+      |gh_msgq_recv() |<--------|Message queue 2  | Tx vIRQ |gh_msgq_send() |
+      |               |         |                 |-------->|               |
+      |               |         |                 |         |               |
+      |               |         |                 |         |               |
+      +---------------+         +-----------------+         +---------------+
diff --git a/Documentation/virt/index.rst b/Documentation/virt/index.rst
index 7fb55ae08598d..15869ee059b35 100644
--- a/Documentation/virt/index.rst
+++ b/Documentation/virt/index.rst
@@ -16,6 +16,7 @@ Virtualization Support
    coco/sev-guest
    coco/tdx-guest
    hyperv/index
+   gunyah/index
 
 .. only:: html and subproject
 
-- 
2.40.0

[PATCH v14 02/25] dt-bindings: Add binding for gunyah hypervisor

[Elliot Berman]

When Linux is booted as a guest under the Gunyah hypervisor, the Gunyah
Resource Manager applies a devicetree overlay describing the virtual
platform configuration of the guest VM, such as the message queue
capability IDs for communicating with the Resource Manager. This
information is not otherwise discoverable by a VM: the Gunyah hypervisor
core does not provide a direct interface to discover capability IDs nor
a way to communicate with RM without having already known the
corresponding message queue capability ID. Add the DT bindings that
Gunyah adheres for the hypervisor node and message queues.

Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
---
 .../bindings/firmware/gunyah-hypervisor.yaml  | 82 +++++++++++++++++++
 1 file changed, 82 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/firmware/gunyah-hypervisor.yaml

diff --git a/Documentation/devicetree/bindings/firmware/gunyah-hypervisor.yaml b/Documentation/devicetree/bindings/firmware/gunyah-hypervisor.yaml
new file mode 100644
index 0000000000000..3fc0b043ac3cf
--- /dev/null
+++ b/Documentation/devicetree/bindings/firmware/gunyah-hypervisor.yaml
@@ -0,0 +1,82 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/firmware/gunyah-hypervisor.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Gunyah Hypervisor
+
+maintainers:
+  - Prakruthi Deepak Heragu <quic_pheragu@quicinc.com>
+  - Elliot Berman <quic_eberman@quicinc.com>
+
+description: |+
+  Gunyah virtual machines use this information to determine the capability IDs
+  of the message queues used to communicate with the Gunyah Resource Manager.
+  See also: https://github.com/quic/gunyah-resource-manager/blob/develop/src/vm_creation/dto_construct.c
+
+properties:
+  compatible:
+    const: gunyah-hypervisor
+
+  "#address-cells":
+    description: Number of cells needed to represent 64-bit capability IDs.
+    const: 2
+
+  "#size-cells":
+    description: must be 0, because capability IDs are not memory address
+                  ranges and do not have a size.
+    const: 0
+
+patternProperties:
+  "^gunyah-resource-mgr(@.*)?":
+    type: object
+    description:
+      Resource Manager node which is required to communicate to Resource
+      Manager VM using Gunyah Message Queues.
+
+    properties:
+      compatible:
+        const: gunyah-resource-manager
+
+      reg:
+        items:
+          - description: Gunyah capability ID of the TX message queue
+          - description: Gunyah capability ID of the RX message queue
+
+      interrupts:
+        items:
+          - description: Interrupt for the TX message queue
+          - description: Interrupt for the RX message queue
+
+    additionalProperties: false
+
+    required:
+      - compatible
+      - reg
+      - interrupts
+
+additionalProperties: false
+
+required:
+  - compatible
+  - "#address-cells"
+  - "#size-cells"
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+
+    hypervisor {
+        #address-cells = <2>;
+        #size-cells = <0>;
+        compatible = "gunyah-hypervisor";
+
+        gunyah-resource-mgr@0 {
+            compatible = "gunyah-resource-manager";
+            interrupts = <GIC_SPI 3 IRQ_TYPE_EDGE_RISING>, /* TX full IRQ */
+                         <GIC_SPI 4 IRQ_TYPE_EDGE_RISING>; /* RX empty IRQ */
+            reg = <0x00000000 0x00000000>, <0x00000000 0x00000001>;
+                  /* TX, RX cap ids */
+        };
+    };
-- 
2.40.0

[PATCH v14 03/25] gunyah: Common types and error codes for Gunyah hypercalls

[Elliot Berman]

Add architecture-independent standard error codes, types, and macros for
Gunyah hypercalls.

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Reviewed-by: Alex Elder <elder@linaro.org>
Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
---
 include/linux/gunyah.h | 83 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 83 insertions(+)
 create mode 100644 include/linux/gunyah.h

diff --git a/include/linux/gunyah.h b/include/linux/gunyah.h
new file mode 100644
index 0000000000000..a4e8ec91961d1
--- /dev/null
+++ b/include/linux/gunyah.h
@@ -0,0 +1,83 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#ifndef _LINUX_GUNYAH_H
+#define _LINUX_GUNYAH_H
+
+#include <linux/errno.h>
+#include <linux/limits.h>
+
+/******************************************************************************/
+/* Common arch-independent definitions for Gunyah hypercalls                  */
+#define GH_CAPID_INVAL	U64_MAX
+#define GH_VMID_ROOT_VM	0xff
+
+enum gh_error {
+	GH_ERROR_OK			= 0,
+	GH_ERROR_UNIMPLEMENTED		= -1,
+	GH_ERROR_RETRY			= -2,
+
+	GH_ERROR_ARG_INVAL		= 1,
+	GH_ERROR_ARG_SIZE		= 2,
+	GH_ERROR_ARG_ALIGN		= 3,
+
+	GH_ERROR_NOMEM			= 10,
+
+	GH_ERROR_ADDR_OVFL		= 20,
+	GH_ERROR_ADDR_UNFL		= 21,
+	GH_ERROR_ADDR_INVAL		= 22,
+
+	GH_ERROR_DENIED			= 30,
+	GH_ERROR_BUSY			= 31,
+	GH_ERROR_IDLE			= 32,
+
+	GH_ERROR_IRQ_BOUND		= 40,
+	GH_ERROR_IRQ_UNBOUND		= 41,
+
+	GH_ERROR_CSPACE_CAP_NULL	= 50,
+	GH_ERROR_CSPACE_CAP_REVOKED	= 51,
+	GH_ERROR_CSPACE_WRONG_OBJ_TYPE	= 52,
+	GH_ERROR_CSPACE_INSUF_RIGHTS	= 53,
+	GH_ERROR_CSPACE_FULL		= 54,
+
+	GH_ERROR_MSGQUEUE_EMPTY		= 60,
+	GH_ERROR_MSGQUEUE_FULL		= 61,
+};
+
+/**
+ * gh_error_remap() - Remap Gunyah hypervisor errors into a Linux error code
+ * @gh_error: Gunyah hypercall return value
+ */
+static inline int gh_error_remap(enum gh_error gh_error)
+{
+	switch (gh_error) {
+	case GH_ERROR_OK:
+		return 0;
+	case GH_ERROR_NOMEM:
+		return -ENOMEM;
+	case GH_ERROR_DENIED:
+	case GH_ERROR_CSPACE_CAP_NULL:
+	case GH_ERROR_CSPACE_CAP_REVOKED:
+	case GH_ERROR_CSPACE_WRONG_OBJ_TYPE:
+	case GH_ERROR_CSPACE_INSUF_RIGHTS:
+	case GH_ERROR_CSPACE_FULL:
+		return -EACCES;
+	case GH_ERROR_BUSY:
+	case GH_ERROR_IDLE:
+		return -EBUSY;
+	case GH_ERROR_IRQ_BOUND:
+	case GH_ERROR_IRQ_UNBOUND:
+	case GH_ERROR_MSGQUEUE_FULL:
+	case GH_ERROR_MSGQUEUE_EMPTY:
+		return -EIO;
+	case GH_ERROR_UNIMPLEMENTED:
+	case GH_ERROR_RETRY:
+		return -EOPNOTSUPP;
+	default:
+		return -EINVAL;
+	}
+}
+
+#endif
-- 
2.40.0

[PATCH v14 04/25] virt: gunyah: Add hypercalls to identify Gunyah

[Elliot Berman]

Add hypercalls to identify when Linux is running a virtual machine under
Gunyah.

There are two calls to help identify Gunyah:

1. gh_hypercall_get_uid() returns a UID when running under a Gunyah
   hypervisor.
2. gh_hypercall_hyp_identify() returns build information and a set of
   feature flags that are supported by Gunyah.

Reviewed-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Reviewed-by: Alex Elder <elder@linaro.org>
Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
---
 arch/arm64/Kbuild                    |  1 +
 arch/arm64/gunyah/Makefile           |  3 ++
 arch/arm64/gunyah/gunyah_hypercall.c | 58 ++++++++++++++++++++++++++++
 drivers/virt/Kconfig                 |  2 +
 drivers/virt/gunyah/Kconfig          | 13 +++++++
 include/linux/gunyah.h               | 31 +++++++++++++++
 6 files changed, 108 insertions(+)
 create mode 100644 arch/arm64/gunyah/Makefile
 create mode 100644 arch/arm64/gunyah/gunyah_hypercall.c
 create mode 100644 drivers/virt/gunyah/Kconfig

diff --git a/arch/arm64/Kbuild b/arch/arm64/Kbuild
index 5bfbf7d79c99b..e4847ba0e3c95 100644
--- a/arch/arm64/Kbuild
+++ b/arch/arm64/Kbuild
@@ -3,6 +3,7 @@ obj-y			+= kernel/ mm/ net/
 obj-$(CONFIG_KVM)	+= kvm/
 obj-$(CONFIG_XEN)	+= xen/
 obj-$(subst m,y,$(CONFIG_HYPERV))	+= hyperv/
+obj-$(CONFIG_GUNYAH)	+= gunyah/
 obj-$(CONFIG_CRYPTO)	+= crypto/
 
 # for cleaning
diff --git a/arch/arm64/gunyah/Makefile b/arch/arm64/gunyah/Makefile
new file mode 100644
index 0000000000000..84f1e38cafb1e
--- /dev/null
+++ b/arch/arm64/gunyah/Makefile
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0
+
+obj-$(CONFIG_GUNYAH) += gunyah_hypercall.o
diff --git a/arch/arm64/gunyah/gunyah_hypercall.c b/arch/arm64/gunyah/gunyah_hypercall.c
new file mode 100644
index 0000000000000..ef48e0b8b5448
--- /dev/null
+++ b/arch/arm64/gunyah/gunyah_hypercall.c
@@ -0,0 +1,58 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#include <linux/arm-smccc.h>
+#include <linux/module.h>
+#include <linux/gunyah.h>
+#include <linux/uuid.h>
+
+/* {c1d58fcd-a453-5fdb-9265-ce36673d5f14} */
+static const uuid_t GUNYAH_UUID =
+	UUID_INIT(0xc1d58fcd, 0xa453, 0x5fdb, 0x92, 0x65, 0xce, 0x36, 0x67, 0x3d, 0x5f, 0x14);
+
+bool arch_is_gh_guest(void)
+{
+	struct arm_smccc_res res;
+	uuid_t uuid;
+	u32 *up;
+
+	arm_smccc_1_1_hvc(ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID, &res);
+
+	up = (u32 *)&uuid.b[0];
+	up[0] = lower_32_bits(res.a0);
+	up[1] = lower_32_bits(res.a1);
+	up[2] = lower_32_bits(res.a2);
+	up[3] = lower_32_bits(res.a3);
+
+	return uuid_equal(&uuid, &GUNYAH_UUID);
+}
+EXPORT_SYMBOL_GPL(arch_is_gh_guest);
+
+#define GH_HYPERCALL(fn)	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, ARM_SMCCC_SMC_64, \
+						   ARM_SMCCC_OWNER_VENDOR_HYP, \
+						   fn)
+
+#define GH_HYPERCALL_HYP_IDENTIFY		GH_HYPERCALL(0x8000)
+
+/**
+ * gh_hypercall_hyp_identify() - Returns build information and feature flags
+ *                               supported by Gunyah.
+ * @hyp_identity: filled by the hypercall with the API info and feature flags.
+ */
+void gh_hypercall_hyp_identify(struct gh_hypercall_hyp_identify_resp *hyp_identity)
+{
+	struct arm_smccc_res res;
+
+	arm_smccc_1_1_hvc(GH_HYPERCALL_HYP_IDENTIFY, &res);
+
+	hyp_identity->api_info = res.a0;
+	hyp_identity->flags[0] = res.a1;
+	hyp_identity->flags[1] = res.a2;
+	hyp_identity->flags[2] = res.a3;
+}
+EXPORT_SYMBOL_GPL(gh_hypercall_hyp_identify);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Gunyah Hypervisor Hypercalls");
diff --git a/drivers/virt/Kconfig b/drivers/virt/Kconfig
index f79ab13a5c28b..85bd6626ffc90 100644
--- a/drivers/virt/Kconfig
+++ b/drivers/virt/Kconfig
@@ -54,4 +54,6 @@ source "drivers/virt/coco/sev-guest/Kconfig"
 
 source "drivers/virt/coco/tdx-guest/Kconfig"
 
+source "drivers/virt/gunyah/Kconfig"
+
 endif
diff --git a/drivers/virt/gunyah/Kconfig b/drivers/virt/gunyah/Kconfig
new file mode 100644
index 0000000000000..1a737694c333d
--- /dev/null
+++ b/drivers/virt/gunyah/Kconfig
@@ -0,0 +1,13 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+config GUNYAH
+	tristate "Gunyah Virtualization drivers"
+	depends on ARM64
+	depends on MAILBOX
+	help
+	  The Gunyah drivers are the helper interfaces that run in a guest VM
+	  such as basic inter-VM IPC and signaling mechanisms, and higher level
+	  services such as memory/device sharing, IRQ sharing, and so on.
+
+	  Say Y/M here to enable the drivers needed to interact in a Gunyah
+	  virtual environment.
diff --git a/include/linux/gunyah.h b/include/linux/gunyah.h
index a4e8ec91961d1..6b36cf4787efb 100644
--- a/include/linux/gunyah.h
+++ b/include/linux/gunyah.h
@@ -6,8 +6,10 @@
 #ifndef _LINUX_GUNYAH_H
 #define _LINUX_GUNYAH_H
 
+#include <linux/bitfield.h>
 #include <linux/errno.h>
 #include <linux/limits.h>
+#include <linux/types.h>
 
 /******************************************************************************/
 /* Common arch-independent definitions for Gunyah hypercalls                  */
@@ -80,4 +82,33 @@ static inline int gh_error_remap(enum gh_error gh_error)
 	}
 }
 
+enum gh_api_feature {
+	GH_FEATURE_DOORBELL 	= 1,
+	GH_FEATURE_MSGQUEUE 	= 2,
+	GH_FEATURE_VCPU 	= 5,
+	GH_FEATURE_MEMEXTENT 	= 6,
+};
+
+bool arch_is_gh_guest(void);
+
+#define GH_API_V1			1
+
+/* Other bits reserved for future use and will be zero */
+#define GH_API_INFO_API_VERSION_MASK	GENMASK_ULL(13, 0)
+#define GH_API_INFO_BIG_ENDIAN		BIT_ULL(14)
+#define GH_API_INFO_IS_64BIT		BIT_ULL(15)
+#define GH_API_INFO_VARIANT_MASK	GENMASK_ULL(63, 56)
+
+struct gh_hypercall_hyp_identify_resp {
+	u64 api_info;
+	u64 flags[3];
+};
+
+static inline u16 gh_api_version(const struct gh_hypercall_hyp_identify_resp *gh_api)
+{
+	return FIELD_GET(GH_API_INFO_API_VERSION_MASK, gh_api->api_info);
+}
+
+void gh_hypercall_hyp_identify(struct gh_hypercall_hyp_identify_resp *hyp_identity);
+
 #endif
-- 
2.40.0

[PATCH v14 05/25] virt: gunyah: msgq: Add hypercalls to send and receive messages

[Elliot Berman]

Add hypercalls to send and receive messages on a Gunyah message queue.

Reviewed-by: Alex Elder <elder@linaro.org>
Reviewed-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
---
 arch/arm64/gunyah/gunyah_hypercall.c | 31 ++++++++++++++++++++++++++++
 include/linux/gunyah.h               |  6 ++++++
 2 files changed, 37 insertions(+)

diff --git a/arch/arm64/gunyah/gunyah_hypercall.c b/arch/arm64/gunyah/gunyah_hypercall.c
index ef48e0b8b5448..c5bf0dd468ec9 100644
--- a/arch/arm64/gunyah/gunyah_hypercall.c
+++ b/arch/arm64/gunyah/gunyah_hypercall.c
@@ -35,6 +35,8 @@ EXPORT_SYMBOL_GPL(arch_is_gh_guest);
 						   fn)
 
 #define GH_HYPERCALL_HYP_IDENTIFY		GH_HYPERCALL(0x8000)
+#define GH_HYPERCALL_MSGQ_SEND			GH_HYPERCALL(0x801B)
+#define GH_HYPERCALL_MSGQ_RECV			GH_HYPERCALL(0x801C)
 
 /**
  * gh_hypercall_hyp_identify() - Returns build information and feature flags
@@ -54,5 +56,34 @@ void gh_hypercall_hyp_identify(struct gh_hypercall_hyp_identify_resp *hyp_identi
 }
 EXPORT_SYMBOL_GPL(gh_hypercall_hyp_identify);
 
+enum gh_error gh_hypercall_msgq_send(u64 capid, size_t size, void *buff, u64 tx_flags, bool *ready)
+{
+	struct arm_smccc_res res;
+
+	arm_smccc_1_1_hvc(GH_HYPERCALL_MSGQ_SEND, capid, size, (uintptr_t)buff, tx_flags, 0, &res);
+
+	if (res.a0 == GH_ERROR_OK)
+		*ready = !!res.a1;
+
+	return res.a0;
+}
+EXPORT_SYMBOL_GPL(gh_hypercall_msgq_send);
+
+enum gh_error gh_hypercall_msgq_recv(u64 capid, void *buff, size_t size, size_t *recv_size,
+					bool *ready)
+{
+	struct arm_smccc_res res;
+
+	arm_smccc_1_1_hvc(GH_HYPERCALL_MSGQ_RECV, capid, (uintptr_t)buff, size, 0, &res);
+
+	if (res.a0 == GH_ERROR_OK) {
+		*recv_size = res.a1;
+		*ready = !!res.a2;
+	}
+
+	return res.a0;
+}
+EXPORT_SYMBOL_GPL(gh_hypercall_msgq_recv);
+
 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("Gunyah Hypervisor Hypercalls");
diff --git a/include/linux/gunyah.h b/include/linux/gunyah.h
index 6b36cf4787efb..01a6f202d037e 100644
--- a/include/linux/gunyah.h
+++ b/include/linux/gunyah.h
@@ -111,4 +111,10 @@ static inline u16 gh_api_version(const struct gh_hypercall_hyp_identify_resp *gh
 
 void gh_hypercall_hyp_identify(struct gh_hypercall_hyp_identify_resp *hyp_identity);
 
+#define GH_HYPERCALL_MSGQ_TX_FLAGS_PUSH		BIT(0)
+
+enum gh_error gh_hypercall_msgq_send(u64 capid, size_t size, void *buff, u64 tx_flags, bool *ready);
+enum gh_error gh_hypercall_msgq_recv(u64 capid, void *buff, size_t size, size_t *recv_size,
+					bool *ready);
+
 #endif
-- 
2.40.0

[PATCH v14 06/25] mailbox: Add Gunyah message queue mailbox

[Elliot Berman]

Gunyah message queues are a unidirectional inter-VM pipe for messages up
to 1024 bytes. This driver supports pairing a receiver message queue and
a transmitter message queue to expose a single mailbox channel.

Reviewed-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
---
 Documentation/virt/gunyah/message-queue.rst |   8 +
 drivers/mailbox/Makefile                    |   2 +
 drivers/mailbox/gunyah-msgq.c               | 219 ++++++++++++++++++++
 include/linux/gunyah.h                      |  57 +++++
 4 files changed, 286 insertions(+)
 create mode 100644 drivers/mailbox/gunyah-msgq.c

diff --git a/Documentation/virt/gunyah/message-queue.rst b/Documentation/virt/gunyah/message-queue.rst
index b352918ae54b4..70d82a4ef32d7 100644
--- a/Documentation/virt/gunyah/message-queue.rst
+++ b/Documentation/virt/gunyah/message-queue.rst
@@ -61,3 +61,11 @@ vIRQ: two TX message queues will have two vIRQs (and two capability IDs).
       |               |         |                 |         |               |
       |               |         |                 |         |               |
       +---------------+         +-----------------+         +---------------+
+
+Gunyah message queues are exposed as mailboxes. To create the mailbox, create
+a mbox_client and call `gh_msgq_init()`. On receipt of the RX_READY interrupt,
+all messages in the RX message queue are read and pushed via the `rx_callback`
+of the registered mbox_client.
+
+.. kernel-doc:: drivers/mailbox/gunyah-msgq.c
+   :identifiers: gh_msgq_init
diff --git a/drivers/mailbox/Makefile b/drivers/mailbox/Makefile
index fc93761171113..5f929bb55e9a5 100644
--- a/drivers/mailbox/Makefile
+++ b/drivers/mailbox/Makefile
@@ -55,6 +55,8 @@ obj-$(CONFIG_MTK_CMDQ_MBOX)	+= mtk-cmdq-mailbox.o
 
 obj-$(CONFIG_ZYNQMP_IPI_MBOX)	+= zynqmp-ipi-mailbox.o
 
+obj-$(CONFIG_GUNYAH)		+= gunyah-msgq.o
+
 obj-$(CONFIG_SUN6I_MSGBOX)	+= sun6i-msgbox.o
 
 obj-$(CONFIG_SPRD_MBOX)		+= sprd-mailbox.o
diff --git a/drivers/mailbox/gunyah-msgq.c b/drivers/mailbox/gunyah-msgq.c
new file mode 100644
index 0000000000000..7f777339278eb
--- /dev/null
+++ b/drivers/mailbox/gunyah-msgq.c
@@ -0,0 +1,219 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#include <linux/mailbox_controller.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/gunyah.h>
+#include <linux/printk.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/wait.h>
+
+#define mbox_chan_to_msgq(chan) (container_of(chan->mbox, struct gh_msgq, mbox))
+
+static irqreturn_t gh_msgq_rx_irq_handler(int irq, void *data)
+{
+	struct gh_msgq *msgq = data;
+	struct gh_msgq_rx_data rx_data;
+	enum gh_error gh_error;
+	bool ready = true;
+
+	while (ready) {
+		gh_error = gh_hypercall_msgq_recv(msgq->rx_ghrsc->capid,
+				&rx_data.data, sizeof(rx_data.data),
+				&rx_data.length, &ready);
+		if (gh_error != GH_ERROR_OK) {
+			if (gh_error != GH_ERROR_MSGQUEUE_EMPTY)
+				dev_warn(msgq->mbox.dev, "Failed to receive data: %d\n", gh_error);
+			break;
+		}
+		if (likely(gh_msgq_chan(msgq)->cl))
+			mbox_chan_received_data(gh_msgq_chan(msgq), &rx_data);
+	}
+
+	return IRQ_HANDLED;
+}
+
+/* Fired when message queue transitions from "full" to "space available" to send messages */
+static irqreturn_t gh_msgq_tx_irq_handler(int irq, void *data)
+{
+	struct gh_msgq *msgq = data;
+
+	mbox_chan_txdone(gh_msgq_chan(msgq), 0);
+
+	return IRQ_HANDLED;
+}
+
+/* Fired after sending message and hypercall told us there was more space available. */
+static void gh_msgq_txdone_tasklet(struct tasklet_struct *tasklet)
+{
+	struct gh_msgq *msgq = container_of(tasklet, struct gh_msgq, txdone_tasklet);
+
+	mbox_chan_txdone(gh_msgq_chan(msgq), msgq->last_ret);
+}
+
+static int gh_msgq_send_data(struct mbox_chan *chan, void *data)
+{
+	struct gh_msgq *msgq = mbox_chan_to_msgq(chan);
+	struct gh_msgq_tx_data *msgq_data = data;
+	u64 tx_flags = 0;
+	enum gh_error gh_error;
+	bool ready;
+
+	if (!msgq->tx_ghrsc)
+		return -EOPNOTSUPP;
+
+	if (msgq_data->push)
+		tx_flags |= GH_HYPERCALL_MSGQ_TX_FLAGS_PUSH;
+
+	gh_error = gh_hypercall_msgq_send(msgq->tx_ghrsc->capid, msgq_data->length, msgq_data->data,
+						tx_flags, &ready);
+
+	/**
+	 * unlikely because Linux tracks state of msgq and should not try to
+	 * send message when msgq is full.
+	 */
+	if (unlikely(gh_error == GH_ERROR_MSGQUEUE_FULL))
+		return -EAGAIN;
+
+	/**
+	 * Propagate all other errors to client. If we return error to mailbox
+	 * framework, then no other messages can be sent and nobody will know
+	 * to retry this message.
+	 */
+	msgq->last_ret = gh_error_remap(gh_error);
+
+	/**
+	 * This message was successfully sent, but message queue isn't ready to
+	 * accept more messages because it's now full. Mailbox framework
+	 * requires that we only report that message was transmitted when
+	 * we're ready to transmit another message. We'll get that in the form
+	 * of tx IRQ once the other side starts to drain the msgq.
+	 */
+	if (gh_error == GH_ERROR_OK) {
+		if (!ready)
+			return 0;
+	} else {
+		dev_err(msgq->mbox.dev, "Failed to send data: %d (%d)\n", gh_error, msgq->last_ret);
+	}
+
+	/**
+	 * We can send more messages. Mailbox framework requires that tx done
+	 * happens asynchronously to sending the message. Gunyah message queues
+	 * tell us right away on the hypercall return whether we can send more
+	 * messages. To work around this, defer the txdone to a tasklet.
+	 */
+	tasklet_schedule(&msgq->txdone_tasklet);
+
+	return 0;
+}
+
+static struct mbox_chan_ops gh_msgq_ops = {
+	.send_data = gh_msgq_send_data,
+};
+
+/**
+ * gh_msgq_init() - Initialize a Gunyah message queue with an mbox_client
+ * @parent: device parent used for the mailbox controller
+ * @msgq: Pointer to the gh_msgq to initialize
+ * @cl: A mailbox client to bind to the mailbox channel that the message queue creates
+ * @tx_ghrsc: optional, the transmission side of the message queue
+ * @rx_ghrsc: optional, the receiving side of the message queue
+ *
+ * At least one of tx_ghrsc and rx_ghrsc must be not NULL. Most message queue use cases come with
+ * a pair of message queues to facilitate bidirectional communication. When tx_ghrsc is set,
+ * the client can send messages with mbox_send_message(gh_msgq_chan(msgq), msg). When rx_ghrsc
+ * is set, the mbox_client must register an .rx_callback() and the message queue driver will
+ * deliver all available messages upon receiving the RX ready interrupt. The messages should be
+ * consumed or copied by the client right away as the gh_msgq_rx_data will be replaced/destroyed
+ * after the callback.
+ *
+ * Returns - 0 on success, negative otherwise
+ */
+int gh_msgq_init(struct device *parent, struct gh_msgq *msgq, struct mbox_client *cl,
+		 struct gh_resource *tx_ghrsc, struct gh_resource *rx_ghrsc)
+{
+	int ret;
+
+	/* Must have at least a tx_ghrsc or rx_ghrsc and that they are the right device types */
+	if ((!tx_ghrsc && !rx_ghrsc) ||
+	    (tx_ghrsc && tx_ghrsc->type != GH_RESOURCE_TYPE_MSGQ_TX) ||
+	    (rx_ghrsc && rx_ghrsc->type != GH_RESOURCE_TYPE_MSGQ_RX))
+		return -EINVAL;
+
+	msgq->mbox.dev = parent;
+	msgq->mbox.ops = &gh_msgq_ops;
+	msgq->mbox.num_chans = 1;
+	msgq->mbox.txdone_irq = true;
+	msgq->mbox.chans = &msgq->mbox_chan;
+
+	ret = mbox_controller_register(&msgq->mbox);
+	if (ret)
+		return ret;
+
+	ret = mbox_bind_client(gh_msgq_chan(msgq), cl);
+	if (ret)
+		goto err_mbox;
+
+	if (tx_ghrsc) {
+		msgq->tx_ghrsc = tx_ghrsc;
+
+		ret = request_irq(msgq->tx_ghrsc->irq, gh_msgq_tx_irq_handler, 0, "gh_msgq_tx",
+				msgq);
+		if (ret)
+			goto err_tx_ghrsc;
+
+		enable_irq_wake(msgq->tx_ghrsc->irq);
+
+		tasklet_setup(&msgq->txdone_tasklet, gh_msgq_txdone_tasklet);
+	}
+
+	if (rx_ghrsc) {
+		msgq->rx_ghrsc = rx_ghrsc;
+
+		ret = request_threaded_irq(msgq->rx_ghrsc->irq, NULL, gh_msgq_rx_irq_handler,
+						IRQF_ONESHOT, "gh_msgq_rx", msgq);
+		if (ret)
+			goto err_tx_irq;
+
+		enable_irq_wake(msgq->rx_ghrsc->irq);
+	}
+
+	return 0;
+err_tx_irq:
+	if (msgq->tx_ghrsc)
+		free_irq(msgq->tx_ghrsc->irq, msgq);
+
+	msgq->rx_ghrsc = NULL;
+err_tx_ghrsc:
+	msgq->tx_ghrsc = NULL;
+err_mbox:
+	mbox_controller_unregister(&msgq->mbox);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(gh_msgq_init);
+
+void gh_msgq_remove(struct gh_msgq *msgq)
+{
+	mbox_free_channel(gh_msgq_chan(msgq));
+
+	if (msgq->rx_ghrsc)
+		free_irq(msgq->rx_ghrsc->irq, msgq);
+
+	if (msgq->tx_ghrsc) {
+		tasklet_kill(&msgq->txdone_tasklet);
+		free_irq(msgq->tx_ghrsc->irq, msgq);
+	}
+
+	mbox_controller_unregister(&msgq->mbox);
+
+	msgq->rx_ghrsc = NULL;
+	msgq->tx_ghrsc = NULL;
+}
+EXPORT_SYMBOL_GPL(gh_msgq_remove);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Gunyah Message Queue Driver");
diff --git a/include/linux/gunyah.h b/include/linux/gunyah.h
index 01a6f202d037e..982e27d10d57f 100644
--- a/include/linux/gunyah.h
+++ b/include/linux/gunyah.h
@@ -8,11 +8,68 @@
 
 #include <linux/bitfield.h>
 #include <linux/errno.h>
+#include <linux/interrupt.h>
 #include <linux/limits.h>
+#include <linux/mailbox_controller.h>
+#include <linux/mailbox_client.h>
 #include <linux/types.h>
 
+/* Matches resource manager's resource types for VM_GET_HYP_RESOURCES RPC */
+enum gh_resource_type {
+	GH_RESOURCE_TYPE_BELL_TX	= 0,
+	GH_RESOURCE_TYPE_BELL_RX	= 1,
+	GH_RESOURCE_TYPE_MSGQ_TX	= 2,
+	GH_RESOURCE_TYPE_MSGQ_RX	= 3,
+	GH_RESOURCE_TYPE_VCPU		= 4,
+};
+
+struct gh_resource {
+	enum gh_resource_type type;
+	u64 capid;
+	unsigned int irq;
+};
+
+/**
+ * Gunyah Message Queues
+ */
+
+#define GH_MSGQ_MAX_MSG_SIZE		240
+
+struct gh_msgq_tx_data {
+	size_t length;
+	bool push;
+	char data[];
+};
+
+struct gh_msgq_rx_data {
+	size_t length;
+	char data[GH_MSGQ_MAX_MSG_SIZE];
+};
+
+struct gh_msgq {
+	struct gh_resource *tx_ghrsc;
+	struct gh_resource *rx_ghrsc;
+
+	/* msgq private */
+	int last_ret; /* Linux error, not GH_STATUS_* */
+	struct mbox_chan mbox_chan;
+	struct mbox_controller mbox;
+	struct tasklet_struct txdone_tasklet;
+};
+
+
+int gh_msgq_init(struct device *parent, struct gh_msgq *msgq, struct mbox_client *cl,
+		     struct gh_resource *tx_ghrsc, struct gh_resource *rx_ghrsc);
+void gh_msgq_remove(struct gh_msgq *msgq);
+
+static inline struct mbox_chan *gh_msgq_chan(struct gh_msgq *msgq)
+{
+	return &msgq->mbox.chans[0];
+}
+
 /******************************************************************************/
 /* Common arch-independent definitions for Gunyah hypercalls                  */
+
 #define GH_CAPID_INVAL	U64_MAX
 #define GH_VMID_ROOT_VM	0xff
 
-- 
2.40.0

[PATCH v14 07/25] gunyah: rsc_mgr: Add resource manager RPC core

[Elliot Berman]

The resource manager is a special virtual machine which is always
running on a Gunyah system. It provides APIs for creating and destroying
VMs, secure memory management, sharing/lending of memory between VMs,
and setup of inter-VM communication. Calls to the resource manager are
made via message queues.

This patch implements the basic probing and RPC mechanism to make those
API calls. Request/response calls can be made with gh_rm_call.
Drivers can also register to notifications pushed by RM via
gh_rm_register_notifier

Specific API calls that resource manager supports will be implemented in
subsequent patches.

Reviewed-by: Alex Elder <elder@linaro.org>
Reviewed-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
---
 drivers/virt/Makefile          |   1 +
 drivers/virt/gunyah/Makefile   |   4 +
 drivers/virt/gunyah/rsc_mgr.c  | 700 +++++++++++++++++++++++++++++++++
 drivers/virt/gunyah/rsc_mgr.h  |  16 +
 include/linux/gunyah_rsc_mgr.h |  21 +
 5 files changed, 742 insertions(+)
 create mode 100644 drivers/virt/gunyah/Makefile
 create mode 100644 drivers/virt/gunyah/rsc_mgr.c
 create mode 100644 drivers/virt/gunyah/rsc_mgr.h
 create mode 100644 include/linux/gunyah_rsc_mgr.h

diff --git a/drivers/virt/Makefile b/drivers/virt/Makefile
index e9aa6fc96fab7..a5817e2d7d718 100644
--- a/drivers/virt/Makefile
+++ b/drivers/virt/Makefile
@@ -12,3 +12,4 @@ obj-$(CONFIG_ACRN_HSM)		+= acrn/
 obj-$(CONFIG_EFI_SECRET)	+= coco/efi_secret/
 obj-$(CONFIG_SEV_GUEST)		+= coco/sev-guest/
 obj-$(CONFIG_INTEL_TDX_GUEST)	+= coco/tdx-guest/
+obj-y				+= gunyah/
diff --git a/drivers/virt/gunyah/Makefile b/drivers/virt/gunyah/Makefile
new file mode 100644
index 0000000000000..0f5aec8346988
--- /dev/null
+++ b/drivers/virt/gunyah/Makefile
@@ -0,0 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0
+
+gunyah-y += rsc_mgr.o
+obj-$(CONFIG_GUNYAH) += gunyah.o
diff --git a/drivers/virt/gunyah/rsc_mgr.c b/drivers/virt/gunyah/rsc_mgr.c
new file mode 100644
index 0000000000000..04c8e131d259f
--- /dev/null
+++ b/drivers/virt/gunyah/rsc_mgr.c
@@ -0,0 +1,700 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#include <linux/of.h>
+#include <linux/slab.h>
+#include <linux/mutex.h>
+#include <linux/sched.h>
+#include <linux/gunyah.h>
+#include <linux/module.h>
+#include <linux/of_irq.h>
+#include <linux/notifier.h>
+#include <linux/workqueue.h>
+#include <linux/completion.h>
+#include <linux/gunyah_rsc_mgr.h>
+#include <linux/platform_device.h>
+
+#include "rsc_mgr.h"
+
+#define RM_RPC_API_VERSION_MASK		GENMASK(3, 0)
+#define RM_RPC_HEADER_WORDS_MASK	GENMASK(7, 4)
+#define RM_RPC_API_VERSION		FIELD_PREP(RM_RPC_API_VERSION_MASK, 1)
+#define RM_RPC_HEADER_WORDS		FIELD_PREP(RM_RPC_HEADER_WORDS_MASK, \
+						(sizeof(struct gh_rm_rpc_hdr) / sizeof(u32)))
+#define RM_RPC_API			(RM_RPC_API_VERSION | RM_RPC_HEADER_WORDS)
+
+#define RM_RPC_TYPE_CONTINUATION	0x0
+#define RM_RPC_TYPE_REQUEST		0x1
+#define RM_RPC_TYPE_REPLY		0x2
+#define RM_RPC_TYPE_NOTIF		0x3
+#define RM_RPC_TYPE_MASK		GENMASK(1, 0)
+
+#define GH_RM_MAX_NUM_FRAGMENTS		62
+#define RM_RPC_FRAGMENTS_MASK		GENMASK(7, 2)
+
+struct gh_rm_rpc_hdr {
+	u8 api;
+	u8 type;
+	__le16 seq;
+	__le32 msg_id;
+} __packed;
+
+struct gh_rm_rpc_reply_hdr {
+	struct gh_rm_rpc_hdr hdr;
+	__le32 err_code; /* GH_RM_ERROR_* */
+} __packed;
+
+#define GH_RM_MAX_MSG_SIZE	(GH_MSGQ_MAX_MSG_SIZE - sizeof(struct gh_rm_rpc_hdr))
+
+/* RM Error codes */
+enum gh_rm_error {
+	GH_RM_ERROR_OK			= 0x0,
+	GH_RM_ERROR_UNIMPLEMENTED	= 0xFFFFFFFF,
+	GH_RM_ERROR_NOMEM		= 0x1,
+	GH_RM_ERROR_NORESOURCE		= 0x2,
+	GH_RM_ERROR_DENIED		= 0x3,
+	GH_RM_ERROR_INVALID		= 0x4,
+	GH_RM_ERROR_BUSY		= 0x5,
+	GH_RM_ERROR_ARGUMENT_INVALID	= 0x6,
+	GH_RM_ERROR_HANDLE_INVALID	= 0x7,
+	GH_RM_ERROR_VALIDATE_FAILED	= 0x8,
+	GH_RM_ERROR_MAP_FAILED		= 0x9,
+	GH_RM_ERROR_MEM_INVALID		= 0xA,
+	GH_RM_ERROR_MEM_INUSE		= 0xB,
+	GH_RM_ERROR_MEM_RELEASED	= 0xC,
+	GH_RM_ERROR_VMID_INVALID	= 0xD,
+	GH_RM_ERROR_LOOKUP_FAILED	= 0xE,
+	GH_RM_ERROR_IRQ_INVALID		= 0xF,
+	GH_RM_ERROR_IRQ_INUSE		= 0x10,
+	GH_RM_ERROR_IRQ_RELEASED	= 0x11,
+};
+
+/**
+ * struct gh_rm_connection - Represents a complete message from resource manager
+ * @payload: Combined payload of all the fragments (msg headers stripped off).
+ * @size: Size of the payload received so far.
+ * @msg_id: Message ID from the header.
+ * @type: RM_RPC_TYPE_REPLY or RM_RPC_TYPE_NOTIF.
+ * @num_fragments: total number of fragments expected to be received.
+ * @fragments_received: fragments received so far.
+ * @reply: Fields used for request/reply sequences
+ * @notification: Fields used for notifiations
+ */
+struct gh_rm_connection {
+	void *payload;
+	size_t size;
+	__le32 msg_id;
+	u8 type;
+
+	u8 num_fragments;
+	u8 fragments_received;
+
+	union {
+		/**
+		 * @ret: Linux return code, there was an error processing connection
+		 * @seq: Sequence ID for the main message.
+		 * @rm_error: For request/reply sequences with standard replies
+		 * @seq_done: Signals caller that the RM reply has been received
+		 */
+		struct {
+			int ret;
+			u16 seq;
+			enum gh_rm_error rm_error;
+			struct completion seq_done;
+		} reply;
+
+		/**
+		 * @rm: Pointer to the RM that launched the connection
+		 * @work: Triggered when all fragments of a notification received
+		 */
+		struct {
+			struct gh_rm *rm;
+			struct work_struct work;
+		} notification;
+	};
+};
+
+/**
+ * struct gh_rm - private data for communicating w/Gunyah resource manager
+ * @dev: pointer to RM platform device
+ * @tx_ghrsc: message queue resource to TX to RM
+ * @rx_ghrsc: message queue resource to RX from RM
+ * @msgq: mailbox instance of TX/RX resources above
+ * @msgq_client: mailbox client of above msgq
+ * @active_rx_connection: ongoing gh_rm_connection for which we're receiving fragments
+ * @last_tx_ret: return value of last mailbox tx
+ * @call_xarray: xarray to allocate & lookup sequence IDs for Request/Response flows
+ * @next_seq: next ID to allocate (for xa_alloc_cyclic)
+ * @cache: cache for allocating Tx messages
+ * @send_lock: synchronization to allow only one request to be sent at a time
+ * @nh: notifier chain for clients interested in RM notification messages
+ */
+struct gh_rm {
+	struct device *dev;
+	struct gh_resource tx_ghrsc;
+	struct gh_resource rx_ghrsc;
+	struct gh_msgq msgq;
+	struct mbox_client msgq_client;
+	struct gh_rm_connection *active_rx_connection;
+	int last_tx_ret;
+
+	struct xarray call_xarray;
+	u32 next_seq;
+
+	struct kmem_cache *cache;
+	struct mutex send_lock;
+	struct blocking_notifier_head nh;
+};
+
+/**
+ * gh_rm_error_remap() - Remap Gunyah resource manager errors into a Linux error code
+ * @rm_error: "Standard" return value from Gunyah resource manager
+ */
+static inline int gh_rm_error_remap(enum gh_rm_error rm_error)
+{
+	switch (rm_error) {
+	case GH_RM_ERROR_OK:
+		return 0;
+	case GH_RM_ERROR_UNIMPLEMENTED:
+		return -EOPNOTSUPP;
+	case GH_RM_ERROR_NOMEM:
+		return -ENOMEM;
+	case GH_RM_ERROR_NORESOURCE:
+		return -ENODEV;
+	case GH_RM_ERROR_DENIED:
+		return -EPERM;
+	case GH_RM_ERROR_BUSY:
+		return -EBUSY;
+	case GH_RM_ERROR_INVALID:
+	case GH_RM_ERROR_ARGUMENT_INVALID:
+	case GH_RM_ERROR_HANDLE_INVALID:
+	case GH_RM_ERROR_VALIDATE_FAILED:
+	case GH_RM_ERROR_MAP_FAILED:
+	case GH_RM_ERROR_MEM_INVALID:
+	case GH_RM_ERROR_MEM_INUSE:
+	case GH_RM_ERROR_MEM_RELEASED:
+	case GH_RM_ERROR_VMID_INVALID:
+	case GH_RM_ERROR_LOOKUP_FAILED:
+	case GH_RM_ERROR_IRQ_INVALID:
+	case GH_RM_ERROR_IRQ_INUSE:
+	case GH_RM_ERROR_IRQ_RELEASED:
+		return -EINVAL;
+	default:
+		return -EBADMSG;
+	}
+}
+
+static int gh_rm_init_connection_payload(struct gh_rm_connection *connection, void *msg,
+					size_t hdr_size, size_t msg_size)
+{
+	size_t max_buf_size, payload_size;
+	struct gh_rm_rpc_hdr *hdr = msg;
+
+	if (msg_size < hdr_size)
+		return -EINVAL;
+
+	payload_size = msg_size - hdr_size;
+
+	connection->num_fragments = FIELD_GET(RM_RPC_FRAGMENTS_MASK, hdr->type);
+	connection->fragments_received = 0;
+
+	/* There's not going to be any payload, no need to allocate buffer. */
+	if (!payload_size && !connection->num_fragments)
+		return 0;
+
+	if (connection->num_fragments > GH_RM_MAX_NUM_FRAGMENTS)
+		return -EINVAL;
+
+	max_buf_size = payload_size + (connection->num_fragments * GH_RM_MAX_MSG_SIZE);
+
+	connection->payload = kzalloc(max_buf_size, GFP_KERNEL);
+	if (!connection->payload)
+		return -ENOMEM;
+
+	memcpy(connection->payload, msg + hdr_size, payload_size);
+	connection->size = payload_size;
+	return 0;
+}
+
+static void gh_rm_abort_connection(struct gh_rm *rm)
+{
+	switch (rm->active_rx_connection->type) {
+	case RM_RPC_TYPE_REPLY:
+		rm->active_rx_connection->reply.ret = -EIO;
+		complete(&rm->active_rx_connection->reply.seq_done);
+		break;
+	case RM_RPC_TYPE_NOTIF:
+		fallthrough;
+	default:
+		kfree(rm->active_rx_connection->payload);
+		kfree(rm->active_rx_connection);
+	}
+
+	rm->active_rx_connection = NULL;
+}
+
+static void gh_rm_notif_work(struct work_struct *work)
+{
+	struct gh_rm_connection *connection = container_of(work, struct gh_rm_connection,
+								notification.work);
+	struct gh_rm *rm = connection->notification.rm;
+
+	blocking_notifier_call_chain(&rm->nh, le32_to_cpu(connection->msg_id), connection->payload);
+
+	put_device(rm->dev);
+	kfree(connection->payload);
+	kfree(connection);
+}
+
+static void gh_rm_process_notif(struct gh_rm *rm, void *msg, size_t msg_size)
+{
+	struct gh_rm_connection *connection;
+	struct gh_rm_rpc_hdr *hdr = msg;
+	int ret;
+
+	if (rm->active_rx_connection)
+		gh_rm_abort_connection(rm);
+
+	connection = kzalloc(sizeof(*connection), GFP_KERNEL);
+	if (!connection)
+		return;
+
+	connection->type = RM_RPC_TYPE_NOTIF;
+	connection->msg_id = hdr->msg_id;
+
+	get_device(rm->dev);
+	connection->notification.rm = rm;
+	INIT_WORK(&connection->notification.work, gh_rm_notif_work);
+
+	ret = gh_rm_init_connection_payload(connection, msg, sizeof(*hdr), msg_size);
+	if (ret) {
+		dev_err(rm->dev, "Failed to initialize connection for notification: %d\n", ret);
+		put_device(rm->dev);
+		kfree(connection);
+		return;
+	}
+
+	rm->active_rx_connection = connection;
+}
+
+static void gh_rm_process_reply(struct gh_rm *rm, void *msg, size_t msg_size)
+{
+	struct gh_rm_rpc_reply_hdr *reply_hdr = msg;
+	struct gh_rm_connection *connection;
+	u16 seq_id;
+
+	seq_id = le16_to_cpu(reply_hdr->hdr.seq);
+	connection = xa_load(&rm->call_xarray, seq_id);
+
+	if (!connection || connection->msg_id != reply_hdr->hdr.msg_id)
+		return;
+
+	if (rm->active_rx_connection)
+		gh_rm_abort_connection(rm);
+
+	if (gh_rm_init_connection_payload(connection, msg, sizeof(*reply_hdr), msg_size)) {
+		dev_err(rm->dev, "Failed to alloc connection buffer for sequence %d\n", seq_id);
+		/* Send connection complete and error the client. */
+		connection->reply.ret = -ENOMEM;
+		complete(&connection->reply.seq_done);
+		return;
+	}
+
+	connection->reply.rm_error = le32_to_cpu(reply_hdr->err_code);
+	rm->active_rx_connection = connection;
+}
+
+static void gh_rm_process_cont(struct gh_rm *rm, struct gh_rm_connection *connection,
+				void *msg, size_t msg_size)
+{
+	struct gh_rm_rpc_hdr *hdr = msg;
+	size_t payload_size = msg_size - sizeof(*hdr);
+
+	if (!rm->active_rx_connection)
+		return;
+
+	/*
+	 * hdr->fragments and hdr->msg_id preserves the value from first reply
+	 * or notif message. To detect mishandling, check it's still intact.
+	 */
+	if (connection->msg_id != hdr->msg_id ||
+		connection->num_fragments != FIELD_GET(RM_RPC_FRAGMENTS_MASK, hdr->type)) {
+		gh_rm_abort_connection(rm);
+		return;
+	}
+
+	memcpy(connection->payload + connection->size, msg + sizeof(*hdr), payload_size);
+	connection->size += payload_size;
+	connection->fragments_received++;
+}
+
+static void gh_rm_try_complete_connection(struct gh_rm *rm)
+{
+	struct gh_rm_connection *connection = rm->active_rx_connection;
+
+	if (!connection || connection->fragments_received != connection->num_fragments)
+		return;
+
+	switch (connection->type) {
+	case RM_RPC_TYPE_REPLY:
+		complete(&connection->reply.seq_done);
+		break;
+	case RM_RPC_TYPE_NOTIF:
+		schedule_work(&connection->notification.work);
+		break;
+	default:
+		dev_err_ratelimited(rm->dev, "Invalid message type (%u) received\n",
+					connection->type);
+		gh_rm_abort_connection(rm);
+		break;
+	}
+
+	rm->active_rx_connection = NULL;
+}
+
+static void gh_rm_msgq_rx_data(struct mbox_client *cl, void *mssg)
+{
+	struct gh_rm *rm = container_of(cl, struct gh_rm, msgq_client);
+	struct gh_msgq_rx_data *rx_data = mssg;
+	size_t msg_size = rx_data->length;
+	void *msg = rx_data->data;
+	struct gh_rm_rpc_hdr *hdr;
+
+	if (msg_size < sizeof(*hdr) || msg_size > GH_MSGQ_MAX_MSG_SIZE)
+		return;
+
+	hdr = msg;
+	if (hdr->api != RM_RPC_API) {
+		dev_err(rm->dev, "Unknown RM RPC API version: %x\n", hdr->api);
+		return;
+	}
+
+	switch (FIELD_GET(RM_RPC_TYPE_MASK, hdr->type)) {
+	case RM_RPC_TYPE_NOTIF:
+		gh_rm_process_notif(rm, msg, msg_size);
+		break;
+	case RM_RPC_TYPE_REPLY:
+		gh_rm_process_reply(rm, msg, msg_size);
+		break;
+	case RM_RPC_TYPE_CONTINUATION:
+		gh_rm_process_cont(rm, rm->active_rx_connection, msg, msg_size);
+		break;
+	default:
+		dev_err(rm->dev, "Invalid message type (%lu) received\n",
+			FIELD_GET(RM_RPC_TYPE_MASK, hdr->type));
+		return;
+	}
+
+	gh_rm_try_complete_connection(rm);
+}
+
+static void gh_rm_msgq_tx_done(struct mbox_client *cl, void *mssg, int r)
+{
+	struct gh_rm *rm = container_of(cl, struct gh_rm, msgq_client);
+
+	kmem_cache_free(rm->cache, mssg);
+	rm->last_tx_ret = r;
+}
+
+static int gh_rm_send_request(struct gh_rm *rm, u32 message_id,
+			      const void *req_buf, size_t req_buf_size,
+			      struct gh_rm_connection *connection)
+{
+	size_t buf_size_remaining = req_buf_size;
+	const void *req_buf_curr = req_buf;
+	struct gh_msgq_tx_data *msg;
+	struct gh_rm_rpc_hdr *hdr, hdr_template;
+	u32 cont_fragments = 0;
+	size_t payload_size;
+	void *payload;
+	int ret;
+
+	if (req_buf_size > GH_RM_MAX_NUM_FRAGMENTS * GH_RM_MAX_MSG_SIZE) {
+		dev_warn(rm->dev, "Limit (%lu bytes) exceeded for the maximum message size: %lu\n",
+			GH_RM_MAX_NUM_FRAGMENTS * GH_RM_MAX_MSG_SIZE, req_buf_size);
+		dump_stack();
+		return -E2BIG;
+	}
+
+	if (req_buf_size)
+		cont_fragments = (req_buf_size - 1) / GH_RM_MAX_MSG_SIZE;
+
+	hdr_template.api = RM_RPC_API;
+	hdr_template.type = FIELD_PREP(RM_RPC_TYPE_MASK, RM_RPC_TYPE_REQUEST) |
+				FIELD_PREP(RM_RPC_FRAGMENTS_MASK, cont_fragments);
+	hdr_template.seq = cpu_to_le16(connection->reply.seq);
+	hdr_template.msg_id = cpu_to_le32(message_id);
+
+	ret = mutex_lock_interruptible(&rm->send_lock);
+	if (ret)
+		return ret;
+
+	do {
+		msg = kmem_cache_zalloc(rm->cache, GFP_KERNEL);
+		if (!msg) {
+			ret = -ENOMEM;
+			goto out;
+		}
+
+		/* Fill header */
+		hdr = (struct gh_rm_rpc_hdr *)&msg->data[0];
+		*hdr = hdr_template;
+
+		/* Copy payload */
+		payload = &msg->data[0] + sizeof(*hdr);
+		payload_size = min(buf_size_remaining, GH_RM_MAX_MSG_SIZE);
+		memcpy(payload, req_buf_curr, payload_size);
+		req_buf_curr += payload_size;
+		buf_size_remaining -= payload_size;
+
+		/* Force the last fragment to immediately alert the receiver */
+		msg->push = !buf_size_remaining;
+		msg->length = sizeof(*hdr) + payload_size;
+
+		ret = mbox_send_message(gh_msgq_chan(&rm->msgq), msg);
+		if (ret < 0) {
+			kmem_cache_free(rm->cache, msg);
+			break;
+		}
+
+		if (rm->last_tx_ret) {
+			ret = rm->last_tx_ret;
+			break;
+		}
+
+		hdr_template.type = FIELD_PREP(RM_RPC_TYPE_MASK, RM_RPC_TYPE_CONTINUATION) |
+					FIELD_PREP(RM_RPC_FRAGMENTS_MASK, cont_fragments);
+	} while (buf_size_remaining);
+
+out:
+	mutex_unlock(&rm->send_lock);
+	return ret < 0 ? ret : 0;
+}
+
+/**
+ * gh_rm_call: Achieve request-response type communication with RPC
+ * @rm: Pointer to Gunyah resource manager internal data
+ * @message_id: The RM RPC message-id
+ * @req_buf: Request buffer that contains the payload
+ * @req_buf_size: Total size of the payload
+ * @resp_buf: Pointer to a response buffer
+ * @resp_buf_size: Size of the response buffer
+ *
+ * Make a request to the Resource Manager and wait for reply back. For a successful
+ * response, the function returns the payload. The size of the payload is set in
+ * resp_buf_size. The resp_buf must be freed by the caller when 0 is returned
+ * and resp_buf_size != 0.
+ *
+ * req_buf should be not NULL for req_buf_size >0. If req_buf_size == 0,
+ * req_buf *can* be NULL and no additional payload is sent.
+ *
+ * Context: Process context. Will sleep waiting for reply.
+ * Return: 0 on success. <0 if error.
+ */
+int gh_rm_call(struct gh_rm *rm, u32 message_id, const void *req_buf, size_t req_buf_size,
+		void **resp_buf, size_t *resp_buf_size)
+{
+	struct gh_rm_connection *connection;
+	u32 seq_id;
+	int ret;
+
+	/* message_id 0 is reserved. req_buf_size implies req_buf is not NULL */
+	if (!rm || !message_id || (!req_buf && req_buf_size))
+		return -EINVAL;
+
+
+	connection = kzalloc(sizeof(*connection), GFP_KERNEL);
+	if (!connection)
+		return -ENOMEM;
+
+	connection->type = RM_RPC_TYPE_REPLY;
+	connection->msg_id = cpu_to_le32(message_id);
+
+	init_completion(&connection->reply.seq_done);
+
+	/* Allocate a new seq number for this connection */
+	ret = xa_alloc_cyclic(&rm->call_xarray, &seq_id, connection, xa_limit_16b, &rm->next_seq,
+				GFP_KERNEL);
+	if (ret < 0)
+		goto free;
+	connection->reply.seq = lower_16_bits(seq_id);
+
+	/* Send the request to the Resource Manager */
+	ret = gh_rm_send_request(rm, message_id, req_buf, req_buf_size, connection);
+	if (ret < 0)
+		goto out;
+
+	/* Wait for response. Uninterruptible because rollback based on what RM did to VM
+	 * requires us to know how RM handled the call.
+	 */
+	wait_for_completion(&connection->reply.seq_done);
+
+	/* Check for internal (kernel) error waiting for the response */
+	if (connection->reply.ret) {
+		ret = connection->reply.ret;
+		if (ret != -ENOMEM)
+			kfree(connection->payload);
+		goto out;
+	}
+
+	/* Got a response, did resource manager give us an error? */
+	if (connection->reply.rm_error != GH_RM_ERROR_OK) {
+		dev_warn(rm->dev, "RM rejected message %08x. Error: %d\n", message_id,
+			connection->reply.rm_error);
+		ret = gh_rm_error_remap(connection->reply.rm_error);
+		kfree(connection->payload);
+		goto out;
+	}
+
+	/* Everything looks good, return the payload */
+	if (resp_buf_size)
+		*resp_buf_size = connection->size;
+	if (connection->size && resp_buf)
+		*resp_buf = connection->payload;
+	else {
+		/* kfree in case RM sent us multiple fragments but never any data in
+		 * those fragments. We would've allocated memory for it, but connection->size == 0
+		 */
+		kfree(connection->payload);
+	}
+
+out:
+	xa_erase(&rm->call_xarray, connection->reply.seq);
+free:
+	kfree(connection);
+	return ret;
+}
+
+
+int gh_rm_notifier_register(struct gh_rm *rm, struct notifier_block *nb)
+{
+	return blocking_notifier_chain_register(&rm->nh, nb);
+}
+EXPORT_SYMBOL_GPL(gh_rm_notifier_register);
+
+int gh_rm_notifier_unregister(struct gh_rm *rm, struct notifier_block *nb)
+{
+	return blocking_notifier_chain_unregister(&rm->nh, nb);
+}
+EXPORT_SYMBOL_GPL(gh_rm_notifier_unregister);
+
+static int gh_msgq_platform_probe_direction(struct platform_device *pdev, bool tx,
+					    struct gh_resource *ghrsc)
+{
+	struct device_node *node = pdev->dev.of_node;
+	int ret;
+	int idx = tx ? 0 : 1;
+
+	ghrsc->type = tx ? GH_RESOURCE_TYPE_MSGQ_TX : GH_RESOURCE_TYPE_MSGQ_RX;
+
+	ghrsc->irq = platform_get_irq(pdev, idx);
+	if (ghrsc->irq < 0) {
+		dev_err(&pdev->dev, "Failed to get irq%d: %d\n", idx, ghrsc->irq);
+		return ghrsc->irq;
+	}
+
+	ret = of_property_read_u64_index(node, "reg", idx, &ghrsc->capid);
+	if (ret) {
+		dev_err(&pdev->dev, "Failed to get capid%d: %d\n", idx, ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int gh_identify(void)
+{
+	struct gh_hypercall_hyp_identify_resp gh_api;
+
+	if (!arch_is_gh_guest())
+		return -ENODEV;
+
+	gh_hypercall_hyp_identify(&gh_api);
+
+	pr_info("Running under Gunyah hypervisor %llx/v%u\n",
+		FIELD_GET(GH_API_INFO_VARIANT_MASK, gh_api.api_info),
+		gh_api_version(&gh_api));
+
+	/* We might move this out to individual drivers if there's ever an API version bump */
+	if (gh_api_version(&gh_api) != GH_API_V1) {
+		pr_info("Unsupported Gunyah version: %u\n", gh_api_version(&gh_api));
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+static int gh_rm_drv_probe(struct platform_device *pdev)
+{
+	struct gh_msgq_tx_data *msg;
+	struct gh_rm *rm;
+	int ret;
+
+	ret = gh_identify();
+	if (ret)
+		return ret;
+
+	rm = devm_kzalloc(&pdev->dev, sizeof(*rm), GFP_KERNEL);
+	if (!rm)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, rm);
+	rm->dev = &pdev->dev;
+
+	mutex_init(&rm->send_lock);
+	BLOCKING_INIT_NOTIFIER_HEAD(&rm->nh);
+	xa_init_flags(&rm->call_xarray, XA_FLAGS_ALLOC);
+	rm->cache = kmem_cache_create("gh_rm", struct_size(msg, data, GH_MSGQ_MAX_MSG_SIZE), 0,
+		SLAB_HWCACHE_ALIGN, NULL);
+	if (!rm->cache)
+		return -ENOMEM;
+
+	ret = gh_msgq_platform_probe_direction(pdev, true, &rm->tx_ghrsc);
+	if (ret)
+		goto err_cache;
+
+	ret = gh_msgq_platform_probe_direction(pdev, false, &rm->rx_ghrsc);
+	if (ret)
+		goto err_cache;
+
+	rm->msgq_client.dev = &pdev->dev;
+	rm->msgq_client.tx_block = true;
+	rm->msgq_client.rx_callback = gh_rm_msgq_rx_data;
+	rm->msgq_client.tx_done = gh_rm_msgq_tx_done;
+
+	return gh_msgq_init(&pdev->dev, &rm->msgq, &rm->msgq_client, &rm->tx_ghrsc, &rm->rx_ghrsc);
+err_cache:
+	kmem_cache_destroy(rm->cache);
+	return ret;
+}
+
+static int gh_rm_drv_remove(struct platform_device *pdev)
+{
+	struct gh_rm *rm = platform_get_drvdata(pdev);
+
+	gh_msgq_remove(&rm->msgq);
+	kmem_cache_destroy(rm->cache);
+
+	return 0;
+}
+
+static const struct of_device_id gh_rm_of_match[] = {
+	{ .compatible = "gunyah-resource-manager" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, gh_rm_of_match);
+
+static struct platform_driver gh_rm_driver = {
+	.probe = gh_rm_drv_probe,
+	.remove = gh_rm_drv_remove,
+	.driver = {
+		.name = "gh_rsc_mgr",
+		.of_match_table = gh_rm_of_match,
+	},
+};
+module_platform_driver(gh_rm_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Gunyah Resource Manager Driver");
diff --git a/drivers/virt/gunyah/rsc_mgr.h b/drivers/virt/gunyah/rsc_mgr.h
new file mode 100644
index 0000000000000..8309b7bf46683
--- /dev/null
+++ b/drivers/virt/gunyah/rsc_mgr.h
@@ -0,0 +1,16 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+#ifndef __GH_RSC_MGR_PRIV_H
+#define __GH_RSC_MGR_PRIV_H
+
+#include <linux/gunyah.h>
+#include <linux/gunyah_rsc_mgr.h>
+#include <linux/types.h>
+
+struct gh_rm;
+int gh_rm_call(struct gh_rm *rsc_mgr, u32 message_id, const void *req_buf, size_t req_buf_size,
+		void **resp_buf, size_t *resp_buf_size);
+
+#endif
diff --git a/include/linux/gunyah_rsc_mgr.h b/include/linux/gunyah_rsc_mgr.h
new file mode 100644
index 0000000000000..f2a312e80af52
--- /dev/null
+++ b/include/linux/gunyah_rsc_mgr.h
@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#ifndef _GUNYAH_RSC_MGR_H
+#define _GUNYAH_RSC_MGR_H
+
+#include <linux/list.h>
+#include <linux/notifier.h>
+#include <linux/gunyah.h>
+
+#define GH_VMID_INVAL		U16_MAX
+
+struct gh_rm;
+int gh_rm_notifier_register(struct gh_rm *rm, struct notifier_block *nb);
+int gh_rm_notifier_unregister(struct gh_rm *rm, struct notifier_block *nb);
+struct device *gh_rm_get(struct gh_rm *rm);
+void gh_rm_put(struct gh_rm *rm);
+
+#endif
-- 
2.40.0

[PATCH v14 08/25] gunyah: rsc_mgr: Add VM lifecycle RPC

[Elliot Berman]

Add Gunyah Resource Manager RPC to launch an unauthenticated VM.

Reviewed-by: Alex Elder <elder@linaro.org>
Reviewed-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
---
 drivers/virt/gunyah/Makefile      |   2 +-
 drivers/virt/gunyah/rsc_mgr_rpc.c | 259 ++++++++++++++++++++++++++++++
 include/linux/gunyah_rsc_mgr.h    |  73 +++++++++
 3 files changed, 333 insertions(+), 1 deletion(-)
 create mode 100644 drivers/virt/gunyah/rsc_mgr_rpc.c

diff --git a/drivers/virt/gunyah/Makefile b/drivers/virt/gunyah/Makefile
index 0f5aec8346988..241bab357b86c 100644
--- a/drivers/virt/gunyah/Makefile
+++ b/drivers/virt/gunyah/Makefile
@@ -1,4 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0
 
-gunyah-y += rsc_mgr.o
+gunyah-y += rsc_mgr.o rsc_mgr_rpc.o
 obj-$(CONFIG_GUNYAH) += gunyah.o
diff --git a/drivers/virt/gunyah/rsc_mgr_rpc.c b/drivers/virt/gunyah/rsc_mgr_rpc.c
new file mode 100644
index 0000000000000..a4a9f0ba4e1fc
--- /dev/null
+++ b/drivers/virt/gunyah/rsc_mgr_rpc.c
@@ -0,0 +1,259 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#include <linux/gunyah_rsc_mgr.h>
+#include "rsc_mgr.h"
+
+/* Message IDs: VM Management */
+#define GH_RM_RPC_VM_ALLOC_VMID			0x56000001
+#define GH_RM_RPC_VM_DEALLOC_VMID		0x56000002
+#define GH_RM_RPC_VM_START			0x56000004
+#define GH_RM_RPC_VM_STOP			0x56000005
+#define GH_RM_RPC_VM_RESET			0x56000006
+#define GH_RM_RPC_VM_CONFIG_IMAGE		0x56000009
+#define GH_RM_RPC_VM_INIT			0x5600000B
+#define GH_RM_RPC_VM_GET_HYP_RESOURCES		0x56000020
+#define GH_RM_RPC_VM_GET_VMID			0x56000024
+
+struct gh_rm_vm_common_vmid_req {
+	__le16 vmid;
+	__le16 _padding;
+} __packed;
+
+/* Call: VM_ALLOC */
+struct gh_rm_vm_alloc_vmid_resp {
+	__le16 vmid;
+	__le16 _padding;
+} __packed;
+
+/* Call: VM_STOP */
+#define GH_RM_VM_STOP_FLAG_FORCE_STOP		BIT(0)
+
+#define GH_RM_VM_STOP_REASON_FORCE_STOP		3
+
+struct gh_rm_vm_stop_req {
+	__le16 vmid;
+	u8 flags;
+	u8 _padding;
+	__le32 stop_reason;
+} __packed;
+
+/* Call: VM_CONFIG_IMAGE */
+struct gh_rm_vm_config_image_req {
+	__le16 vmid;
+	__le16 auth_mech;
+	__le32 mem_handle;
+	__le64 image_offset;
+	__le64 image_size;
+	__le64 dtb_offset;
+	__le64 dtb_size;
+} __packed;
+
+/*
+ * Several RM calls take only a VMID as a parameter and give only standard
+ * response back. Deduplicate boilerplate code by using this common call.
+ */
+static int gh_rm_common_vmid_call(struct gh_rm *rm, u32 message_id, u16 vmid)
+{
+	struct gh_rm_vm_common_vmid_req req_payload = {
+		.vmid = cpu_to_le16(vmid),
+	};
+
+	return gh_rm_call(rm, message_id, &req_payload, sizeof(req_payload), NULL, NULL);
+}
+
+/**
+ * gh_rm_alloc_vmid() - Allocate a new VM in Gunyah. Returns the VM identifier.
+ * @rm: Handle to a Gunyah resource manager
+ * @vmid: Use 0 to dynamically allocate a VM. A reserved VMID can be supplied
+ *        to request allocation of a platform-defined VM.
+ *
+ * Returns - the allocated VMID or negative value on error
+ */
+int gh_rm_alloc_vmid(struct gh_rm *rm, u16 vmid)
+{
+	struct gh_rm_vm_common_vmid_req req_payload = {
+		.vmid = cpu_to_le16(vmid),
+	};
+	struct gh_rm_vm_alloc_vmid_resp *resp_payload;
+	size_t resp_size;
+	void *resp;
+	int ret;
+
+	ret = gh_rm_call(rm, GH_RM_RPC_VM_ALLOC_VMID, &req_payload, sizeof(req_payload), &resp,
+			&resp_size);
+	if (ret)
+		return ret;
+
+	if (!vmid) {
+		resp_payload = resp;
+		ret = le16_to_cpu(resp_payload->vmid);
+		kfree(resp);
+	}
+
+	return ret;
+}
+
+/**
+ * gh_rm_dealloc_vmid() - Dispose of a VMID
+ * @rm: Handle to a Gunyah resource manager
+ * @vmid: VM identifier allocated with gh_rm_alloc_vmid
+ */
+int gh_rm_dealloc_vmid(struct gh_rm *rm, u16 vmid)
+{
+	return gh_rm_common_vmid_call(rm, GH_RM_RPC_VM_DEALLOC_VMID, vmid);
+}
+
+/**
+ * gh_rm_vm_reset() - Reset a VM's resources
+ * @rm: Handle to a Gunyah resource manager
+ * @vmid: VM identifier allocated with gh_rm_alloc_vmid
+ *
+ * As part of tearing down the VM, request RM to clean up all the VM resources
+ * associated with the VM. Only after this, Linux can clean up all the
+ * references it maintains to resources.
+ */
+int gh_rm_vm_reset(struct gh_rm *rm, u16 vmid)
+{
+	return gh_rm_common_vmid_call(rm, GH_RM_RPC_VM_RESET, vmid);
+}
+
+/**
+ * gh_rm_vm_start() - Move a VM into "ready to run" state
+ * @rm: Handle to a Gunyah resource manager
+ * @vmid: VM identifier allocated with gh_rm_alloc_vmid
+ *
+ * On VMs which use proxy scheduling, vcpu_run is needed to actually run the VM.
+ * On VMs which use Gunyah's scheduling, the vCPUs start executing in accordance with Gunyah
+ * scheduling policies.
+ */
+int gh_rm_vm_start(struct gh_rm *rm, u16 vmid)
+{
+	return gh_rm_common_vmid_call(rm, GH_RM_RPC_VM_START, vmid);
+}
+
+/**
+ * gh_rm_vm_stop() - Send a request to Resource Manager VM to forcibly stop a VM.
+ * @rm: Handle to a Gunyah resource manager
+ * @vmid: VM identifier allocated with gh_rm_alloc_vmid
+ */
+int gh_rm_vm_stop(struct gh_rm *rm, u16 vmid)
+{
+	struct gh_rm_vm_stop_req req_payload = {
+		.vmid = cpu_to_le16(vmid),
+		.flags = GH_RM_VM_STOP_FLAG_FORCE_STOP,
+		.stop_reason = cpu_to_le32(GH_RM_VM_STOP_REASON_FORCE_STOP),
+	};
+
+	return gh_rm_call(rm, GH_RM_RPC_VM_STOP, &req_payload, sizeof(req_payload), NULL, NULL);
+}
+
+/**
+ * gh_rm_vm_configure() - Prepare a VM to start and provide the common
+ *			  configuration needed by RM to configure a VM
+ * @rm: Handle to a Gunyah resource manager
+ * @vmid: VM identifier allocated with gh_rm_alloc_vmid
+ * @auth_mechanism: Authentication mechanism used by resource manager to verify
+ *                  the virtual machine
+ * @mem_handle: Handle to a previously shared memparcel that contains all parts
+ *              of the VM image subject to authentication.
+ * @image_offset: Start address of VM image, relative to the start of memparcel
+ * @image_size: Size of the VM image
+ * @dtb_offset: Start address of the devicetree binary with VM configuration,
+ *              relative to start of memparcel.
+ * @dtb_size: Maximum size of devicetree binary.
+ */
+int gh_rm_vm_configure(struct gh_rm *rm, u16 vmid, enum gh_rm_vm_auth_mechanism auth_mechanism,
+		u32 mem_handle, u64 image_offset, u64 image_size, u64 dtb_offset, u64 dtb_size)
+{
+	struct gh_rm_vm_config_image_req req_payload = {
+		.vmid = cpu_to_le16(vmid),
+		.auth_mech = cpu_to_le16(auth_mechanism),
+		.mem_handle = cpu_to_le32(mem_handle),
+		.image_offset = cpu_to_le64(image_offset),
+		.image_size = cpu_to_le64(image_size),
+		.dtb_offset = cpu_to_le64(dtb_offset),
+		.dtb_size = cpu_to_le64(dtb_size),
+	};
+
+	return gh_rm_call(rm, GH_RM_RPC_VM_CONFIG_IMAGE, &req_payload, sizeof(req_payload),
+			  NULL, NULL);
+}
+
+/**
+ * gh_rm_vm_init() - Move the VM to initialized state.
+ * @rm: Handle to a Gunyah resource manager
+ * @vmid: VM identifier
+ *
+ * RM will allocate needed resources for the VM.
+ */
+int gh_rm_vm_init(struct gh_rm *rm, u16 vmid)
+{
+	return gh_rm_common_vmid_call(rm, GH_RM_RPC_VM_INIT, vmid);
+}
+
+/**
+ * gh_rm_get_hyp_resources() - Retrieve hypervisor resources (capabilities) associated with a VM
+ * @rm: Handle to a Gunyah resource manager
+ * @vmid: VMID of the other VM to get the resources of
+ * @resources: Set by gh_rm_get_hyp_resources and contains the returned hypervisor resources.
+ *             Caller must free the resources pointer if successful.
+ */
+int gh_rm_get_hyp_resources(struct gh_rm *rm, u16 vmid,
+				struct gh_rm_hyp_resources **resources)
+{
+	struct gh_rm_vm_common_vmid_req req_payload = {
+		.vmid = cpu_to_le16(vmid),
+	};
+	struct gh_rm_hyp_resources *resp;
+	size_t resp_size;
+	int ret;
+
+	ret = gh_rm_call(rm, GH_RM_RPC_VM_GET_HYP_RESOURCES,
+			 &req_payload, sizeof(req_payload),
+			 (void **)&resp, &resp_size);
+	if (ret)
+		return ret;
+
+	if (!resp_size)
+		return -EBADMSG;
+
+	if (resp_size < struct_size(resp, entries, 0) ||
+		resp_size != struct_size(resp, entries, le32_to_cpu(resp->n_entries))) {
+		kfree(resp);
+		return -EBADMSG;
+	}
+
+	*resources = resp;
+	return 0;
+}
+
+/**
+ * gh_rm_get_vmid() - Retrieve VMID of this virtual machine
+ * @rm: Handle to a Gunyah resource manager
+ * @vmid: Filled with the VMID of this VM
+ */
+int gh_rm_get_vmid(struct gh_rm *rm, u16 *vmid)
+{
+	static u16 cached_vmid = GH_VMID_INVAL;
+	size_t resp_size;
+	__le32 *resp;
+	int ret;
+
+	if (cached_vmid != GH_VMID_INVAL) {
+		*vmid = cached_vmid;
+		return 0;
+	}
+
+	ret = gh_rm_call(rm, GH_RM_RPC_VM_GET_VMID, NULL, 0, (void **)&resp, &resp_size);
+	if (ret)
+		return ret;
+
+	*vmid = cached_vmid = lower_16_bits(le32_to_cpu(*resp));
+	kfree(resp);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(gh_rm_get_vmid);
diff --git a/include/linux/gunyah_rsc_mgr.h b/include/linux/gunyah_rsc_mgr.h
index f2a312e80af52..1ac66d9004d2b 100644
--- a/include/linux/gunyah_rsc_mgr.h
+++ b/include/linux/gunyah_rsc_mgr.h
@@ -18,4 +18,77 @@ int gh_rm_notifier_unregister(struct gh_rm *rm, struct notifier_block *nb);
 struct device *gh_rm_get(struct gh_rm *rm);
 void gh_rm_put(struct gh_rm *rm);
 
+struct gh_rm_vm_exited_payload {
+	__le16 vmid;
+	__le16 exit_type;
+	__le32 exit_reason_size;
+	u8 exit_reason[];
+} __packed;
+
+#define GH_RM_NOTIFICATION_VM_EXITED		 0x56100001
+
+enum gh_rm_vm_status {
+	GH_RM_VM_STATUS_NO_STATE	= 0,
+	GH_RM_VM_STATUS_INIT		= 1,
+	GH_RM_VM_STATUS_READY		= 2,
+	GH_RM_VM_STATUS_RUNNING		= 3,
+	GH_RM_VM_STATUS_PAUSED		= 4,
+	GH_RM_VM_STATUS_LOAD		= 5,
+	GH_RM_VM_STATUS_AUTH		= 6,
+	GH_RM_VM_STATUS_INIT_FAILED	= 8,
+	GH_RM_VM_STATUS_EXITED		= 9,
+	GH_RM_VM_STATUS_RESETTING	= 10,
+	GH_RM_VM_STATUS_RESET		= 11,
+};
+
+struct gh_rm_vm_status_payload {
+	__le16 vmid;
+	u16 reserved;
+	u8 vm_status;
+	u8 os_status;
+	__le16 app_status;
+} __packed;
+
+#define GH_RM_NOTIFICATION_VM_STATUS		 0x56100008
+
+/* RPC Calls */
+int gh_rm_alloc_vmid(struct gh_rm *rm, u16 vmid);
+int gh_rm_dealloc_vmid(struct gh_rm *rm, u16 vmid);
+int gh_rm_vm_reset(struct gh_rm *rm, u16 vmid);
+int gh_rm_vm_start(struct gh_rm *rm, u16 vmid);
+int gh_rm_vm_stop(struct gh_rm *rm, u16 vmid);
+
+enum gh_rm_vm_auth_mechanism {
+	GH_RM_VM_AUTH_NONE		= 0,
+	GH_RM_VM_AUTH_QCOM_PIL_ELF	= 1,
+	GH_RM_VM_AUTH_QCOM_ANDROID_PVM	= 2,
+};
+
+int gh_rm_vm_configure(struct gh_rm *rm, u16 vmid, enum gh_rm_vm_auth_mechanism auth_mechanism,
+			u32 mem_handle, u64 image_offset, u64 image_size,
+			u64 dtb_offset, u64 dtb_size);
+int gh_rm_vm_init(struct gh_rm *rm, u16 vmid);
+
+struct gh_rm_hyp_resource {
+	u8 type;
+	u8 reserved;
+	__le16 partner_vmid;
+	__le32 resource_handle;
+	__le32 resource_label;
+	__le64 cap_id;
+	__le32 virq_handle;
+	__le32 virq;
+	__le64 base;
+	__le64 size;
+} __packed;
+
+struct gh_rm_hyp_resources {
+	__le32 n_entries;
+	struct gh_rm_hyp_resource entries[];
+} __packed;
+
+int gh_rm_get_hyp_resources(struct gh_rm *rm, u16 vmid,
+				struct gh_rm_hyp_resources **resources);
+int gh_rm_get_vmid(struct gh_rm *rm, u16 *vmid);
+
 #endif
-- 
2.40.0

[PATCH v14 09/25] gunyah: vm_mgr: Introduce basic VM Manager

[Elliot Berman]

Gunyah VM manager is a kernel moduel which exposes an interface to
Gunyah userspace to load, run, and interact with other Gunyah virtual
machines. The interface is a character device at /dev/gunyah.

Add a basic VM manager driver. Upcoming patches will add more ioctls
into this driver.

Reviewed-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Reviewed-by: Alex Elder <elder@linaro.org>
Co-developed-by: Prakruthi Deepak Heragu <quic_pheragu@quicinc.com>
Signed-off-by: Prakruthi Deepak Heragu <quic_pheragu@quicinc.com>
Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
---
 .../userspace-api/ioctl/ioctl-number.rst      |  1 +
 drivers/virt/gunyah/Makefile                  |  2 +-
 drivers/virt/gunyah/rsc_mgr.c                 | 49 +++++++++-
 drivers/virt/gunyah/vm_mgr.c                  | 93 +++++++++++++++++++
 drivers/virt/gunyah/vm_mgr.h                  | 20 ++++
 include/uapi/linux/gunyah.h                   | 23 +++++
 6 files changed, 186 insertions(+), 2 deletions(-)
 create mode 100644 drivers/virt/gunyah/vm_mgr.c
 create mode 100644 drivers/virt/gunyah/vm_mgr.h
 create mode 100644 include/uapi/linux/gunyah.h

diff --git a/Documentation/userspace-api/ioctl/ioctl-number.rst b/Documentation/userspace-api/ioctl/ioctl-number.rst
index 4f7b23faebb98..c7d7afa17a3dd 100644
--- a/Documentation/userspace-api/ioctl/ioctl-number.rst
+++ b/Documentation/userspace-api/ioctl/ioctl-number.rst
@@ -137,6 +137,7 @@ Code  Seq#    Include File                                           Comments
 'F'   DD     video/sstfb.h                                           conflict!
 'G'   00-3F  drivers/misc/sgi-gru/grulib.h                           conflict!
 'G'   00-0F  xen/gntalloc.h, xen/gntdev.h                            conflict!
+'G'   00-0F  linux/gunyah.h                                          conflict!
 'H'   00-7F  linux/hiddev.h                                          conflict!
 'H'   00-0F  linux/hidraw.h                                          conflict!
 'H'   01     linux/mei.h                                             conflict!
diff --git a/drivers/virt/gunyah/Makefile b/drivers/virt/gunyah/Makefile
index 241bab357b86c..e47e25895299c 100644
--- a/drivers/virt/gunyah/Makefile
+++ b/drivers/virt/gunyah/Makefile
@@ -1,4 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0
 
-gunyah-y += rsc_mgr.o rsc_mgr_rpc.o
+gunyah-y += rsc_mgr.o rsc_mgr_rpc.o vm_mgr.o
 obj-$(CONFIG_GUNYAH) += gunyah.o
diff --git a/drivers/virt/gunyah/rsc_mgr.c b/drivers/virt/gunyah/rsc_mgr.c
index 04c8e131d259f..a0faf126ee56e 100644
--- a/drivers/virt/gunyah/rsc_mgr.c
+++ b/drivers/virt/gunyah/rsc_mgr.c
@@ -15,8 +15,10 @@
 #include <linux/completion.h>
 #include <linux/gunyah_rsc_mgr.h>
 #include <linux/platform_device.h>
+#include <linux/miscdevice.h>
 
 #include "rsc_mgr.h"
+#include "vm_mgr.h"
 
 #define RM_RPC_API_VERSION_MASK		GENMASK(3, 0)
 #define RM_RPC_HEADER_WORDS_MASK	GENMASK(7, 4)
@@ -130,6 +132,7 @@ struct gh_rm_connection {
  * @cache: cache for allocating Tx messages
  * @send_lock: synchronization to allow only one request to be sent at a time
  * @nh: notifier chain for clients interested in RM notification messages
+ * @miscdev: /dev/gunyah
  */
 struct gh_rm {
 	struct device *dev;
@@ -146,6 +149,8 @@ struct gh_rm {
 	struct kmem_cache *cache;
 	struct mutex send_lock;
 	struct blocking_notifier_head nh;
+
+	struct miscdevice miscdev;
 };
 
 /**
@@ -580,6 +585,33 @@ int gh_rm_notifier_unregister(struct gh_rm *rm, struct notifier_block *nb)
 }
 EXPORT_SYMBOL_GPL(gh_rm_notifier_unregister);
 
+struct device *gh_rm_get(struct gh_rm *rm)
+{
+	return get_device(rm->miscdev.this_device);
+}
+EXPORT_SYMBOL_GPL(gh_rm_get);
+
+void gh_rm_put(struct gh_rm *rm)
+{
+	put_device(rm->miscdev.this_device);
+}
+EXPORT_SYMBOL_GPL(gh_rm_put);
+
+static long gh_dev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
+{
+	struct miscdevice *miscdev = filp->private_data;
+	struct gh_rm *rm = container_of(miscdev, struct gh_rm, miscdev);
+
+	return gh_dev_vm_mgr_ioctl(rm, cmd, arg);
+}
+
+static const struct file_operations gh_dev_fops = {
+	.owner		= THIS_MODULE,
+	.unlocked_ioctl	= gh_dev_ioctl,
+	.compat_ioctl	= compat_ptr_ioctl,
+	.llseek		= noop_llseek,
+};
+
 static int gh_msgq_platform_probe_direction(struct platform_device *pdev, bool tx,
 					    struct gh_resource *ghrsc)
 {
@@ -664,7 +696,21 @@ static int gh_rm_drv_probe(struct platform_device *pdev)
 	rm->msgq_client.rx_callback = gh_rm_msgq_rx_data;
 	rm->msgq_client.tx_done = gh_rm_msgq_tx_done;
 
-	return gh_msgq_init(&pdev->dev, &rm->msgq, &rm->msgq_client, &rm->tx_ghrsc, &rm->rx_ghrsc);
+	ret = gh_msgq_init(&pdev->dev, &rm->msgq, &rm->msgq_client, &rm->tx_ghrsc, &rm->rx_ghrsc);
+	if (ret)
+		goto err_cache;
+
+	rm->miscdev.name = "gunyah";
+	rm->miscdev.minor = MISC_DYNAMIC_MINOR;
+	rm->miscdev.fops = &gh_dev_fops;
+
+	ret = misc_register(&rm->miscdev);
+	if (ret)
+		goto err_msgq;
+
+	return 0;
+err_msgq:
+	gh_msgq_remove(&rm->msgq);
 err_cache:
 	kmem_cache_destroy(rm->cache);
 	return ret;
@@ -674,6 +720,7 @@ static int gh_rm_drv_remove(struct platform_device *pdev)
 {
 	struct gh_rm *rm = platform_get_drvdata(pdev);
 
+	misc_deregister(&rm->miscdev);
 	gh_msgq_remove(&rm->msgq);
 	kmem_cache_destroy(rm->cache);
 
diff --git a/drivers/virt/gunyah/vm_mgr.c b/drivers/virt/gunyah/vm_mgr.c
new file mode 100644
index 0000000000000..a43401cb34f7d
--- /dev/null
+++ b/drivers/virt/gunyah/vm_mgr.c
@@ -0,0 +1,93 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#define pr_fmt(fmt) "gh_vm_mgr: " fmt
+
+#include <linux/anon_inodes.h>
+#include <linux/file.h>
+#include <linux/gunyah_rsc_mgr.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+
+#include <uapi/linux/gunyah.h>
+
+#include "vm_mgr.h"
+
+static __must_check struct gh_vm *gh_vm_alloc(struct gh_rm *rm)
+{
+	struct gh_vm *ghvm;
+
+	ghvm = kzalloc(sizeof(*ghvm), GFP_KERNEL);
+	if (!ghvm)
+		return ERR_PTR(-ENOMEM);
+
+	ghvm->parent = gh_rm_get(rm);
+	ghvm->rm = rm;
+
+	return ghvm;
+}
+
+static int gh_vm_release(struct inode *inode, struct file *filp)
+{
+	struct gh_vm *ghvm = filp->private_data;
+
+	gh_rm_put(ghvm->rm);
+	kfree(ghvm);
+	return 0;
+}
+
+static const struct file_operations gh_vm_fops = {
+	.owner = THIS_MODULE,
+	.release = gh_vm_release,
+	.llseek = noop_llseek,
+};
+
+static long gh_dev_ioctl_create_vm(struct gh_rm *rm, unsigned long arg)
+{
+	struct gh_vm *ghvm;
+	struct file *file;
+	int fd, err;
+
+	/* arg reserved for future use. */
+	if (arg)
+		return -EINVAL;
+
+	ghvm = gh_vm_alloc(rm);
+	if (IS_ERR(ghvm))
+		return PTR_ERR(ghvm);
+
+	fd = get_unused_fd_flags(O_CLOEXEC);
+	if (fd < 0) {
+		err = fd;
+		goto err_destroy_vm;
+	}
+
+	file = anon_inode_getfile("gunyah-vm", &gh_vm_fops, ghvm, O_RDWR);
+	if (IS_ERR(file)) {
+		err = PTR_ERR(file);
+		goto err_put_fd;
+	}
+
+	fd_install(fd, file);
+
+	return fd;
+
+err_put_fd:
+	put_unused_fd(fd);
+err_destroy_vm:
+	gh_rm_put(ghvm->rm);
+	kfree(ghvm);
+	return err;
+}
+
+long gh_dev_vm_mgr_ioctl(struct gh_rm *rm, unsigned int cmd, unsigned long arg)
+{
+	switch (cmd) {
+	case GH_CREATE_VM:
+		return gh_dev_ioctl_create_vm(rm, arg);
+	default:
+		return -ENOTTY;
+	}
+}
diff --git a/drivers/virt/gunyah/vm_mgr.h b/drivers/virt/gunyah/vm_mgr.h
new file mode 100644
index 0000000000000..1e94b58d7d34d
--- /dev/null
+++ b/drivers/virt/gunyah/vm_mgr.h
@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#ifndef _GH_VM_MGR_H
+#define _GH_VM_MGR_H
+
+#include <linux/gunyah_rsc_mgr.h>
+
+#include <uapi/linux/gunyah.h>
+
+long gh_dev_vm_mgr_ioctl(struct gh_rm *rm, unsigned int cmd, unsigned long arg);
+
+struct gh_vm {
+	struct gh_rm *rm;
+	struct device *parent;
+};
+
+#endif
diff --git a/include/uapi/linux/gunyah.h b/include/uapi/linux/gunyah.h
new file mode 100644
index 0000000000000..86b9cb60118dd
--- /dev/null
+++ b/include/uapi/linux/gunyah.h
@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: GPL-2.0-only WITH Linux-syscall-note */
+/*
+ * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#ifndef _UAPI_LINUX_GUNYAH_H
+#define _UAPI_LINUX_GUNYAH_H
+
+/*
+ * Userspace interface for /dev/gunyah - gunyah based virtual machine
+ */
+
+#include <linux/types.h>
+#include <linux/ioctl.h>
+
+#define GH_IOCTL_TYPE			'G'
+
+/*
+ * ioctls for /dev/gunyah fds:
+ */
+#define GH_CREATE_VM			_IO(GH_IOCTL_TYPE, 0x0) /* Returns a Gunyah VM fd */
+
+#endif
-- 
2.40.0

[PATCH v14 10/25] gunyah: rsc_mgr: Add RPC for sharing memory

[Elliot Berman]

Gunyah resource manager provides API to manipulate stage 2 page tables.
Manipulations are represented as a memory parcel. Memory parcels
describe a list of memory regions (intermediate physical address--IPA--and
size), a list of new permissions for VMs, and the memory type (DDR or
MMIO). Each memory parcel is uniquely identified by a handle allocated by
Gunyah. There are a few types of memory parcel sharing which Gunyah
supports:

 - Sharing: the guest and host VM both have access
 - Lending: only the guest has access; host VM loses access
 - Donating: Permanently lent (not reclaimed even if guest shuts down)

Memory parcels that have been shared or lent can be reclaimed by the
host via an additional call. The reclaim operation restores the original
access the host VM had to the memory parcel and removes the access to
other VM.

One point to note that memory parcels don't describe where in the guest
VM the memory parcel should reside. The guest VM must accept the memory
parcel either explicitly via a "gh_rm_mem_accept" call (not introduced
here) or be configured to accept it automatically at boot. When the guest
VM accepts the memory parcel, it also mentions the IPA it wants to place
memory parcel. Although the region might be discontiguous on the host,
the memory parcel is place contiguously in the guest memory at the
specified IPA.

Reviewed-by: Alex Elder <elder@linaro.org>
Reviewed-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Co-developed-by: Prakruthi Deepak Heragu <quic_pheragu@quicinc.com>
Signed-off-by: Prakruthi Deepak Heragu <quic_pheragu@quicinc.com>
Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
---
 drivers/virt/gunyah/rsc_mgr_rpc.c | 227 ++++++++++++++++++++++++++++++
 include/linux/gunyah_rsc_mgr.h    |  48 +++++++
 2 files changed, 275 insertions(+)

diff --git a/drivers/virt/gunyah/rsc_mgr_rpc.c b/drivers/virt/gunyah/rsc_mgr_rpc.c
index a4a9f0ba4e1fc..25064123a31c3 100644
--- a/drivers/virt/gunyah/rsc_mgr_rpc.c
+++ b/drivers/virt/gunyah/rsc_mgr_rpc.c
@@ -6,6 +6,12 @@
 #include <linux/gunyah_rsc_mgr.h>
 #include "rsc_mgr.h"
 
+/* Message IDs: Memory Management */
+#define GH_RM_RPC_MEM_LEND			0x51000012
+#define GH_RM_RPC_MEM_SHARE			0x51000013
+#define GH_RM_RPC_MEM_RECLAIM			0x51000015
+#define GH_RM_RPC_MEM_APPEND			0x51000018
+
 /* Message IDs: VM Management */
 #define GH_RM_RPC_VM_ALLOC_VMID			0x56000001
 #define GH_RM_RPC_VM_DEALLOC_VMID		0x56000002
@@ -22,6 +28,46 @@ struct gh_rm_vm_common_vmid_req {
 	__le16 _padding;
 } __packed;
 
+/* Call: MEM_LEND, MEM_SHARE */
+#define GH_MEM_SHARE_REQ_FLAGS_APPEND		BIT(1)
+
+struct gh_rm_mem_share_req_header {
+	u8 mem_type;
+	u8 _padding0;
+	u8 flags;
+	u8 _padding1;
+	__le32 label;
+} __packed;
+
+struct gh_rm_mem_share_req_acl_section {
+	__le32 n_entries;
+	struct gh_rm_mem_acl_entry entries[];
+};
+
+struct gh_rm_mem_share_req_mem_section {
+	__le16 n_entries;
+	__le16 _padding;
+	struct gh_rm_mem_entry entries[];
+};
+
+/* Call: MEM_RELEASE */
+struct gh_rm_mem_release_req {
+	__le32 mem_handle;
+	u8 flags; /* currently not used */
+	u8 _padding0;
+	__le16 _padding1;
+} __packed;
+
+/* Call: MEM_APPEND */
+#define GH_MEM_APPEND_REQ_FLAGS_END		BIT(0)
+
+struct gh_rm_mem_append_req_header {
+	__le32 mem_handle;
+	u8 flags;
+	u8 _padding0;
+	__le16 _padding1;
+} __packed;
+
 /* Call: VM_ALLOC */
 struct gh_rm_vm_alloc_vmid_resp {
 	__le16 vmid;
@@ -51,6 +97,8 @@ struct gh_rm_vm_config_image_req {
 	__le64 dtb_size;
 } __packed;
 
+#define GH_RM_MAX_MEM_ENTRIES	512
+
 /*
  * Several RM calls take only a VMID as a parameter and give only standard
  * response back. Deduplicate boilerplate code by using this common call.
@@ -64,6 +112,185 @@ static int gh_rm_common_vmid_call(struct gh_rm *rm, u32 message_id, u16 vmid)
 	return gh_rm_call(rm, message_id, &req_payload, sizeof(req_payload), NULL, NULL);
 }
 
+static int _gh_rm_mem_append(struct gh_rm *rm, u32 mem_handle, bool end_append,
+			struct gh_rm_mem_entry *mem_entries, size_t n_mem_entries)
+{
+	struct gh_rm_mem_share_req_mem_section *mem_section;
+	struct gh_rm_mem_append_req_header *req_header;
+	size_t msg_size = 0;
+	void *msg;
+	int ret;
+
+	msg_size += sizeof(struct gh_rm_mem_append_req_header);
+	msg_size += struct_size(mem_section, entries, n_mem_entries);
+
+	msg = kzalloc(msg_size, GFP_KERNEL);
+	if (!msg)
+		return -ENOMEM;
+
+	req_header = msg;
+	mem_section = (void *)(req_header + 1);
+
+	req_header->mem_handle = cpu_to_le32(mem_handle);
+	if (end_append)
+		req_header->flags |= GH_MEM_APPEND_REQ_FLAGS_END;
+
+	mem_section->n_entries = cpu_to_le16(n_mem_entries);
+	memcpy(mem_section->entries, mem_entries, sizeof(*mem_entries) * n_mem_entries);
+
+	ret = gh_rm_call(rm, GH_RM_RPC_MEM_APPEND, msg, msg_size, NULL, NULL);
+	kfree(msg);
+
+	return ret;
+}
+
+static int gh_rm_mem_append(struct gh_rm *rm, u32 mem_handle,
+			struct gh_rm_mem_entry *mem_entries, size_t n_mem_entries)
+{
+	bool end_append;
+	int ret = 0;
+	size_t n;
+
+	while (n_mem_entries) {
+		if (n_mem_entries > GH_RM_MAX_MEM_ENTRIES) {
+			end_append = false;
+			n = GH_RM_MAX_MEM_ENTRIES;
+		} else {
+			end_append = true;
+			n = n_mem_entries;
+		}
+
+		ret = _gh_rm_mem_append(rm, mem_handle, end_append, mem_entries, n);
+		if (ret)
+			break;
+
+		mem_entries += n;
+		n_mem_entries -= n;
+	}
+
+	return ret;
+}
+
+static int gh_rm_mem_lend_common(struct gh_rm *rm, u32 message_id, struct gh_rm_mem_parcel *p)
+{
+	size_t msg_size = 0, initial_mem_entries = p->n_mem_entries, resp_size;
+	size_t acl_section_size, mem_section_size;
+	struct gh_rm_mem_share_req_acl_section *acl_section;
+	struct gh_rm_mem_share_req_mem_section *mem_section;
+	struct gh_rm_mem_share_req_header *req_header;
+	u32 *attr_section;
+	__le32 *resp;
+	void *msg;
+	int ret;
+
+	if (!p->acl_entries || !p->n_acl_entries || !p->mem_entries || !p->n_mem_entries ||
+	    p->n_acl_entries > U8_MAX || p->mem_handle != GH_MEM_HANDLE_INVAL)
+		return -EINVAL;
+
+	if (initial_mem_entries > GH_RM_MAX_MEM_ENTRIES)
+		initial_mem_entries = GH_RM_MAX_MEM_ENTRIES;
+
+	acl_section_size = struct_size(acl_section, entries, p->n_acl_entries);
+	mem_section_size = struct_size(mem_section, entries, initial_mem_entries);
+	/* The format of the message goes:
+	 * request header
+	 * ACL entries (which VMs get what kind of access to this memory parcel)
+	 * Memory entries (list of memory regions to share)
+	 * Memory attributes (currently unused, we'll hard-code the size to 0)
+	 */
+	msg_size += sizeof(struct gh_rm_mem_share_req_header);
+	msg_size += acl_section_size;
+	msg_size += mem_section_size;
+	msg_size += sizeof(u32); /* for memory attributes, currently unused */
+
+	msg = kzalloc(msg_size, GFP_KERNEL);
+	if (!msg)
+		return -ENOMEM;
+
+	req_header = msg;
+	acl_section = (void *)req_header + sizeof(*req_header);
+	mem_section = (void *)acl_section + acl_section_size;
+	attr_section = (void *)mem_section + mem_section_size;
+
+	req_header->mem_type = p->mem_type;
+	if (initial_mem_entries != p->n_mem_entries)
+		req_header->flags |= GH_MEM_SHARE_REQ_FLAGS_APPEND;
+	req_header->label = cpu_to_le32(p->label);
+
+	acl_section->n_entries = cpu_to_le32(p->n_acl_entries);
+	memcpy(acl_section->entries, p->acl_entries,
+		flex_array_size(acl_section, entries, p->n_acl_entries));
+
+	mem_section->n_entries = cpu_to_le16(initial_mem_entries);
+	memcpy(mem_section->entries, p->mem_entries,
+		flex_array_size(mem_section, entries, initial_mem_entries));
+
+	/* Set n_entries for memory attribute section to 0 */
+	*attr_section = 0;
+
+	ret = gh_rm_call(rm, message_id, msg, msg_size, (void **)&resp, &resp_size);
+	kfree(msg);
+
+	if (ret)
+		return ret;
+
+	p->mem_handle = le32_to_cpu(*resp);
+	kfree(resp);
+
+	if (initial_mem_entries != p->n_mem_entries) {
+		ret = gh_rm_mem_append(rm, p->mem_handle,
+					&p->mem_entries[initial_mem_entries],
+					p->n_mem_entries - initial_mem_entries);
+		if (ret) {
+			gh_rm_mem_reclaim(rm, p);
+			p->mem_handle = GH_MEM_HANDLE_INVAL;
+		}
+	}
+
+	return ret;
+}
+
+/**
+ * gh_rm_mem_lend() - Lend memory to other virtual machines.
+ * @rm: Handle to a Gunyah resource manager
+ * @parcel: Information about the memory to be lent.
+ *
+ * Lending removes Linux's access to the memory while the memory parcel is lent.
+ */
+int gh_rm_mem_lend(struct gh_rm *rm, struct gh_rm_mem_parcel *parcel)
+{
+	return gh_rm_mem_lend_common(rm, GH_RM_RPC_MEM_LEND, parcel);
+}
+
+
+/**
+ * gh_rm_mem_share() - Share memory with other virtual machines.
+ * @rm: Handle to a Gunyah resource manager
+ * @parcel: Information about the memory to be shared.
+ *
+ * Sharing keeps Linux's access to the memory while the memory parcel is shared.
+ */
+int gh_rm_mem_share(struct gh_rm *rm, struct gh_rm_mem_parcel *parcel)
+{
+	return gh_rm_mem_lend_common(rm, GH_RM_RPC_MEM_SHARE, parcel);
+}
+
+/**
+ * gh_rm_mem_reclaim() - Reclaim a memory parcel
+ * @rm: Handle to a Gunyah resource manager
+ * @parcel: Information about the memory to be reclaimed.
+ *
+ * RM maps the associated memory back into the stage-2 page tables of the owner VM.
+ */
+int gh_rm_mem_reclaim(struct gh_rm *rm, struct gh_rm_mem_parcel *parcel)
+{
+	struct gh_rm_mem_release_req req = {
+		.mem_handle = cpu_to_le32(parcel->mem_handle),
+	};
+
+	return gh_rm_call(rm, GH_RM_RPC_MEM_RECLAIM, &req, sizeof(req), NULL, NULL);
+}
+
 /**
  * gh_rm_alloc_vmid() - Allocate a new VM in Gunyah. Returns the VM identifier.
  * @rm: Handle to a Gunyah resource manager
diff --git a/include/linux/gunyah_rsc_mgr.h b/include/linux/gunyah_rsc_mgr.h
index 1ac66d9004d2b..dfac088420bda 100644
--- a/include/linux/gunyah_rsc_mgr.h
+++ b/include/linux/gunyah_rsc_mgr.h
@@ -11,6 +11,7 @@
 #include <linux/gunyah.h>
 
 #define GH_VMID_INVAL		U16_MAX
+#define GH_MEM_HANDLE_INVAL	U32_MAX
 
 struct gh_rm;
 int gh_rm_notifier_register(struct gh_rm *rm, struct notifier_block *nb);
@@ -51,7 +52,54 @@ struct gh_rm_vm_status_payload {
 
 #define GH_RM_NOTIFICATION_VM_STATUS		 0x56100008
 
+#define GH_RM_ACL_X		BIT(0)
+#define GH_RM_ACL_W		BIT(1)
+#define GH_RM_ACL_R		BIT(2)
+
+struct gh_rm_mem_acl_entry {
+	__le16 vmid;
+	u8 perms;
+	u8 reserved;
+} __packed;
+
+struct gh_rm_mem_entry {
+	__le64 phys_addr;
+	__le64 size;
+} __packed;
+
+enum gh_rm_mem_type {
+	GH_RM_MEM_TYPE_NORMAL	= 0,
+	GH_RM_MEM_TYPE_IO	= 1,
+};
+
+/*
+ * struct gh_rm_mem_parcel - Info about memory to be lent/shared/donated/reclaimed
+ * @mem_type: The type of memory: normal (DDR) or IO
+ * @label: An client-specified identifier which can be used by the other VMs to identify the purpose
+ *         of the memory parcel.
+ * @n_acl_entries: Count of the number of entries in the @acl_entries array.
+ * @acl_entries: An array of access control entries. Each entry specifies a VM and what access
+ *               is allowed for the memory parcel.
+ * @n_mem_entries: Count of the number of entries in the @mem_entries array.
+ * @mem_entries: An array of regions to be associated with the memory parcel. Addresses should be
+ *               (intermediate) physical addresses from Linux's perspective.
+ * @mem_handle: On success, filled with memory handle that RM allocates for this memory parcel
+ */
+struct gh_rm_mem_parcel {
+	enum gh_rm_mem_type mem_type;
+	u32 label;
+	size_t n_acl_entries;
+	struct gh_rm_mem_acl_entry *acl_entries;
+	size_t n_mem_entries;
+	struct gh_rm_mem_entry *mem_entries;
+	u32 mem_handle;
+};
+
 /* RPC Calls */
+int gh_rm_mem_lend(struct gh_rm *rm, struct gh_rm_mem_parcel *parcel);
+int gh_rm_mem_share(struct gh_rm *rm, struct gh_rm_mem_parcel *parcel);
+int gh_rm_mem_reclaim(struct gh_rm *rm, struct gh_rm_mem_parcel *parcel);
+
 int gh_rm_alloc_vmid(struct gh_rm *rm, u16 vmid);
 int gh_rm_dealloc_vmid(struct gh_rm *rm, u16 vmid);
 int gh_rm_vm_reset(struct gh_rm *rm, u16 vmid);
-- 
2.40.0

[PATCH v14 11/25] gunyah: vm_mgr: Add/remove user memory regions

[Elliot Berman]

When launching a virtual machine, Gunyah userspace allocates memory for
the guest and informs Gunyah about these memory regions through
SET_USER_MEMORY_REGION ioctl.

Co-developed-by: Prakruthi Deepak Heragu <quic_pheragu@quicinc.com>
Signed-off-by: Prakruthi Deepak Heragu <quic_pheragu@quicinc.com>
Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
---
 drivers/virt/gunyah/Makefile    |   2 +-
 drivers/virt/gunyah/vm_mgr.c    |  59 +++++++-
 drivers/virt/gunyah/vm_mgr.h    |  26 ++++
 drivers/virt/gunyah/vm_mgr_mm.c | 232 ++++++++++++++++++++++++++++++++
 include/uapi/linux/gunyah.h     |  37 +++++
 5 files changed, 352 insertions(+), 4 deletions(-)
 create mode 100644 drivers/virt/gunyah/vm_mgr_mm.c

diff --git a/drivers/virt/gunyah/Makefile b/drivers/virt/gunyah/Makefile
index e47e25895299c..bacf78b8fa337 100644
--- a/drivers/virt/gunyah/Makefile
+++ b/drivers/virt/gunyah/Makefile
@@ -1,4 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0
 
-gunyah-y += rsc_mgr.o rsc_mgr_rpc.o vm_mgr.o
+gunyah-y += rsc_mgr.o rsc_mgr_rpc.o vm_mgr.o vm_mgr_mm.o
 obj-$(CONFIG_GUNYAH) += gunyah.o
diff --git a/drivers/virt/gunyah/vm_mgr.c b/drivers/virt/gunyah/vm_mgr.c
index a43401cb34f7d..297427952b8c7 100644
--- a/drivers/virt/gunyah/vm_mgr.c
+++ b/drivers/virt/gunyah/vm_mgr.c
@@ -15,6 +15,8 @@
 
 #include "vm_mgr.h"
 
+static void gh_vm_free(struct work_struct *work);
+
 static __must_check struct gh_vm *gh_vm_alloc(struct gh_rm *rm)
 {
 	struct gh_vm *ghvm;
@@ -26,20 +28,72 @@ static __must_check struct gh_vm *gh_vm_alloc(struct gh_rm *rm)
 	ghvm->parent = gh_rm_get(rm);
 	ghvm->rm = rm;
 
+	mmgrab(current->mm);
+	ghvm->mm = current->mm;
+	mutex_init(&ghvm->mm_lock);
+	INIT_LIST_HEAD(&ghvm->memory_mappings);
+	INIT_WORK(&ghvm->free_work, gh_vm_free);
+
 	return ghvm;
 }
 
-static int gh_vm_release(struct inode *inode, struct file *filp)
+static long gh_vm_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 {
 	struct gh_vm *ghvm = filp->private_data;
+	void __user *argp = (void __user *)arg;
+	long r;
+
+	switch (cmd) {
+	case GH_VM_SET_USER_MEM_REGION: {
+		struct gh_userspace_memory_region region;
+
+		/* only allow owner task to add memory */
+		if (ghvm->mm != current->mm)
+			return -EPERM;
+
+		if (copy_from_user(&region, argp, sizeof(region)))
+			return -EFAULT;
+
+		/* All other flag bits are reserved for future use */
+		if (region.flags & ~(GH_MEM_ALLOW_READ | GH_MEM_ALLOW_WRITE | GH_MEM_ALLOW_EXEC))
+			return -EINVAL;
+
+		r = gh_vm_mem_alloc(ghvm, &region);
+		break;
+	}
+	default:
+		r = -ENOTTY;
+		break;
+	}
 
+	return r;
+}
+
+static void gh_vm_free(struct work_struct *work)
+{
+	struct gh_vm *ghvm = container_of(work, struct gh_vm, free_work);
+
+	gh_vm_mem_reclaim(ghvm);
 	gh_rm_put(ghvm->rm);
+	mmdrop(ghvm->mm);
 	kfree(ghvm);
+}
+
+static int gh_vm_release(struct inode *inode, struct file *filp)
+{
+	struct gh_vm *ghvm = filp->private_data;
+
+	/* VM will be reset and make RM calls which can interruptible sleep.
+	 * Defer to a work so this thread can receive signal.
+	 */
+	schedule_work(&ghvm->free_work);
 	return 0;
 }
 
 static const struct file_operations gh_vm_fops = {
 	.owner = THIS_MODULE,
+	.unlocked_ioctl = gh_vm_ioctl,
+	.compat_ioctl	= compat_ptr_ioctl,
 	.release = gh_vm_release,
 	.llseek = noop_llseek,
 };
@@ -77,8 +131,7 @@ static long gh_dev_ioctl_create_vm(struct gh_rm *rm, unsigned long arg)
 err_put_fd:
 	put_unused_fd(fd);
 err_destroy_vm:
-	gh_rm_put(ghvm->rm);
-	kfree(ghvm);
+	gh_vm_free(&ghvm->free_work);
 	return err;
 }
 
diff --git a/drivers/virt/gunyah/vm_mgr.h b/drivers/virt/gunyah/vm_mgr.h
index 1e94b58d7d34d..434ef9f662a7a 100644
--- a/drivers/virt/gunyah/vm_mgr.h
+++ b/drivers/virt/gunyah/vm_mgr.h
@@ -7,14 +7,40 @@
 #define _GH_VM_MGR_H
 
 #include <linux/gunyah_rsc_mgr.h>
+#include <linux/list.h>
+#include <linux/miscdevice.h>
+#include <linux/mutex.h>
 
 #include <uapi/linux/gunyah.h>
 
 long gh_dev_vm_mgr_ioctl(struct gh_rm *rm, unsigned int cmd, unsigned long arg);
 
+enum gh_vm_mem_share_type {
+	VM_MEM_SHARE,
+	VM_MEM_LEND,
+};
+
+struct gh_vm_mem {
+	struct list_head list;
+	enum gh_vm_mem_share_type share_type;
+	struct gh_rm_mem_parcel parcel;
+
+	__u64 guest_phys_addr;
+	struct page **pages;
+	unsigned long npages;
+};
+
 struct gh_vm {
 	struct gh_rm *rm;
 	struct device *parent;
+
+	struct work_struct free_work;
+	struct mm_struct *mm; /* userspace tied to this vm */
+	struct mutex mm_lock;
+	struct list_head memory_mappings;
 };
 
+int gh_vm_mem_alloc(struct gh_vm *ghvm, struct gh_userspace_memory_region *region);
+void gh_vm_mem_reclaim(struct gh_vm *ghvm);
+
 #endif
diff --git a/drivers/virt/gunyah/vm_mgr_mm.c b/drivers/virt/gunyah/vm_mgr_mm.c
new file mode 100644
index 0000000000000..6974607f02edd
--- /dev/null
+++ b/drivers/virt/gunyah/vm_mgr_mm.c
@@ -0,0 +1,232 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#define pr_fmt(fmt) "gh_vm_mgr: " fmt
+
+#include <linux/gunyah_rsc_mgr.h>
+#include <linux/mm.h>
+
+#include <uapi/linux/gunyah.h>
+
+#include "vm_mgr.h"
+
+static bool pages_are_mergeable(struct page *a, struct page *b)
+{
+	return page_to_pfn(a) + 1 == page_to_pfn(b);
+}
+
+static bool gh_vm_mem_overlap(struct gh_vm_mem *a, u64 addr, u64 size)
+{
+	u64 a_end = a->guest_phys_addr + (a->npages << PAGE_SHIFT);
+	u64 end = addr + size;
+
+	return a->guest_phys_addr < end && addr < a_end;
+}
+
+static struct gh_vm_mem *__gh_vm_mem_find_by_label(struct gh_vm *ghvm, u32 label)
+	__must_hold(&ghvm->mm_lock)
+{
+	struct gh_vm_mem *mapping;
+
+	list_for_each_entry(mapping, &ghvm->memory_mappings, list)
+		if (mapping->parcel.label == label)
+			return mapping;
+
+	return NULL;
+}
+
+static void gh_vm_mem_reclaim_mapping(struct gh_vm *ghvm, struct gh_vm_mem *mapping)
+	__must_hold(&ghvm->mm_lock)
+{
+	int ret = 0;
+
+	if (mapping->parcel.mem_handle != GH_MEM_HANDLE_INVAL) {
+		ret = gh_rm_mem_reclaim(ghvm->rm, &mapping->parcel);
+		if (ret)
+			pr_warn("Failed to reclaim memory parcel for label %d: %d\n",
+				mapping->parcel.label, ret);
+	}
+
+	if (!ret) {
+		unpin_user_pages(mapping->pages, mapping->npages);
+		account_locked_vm(ghvm->mm, mapping->npages, false);
+	}
+
+	kfree(mapping->pages);
+	kfree(mapping->parcel.acl_entries);
+	kfree(mapping->parcel.mem_entries);
+
+	list_del(&mapping->list);
+}
+
+void gh_vm_mem_reclaim(struct gh_vm *ghvm)
+{
+	struct gh_vm_mem *mapping, *tmp;
+
+	mutex_lock(&ghvm->mm_lock);
+
+	list_for_each_entry_safe(mapping, tmp, &ghvm->memory_mappings, list) {
+		gh_vm_mem_reclaim_mapping(ghvm, mapping);
+		kfree(mapping);
+	}
+
+	mutex_unlock(&ghvm->mm_lock);
+}
+
+int gh_vm_mem_alloc(struct gh_vm *ghvm, struct gh_userspace_memory_region *region)
+{
+	struct gh_vm_mem *mapping, *tmp_mapping;
+	struct page *curr_page, *prev_page;
+	struct gh_rm_mem_parcel *parcel;
+	int i, j, pinned, ret = 0;
+	unsigned int gup_flags;
+	size_t entry_size;
+	u16 vmid;
+
+	if (!region->memory_size || !PAGE_ALIGNED(region->memory_size) ||
+		!PAGE_ALIGNED(region->userspace_addr) ||
+		!PAGE_ALIGNED(region->guest_phys_addr))
+		return -EINVAL;
+
+	if (overflows_type(region->guest_phys_addr + region->memory_size, u64))
+		return -EOVERFLOW;
+
+	ret = mutex_lock_interruptible(&ghvm->mm_lock);
+	if (ret)
+		return ret;
+
+	mapping = __gh_vm_mem_find_by_label(ghvm, region->label);
+	if (mapping) {
+		ret = -EEXIST;
+		goto unlock;
+	}
+
+	list_for_each_entry(tmp_mapping, &ghvm->memory_mappings, list) {
+		if (gh_vm_mem_overlap(tmp_mapping, region->guest_phys_addr,
+					region->memory_size)) {
+			ret = -EEXIST;
+			goto unlock;
+		}
+	}
+
+	mapping = kzalloc(sizeof(*mapping), GFP_KERNEL_ACCOUNT);
+	if (!mapping) {
+		ret = -ENOMEM;
+		goto unlock;
+	}
+
+	mapping->guest_phys_addr = region->guest_phys_addr;
+	mapping->npages = region->memory_size >> PAGE_SHIFT;
+	parcel = &mapping->parcel;
+	parcel->label = region->label;
+	parcel->mem_handle = GH_MEM_HANDLE_INVAL; /* to be filled later by mem_share/mem_lend */
+	parcel->mem_type = GH_RM_MEM_TYPE_NORMAL;
+
+	ret = account_locked_vm(ghvm->mm, mapping->npages, true);
+	if (ret)
+		goto free_mapping;
+
+	mapping->pages = kcalloc(mapping->npages, sizeof(*mapping->pages), GFP_KERNEL_ACCOUNT);
+	if (!mapping->pages) {
+		ret = -ENOMEM;
+		mapping->npages = 0; /* update npages for reclaim */
+		goto unlock_pages;
+	}
+
+	gup_flags = FOLL_LONGTERM;
+	if (region->flags & GH_MEM_ALLOW_WRITE)
+		gup_flags |= FOLL_WRITE;
+
+	pinned = pin_user_pages_fast(region->userspace_addr, mapping->npages,
+					gup_flags, mapping->pages);
+	if (pinned < 0) {
+		ret = pinned;
+		goto free_pages;
+	} else if (pinned != mapping->npages) {
+		ret = -EFAULT;
+		mapping->npages = pinned; /* update npages for reclaim */
+		goto unpin_pages;
+	}
+
+	parcel->n_acl_entries = 2;
+	mapping->share_type = VM_MEM_SHARE;
+	parcel->acl_entries = kcalloc(parcel->n_acl_entries, sizeof(*parcel->acl_entries),
+					GFP_KERNEL);
+	if (!parcel->acl_entries) {
+		ret = -ENOMEM;
+		goto unpin_pages;
+	}
+
+	/* acl_entries[0].vmid will be this VM's vmid. We'll fill it when the
+	 * VM is starting and we know the VM's vmid.
+	 */
+	if (region->flags & GH_MEM_ALLOW_READ)
+		parcel->acl_entries[0].perms |= GH_RM_ACL_R;
+	if (region->flags & GH_MEM_ALLOW_WRITE)
+		parcel->acl_entries[0].perms |= GH_RM_ACL_W;
+	if (region->flags & GH_MEM_ALLOW_EXEC)
+		parcel->acl_entries[0].perms |= GH_RM_ACL_X;
+
+	ret = gh_rm_get_vmid(ghvm->rm, &vmid);
+	if (ret)
+		goto free_acl;
+
+	parcel->acl_entries[1].vmid = cpu_to_le16(vmid);
+	/* Host assumed to have all these permissions. Gunyah will not
+	 * grant new permissions if host actually had less than RWX
+	 */
+	parcel->acl_entries[1].perms = GH_RM_ACL_R | GH_RM_ACL_W | GH_RM_ACL_X;
+
+	parcel->n_mem_entries = 1;
+	for (i = 1; i < mapping->npages; i++) {
+		if (!pages_are_mergeable(mapping->pages[i - 1], mapping->pages[i]))
+			parcel->n_mem_entries++;
+	}
+
+	parcel->mem_entries = kcalloc(parcel->n_mem_entries,
+					sizeof(parcel->mem_entries[0]),
+					GFP_KERNEL_ACCOUNT);
+	if (!parcel->mem_entries) {
+		ret = -ENOMEM;
+		goto free_acl;
+	}
+
+	/* reduce number of entries by combining contiguous pages into single memory entry */
+	prev_page = mapping->pages[0];
+	parcel->mem_entries[0].phys_addr = cpu_to_le64(page_to_phys(prev_page));
+	entry_size = PAGE_SIZE;
+	for (i = 1, j = 0; i < mapping->npages; i++) {
+		curr_page = mapping->pages[i];
+		if (pages_are_mergeable(prev_page, curr_page)) {
+			entry_size += PAGE_SIZE;
+		} else {
+			parcel->mem_entries[j].size = cpu_to_le64(entry_size);
+			j++;
+			parcel->mem_entries[j].phys_addr =
+				cpu_to_le64(page_to_phys(curr_page));
+			entry_size = PAGE_SIZE;
+		}
+
+		prev_page = curr_page;
+	}
+	parcel->mem_entries[j].size = cpu_to_le64(entry_size);
+
+	list_add(&mapping->list, &ghvm->memory_mappings);
+	mutex_unlock(&ghvm->mm_lock);
+	return 0;
+free_acl:
+	kfree(parcel->acl_entries);
+unpin_pages:
+	unpin_user_pages(mapping->pages, pinned);
+free_pages:
+	kfree(mapping->pages);
+unlock_pages:
+	account_locked_vm(ghvm->mm, mapping->npages, false);
+free_mapping:
+	kfree(mapping);
+unlock:
+	mutex_unlock(&ghvm->mm_lock);
+	return ret;
+}
diff --git a/include/uapi/linux/gunyah.h b/include/uapi/linux/gunyah.h
index 86b9cb60118dd..91d6dd26fcc89 100644
--- a/include/uapi/linux/gunyah.h
+++ b/include/uapi/linux/gunyah.h
@@ -20,4 +20,41 @@
  */
 #define GH_CREATE_VM			_IO(GH_IOCTL_TYPE, 0x0) /* Returns a Gunyah VM fd */
 
+/*
+ * ioctls for VM fds
+ */
+
+/**
+ * enum gh_mem_flags - Possible flags on &struct gh_userspace_memory_region
+ * @GH_MEM_ALLOW_READ: Allow guest to read the memory
+ * @GH_MEM_ALLOW_WRITE: Allow guest to write to the memory
+ * @GH_MEM_ALLOW_EXEC: Allow guest to execute instructions in the memory
+ */
+enum gh_mem_flags {
+	GH_MEM_ALLOW_READ	= 1UL << 0,
+	GH_MEM_ALLOW_WRITE	= 1UL << 1,
+	GH_MEM_ALLOW_EXEC	= 1UL << 2,
+};
+
+/**
+ * struct gh_userspace_memory_region - Userspace memory descripion for GH_VM_SET_USER_MEM_REGION
+ * @label: Identifer to the region which is unique to the VM.
+ * @flags: Flags for memory parcel behavior. See &enum gh_mem_flags.
+ * @guest_phys_addr: Location of the memory region in guest's memory space (page-aligned)
+ * @memory_size: Size of the region (page-aligned)
+ * @userspace_addr: Location of the memory region in caller (userspace)'s memory
+ *
+ * See Documentation/virt/gunyah/vm-manager.rst for further details.
+ */
+struct gh_userspace_memory_region {
+	__u32 label;
+	__u32 flags;
+	__u64 guest_phys_addr;
+	__u64 memory_size;
+	__u64 userspace_addr;
+};
+
+#define GH_VM_SET_USER_MEM_REGION	_IOW(GH_IOCTL_TYPE, 0x1, \
+						struct gh_userspace_memory_region)
+
 #endif
-- 
2.40.0

[PATCH v14 12/25] gunyah: vm_mgr: Add ioctls to support basic non-proxy VM boot

[Elliot Berman]

Add remaining ioctls to support non-proxy VM boot:

 - Gunyah Resource Manager uses the VM's devicetree to configure the
   virtual machine. The location of the devicetree in the guest's
   virtual memory can be declared via the SET_DTB_CONFIG ioctl.
 - Trigger start of the virtual machine with VM_START ioctl.

Reviewed-by: Alex Elder <elder@linaro.org>
Co-developed-by: Prakruthi Deepak Heragu <quic_pheragu@quicinc.com>
Signed-off-by: Prakruthi Deepak Heragu <quic_pheragu@quicinc.com>
Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
---
 drivers/virt/gunyah/vm_mgr.c    | 215 ++++++++++++++++++++++++++++++++
 drivers/virt/gunyah/vm_mgr.h    |  11 ++
 drivers/virt/gunyah/vm_mgr_mm.c |  20 +++
 include/uapi/linux/gunyah.h     |  15 +++
 4 files changed, 261 insertions(+)

diff --git a/drivers/virt/gunyah/vm_mgr.c b/drivers/virt/gunyah/vm_mgr.c
index 297427952b8c7..562ae6ed4a5f1 100644
--- a/drivers/virt/gunyah/vm_mgr.c
+++ b/drivers/virt/gunyah/vm_mgr.c
@@ -17,6 +17,68 @@
 
 static void gh_vm_free(struct work_struct *work);
 
+static int gh_vm_rm_notification_status(struct gh_vm *ghvm, void *data)
+{
+	struct gh_rm_vm_status_payload *payload = data;
+
+	if (le16_to_cpu(payload->vmid) != ghvm->vmid)
+		return NOTIFY_OK;
+
+	/* All other state transitions are synchronous to a corresponding RM call */
+	if (payload->vm_status == GH_RM_VM_STATUS_RESET) {
+		down_write(&ghvm->status_lock);
+		ghvm->vm_status = payload->vm_status;
+		up_write(&ghvm->status_lock);
+		wake_up(&ghvm->vm_status_wait);
+	}
+
+	return NOTIFY_DONE;
+}
+
+static int gh_vm_rm_notification_exited(struct gh_vm *ghvm, void *data)
+{
+	struct gh_rm_vm_exited_payload *payload = data;
+
+	if (le16_to_cpu(payload->vmid) != ghvm->vmid)
+		return NOTIFY_OK;
+
+	down_write(&ghvm->status_lock);
+	ghvm->vm_status = GH_RM_VM_STATUS_EXITED;
+	up_write(&ghvm->status_lock);
+	wake_up(&ghvm->vm_status_wait);
+
+	return NOTIFY_DONE;
+}
+
+static int gh_vm_rm_notification(struct notifier_block *nb, unsigned long action, void *data)
+{
+	struct gh_vm *ghvm = container_of(nb, struct gh_vm, nb);
+
+	switch (action) {
+	case GH_RM_NOTIFICATION_VM_STATUS:
+		return gh_vm_rm_notification_status(ghvm, data);
+	case GH_RM_NOTIFICATION_VM_EXITED:
+		return gh_vm_rm_notification_exited(ghvm, data);
+	default:
+		return NOTIFY_OK;
+	}
+}
+
+static void gh_vm_stop(struct gh_vm *ghvm)
+{
+	int ret;
+
+	down_write(&ghvm->status_lock);
+	if (ghvm->vm_status == GH_RM_VM_STATUS_RUNNING) {
+		ret = gh_rm_vm_stop(ghvm->rm, ghvm->vmid);
+		if (ret)
+			dev_warn(ghvm->parent, "Failed to stop VM: %d\n", ret);
+	}
+	up_write(&ghvm->status_lock);
+
+	wait_event(ghvm->vm_status_wait, ghvm->vm_status == GH_RM_VM_STATUS_EXITED);
+}
+
 static __must_check struct gh_vm *gh_vm_alloc(struct gh_rm *rm)
 {
 	struct gh_vm *ghvm;
@@ -26,17 +88,130 @@ static __must_check struct gh_vm *gh_vm_alloc(struct gh_rm *rm)
 		return ERR_PTR(-ENOMEM);
 
 	ghvm->parent = gh_rm_get(rm);
+	ghvm->vmid = GH_VMID_INVAL;
 	ghvm->rm = rm;
 
 	mmgrab(current->mm);
 	ghvm->mm = current->mm;
 	mutex_init(&ghvm->mm_lock);
 	INIT_LIST_HEAD(&ghvm->memory_mappings);
+	init_rwsem(&ghvm->status_lock);
+	init_waitqueue_head(&ghvm->vm_status_wait);
 	INIT_WORK(&ghvm->free_work, gh_vm_free);
+	ghvm->vm_status = GH_RM_VM_STATUS_NO_STATE;
 
 	return ghvm;
 }
 
+static int gh_vm_start(struct gh_vm *ghvm)
+{
+	struct gh_vm_mem *mapping;
+	u64 dtb_offset;
+	u32 mem_handle;
+	int ret;
+
+	down_write(&ghvm->status_lock);
+	if (ghvm->vm_status != GH_RM_VM_STATUS_NO_STATE) {
+		up_write(&ghvm->status_lock);
+		return 0;
+	}
+
+	ghvm->nb.notifier_call = gh_vm_rm_notification;
+	ret = gh_rm_notifier_register(ghvm->rm, &ghvm->nb);
+	if (ret)
+		goto err;
+
+	ret = gh_rm_alloc_vmid(ghvm->rm, 0);
+	if (ret < 0) {
+		gh_rm_notifier_unregister(ghvm->rm, &ghvm->nb);
+		goto err;
+	}
+	ghvm->vmid = ret;
+	ghvm->vm_status = GH_RM_VM_STATUS_LOAD;
+
+	mutex_lock(&ghvm->mm_lock);
+	list_for_each_entry(mapping, &ghvm->memory_mappings, list) {
+		mapping->parcel.acl_entries[0].vmid = cpu_to_le16(ghvm->vmid);
+		ret = gh_rm_mem_share(ghvm->rm, &mapping->parcel);
+		if (ret) {
+			dev_warn(ghvm->parent, "Failed to share parcel %d: %d\n",
+				mapping->parcel.label, ret);
+			mutex_unlock(&ghvm->mm_lock);
+			goto err;
+		}
+	}
+	mutex_unlock(&ghvm->mm_lock);
+
+	mapping = gh_vm_mem_find_by_addr(ghvm, ghvm->dtb_config.guest_phys_addr,
+					ghvm->dtb_config.size);
+	if (!mapping) {
+		dev_warn(ghvm->parent, "Failed to find the memory_handle for DTB\n");
+		ret = -EINVAL;
+		goto err;
+	}
+
+	mem_handle = mapping->parcel.mem_handle;
+	dtb_offset = ghvm->dtb_config.guest_phys_addr - mapping->guest_phys_addr;
+
+	ret = gh_rm_vm_configure(ghvm->rm, ghvm->vmid, ghvm->auth, mem_handle,
+				0, 0, dtb_offset, ghvm->dtb_config.size);
+	if (ret) {
+		dev_warn(ghvm->parent, "Failed to configure VM: %d\n", ret);
+		goto err;
+	}
+
+	ret = gh_rm_vm_init(ghvm->rm, ghvm->vmid);
+	if (ret) {
+		ghvm->vm_status = GH_RM_VM_STATUS_INIT_FAILED;
+		dev_warn(ghvm->parent, "Failed to initialize VM: %d\n", ret);
+		goto err;
+	}
+	ghvm->vm_status = GH_RM_VM_STATUS_READY;
+
+	ret = gh_rm_vm_start(ghvm->rm, ghvm->vmid);
+	if (ret) {
+		dev_warn(ghvm->parent, "Failed to start VM: %d\n", ret);
+		goto err;
+	}
+
+	ghvm->vm_status = GH_RM_VM_STATUS_RUNNING;
+	up_write(&ghvm->status_lock);
+	return ret;
+err:
+	/* gh_vm_free will handle releasing resources and reclaiming memory */
+	up_write(&ghvm->status_lock);
+	return ret;
+}
+
+static int gh_vm_ensure_started(struct gh_vm *ghvm)
+{
+	int ret;
+
+	ret = down_read_interruptible(&ghvm->status_lock);
+	if (ret)
+		return ret;
+
+	/* Unlikely because VM is typically started */
+	if (unlikely(ghvm->vm_status == GH_RM_VM_STATUS_NO_STATE)) {
+		up_read(&ghvm->status_lock);
+		ret = gh_vm_start(ghvm);
+		if (ret)
+			return ret;
+		/** gh_vm_start() is guaranteed to bring status out of
+		 * GH_RM_VM_STATUS_LOAD, thus infinitely recursive call is not
+		 * possible
+		 */
+		return gh_vm_ensure_started(ghvm);
+	}
+
+	/* Unlikely because VM is typically running */
+	if (unlikely(ghvm->vm_status != GH_RM_VM_STATUS_RUNNING))
+		ret = -ENODEV;
+
+	up_read(&ghvm->status_lock);
+	return ret;
+}
+
 static long gh_vm_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 {
 	struct gh_vm *ghvm = filp->private_data;
@@ -61,6 +236,24 @@ static long gh_vm_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 		r = gh_vm_mem_alloc(ghvm, &region);
 		break;
 	}
+	case GH_VM_SET_DTB_CONFIG: {
+		struct gh_vm_dtb_config dtb_config;
+
+		if (copy_from_user(&dtb_config, argp, sizeof(dtb_config)))
+			return -EFAULT;
+
+		if (overflows_type(dtb_config.guest_phys_addr + dtb_config.size, u64))
+			return -EOVERFLOW;
+
+		ghvm->dtb_config = dtb_config;
+
+		r = 0;
+		break;
+	}
+	case GH_VM_START: {
+		r = gh_vm_ensure_started(ghvm);
+		break;
+	}
 	default:
 		r = -ENOTTY;
 		break;
@@ -72,8 +265,30 @@ static long gh_vm_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 static void gh_vm_free(struct work_struct *work)
 {
 	struct gh_vm *ghvm = container_of(work, struct gh_vm, free_work);
+	int ret;
+
+	if (ghvm->vm_status == GH_RM_VM_STATUS_RUNNING)
+		gh_vm_stop(ghvm);
+
+	if (ghvm->vm_status != GH_RM_VM_STATUS_NO_STATE &&
+	    ghvm->vm_status != GH_RM_VM_STATUS_LOAD &&
+	    ghvm->vm_status != GH_RM_VM_STATUS_RESET) {
+		ret = gh_rm_vm_reset(ghvm->rm, ghvm->vmid);
+		if (ret)
+			dev_err(ghvm->parent, "Failed to reset the vm: %d\n", ret);
+		wait_event(ghvm->vm_status_wait, ghvm->vm_status == GH_RM_VM_STATUS_RESET);
+	}
 
 	gh_vm_mem_reclaim(ghvm);
+
+	if (ghvm->vm_status > GH_RM_VM_STATUS_NO_STATE) {
+		gh_rm_notifier_unregister(ghvm->rm, &ghvm->nb);
+
+		ret = gh_rm_dealloc_vmid(ghvm->rm, ghvm->vmid);
+		if (ret)
+			dev_warn(ghvm->parent, "Failed to deallocate vmid: %d\n", ret);
+	}
+
 	gh_rm_put(ghvm->rm);
 	mmdrop(ghvm->mm);
 	kfree(ghvm);
diff --git a/drivers/virt/gunyah/vm_mgr.h b/drivers/virt/gunyah/vm_mgr.h
index 434ef9f662a7a..4173bd51f83fe 100644
--- a/drivers/virt/gunyah/vm_mgr.h
+++ b/drivers/virt/gunyah/vm_mgr.h
@@ -10,6 +10,8 @@
 #include <linux/list.h>
 #include <linux/miscdevice.h>
 #include <linux/mutex.h>
+#include <linux/rwsem.h>
+#include <linux/wait.h>
 
 #include <uapi/linux/gunyah.h>
 
@@ -31,8 +33,16 @@ struct gh_vm_mem {
 };
 
 struct gh_vm {
+	u16 vmid;
 	struct gh_rm *rm;
 	struct device *parent;
+	enum gh_rm_vm_auth_mechanism auth;
+	struct gh_vm_dtb_config dtb_config;
+
+	struct notifier_block nb;
+	enum gh_rm_vm_status vm_status;
+	wait_queue_head_t vm_status_wait;
+	struct rw_semaphore status_lock;
 
 	struct work_struct free_work;
 	struct mm_struct *mm; /* userspace tied to this vm */
@@ -42,5 +52,6 @@ struct gh_vm {
 
 int gh_vm_mem_alloc(struct gh_vm *ghvm, struct gh_userspace_memory_region *region);
 void gh_vm_mem_reclaim(struct gh_vm *ghvm);
+struct gh_vm_mem *gh_vm_mem_find_by_addr(struct gh_vm *ghvm, u64 guest_phys_addr, u32 size);
 
 #endif
diff --git a/drivers/virt/gunyah/vm_mgr_mm.c b/drivers/virt/gunyah/vm_mgr_mm.c
index 6974607f02edd..f8a09e86d6bc1 100644
--- a/drivers/virt/gunyah/vm_mgr_mm.c
+++ b/drivers/virt/gunyah/vm_mgr_mm.c
@@ -75,6 +75,26 @@ void gh_vm_mem_reclaim(struct gh_vm *ghvm)
 	mutex_unlock(&ghvm->mm_lock);
 }
 
+struct gh_vm_mem *gh_vm_mem_find_by_addr(struct gh_vm *ghvm, u64 guest_phys_addr, u32 size)
+{
+	struct gh_vm_mem *mapping;
+
+	if (overflows_type(guest_phys_addr + size, u64))
+		return NULL;
+
+	mutex_lock(&ghvm->mm_lock);
+
+	list_for_each_entry(mapping, &ghvm->memory_mappings, list) {
+		if (gh_vm_mem_overlap(mapping, guest_phys_addr, size))
+			goto unlock;
+	}
+
+	mapping = NULL;
+unlock:
+	mutex_unlock(&ghvm->mm_lock);
+	return mapping;
+}
+
 int gh_vm_mem_alloc(struct gh_vm *ghvm, struct gh_userspace_memory_region *region)
 {
 	struct gh_vm_mem *mapping, *tmp_mapping;
diff --git a/include/uapi/linux/gunyah.h b/include/uapi/linux/gunyah.h
index 91d6dd26fcc89..4b63d0b9b8ba7 100644
--- a/include/uapi/linux/gunyah.h
+++ b/include/uapi/linux/gunyah.h
@@ -57,4 +57,19 @@ struct gh_userspace_memory_region {
 #define GH_VM_SET_USER_MEM_REGION	_IOW(GH_IOCTL_TYPE, 0x1, \
 						struct gh_userspace_memory_region)
 
+/**
+ * struct gh_vm_dtb_config - Set the location of the VM's devicetree blob
+ * @guest_phys_addr: Address of the VM's devicetree in guest memory.
+ * @size: Maximum size of the devicetree including space for overlays.
+ *        Resource manager applies an overlay to the DTB and dtb_size should
+ *        include room for the overlay. A page of memory is typicaly plenty.
+ */
+struct gh_vm_dtb_config {
+	__u64 guest_phys_addr;
+	__u64 size;
+};
+#define GH_VM_SET_DTB_CONFIG	_IOW(GH_IOCTL_TYPE, 0x2, struct gh_vm_dtb_config)
+
+#define GH_VM_START		_IO(GH_IOCTL_TYPE, 0x3)
+
 #endif
-- 
2.40.0

[PATCH v14 13/25] samples: Add sample userspace Gunyah VM Manager

[Elliot Berman]

Add a sample Gunyah VMM capable of launching a non-proxy scheduled VM.

Reviewed-by: Alex Elder <elder@linaro.org>
Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
---
 samples/Kconfig              |  10 ++
 samples/Makefile             |   1 +
 samples/gunyah/.gitignore    |   2 +
 samples/gunyah/Makefile      |   6 +
 samples/gunyah/gunyah_vmm.c  | 266 +++++++++++++++++++++++++++++++++++
 samples/gunyah/sample_vm.dts |  68 +++++++++
 6 files changed, 353 insertions(+)
 create mode 100644 samples/gunyah/.gitignore
 create mode 100644 samples/gunyah/Makefile
 create mode 100644 samples/gunyah/gunyah_vmm.c
 create mode 100644 samples/gunyah/sample_vm.dts

diff --git a/samples/Kconfig b/samples/Kconfig
index b2db430bd3ff3..567c7a706c010 100644
--- a/samples/Kconfig
+++ b/samples/Kconfig
@@ -280,6 +280,16 @@ config SAMPLE_KMEMLEAK
           Build a sample program which have explicitly leaks memory to test
           kmemleak
 
+config SAMPLE_GUNYAH
+	bool "Build example Gunyah Virtual Machine Manager"
+	depends on CC_CAN_LINK && HEADERS_INSTALL
+	depends on GUNYAH
+	help
+	  Build an example Gunyah VMM userspace program capable of launching
+	  a basic virtual machine under the Gunyah hypervisor.
+	  This demonstrates how to create a virtual machine under the Gunyah
+	  hypervisor.
+
 source "samples/rust/Kconfig"
 
 endif # SAMPLES
diff --git a/samples/Makefile b/samples/Makefile
index 7727f1a0d6d15..e1b92dec169f3 100644
--- a/samples/Makefile
+++ b/samples/Makefile
@@ -37,3 +37,4 @@ obj-$(CONFIG_SAMPLE_KMEMLEAK)		+= kmemleak/
 obj-$(CONFIG_SAMPLE_CORESIGHT_SYSCFG)	+= coresight/
 obj-$(CONFIG_SAMPLE_FPROBE)		+= fprobe/
 obj-$(CONFIG_SAMPLES_RUST)		+= rust/
+obj-$(CONFIG_SAMPLE_GUNYAH)		+= gunyah/
diff --git a/samples/gunyah/.gitignore b/samples/gunyah/.gitignore
new file mode 100644
index 0000000000000..adc7d1589fde6
--- /dev/null
+++ b/samples/gunyah/.gitignore
@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0
+/gunyah_vmm
diff --git a/samples/gunyah/Makefile b/samples/gunyah/Makefile
new file mode 100644
index 0000000000000..faf14f9bb3374
--- /dev/null
+++ b/samples/gunyah/Makefile
@@ -0,0 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+userprogs-always-y += gunyah_vmm
+dtb-y += sample_vm.dtb
+
+userccflags += -I usr/include
diff --git a/samples/gunyah/gunyah_vmm.c b/samples/gunyah/gunyah_vmm.c
new file mode 100644
index 0000000000000..6f636ac227c69
--- /dev/null
+++ b/samples/gunyah/gunyah_vmm.c
@@ -0,0 +1,266 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <sys/ioctl.h>
+#include <getopt.h>
+#include <limits.h>
+#include <stdint.h>
+#include <fcntl.h>
+#include <string.h>
+#include <sys/sysmacros.h>
+#define __USE_GNU
+#include <sys/mman.h>
+
+#include <linux/gunyah.h>
+
+#define DEFAULT_GUEST_BASE	0x80000000
+#define DEFAULT_GUEST_SIZE	0x6400000 /* 100 MiB */
+#define DEFAULT_DTB_OFFSET	0x45f0000 /* 70MiB - 64 KiB */
+#define DEFAULT_RAMDISK_OFFSET	0x4600000 /* 70MiB */
+
+struct vm_config {
+	int image_fd;
+	int dtb_fd;
+	int ramdisk_fd;
+
+	uint64_t guest_base;
+	uint64_t guest_size;
+
+	off_t image_size;
+	uint64_t dtb_offset;
+	off_t dtb_size;
+	uint64_t ramdisk_offset;
+	off_t ramdisk_size;
+};
+
+static struct option options[] = {
+	{ "help", no_argument, NULL, 'h' },
+	{ "image", required_argument, NULL, 'i' },
+	{ "dtb", required_argument, NULL, 'd' },
+	{ "ramdisk", optional_argument, NULL, 'r' },
+	{ "base", optional_argument, NULL, 'B' },
+	{ "size", optional_argument, NULL, 'S' },
+	{ "dtb_offset", optional_argument, NULL, 'D' },
+	{ "ramdisk_offset", optional_argument, NULL, 'R' },
+	{ }
+};
+
+static void print_help(char *cmd)
+{
+	printf("gunyah_vmm, a sample tool to launch Gunyah VMs\n"
+	       "Usage: %s <options>\n"
+	       "       --help,    -h  this menu\n"
+	       "       --image,   -i <image> VM image file to load (e.g. a kernel Image) [Required]\n"
+	       "       --dtb,     -d <dtb>   Devicetree file to load [Required]\n"
+	       "       --ramdisk, -r <ramdisk>  Ramdisk file to load\n"
+	       "       --base,    -B <address>  Set the base address of guest's memory [Default: 0x%08x]\n"
+	       "       --size,    -S <number>   The number of bytes large to make the guest's memory [Default: 0x%08x]\n"
+	       "        --dtb_offset,  -D <number>  Offset into guest memory to load the DTB [Default: 0x%08x]\n"
+	       "        --ramdisk_offset, -R <number>  Offset into guest memory to load a ramdisk [Default: 0x%08x]\n"
+	       , cmd, DEFAULT_GUEST_BASE, DEFAULT_GUEST_SIZE,
+	       DEFAULT_DTB_OFFSET, DEFAULT_RAMDISK_OFFSET);
+}
+
+int main(int argc, char **argv)
+{
+	int gunyah_fd, vm_fd, guest_fd;
+	struct gh_userspace_memory_region guest_mem_desc = { 0 };
+	struct gh_vm_dtb_config dtb_config = { 0 };
+	char *guest_mem;
+	struct vm_config config = {
+		/* Defaults good enough to boot static kernel and a basic ramdisk */
+		.image_fd = -1,
+		.dtb_fd = -1,
+		.ramdisk_fd = -1,
+		.guest_base = DEFAULT_GUEST_BASE,
+		.guest_size = DEFAULT_GUEST_SIZE,
+		.dtb_offset = DEFAULT_DTB_OFFSET,
+		.ramdisk_offset = DEFAULT_RAMDISK_OFFSET,
+	};
+	struct stat st;
+	int opt, optidx, ret = 0;
+	long l;
+
+	while ((opt = getopt_long(argc, argv, "hi:d:r:B:S:D:R:c:", options, &optidx)) != -1) {
+		switch (opt) {
+		case 'i':
+			config.image_fd = open(optarg, O_RDONLY | O_CLOEXEC);
+			if (config.image_fd < 0) {
+				perror("Failed to open image");
+				return -1;
+			}
+			if (stat(optarg, &st) < 0) {
+				perror("Failed to stat image");
+				return -1;
+			}
+			config.image_size = st.st_size;
+			break;
+		case 'd':
+			config.dtb_fd = open(optarg, O_RDONLY | O_CLOEXEC);
+			if (config.dtb_fd < 0) {
+				perror("Failed to open dtb");
+				return -1;
+			}
+			if (stat(optarg, &st) < 0) {
+				perror("Failed to stat dtb");
+				return -1;
+			}
+			config.dtb_size = st.st_size;
+			break;
+		case 'r':
+			config.ramdisk_fd = open(optarg, O_RDONLY | O_CLOEXEC);
+			if (config.ramdisk_fd < 0) {
+				perror("Failed to open ramdisk");
+				return -1;
+			}
+			if (stat(optarg, &st) < 0) {
+				perror("Failed to stat ramdisk");
+				return -1;
+			}
+			config.ramdisk_size = st.st_size;
+			break;
+		case 'B':
+			l = strtol(optarg, NULL, 0);
+			if (l == LONG_MIN) {
+				perror("Failed to parse base address");
+				return -1;
+			}
+			config.guest_base = l;
+			break;
+		case 'S':
+			l = strtol(optarg, NULL, 0);
+			if (l == LONG_MIN) {
+				perror("Failed to parse memory size");
+				return -1;
+			}
+			config.guest_size = l;
+			break;
+		case 'D':
+			l = strtol(optarg, NULL, 0);
+			if (l == LONG_MIN) {
+				perror("Failed to parse dtb offset");
+				return -1;
+			}
+			config.dtb_offset = l;
+			break;
+		case 'R':
+			l = strtol(optarg, NULL, 0);
+			if (l == LONG_MIN) {
+				perror("Failed to parse ramdisk offset");
+				return -1;
+			}
+			config.ramdisk_offset = l;
+			break;
+		case 'h':
+			print_help(argv[0]);
+			return 0;
+		default:
+			print_help(argv[0]);
+			return -1;
+		}
+	}
+
+	if (config.image_fd == -1 || config.dtb_fd == -1) {
+		print_help(argv[0]);
+		return -1;
+	}
+
+	if (config.image_size > config.guest_size) {
+		fprintf(stderr, "Image size puts it outside guest memory. Make image smaller or increase guest memory size.\n");
+		return -1;
+	}
+
+	if (config.dtb_offset + config.dtb_size > config.guest_size) {
+		fprintf(stderr, "DTB offset and size puts it outside guest memory. Make dtb smaller or increase guest memory size.\n");
+		return -1;
+	}
+
+	if (config.ramdisk_fd == -1 &&
+		config.ramdisk_offset + config.ramdisk_size > config.guest_size) {
+		fprintf(stderr, "Ramdisk offset and size puts it outside guest memory. Make ramdisk smaller or increase guest memory size.\n");
+		return -1;
+	}
+
+	gunyah_fd = open("/dev/gunyah", O_RDWR | O_CLOEXEC);
+	if (gunyah_fd < 0) {
+		perror("Failed to open /dev/gunyah");
+		return -1;
+	}
+
+	vm_fd = ioctl(gunyah_fd, GH_CREATE_VM, 0);
+	if (vm_fd < 0) {
+		perror("Failed to create vm");
+		return -1;
+	}
+
+	guest_fd = memfd_create("guest_memory", MFD_CLOEXEC);
+	if (guest_fd < 0) {
+		perror("Failed to create guest memfd");
+		return -1;
+	}
+
+	if (ftruncate(guest_fd, config.guest_size) < 0) {
+		perror("Failed to grow guest memory");
+		return -1;
+	}
+
+	guest_mem = mmap(NULL, config.guest_size, PROT_READ | PROT_WRITE, MAP_SHARED, guest_fd, 0);
+	if (guest_mem == MAP_FAILED) {
+		perror("Not enough memory");
+		return -1;
+	}
+
+	if (read(config.image_fd, guest_mem, config.image_size) < 0) {
+		perror("Failed to read image into guest memory");
+		return -1;
+	}
+
+	if (read(config.dtb_fd, guest_mem + config.dtb_offset, config.dtb_size) < 0) {
+		perror("Failed to read dtb into guest memory");
+		return -1;
+	}
+
+	if (config.ramdisk_fd > 0 &&
+		read(config.ramdisk_fd, guest_mem + config.ramdisk_offset,
+			config.ramdisk_size) < 0) {
+		perror("Failed to read ramdisk into guest memory");
+		return -1;
+	}
+
+	guest_mem_desc.label = 0;
+	guest_mem_desc.flags = GH_MEM_ALLOW_READ | GH_MEM_ALLOW_WRITE | GH_MEM_ALLOW_EXEC;
+	guest_mem_desc.guest_phys_addr = config.guest_base;
+	guest_mem_desc.memory_size = config.guest_size;
+	guest_mem_desc.userspace_addr = (__u64)guest_mem;
+
+	if (ioctl(vm_fd, GH_VM_SET_USER_MEM_REGION, &guest_mem_desc) < 0) {
+		perror("Failed to register guest memory with VM");
+		return -1;
+	}
+
+	dtb_config.guest_phys_addr = config.guest_base + config.dtb_offset;
+	dtb_config.size = config.dtb_size;
+	if (ioctl(vm_fd, GH_VM_SET_DTB_CONFIG, &dtb_config) < 0) {
+		perror("Failed to set DTB configuration for VM");
+		return -1;
+	}
+
+	ret = ioctl(vm_fd, GH_VM_START);
+	if (ret) {
+		perror("GH_VM_START failed");
+		return -1;
+	}
+
+	while (1)
+		pause();
+
+	return 0;
+}
diff --git a/samples/gunyah/sample_vm.dts b/samples/gunyah/sample_vm.dts
new file mode 100644
index 0000000000000..293bbc0469c8f
--- /dev/null
+++ b/samples/gunyah/sample_vm.dts
@@ -0,0 +1,68 @@
+// SPDX-License-Identifier: BSD-3-Clause
+/*
+ * Copyright (c) 2022 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+/dts-v1/;
+
+/ {
+	#address-cells = <2>;
+	#size-cells = <2>;
+	interrupt-parent = <&intc>;
+
+	chosen {
+		bootargs = "nokaslr";
+	};
+
+	cpus {
+		#address-cells = <0x2>;
+		#size-cells = <0>;
+
+		cpu@0 {
+			device_type = "cpu";
+			compatible = "arm,armv8";
+			reg = <0 0>;
+		};
+	};
+
+	intc: interrupt-controller@3FFF0000 {
+		compatible = "arm,gic-v3";
+		#interrupt-cells = <3>;
+		#address-cells = <2>;
+		#size-cells = <2>;
+		interrupt-controller;
+		reg = <0 0x3FFF0000 0 0x10000>,
+		      <0 0x3FFD0000 0 0x20000>;
+	};
+
+	timer {
+		compatible = "arm,armv8-timer";
+		always-on;
+		interrupts = <1 13 0x108>,
+			     <1 14 0x108>,
+			     <1 11 0x108>,
+			     <1 10 0x108>;
+		clock-frequency = <19200000>;
+	};
+
+	gunyah-vm-config {
+		image-name = "linux_vm_0";
+
+		memory {
+			#address-cells = <2>;
+			#size-cells = <2>;
+
+			base-address = <0 0x80000000>;
+		};
+
+		interrupts {
+			config = <&intc>;
+		};
+
+		vcpus {
+			affinity-map = < 0 >;
+			sched-priority = < (-1) >;
+			sched-timeslice = < 2000 >;
+		};
+	};
+};
-- 
2.40.0

[PATCH v14 14/25] gunyah: rsc_mgr: Add platform ops on mem_lend/mem_reclaim

[Elliot Berman]

On Qualcomm platforms, there is a firmware entity which controls access
to physical pages. In order to share memory with another VM, this entity
needs to be informed that the guest VM should have access to the memory.

Reviewed-by: Alex Elder <elder@linaro.org>
Co-developed-by: Prakruthi Deepak Heragu <quic_pheragu@quicinc.com>
Signed-off-by: Prakruthi Deepak Heragu <quic_pheragu@quicinc.com>
Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
---
 drivers/virt/gunyah/Kconfig                 |  4 ++
 drivers/virt/gunyah/Makefile                |  2 +
 drivers/virt/gunyah/gunyah_platform_hooks.c | 80 +++++++++++++++++++++
 drivers/virt/gunyah/rsc_mgr.h               |  3 +
 drivers/virt/gunyah/rsc_mgr_rpc.c           | 18 ++++-
 include/linux/gunyah_rsc_mgr.h              | 17 +++++
 6 files changed, 122 insertions(+), 2 deletions(-)
 create mode 100644 drivers/virt/gunyah/gunyah_platform_hooks.c

diff --git a/drivers/virt/gunyah/Kconfig b/drivers/virt/gunyah/Kconfig
index 1a737694c333d..de815189dab6c 100644
--- a/drivers/virt/gunyah/Kconfig
+++ b/drivers/virt/gunyah/Kconfig
@@ -4,6 +4,7 @@ config GUNYAH
 	tristate "Gunyah Virtualization drivers"
 	depends on ARM64
 	depends on MAILBOX
+	select GUNYAH_PLATFORM_HOOKS
 	help
 	  The Gunyah drivers are the helper interfaces that run in a guest VM
 	  such as basic inter-VM IPC and signaling mechanisms, and higher level
@@ -11,3 +12,6 @@ config GUNYAH
 
 	  Say Y/M here to enable the drivers needed to interact in a Gunyah
 	  virtual environment.
+
+config GUNYAH_PLATFORM_HOOKS
+	tristate
diff --git a/drivers/virt/gunyah/Makefile b/drivers/virt/gunyah/Makefile
index bacf78b8fa337..4fbeee521d60a 100644
--- a/drivers/virt/gunyah/Makefile
+++ b/drivers/virt/gunyah/Makefile
@@ -1,4 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0
 
+obj-$(CONFIG_GUNYAH_PLATFORM_HOOKS) += gunyah_platform_hooks.o
+
 gunyah-y += rsc_mgr.o rsc_mgr_rpc.o vm_mgr.o vm_mgr_mm.o
 obj-$(CONFIG_GUNYAH) += gunyah.o
diff --git a/drivers/virt/gunyah/gunyah_platform_hooks.c b/drivers/virt/gunyah/gunyah_platform_hooks.c
new file mode 100644
index 0000000000000..905515b4589e3
--- /dev/null
+++ b/drivers/virt/gunyah/gunyah_platform_hooks.c
@@ -0,0 +1,80 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#include <linux/module.h>
+#include <linux/rwsem.h>
+#include <linux/gunyah_rsc_mgr.h>
+
+#include "rsc_mgr.h"
+
+static const struct gh_rm_platform_ops *rm_platform_ops;
+static DECLARE_RWSEM(rm_platform_ops_lock);
+
+int gh_rm_platform_pre_mem_share(struct gh_rm *rm, struct gh_rm_mem_parcel *mem_parcel)
+{
+	int ret = 0;
+
+	down_read(&rm_platform_ops_lock);
+	if (rm_platform_ops && rm_platform_ops->pre_mem_share)
+		ret = rm_platform_ops->pre_mem_share(rm, mem_parcel);
+	up_read(&rm_platform_ops_lock);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(gh_rm_platform_pre_mem_share);
+
+int gh_rm_platform_post_mem_reclaim(struct gh_rm *rm, struct gh_rm_mem_parcel *mem_parcel)
+{
+	int ret = 0;
+
+	down_read(&rm_platform_ops_lock);
+	if (rm_platform_ops && rm_platform_ops->post_mem_reclaim)
+		ret = rm_platform_ops->post_mem_reclaim(rm, mem_parcel);
+	up_read(&rm_platform_ops_lock);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(gh_rm_platform_post_mem_reclaim);
+
+int gh_rm_register_platform_ops(const struct gh_rm_platform_ops *platform_ops)
+{
+	int ret = 0;
+
+	down_write(&rm_platform_ops_lock);
+	if (!rm_platform_ops)
+		rm_platform_ops = platform_ops;
+	else
+		ret = -EEXIST;
+	up_write(&rm_platform_ops_lock);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(gh_rm_register_platform_ops);
+
+void gh_rm_unregister_platform_ops(const struct gh_rm_platform_ops *platform_ops)
+{
+	down_write(&rm_platform_ops_lock);
+	if (rm_platform_ops == platform_ops)
+		rm_platform_ops = NULL;
+	up_write(&rm_platform_ops_lock);
+}
+EXPORT_SYMBOL_GPL(gh_rm_unregister_platform_ops);
+
+static void _devm_gh_rm_unregister_platform_ops(void *data)
+{
+	gh_rm_unregister_platform_ops((const struct gh_rm_platform_ops *)data);
+}
+
+int devm_gh_rm_register_platform_ops(struct device *dev, const struct gh_rm_platform_ops *ops)
+{
+	int ret;
+
+	ret = gh_rm_register_platform_ops(ops);
+	if (ret)
+		return ret;
+
+	return devm_add_action(dev, _devm_gh_rm_unregister_platform_ops, (void *)ops);
+}
+EXPORT_SYMBOL_GPL(devm_gh_rm_register_platform_ops);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Gunyah Platform Hooks");
diff --git a/drivers/virt/gunyah/rsc_mgr.h b/drivers/virt/gunyah/rsc_mgr.h
index 8309b7bf46683..3d43bb79ff447 100644
--- a/drivers/virt/gunyah/rsc_mgr.h
+++ b/drivers/virt/gunyah/rsc_mgr.h
@@ -13,4 +13,7 @@ struct gh_rm;
 int gh_rm_call(struct gh_rm *rsc_mgr, u32 message_id, const void *req_buf, size_t req_buf_size,
 		void **resp_buf, size_t *resp_buf_size);
 
+int gh_rm_platform_pre_mem_share(struct gh_rm *rm, struct gh_rm_mem_parcel *mem_parcel);
+int gh_rm_platform_post_mem_reclaim(struct gh_rm *rm, struct gh_rm_mem_parcel *mem_parcel);
+
 #endif
diff --git a/drivers/virt/gunyah/rsc_mgr_rpc.c b/drivers/virt/gunyah/rsc_mgr_rpc.c
index 25064123a31c3..d0548db1500c2 100644
--- a/drivers/virt/gunyah/rsc_mgr_rpc.c
+++ b/drivers/virt/gunyah/rsc_mgr_rpc.c
@@ -207,6 +207,12 @@ static int gh_rm_mem_lend_common(struct gh_rm *rm, u32 message_id, struct gh_rm_
 	if (!msg)
 		return -ENOMEM;
 
+	ret = gh_rm_platform_pre_mem_share(rm, p);
+	if (ret) {
+		kfree(msg);
+		return ret;
+	}
+
 	req_header = msg;
 	acl_section = (void *)req_header + sizeof(*req_header);
 	mem_section = (void *)acl_section + acl_section_size;
@@ -231,8 +237,10 @@ static int gh_rm_mem_lend_common(struct gh_rm *rm, u32 message_id, struct gh_rm_
 	ret = gh_rm_call(rm, message_id, msg, msg_size, (void **)&resp, &resp_size);
 	kfree(msg);
 
-	if (ret)
+	if (ret) {
+		gh_rm_platform_post_mem_reclaim(rm, p);
 		return ret;
+	}
 
 	p->mem_handle = le32_to_cpu(*resp);
 	kfree(resp);
@@ -287,8 +295,14 @@ int gh_rm_mem_reclaim(struct gh_rm *rm, struct gh_rm_mem_parcel *parcel)
 	struct gh_rm_mem_release_req req = {
 		.mem_handle = cpu_to_le32(parcel->mem_handle),
 	};
+	int ret;
+
+	ret = gh_rm_call(rm, GH_RM_RPC_MEM_RECLAIM, &req, sizeof(req), NULL, NULL);
+	/* Only call the platform mem reclaim hooks if we reclaimed the memory */
+	if (ret)
+		return ret;
 
-	return gh_rm_call(rm, GH_RM_RPC_MEM_RECLAIM, &req, sizeof(req), NULL, NULL);
+	return gh_rm_platform_post_mem_reclaim(rm, parcel);
 }
 
 /**
diff --git a/include/linux/gunyah_rsc_mgr.h b/include/linux/gunyah_rsc_mgr.h
index dfac088420bda..cac4476b46ade 100644
--- a/include/linux/gunyah_rsc_mgr.h
+++ b/include/linux/gunyah_rsc_mgr.h
@@ -139,4 +139,21 @@ int gh_rm_get_hyp_resources(struct gh_rm *rm, u16 vmid,
 				struct gh_rm_hyp_resources **resources);
 int gh_rm_get_vmid(struct gh_rm *rm, u16 *vmid);
 
+struct gh_rm_platform_ops {
+	int (*pre_mem_share)(struct gh_rm *rm, struct gh_rm_mem_parcel *mem_parcel);
+	int (*post_mem_reclaim)(struct gh_rm *rm, struct gh_rm_mem_parcel *mem_parcel);
+};
+
+#if IS_ENABLED(CONFIG_GUNYAH_PLATFORM_HOOKS)
+int gh_rm_register_platform_ops(const struct gh_rm_platform_ops *platform_ops);
+void gh_rm_unregister_platform_ops(const struct gh_rm_platform_ops *platform_ops);
+int devm_gh_rm_register_platform_ops(struct device *dev, const struct gh_rm_platform_ops *ops);
+#else
+static inline int gh_rm_register_platform_ops(const struct gh_rm_platform_ops *platform_ops)
+	{ return 0; }
+static inline void gh_rm_unregister_platform_ops(const struct gh_rm_platform_ops *platform_ops) { }
+static inline int devm_gh_rm_register_platform_ops(struct device *dev,
+	const struct gh_rm_platform_ops *ops) { return 0; }
+#endif
+
 #endif
-- 
2.40.0

[PATCH v14 15/25] virt: gunyah: Add Qualcomm Gunyah platform ops

[Elliot Berman]

Qualcomm platforms have a firmware entity which performs access control
to physical pages. Dynamically started Gunyah virtual machines use the
QCOM_SCM_RM_MANAGED_VMID for access. Linux thus needs to assign access
to the memory used by guest VMs. Gunyah doesn't do this operation for us
since it is the current VM (typically VMID_HLOS) delegating the access
and not Gunyah itself. Use the Gunyah platform ops to achieve this so
that only Qualcomm platforms attempt to make the needed SCM calls.

Reviewed-by: Alex Elder <elder@linaro.org>
Co-developed-by: Prakruthi Deepak Heragu <quic_pheragu@quicinc.com>
Signed-off-by: Prakruthi Deepak Heragu <quic_pheragu@quicinc.com>
Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
---
 drivers/virt/gunyah/Kconfig       |  13 +++
 drivers/virt/gunyah/Makefile      |   1 +
 drivers/virt/gunyah/gunyah_qcom.c | 153 ++++++++++++++++++++++++++++++
 3 files changed, 167 insertions(+)
 create mode 100644 drivers/virt/gunyah/gunyah_qcom.c

diff --git a/drivers/virt/gunyah/Kconfig b/drivers/virt/gunyah/Kconfig
index de815189dab6c..0421b751aad4f 100644
--- a/drivers/virt/gunyah/Kconfig
+++ b/drivers/virt/gunyah/Kconfig
@@ -5,6 +5,7 @@ config GUNYAH
 	depends on ARM64
 	depends on MAILBOX
 	select GUNYAH_PLATFORM_HOOKS
+	imply GUNYAH_QCOM_PLATFORM if ARCH_QCOM
 	help
 	  The Gunyah drivers are the helper interfaces that run in a guest VM
 	  such as basic inter-VM IPC and signaling mechanisms, and higher level
@@ -15,3 +16,15 @@ config GUNYAH
 
 config GUNYAH_PLATFORM_HOOKS
 	tristate
+
+config GUNYAH_QCOM_PLATFORM
+	tristate "Support for Gunyah on Qualcomm platforms"
+	depends on GUNYAH
+	select GUNYAH_PLATFORM_HOOKS
+	select QCOM_SCM
+	help
+	  Enable support for interacting with Gunyah on Qualcomm
+	  platforms. Interaction with Qualcomm firmware requires
+	  extra platform-specific support.
+
+	  Say Y/M here to use Gunyah on Qualcomm platforms.
diff --git a/drivers/virt/gunyah/Makefile b/drivers/virt/gunyah/Makefile
index 4fbeee521d60a..2aa9ff038ed02 100644
--- a/drivers/virt/gunyah/Makefile
+++ b/drivers/virt/gunyah/Makefile
@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0
 
 obj-$(CONFIG_GUNYAH_PLATFORM_HOOKS) += gunyah_platform_hooks.o
+obj-$(CONFIG_GUNYAH_QCOM_PLATFORM) += gunyah_qcom.o
 
 gunyah-y += rsc_mgr.o rsc_mgr_rpc.o vm_mgr.o vm_mgr_mm.o
 obj-$(CONFIG_GUNYAH) += gunyah.o
diff --git a/drivers/virt/gunyah/gunyah_qcom.c b/drivers/virt/gunyah/gunyah_qcom.c
new file mode 100644
index 0000000000000..f06a598f2e1b3
--- /dev/null
+++ b/drivers/virt/gunyah/gunyah_qcom.c
@@ -0,0 +1,153 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2023 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#include <linux/arm-smccc.h>
+#include <linux/gunyah_rsc_mgr.h>
+#include <linux/module.h>
+#include <linux/firmware/qcom/qcom_scm.h>
+#include <linux/types.h>
+#include <linux/uuid.h>
+
+#define QCOM_SCM_RM_MANAGED_VMID	0x3A
+#define QCOM_SCM_MAX_MANAGED_VMID	0x3F
+
+static int qcom_scm_gh_rm_pre_mem_share(struct gh_rm *rm, struct gh_rm_mem_parcel *mem_parcel)
+{
+	struct qcom_scm_vmperm *new_perms;
+	u64 src, src_cpy;
+	int ret = 0, i, n;
+	u16 vmid;
+
+	new_perms = kcalloc(mem_parcel->n_acl_entries, sizeof(*new_perms), GFP_KERNEL);
+	if (!new_perms)
+		return -ENOMEM;
+
+	for (n = 0; n < mem_parcel->n_acl_entries; n++) {
+		vmid = le16_to_cpu(mem_parcel->acl_entries[n].vmid);
+		if (vmid <= QCOM_SCM_MAX_MANAGED_VMID)
+			new_perms[n].vmid = vmid;
+		else
+			new_perms[n].vmid = QCOM_SCM_RM_MANAGED_VMID;
+		if (mem_parcel->acl_entries[n].perms & GH_RM_ACL_X)
+			new_perms[n].perm |= QCOM_SCM_PERM_EXEC;
+		if (mem_parcel->acl_entries[n].perms & GH_RM_ACL_W)
+			new_perms[n].perm |= QCOM_SCM_PERM_WRITE;
+		if (mem_parcel->acl_entries[n].perms & GH_RM_ACL_R)
+			new_perms[n].perm |= QCOM_SCM_PERM_READ;
+	}
+
+	src = BIT_ULL(QCOM_SCM_VMID_HLOS);
+
+	for (i = 0; i < mem_parcel->n_mem_entries; i++) {
+		src_cpy = src;
+		ret = qcom_scm_assign_mem(le64_to_cpu(mem_parcel->mem_entries[i].phys_addr),
+						le64_to_cpu(mem_parcel->mem_entries[i].size),
+						&src_cpy, new_perms, mem_parcel->n_acl_entries);
+		if (ret)
+			break;
+	}
+
+	if (!ret)
+		goto out;
+
+	src = 0;
+	for (n = 0; n < mem_parcel->n_acl_entries; n++) {
+		vmid = le16_to_cpu(mem_parcel->acl_entries[n].vmid);
+		if (vmid <= QCOM_SCM_MAX_MANAGED_VMID)
+			src |= BIT_ULL(vmid);
+		else
+			src |= BIT_ULL(QCOM_SCM_RM_MANAGED_VMID);
+	}
+
+	new_perms[0].vmid = QCOM_SCM_VMID_HLOS;
+
+	for (i--; i >= 0; i--) {
+		src_cpy = src;
+		WARN_ON_ONCE(qcom_scm_assign_mem(
+				le64_to_cpu(mem_parcel->mem_entries[i].phys_addr),
+				le64_to_cpu(mem_parcel->mem_entries[i].size),
+				&src_cpy, new_perms, 1));
+	}
+
+out:
+	kfree(new_perms);
+	return ret;
+}
+
+static int qcom_scm_gh_rm_post_mem_reclaim(struct gh_rm *rm, struct gh_rm_mem_parcel *mem_parcel)
+{
+	struct qcom_scm_vmperm new_perms;
+	u64 src = 0, src_cpy;
+	int ret = 0, i, n;
+	u16 vmid;
+
+	new_perms.vmid = QCOM_SCM_VMID_HLOS;
+	new_perms.perm = QCOM_SCM_PERM_EXEC | QCOM_SCM_PERM_WRITE | QCOM_SCM_PERM_READ;
+
+	for (n = 0; n < mem_parcel->n_acl_entries; n++) {
+		vmid = le16_to_cpu(mem_parcel->acl_entries[n].vmid);
+		if (vmid <= QCOM_SCM_MAX_MANAGED_VMID)
+			src |= (1ull << vmid);
+		else
+			src |= (1ull << QCOM_SCM_RM_MANAGED_VMID);
+	}
+
+	for (i = 0; i < mem_parcel->n_mem_entries; i++) {
+		src_cpy = src;
+		ret = qcom_scm_assign_mem(le64_to_cpu(mem_parcel->mem_entries[i].phys_addr),
+						le64_to_cpu(mem_parcel->mem_entries[i].size),
+						&src_cpy, &new_perms, 1);
+		WARN_ON_ONCE(ret);
+	}
+
+	return ret;
+}
+
+static struct gh_rm_platform_ops qcom_scm_gh_rm_platform_ops = {
+	.pre_mem_share = qcom_scm_gh_rm_pre_mem_share,
+	.post_mem_reclaim = qcom_scm_gh_rm_post_mem_reclaim,
+};
+
+/* {19bd54bd-0b37-571b-946f-609b54539de6} */
+static const uuid_t QCOM_EXT_UUID =
+	UUID_INIT(0x19bd54bd, 0x0b37, 0x571b, 0x94, 0x6f, 0x60, 0x9b, 0x54, 0x53, 0x9d, 0xe6);
+
+#define GH_QCOM_EXT_CALL_UUID_ID	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, ARM_SMCCC_SMC_32, \
+							   ARM_SMCCC_OWNER_VENDOR_HYP, 0x3f01)
+
+static bool gh_has_qcom_extensions(void)
+{
+	struct arm_smccc_res res;
+	uuid_t uuid;
+	u32 *up;
+
+	arm_smccc_1_1_smc(GH_QCOM_EXT_CALL_UUID_ID, &res);
+
+	up = (u32 *)&uuid.b[0];
+	up[0] = lower_32_bits(res.a0);
+	up[1] = lower_32_bits(res.a1);
+	up[2] = lower_32_bits(res.a2);
+	up[3] = lower_32_bits(res.a3);
+
+	return uuid_equal(&uuid, &QCOM_EXT_UUID);
+}
+
+static int __init qcom_gh_platform_hooks_register(void)
+{
+	if (!gh_has_qcom_extensions())
+		return -ENODEV;
+
+	return gh_rm_register_platform_ops(&qcom_scm_gh_rm_platform_ops);
+}
+
+static void __exit qcom_gh_platform_hooks_unregister(void)
+{
+	gh_rm_unregister_platform_ops(&qcom_scm_gh_rm_platform_ops);
+}
+
+module_init(qcom_gh_platform_hooks_register);
+module_exit(qcom_gh_platform_hooks_unregister);
+MODULE_DESCRIPTION("Qualcomm Technologies, Inc. Platform Hooks for Gunyah");
+MODULE_LICENSE("GPL");
-- 
2.40.0

[PATCH v14 16/25] docs: gunyah: Document Gunyah VM Manager

[Elliot Berman]

Document the ioctls and usage of Gunyah VM Manager driver.

Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
---
 Documentation/virt/gunyah/index.rst      |  1 +
 Documentation/virt/gunyah/vm-manager.rst | 83 ++++++++++++++++++++++++
 2 files changed, 84 insertions(+)
 create mode 100644 Documentation/virt/gunyah/vm-manager.rst

diff --git a/Documentation/virt/gunyah/index.rst b/Documentation/virt/gunyah/index.rst
index 74aa345e0a144..7058249825b16 100644
--- a/Documentation/virt/gunyah/index.rst
+++ b/Documentation/virt/gunyah/index.rst
@@ -7,6 +7,7 @@ Gunyah Hypervisor
 .. toctree::
    :maxdepth: 1
 
+   vm-manager
    message-queue
 
 Gunyah is a Type-1 hypervisor which is independent of any OS kernel, and runs in
diff --git a/Documentation/virt/gunyah/vm-manager.rst b/Documentation/virt/gunyah/vm-manager.rst
new file mode 100644
index 0000000000000..df0e1a8279bf5
--- /dev/null
+++ b/Documentation/virt/gunyah/vm-manager.rst
@@ -0,0 +1,83 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+=======================
+Virtual Machine Manager
+=======================
+
+The Gunyah Virtual Machine Manager is a Linux driver to support launching
+virtual machines using Gunyah. It presently supports launching virtual machines
+scheduled by Gunyah's scheduler.
+
+Configuration of a Gunyah virtual machine is done via a devicetree. When the VM
+is launched, memory is provided by the host VM which contains the devictree.
+Gunyah reads the devicetree to configure the memory map and create resources
+such as vCPUs for the VM. Memory can be shared with the VM with
+`GH_VM_SET_USER_MEM_REGION`_. Userspace can interact with the resources in Linux
+by adding "functions" to the VM.
+
+Sample Userspace VMM
+====================
+
+A sample userspace VMM is included in samples/gunyah/ along with a minimal
+devicetree that can be used to launch a VM. To build this sample, enable
+CONFIG_SAMPLE_GUNYAH.
+
+IOCTLs and userspace VMM flows
+==============================
+
+The kernel exposes a char device interface at /dev/gunyah.
+
+To create a VM, use the `GH_CREATE_VM`_ ioctl. A successful call will return a
+"Gunyah VM" file descriptor.
+
+/dev/gunyah API Descriptions
+----------------------------
+
+GH_CREATE_VM
+~~~~~~~~~~~~
+
+Creates a Gunyah VM. The argument is reserved for future use and must be 0.
+A successful call will return a Gunyah VM file descriptor. See
+`Gunyah VM API Descriptions`_ for list of IOCTLs that can be made on this file
+file descriptor.
+
+Gunyah VM API Descriptions
+--------------------------
+
+GH_VM_SET_USER_MEM_REGION
+~~~~~~~~~~~~~~~~~~~~~~~~~
+
+This ioctl allows the user to create or delete a memory parcel for a guest
+virtual machine. Each memory region is uniquely identified by a label;
+attempting to create two regions with the same label is not allowed. Labels are
+unique per virtual machine.
+
+While VMM is guest-agnostic and allows runtime addition of memory regions,
+Linux guest virtual machines do not support accepting memory regions at runtime.
+Thus, for Linux guests, memory regions should be provided before starting the VM
+and the VM must be configured via the devicetree to accept these at boot-up.
+
+The guest physical address is used by Linux kernel to check that the requested
+user regions do not overlap and to help find the corresponding memory region
+for calls like `GH_VM_SET_DTB_CONFIG`_. It must be page aligned.
+
+To add a memory region, call `GH_VM_SET_USER_MEM_REGION`_ with fields set as
+described above.
+
+.. kernel-doc:: include/uapi/linux/gunyah.h
+   :identifiers: gh_userspace_memory_region gh_mem_flags
+
+GH_VM_SET_DTB_CONFIG
+~~~~~~~~~~~~~~~~~~~~
+
+This ioctl sets the location of the VM's devicetree blob and is used by Gunyah
+Resource Manager to allocate resources. The guest physical memory must be part
+of the primary memory parcel provided to the VM prior to GH_VM_START.
+
+.. kernel-doc:: include/uapi/linux/gunyah.h
+   :identifiers: gh_vm_dtb_config
+
+GH_VM_START
+~~~~~~~~~~~
+
+This ioctl starts the VM.
-- 
2.40.0

[PATCH v14 17/25] virt: gunyah: Translate gh_rm_hyp_resource into gunyah_resource

[Elliot Berman]

When booting a Gunyah virtual machine, the host VM may gain capabilities
to interact with resources for the guest virtual machine. Examples of
such resources are vCPUs or message queues. To use those resources, we
need to translate the RM response into a gunyah_resource structure which
are useful to Linux drivers. Presently, Linux drivers need only to know
the type of resource, the capability ID, and an interrupt.

On ARM64 systems, the interrupt reported by Gunyah is the GIC interrupt
ID number and always a SPI.

Reviewed-by: Alex Elder <elder@linaro.org>
Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
---
 arch/arm64/include/asm/gunyah.h |  24 +++++
 drivers/virt/gunyah/rsc_mgr.c   | 164 +++++++++++++++++++++++++++++++-
 include/linux/gunyah.h          |   3 +
 include/linux/gunyah_rsc_mgr.h  |   3 +
 4 files changed, 193 insertions(+), 1 deletion(-)
 create mode 100644 arch/arm64/include/asm/gunyah.h

diff --git a/arch/arm64/include/asm/gunyah.h b/arch/arm64/include/asm/gunyah.h
new file mode 100644
index 0000000000000..c83d983b0f4e0
--- /dev/null
+++ b/arch/arm64/include/asm/gunyah.h
@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+#ifndef _ASM_GUNYAH_H
+#define _ASM_GUNYAH_H
+
+#include <linux/irq.h>
+#include <dt-bindings/interrupt-controller/arm-gic.h>
+
+static inline int arch_gh_fill_irq_fwspec_params(u32 virq, struct irq_fwspec *fwspec)
+{
+	/* Assume that Gunyah gave us an SPI; defensively check it */
+	if (WARN_ON(virq < 32 || virq > 1019))
+		return -EINVAL;
+
+	fwspec->param_count = 3;
+	fwspec->param[0] = GIC_SPI;
+	fwspec->param[1] = virq - 32;
+	fwspec->param[2] = IRQ_TYPE_EDGE_RISING;
+	return 0;
+}
+
+#endif
diff --git a/drivers/virt/gunyah/rsc_mgr.c b/drivers/virt/gunyah/rsc_mgr.c
index a0faf126ee56e..3255ae1855990 100644
--- a/drivers/virt/gunyah/rsc_mgr.c
+++ b/drivers/virt/gunyah/rsc_mgr.c
@@ -17,6 +17,8 @@
 #include <linux/platform_device.h>
 #include <linux/miscdevice.h>
 
+#include <asm/gunyah.h>
+
 #include "rsc_mgr.h"
 #include "vm_mgr.h"
 
@@ -133,6 +135,7 @@ struct gh_rm_connection {
  * @send_lock: synchronization to allow only one request to be sent at a time
  * @nh: notifier chain for clients interested in RM notification messages
  * @miscdev: /dev/gunyah
+ * @irq_domain: Domain to translate Gunyah hwirqs to Linux irqs
  */
 struct gh_rm {
 	struct device *dev;
@@ -151,6 +154,7 @@ struct gh_rm {
 	struct blocking_notifier_head nh;
 
 	struct miscdevice miscdev;
+	struct irq_domain *irq_domain;
 };
 
 /**
@@ -191,6 +195,135 @@ static inline int gh_rm_error_remap(enum gh_rm_error rm_error)
 	}
 }
 
+struct gh_irq_chip_data {
+	u32 gh_virq;
+};
+
+static struct irq_chip gh_rm_irq_chip = {
+	.name			= "Gunyah",
+	.irq_enable		= irq_chip_enable_parent,
+	.irq_disable		= irq_chip_disable_parent,
+	.irq_ack		= irq_chip_ack_parent,
+	.irq_mask		= irq_chip_mask_parent,
+	.irq_mask_ack		= irq_chip_mask_ack_parent,
+	.irq_unmask		= irq_chip_unmask_parent,
+	.irq_eoi		= irq_chip_eoi_parent,
+	.irq_set_affinity	= irq_chip_set_affinity_parent,
+	.irq_set_type		= irq_chip_set_type_parent,
+	.irq_set_wake		= irq_chip_set_wake_parent,
+	.irq_set_vcpu_affinity	= irq_chip_set_vcpu_affinity_parent,
+	.irq_retrigger		= irq_chip_retrigger_hierarchy,
+	.irq_get_irqchip_state	= irq_chip_get_parent_state,
+	.irq_set_irqchip_state	= irq_chip_set_parent_state,
+	.flags			= IRQCHIP_SET_TYPE_MASKED |
+				  IRQCHIP_SKIP_SET_WAKE |
+				  IRQCHIP_MASK_ON_SUSPEND,
+};
+
+static int gh_rm_irq_domain_alloc(struct irq_domain *d, unsigned int virq, unsigned int nr_irqs,
+				 void *arg)
+{
+	struct gh_irq_chip_data *chip_data, *spec = arg;
+	struct irq_fwspec parent_fwspec = {};
+	struct gh_rm *rm = d->host_data;
+	u32 gh_virq = spec->gh_virq;
+	int ret;
+
+	if (nr_irqs != 1)
+		return -EINVAL;
+
+	chip_data = kzalloc(sizeof(*chip_data), GFP_KERNEL);
+	if (!chip_data)
+		return -ENOMEM;
+
+	chip_data->gh_virq = gh_virq;
+
+	ret = irq_domain_set_hwirq_and_chip(d, virq, chip_data->gh_virq, &gh_rm_irq_chip,
+						chip_data);
+	if (ret)
+		goto err_free_irq_data;
+
+	parent_fwspec.fwnode = d->parent->fwnode;
+	ret = arch_gh_fill_irq_fwspec_params(chip_data->gh_virq, &parent_fwspec);
+	if (ret) {
+		dev_err(rm->dev, "virq translation failed %u: %d\n", chip_data->gh_virq, ret);
+		goto err_free_irq_data;
+	}
+
+	ret = irq_domain_alloc_irqs_parent(d, virq, nr_irqs, &parent_fwspec);
+	if (ret)
+		goto err_free_irq_data;
+
+	return ret;
+err_free_irq_data:
+	kfree(chip_data);
+	return ret;
+}
+
+static void gh_rm_irq_domain_free_single(struct irq_domain *d, unsigned int virq)
+{
+	struct irq_data *irq_data;
+
+	irq_data = irq_domain_get_irq_data(d, virq);
+	if (!irq_data)
+		return;
+
+	kfree(irq_data->chip_data);
+	irq_data->chip_data = NULL;
+}
+
+static void gh_rm_irq_domain_free(struct irq_domain *d, unsigned int virq, unsigned int nr_irqs)
+{
+	unsigned int i;
+
+	for (i = 0; i < nr_irqs; i++)
+		gh_rm_irq_domain_free_single(d, virq);
+}
+
+static const struct irq_domain_ops gh_rm_irq_domain_ops = {
+	.alloc		= gh_rm_irq_domain_alloc,
+	.free		= gh_rm_irq_domain_free,
+};
+
+struct gh_resource *gh_rm_alloc_resource(struct gh_rm *rm, struct gh_rm_hyp_resource *hyp_resource)
+{
+	struct gh_resource *ghrsc;
+	int ret;
+
+	ghrsc = kzalloc(sizeof(*ghrsc), GFP_KERNEL);
+	if (!ghrsc)
+		return NULL;
+
+	ghrsc->type = hyp_resource->type;
+	ghrsc->capid = le64_to_cpu(hyp_resource->cap_id);
+	ghrsc->irq = IRQ_NOTCONNECTED;
+	ghrsc->rm_label = le32_to_cpu(hyp_resource->resource_label);
+	if (hyp_resource->virq) {
+		struct gh_irq_chip_data irq_data = {
+			.gh_virq = le32_to_cpu(hyp_resource->virq),
+		};
+
+		ret = irq_domain_alloc_irqs(rm->irq_domain, 1, NUMA_NO_NODE, &irq_data);
+		if (ret < 0) {
+			dev_err(rm->dev,
+				"Failed to allocate interrupt for resource %d label: %d: %d\n",
+				ghrsc->type, ghrsc->rm_label, ret);
+			kfree(ghrsc);
+			return NULL;
+		} else {
+			ghrsc->irq = ret;
+		}
+	}
+
+	return ghrsc;
+}
+
+void gh_rm_free_resource(struct gh_resource *ghrsc)
+{
+	irq_dispose_mapping(ghrsc->irq);
+	kfree(ghrsc);
+}
+
 static int gh_rm_init_connection_payload(struct gh_rm_connection *connection, void *msg,
 					size_t hdr_size, size_t msg_size)
 {
@@ -660,6 +793,8 @@ static int gh_identify(void)
 
 static int gh_rm_drv_probe(struct platform_device *pdev)
 {
+	struct irq_domain *parent_irq_domain;
+	struct device_node *parent_irq_node;
 	struct gh_msgq_tx_data *msg;
 	struct gh_rm *rm;
 	int ret;
@@ -700,15 +835,41 @@ static int gh_rm_drv_probe(struct platform_device *pdev)
 	if (ret)
 		goto err_cache;
 
+	parent_irq_node = of_irq_find_parent(pdev->dev.of_node);
+	if (!parent_irq_node) {
+		dev_err(&pdev->dev, "Failed to find interrupt parent of resource manager\n");
+		ret = -ENODEV;
+		goto err_msgq;
+	}
+
+	parent_irq_domain = irq_find_host(parent_irq_node);
+	if (!parent_irq_domain) {
+		dev_err(&pdev->dev, "Failed to find interrupt parent domain of resource manager\n");
+		ret = -ENODEV;
+		goto err_msgq;
+	}
+
+	rm->irq_domain = irq_domain_add_hierarchy(parent_irq_domain, 0, 0, pdev->dev.of_node,
+							&gh_rm_irq_domain_ops, NULL);
+	if (!rm->irq_domain) {
+		dev_err(&pdev->dev, "Failed to add irq domain\n");
+		ret = -ENODEV;
+		goto err_msgq;
+	}
+	rm->irq_domain->host_data = rm;
+
+	rm->miscdev.parent = &pdev->dev;
 	rm->miscdev.name = "gunyah";
 	rm->miscdev.minor = MISC_DYNAMIC_MINOR;
 	rm->miscdev.fops = &gh_dev_fops;
 
 	ret = misc_register(&rm->miscdev);
 	if (ret)
-		goto err_msgq;
+		goto err_irq_domain;
 
 	return 0;
+err_irq_domain:
+	irq_domain_remove(rm->irq_domain);
 err_msgq:
 	gh_msgq_remove(&rm->msgq);
 err_cache:
@@ -721,6 +882,7 @@ static int gh_rm_drv_remove(struct platform_device *pdev)
 	struct gh_rm *rm = platform_get_drvdata(pdev);
 
 	misc_deregister(&rm->miscdev);
+	irq_domain_remove(rm->irq_domain);
 	gh_msgq_remove(&rm->msgq);
 	kmem_cache_destroy(rm->cache);
 
diff --git a/include/linux/gunyah.h b/include/linux/gunyah.h
index 982e27d10d57f..4b398b59c2c5a 100644
--- a/include/linux/gunyah.h
+++ b/include/linux/gunyah.h
@@ -27,6 +27,9 @@ struct gh_resource {
 	enum gh_resource_type type;
 	u64 capid;
 	unsigned int irq;
+
+	struct list_head list;
+	u32 rm_label;
 };
 
 /**
diff --git a/include/linux/gunyah_rsc_mgr.h b/include/linux/gunyah_rsc_mgr.h
index cac4476b46ade..c0cf8b4dc7beb 100644
--- a/include/linux/gunyah_rsc_mgr.h
+++ b/include/linux/gunyah_rsc_mgr.h
@@ -139,6 +139,9 @@ int gh_rm_get_hyp_resources(struct gh_rm *rm, u16 vmid,
 				struct gh_rm_hyp_resources **resources);
 int gh_rm_get_vmid(struct gh_rm *rm, u16 *vmid);
 
+struct gh_resource *gh_rm_alloc_resource(struct gh_rm *rm, struct gh_rm_hyp_resource *hyp_resource);
+void gh_rm_free_resource(struct gh_resource *ghrsc);
+
 struct gh_rm_platform_ops {
 	int (*pre_mem_share)(struct gh_rm *rm, struct gh_rm_mem_parcel *mem_parcel);
 	int (*post_mem_reclaim)(struct gh_rm *rm, struct gh_rm_mem_parcel *mem_parcel);
-- 
2.40.0

[PATCH v14 18/25] gunyah: vm_mgr: Add framework for VM Functions

[Elliot Berman]

Introduce a framework for Gunyah userspace to install VM functions. VM
functions are optional interfaces to the virtual machine. vCPUs,
ioeventfs, and irqfds are examples of such VM functions and are
implemented in subsequent patches.

A generic framework is implemented instead of individual ioctls to
create vCPUs, irqfds, etc., in order to simplify the VM manager core
implementation and allow dynamic loading of VM function modules.

Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
---
 Documentation/virt/gunyah/vm-manager.rst |  18 ++
 drivers/virt/gunyah/vm_mgr.c             | 213 ++++++++++++++++++++++-
 drivers/virt/gunyah/vm_mgr.h             |   4 +
 include/linux/gunyah_vm_mgr.h            |  97 +++++++++++
 include/uapi/linux/gunyah.h              |  18 ++
 5 files changed, 347 insertions(+), 3 deletions(-)
 create mode 100644 include/linux/gunyah_vm_mgr.h

diff --git a/Documentation/virt/gunyah/vm-manager.rst b/Documentation/virt/gunyah/vm-manager.rst
index df0e1a8279bf5..cbc79bd8749b4 100644
--- a/Documentation/virt/gunyah/vm-manager.rst
+++ b/Documentation/virt/gunyah/vm-manager.rst
@@ -15,6 +15,24 @@ such as vCPUs for the VM. Memory can be shared with the VM with
 `GH_VM_SET_USER_MEM_REGION`_. Userspace can interact with the resources in Linux
 by adding "functions" to the VM.
 
+Gunyah Functions
+================
+
+Components of a Gunyah VM's configuration that need kernel configuration are
+called "functions" and are built on top of a framework. Functions are identified
+by a string and have some argument(s) to configure them. They are typically
+created by the `GH_VM_ADD_FUNCTION`_ ioctl.
+
+Functions typically will always do at least one of these operations:
+
+1. Create resource ticket(s). Resource tickets allow a function to register
+   itself as the client for a Gunyah resource (e.g. doorbell or vCPU) and
+   the function is given the pointer to the &struct gh_resource when the
+   VM is starting.
+
+2. Register IO handler(s). IO handlers allow a function to handle stage-2 faults
+   from the virtual machine.
+
 Sample Userspace VMM
 ====================
 
diff --git a/drivers/virt/gunyah/vm_mgr.c b/drivers/virt/gunyah/vm_mgr.c
index 562ae6ed4a5f1..cfd79bc9900fd 100644
--- a/drivers/virt/gunyah/vm_mgr.c
+++ b/drivers/virt/gunyah/vm_mgr.c
@@ -6,10 +6,13 @@
 #define pr_fmt(fmt) "gh_vm_mgr: " fmt
 
 #include <linux/anon_inodes.h>
+#include <linux/compat.h>
 #include <linux/file.h>
 #include <linux/gunyah_rsc_mgr.h>
+#include <linux/gunyah_vm_mgr.h>
 #include <linux/miscdevice.h>
 #include <linux/module.h>
+#include <linux/xarray.h>
 
 #include <uapi/linux/gunyah.h>
 
@@ -17,6 +20,169 @@
 
 static void gh_vm_free(struct work_struct *work);
 
+static DEFINE_XARRAY(gh_vm_functions);
+
+static void gh_vm_put_function(struct gh_vm_function *fn)
+{
+	module_put(fn->mod);
+}
+
+static struct gh_vm_function *gh_vm_get_function(u32 type)
+{
+	struct gh_vm_function *fn;
+
+	fn = xa_load(&gh_vm_functions, type);
+	if (!fn) {
+		request_module("ghfunc:%d", type);
+
+		fn = xa_load(&gh_vm_functions, type);
+	}
+
+	if (!fn || !try_module_get(fn->mod))
+		fn = ERR_PTR(-ENOENT);
+
+	return fn;
+}
+
+static void gh_vm_remove_function_instance(struct gh_vm_function_instance *inst)
+	__must_hold(&inst->ghvm->fn_lock)
+{
+	inst->fn->unbind(inst);
+	list_del(&inst->vm_list);
+	gh_vm_put_function(inst->fn);
+	kfree(inst->argp);
+	kfree(inst);
+}
+
+static void gh_vm_remove_functions(struct gh_vm *ghvm)
+{
+	struct gh_vm_function_instance *inst, *iiter;
+
+	mutex_lock(&ghvm->fn_lock);
+	list_for_each_entry_safe(inst, iiter, &ghvm->functions, vm_list) {
+		gh_vm_remove_function_instance(inst);
+	}
+	mutex_unlock(&ghvm->fn_lock);
+}
+
+static long gh_vm_add_function_instance(struct gh_vm *ghvm, struct gh_fn_desc *f)
+{
+	struct gh_vm_function_instance *inst;
+	void __user *argp;
+	long r = 0;
+
+	if (f->arg_size > GH_FN_MAX_ARG_SIZE) {
+		dev_err_ratelimited(ghvm->parent, "%s: arg_size > %d\n",
+					__func__, GH_FN_MAX_ARG_SIZE);
+		return -EINVAL;
+	}
+
+	inst = kzalloc(sizeof(*inst), GFP_KERNEL);
+	if (!inst)
+		return -ENOMEM;
+
+	inst->arg_size = f->arg_size;
+	if (inst->arg_size) {
+		inst->argp = kzalloc(inst->arg_size, GFP_KERNEL);
+		if (!inst->argp) {
+			r = -ENOMEM;
+			goto free;
+		}
+
+		argp = u64_to_user_ptr(f->arg);
+		if (copy_from_user(inst->argp, argp, f->arg_size)) {
+			r = -EFAULT;
+			goto free_arg;
+		}
+	}
+
+	inst->fn = gh_vm_get_function(f->type);
+	if (IS_ERR(inst->fn)) {
+		r = PTR_ERR(inst->fn);
+		goto free_arg;
+	}
+
+	inst->ghvm = ghvm;
+	inst->rm = ghvm->rm;
+
+	mutex_lock(&ghvm->fn_lock);
+	r = inst->fn->bind(inst);
+	if (r < 0) {
+		mutex_unlock(&ghvm->fn_lock);
+		gh_vm_put_function(inst->fn);
+		goto free_arg;
+	}
+
+	list_add(&inst->vm_list, &ghvm->functions);
+	mutex_unlock(&ghvm->fn_lock);
+
+	return r;
+free_arg:
+	kfree(inst->argp);
+free:
+	kfree(inst);
+	return r;
+}
+
+static long gh_vm_rm_function_instance(struct gh_vm *ghvm, struct gh_fn_desc *f)
+{
+	struct gh_vm_function_instance *inst, *iter;
+	void __user *user_argp;
+	void *argp;
+	long r = 0;
+
+	r = mutex_lock_interruptible(&ghvm->fn_lock);
+	if (r)
+		return r;
+
+	if (f->arg_size) {
+		argp = kzalloc(f->arg_size, GFP_KERNEL);
+		if (!argp) {
+			r = -ENOMEM;
+			goto out;
+		}
+
+		user_argp = u64_to_user_ptr(f->arg);
+		if (copy_from_user(argp, user_argp, f->arg_size)) {
+			r = -EFAULT;
+			kfree(argp);
+			goto out;
+		}
+
+		r = -ENOENT;
+		list_for_each_entry_safe(inst, iter, &ghvm->functions, vm_list) {
+			if (inst->fn->type == f->type &&
+				inst->fn->compare(inst, argp, f->arg_size)) {
+				gh_vm_remove_function_instance(inst);
+				r = 0;
+			}
+		}
+
+		kfree(argp);
+	}
+
+out:
+	mutex_unlock(&ghvm->fn_lock);
+	return r;
+}
+
+int gh_vm_function_register(struct gh_vm_function *fn)
+{
+	if (!fn->bind || !fn->unbind)
+		return -EINVAL;
+
+	return xa_err(xa_store(&gh_vm_functions, fn->type, fn, GFP_KERNEL));
+}
+EXPORT_SYMBOL_GPL(gh_vm_function_register);
+
+void gh_vm_function_unregister(struct gh_vm_function *fn)
+{
+	/* Expecting unregister to only come when unloading a module */
+	WARN_ON(fn->mod && module_refcount(fn->mod));
+	xa_erase(&gh_vm_functions, fn->type);
+}
+EXPORT_SYMBOL_GPL(gh_vm_function_unregister);
+
 static int gh_vm_rm_notification_status(struct gh_vm *ghvm, void *data)
 {
 	struct gh_rm_vm_status_payload *payload = data;
@@ -98,6 +264,8 @@ static __must_check struct gh_vm *gh_vm_alloc(struct gh_rm *rm)
 	init_rwsem(&ghvm->status_lock);
 	init_waitqueue_head(&ghvm->vm_status_wait);
 	INIT_WORK(&ghvm->free_work, gh_vm_free);
+	kref_init(&ghvm->kref);
+	INIT_LIST_HEAD(&ghvm->functions);
 	ghvm->vm_status = GH_RM_VM_STATUS_NO_STATE;
 
 	return ghvm;
@@ -254,6 +422,24 @@ static long gh_vm_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 		r = gh_vm_ensure_started(ghvm);
 		break;
 	}
+	case GH_VM_ADD_FUNCTION: {
+		struct gh_fn_desc f;
+
+		if (copy_from_user(&f, argp, sizeof(f)))
+			return -EFAULT;
+
+		r = gh_vm_add_function_instance(ghvm, &f);
+		break;
+	}
+	case GH_VM_REMOVE_FUNCTION: {
+		struct gh_fn_desc f;
+
+		if (copy_from_user(&f, argp, sizeof(f)))
+			return -EFAULT;
+
+		r = gh_vm_rm_function_instance(ghvm, &f);
+		break;
+	}
 	default:
 		r = -ENOTTY;
 		break;
@@ -270,6 +456,8 @@ static void gh_vm_free(struct work_struct *work)
 	if (ghvm->vm_status == GH_RM_VM_STATUS_RUNNING)
 		gh_vm_stop(ghvm);
 
+	gh_vm_remove_functions(ghvm);
+
 	if (ghvm->vm_status != GH_RM_VM_STATUS_NO_STATE &&
 	    ghvm->vm_status != GH_RM_VM_STATUS_LOAD &&
 	    ghvm->vm_status != GH_RM_VM_STATUS_RESET) {
@@ -294,14 +482,33 @@ static void gh_vm_free(struct work_struct *work)
 	kfree(ghvm);
 }
 
-static int gh_vm_release(struct inode *inode, struct file *filp)
+int __must_check gh_vm_get(struct gh_vm *ghvm)
 {
-	struct gh_vm *ghvm = filp->private_data;
+	return kref_get_unless_zero(&ghvm->kref);
+}
+EXPORT_SYMBOL_GPL(gh_vm_get);
+
+static void _gh_vm_put(struct kref *kref)
+{
+	struct gh_vm *ghvm = container_of(kref, struct gh_vm, kref);
 
 	/* VM will be reset and make RM calls which can interruptible sleep.
 	 * Defer to a work so this thread can receive signal.
 	 */
 	schedule_work(&ghvm->free_work);
+}
+
+void gh_vm_put(struct gh_vm *ghvm)
+{
+	kref_put(&ghvm->kref, _gh_vm_put);
+}
+EXPORT_SYMBOL_GPL(gh_vm_put);
+
+static int gh_vm_release(struct inode *inode, struct file *filp)
+{
+	struct gh_vm *ghvm = filp->private_data;
+
+	gh_vm_put(ghvm);
 	return 0;
 }
 
@@ -346,7 +553,7 @@ static long gh_dev_ioctl_create_vm(struct gh_rm *rm, unsigned long arg)
 err_put_fd:
 	put_unused_fd(fd);
 err_destroy_vm:
-	gh_vm_free(&ghvm->free_work);
+	gh_vm_put(ghvm);
 	return err;
 }
 
diff --git a/drivers/virt/gunyah/vm_mgr.h b/drivers/virt/gunyah/vm_mgr.h
index 4173bd51f83fe..c4bec1469ae8c 100644
--- a/drivers/virt/gunyah/vm_mgr.h
+++ b/drivers/virt/gunyah/vm_mgr.h
@@ -8,6 +8,7 @@
 
 #include <linux/gunyah_rsc_mgr.h>
 #include <linux/list.h>
+#include <linux/kref.h>
 #include <linux/miscdevice.h>
 #include <linux/mutex.h>
 #include <linux/rwsem.h>
@@ -45,9 +46,12 @@ struct gh_vm {
 	struct rw_semaphore status_lock;
 
 	struct work_struct free_work;
+	struct kref kref;
 	struct mm_struct *mm; /* userspace tied to this vm */
 	struct mutex mm_lock;
 	struct list_head memory_mappings;
+	struct mutex fn_lock;
+	struct list_head functions;
 };
 
 int gh_vm_mem_alloc(struct gh_vm *ghvm, struct gh_userspace_memory_region *region);
diff --git a/include/linux/gunyah_vm_mgr.h b/include/linux/gunyah_vm_mgr.h
new file mode 100644
index 0000000000000..6e4dd6fa5f96d
--- /dev/null
+++ b/include/linux/gunyah_vm_mgr.h
@@ -0,0 +1,97 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#ifndef _GUNYAH_VM_MGR_H
+#define _GUNYAH_VM_MGR_H
+
+#include <linux/compiler_types.h>
+#include <linux/gunyah.h>
+#include <linux/gunyah_rsc_mgr.h>
+#include <linux/list.h>
+#include <linux/mod_devicetable.h>
+#include <linux/notifier.h>
+
+#include <uapi/linux/gunyah.h>
+
+struct gh_vm;
+
+int __must_check gh_vm_get(struct gh_vm *ghvm);
+void gh_vm_put(struct gh_vm *ghvm);
+
+struct gh_vm_function_instance;
+/**
+ * struct gh_vm_function - Represents a function type
+ * @type: value from &enum gh_fn_type
+ * @name: friendly name for debug purposes
+ * @mod: owner of the function type
+ * @bind: Called when a new function of this type has been allocated.
+ * @unbind: Called when the function instance is being destroyed.
+ * @compare: Compare function instance @f's argument to the provided arg.
+ *           Return true if they are equivalent. Used on GH_VM_REMOVE_FUNCTION.
+ */
+struct gh_vm_function {
+	u32 type;
+	const char *name;
+	struct module *mod;
+	long (*bind)(struct gh_vm_function_instance *f);
+	void (*unbind)(struct gh_vm_function_instance *f);
+	bool (*compare)(const struct gh_vm_function_instance *f, const void *arg, size_t size);
+};
+
+/**
+ * struct gh_vm_function_instance - Represents one function instance
+ * @arg_size: size of user argument
+ * @argp: pointer to user argument
+ * @ghvm: Pointer to VM instance
+ * @rm: Pointer to resource manager for the VM instance
+ * @fn: The ops for the function
+ * @data: Private data for function
+ * @vm_list: for gh_vm's functions list
+ * @fn_list: for gh_vm_function's instances list
+ */
+struct gh_vm_function_instance {
+	size_t arg_size;
+	void *argp;
+	struct gh_vm *ghvm;
+	struct gh_rm *rm;
+	struct gh_vm_function *fn;
+	void *data;
+	struct list_head vm_list;
+};
+
+int gh_vm_function_register(struct gh_vm_function *f);
+void gh_vm_function_unregister(struct gh_vm_function *f);
+
+/* Since the function identifiers were setup in a uapi header as an
+ * enum and we do no want to change that, the user must supply the expanded
+ * constant as well and the compiler checks they are the same.
+ * See also MODULE_ALIAS_RDMA_NETLINK.
+ */
+#define MODULE_ALIAS_GH_VM_FUNCTION(_type, _idx)			\
+	static inline void __maybe_unused __chk##_idx(void)		\
+	{								\
+		BUILD_BUG_ON(_type != _idx);				\
+	}								\
+	MODULE_ALIAS("ghfunc:" __stringify(_idx))
+
+#define DECLARE_GH_VM_FUNCTION(_name, _type, _bind, _unbind, _compare)	\
+	static struct gh_vm_function _name = {				\
+		.type = _type,						\
+		.name = __stringify(_name),				\
+		.mod = THIS_MODULE,					\
+		.bind = _bind,						\
+		.unbind = _unbind,					\
+		.compare = _compare,					\
+	}
+
+#define module_gh_vm_function(__gf)					\
+	module_driver(__gf, gh_vm_function_register, gh_vm_function_unregister)
+
+#define DECLARE_GH_VM_FUNCTION_INIT(_name, _type, _idx, _bind, _unbind, _compare)	\
+	DECLARE_GH_VM_FUNCTION(_name, _type, _bind, _unbind, _compare);			\
+	module_gh_vm_function(_name);							\
+	MODULE_ALIAS_GH_VM_FUNCTION(_type, _idx)
+
+#endif
diff --git a/include/uapi/linux/gunyah.h b/include/uapi/linux/gunyah.h
index 4b63d0b9b8ba7..bb07118a351fd 100644
--- a/include/uapi/linux/gunyah.h
+++ b/include/uapi/linux/gunyah.h
@@ -72,4 +72,22 @@ struct gh_vm_dtb_config {
 
 #define GH_VM_START		_IO(GH_IOCTL_TYPE, 0x3)
 
+#define GH_FN_MAX_ARG_SIZE		256
+
+/**
+ * struct gh_fn_desc - Arguments to create a VM function
+ * @type: Type of the function. See &enum gh_fn_type.
+ * @arg_size: Size of argument to pass to the function. arg_size <= GH_FN_MAX_ARG_SIZE
+ * @arg: Pointer to argument given to the function. See &enum gh_fn_type for expected
+ *       arguments for a function type.
+ */
+struct gh_fn_desc {
+	__u32 type;
+	__u32 arg_size;
+	__u64 arg;
+};
+
+#define GH_VM_ADD_FUNCTION	_IOW(GH_IOCTL_TYPE, 0x4, struct gh_fn_desc)
+#define GH_VM_REMOVE_FUNCTION	_IOW(GH_IOCTL_TYPE, 0x7, struct gh_fn_desc)
+
 #endif
-- 
2.40.0

[PATCH v14 19/25] virt: gunyah: Add resource tickets

[Elliot Berman]

Some VM functions need to acquire Gunyah resources. For instance, Gunyah
vCPUs are exposed to the host as a resource. The Gunyah vCPU function
will register a resource ticket and be able to interact with the
hypervisor once the resource ticket is filled.

Resource tickets are the mechanism for functions to acquire ownership of
Gunyah resources. Gunyah functions can be created before the VM's
resources are created and made available to Linux. A resource ticket
identifies a type of resource and a label of a resource which the ticket
holder is interested in.

Resources are created by Gunyah as configured in the VM's devicetree
configuration. Gunyah doesn't process the label and that makes it
possible for userspace to create multiple resources with the same label.
Resource ticket owners need to be prepared for populate to be called
multiple times if userspace created multiple resources with the same
label.

Reviewed-by: Alex Elder <elder@linaro.org>
Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
---
 drivers/virt/gunyah/vm_mgr.c  | 117 +++++++++++++++++++++++++++++++++-
 drivers/virt/gunyah/vm_mgr.h  |   4 ++
 include/linux/gunyah_vm_mgr.h |  31 +++++++++
 3 files changed, 151 insertions(+), 1 deletion(-)

diff --git a/drivers/virt/gunyah/vm_mgr.c b/drivers/virt/gunyah/vm_mgr.c
index cfd79bc9900fd..d6aa1731148ae 100644
--- a/drivers/virt/gunyah/vm_mgr.c
+++ b/drivers/virt/gunyah/vm_mgr.c
@@ -183,6 +183,99 @@ void gh_vm_function_unregister(struct gh_vm_function *fn)
 }
 EXPORT_SYMBOL_GPL(gh_vm_function_unregister);
 
+int gh_vm_add_resource_ticket(struct gh_vm *ghvm, struct gh_vm_resource_ticket *ticket)
+{
+	struct gh_vm_resource_ticket *iter;
+	struct gh_resource *ghrsc, *rsc_iter;
+	int ret = 0;
+
+	mutex_lock(&ghvm->resources_lock);
+	list_for_each_entry(iter, &ghvm->resource_tickets, vm_list) {
+		if (iter->resource_type == ticket->resource_type && iter->label == ticket->label) {
+			ret = -EEXIST;
+			goto out;
+		}
+	}
+
+	if (!try_module_get(ticket->owner)) {
+		ret = -ENODEV;
+		goto out;
+	}
+
+	list_add(&ticket->vm_list, &ghvm->resource_tickets);
+	INIT_LIST_HEAD(&ticket->resources);
+
+	list_for_each_entry_safe(ghrsc, rsc_iter, &ghvm->resources, list) {
+		if (ghrsc->type == ticket->resource_type && ghrsc->rm_label == ticket->label) {
+			if (ticket->populate(ticket, ghrsc))
+				list_move(&ghrsc->list, &ticket->resources);
+		}
+	}
+out:
+	mutex_unlock(&ghvm->resources_lock);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(gh_vm_add_resource_ticket);
+
+void gh_vm_remove_resource_ticket(struct gh_vm *ghvm, struct gh_vm_resource_ticket *ticket)
+{
+	struct gh_resource *ghrsc, *iter;
+
+	mutex_lock(&ghvm->resources_lock);
+	list_for_each_entry_safe(ghrsc, iter, &ticket->resources, list) {
+		ticket->unpopulate(ticket, ghrsc);
+		list_move(&ghrsc->list, &ghvm->resources);
+	}
+
+	module_put(ticket->owner);
+	list_del(&ticket->vm_list);
+	mutex_unlock(&ghvm->resources_lock);
+}
+EXPORT_SYMBOL_GPL(gh_vm_remove_resource_ticket);
+
+static void gh_vm_add_resource(struct gh_vm *ghvm, struct gh_resource *ghrsc)
+{
+	struct gh_vm_resource_ticket *ticket;
+
+	mutex_lock(&ghvm->resources_lock);
+	list_for_each_entry(ticket, &ghvm->resource_tickets, vm_list) {
+		if (ghrsc->type == ticket->resource_type && ghrsc->rm_label == ticket->label) {
+			if (ticket->populate(ticket, ghrsc))
+				list_add(&ghrsc->list, &ticket->resources);
+			else
+				list_add(&ghrsc->list, &ghvm->resources);
+			/* unconditonal -- we prevent multiple identical
+			 * resource tickets so there will not be some other
+			 * ticket elsewhere in the list if populate() failed.
+			 */
+			goto found;
+		}
+	}
+	list_add(&ghrsc->list, &ghvm->resources);
+found:
+	mutex_unlock(&ghvm->resources_lock);
+}
+
+static void gh_vm_clean_resources(struct gh_vm *ghvm)
+{
+	struct gh_vm_resource_ticket *ticket, *titer;
+	struct gh_resource *ghrsc, *riter;
+
+	mutex_lock(&ghvm->resources_lock);
+	if (!list_empty(&ghvm->resource_tickets)) {
+		dev_warn(ghvm->parent, "Dangling resource tickets:\n");
+		list_for_each_entry_safe(ticket, titer, &ghvm->resource_tickets, vm_list) {
+			dev_warn(ghvm->parent, "  %pS\n", ticket->populate);
+			gh_vm_remove_resource_ticket(ghvm, ticket);
+		}
+	}
+
+	list_for_each_entry_safe(ghrsc, riter, &ghvm->resources, list) {
+		gh_rm_free_resource(ghrsc);
+	}
+	mutex_unlock(&ghvm->resources_lock);
+}
+
 static int gh_vm_rm_notification_status(struct gh_vm *ghvm, void *data)
 {
 	struct gh_rm_vm_status_payload *payload = data;
@@ -265,6 +358,9 @@ static __must_check struct gh_vm *gh_vm_alloc(struct gh_rm *rm)
 	init_waitqueue_head(&ghvm->vm_status_wait);
 	INIT_WORK(&ghvm->free_work, gh_vm_free);
 	kref_init(&ghvm->kref);
+	mutex_init(&ghvm->resources_lock);
+	INIT_LIST_HEAD(&ghvm->resources);
+	INIT_LIST_HEAD(&ghvm->resource_tickets);
 	INIT_LIST_HEAD(&ghvm->functions);
 	ghvm->vm_status = GH_RM_VM_STATUS_NO_STATE;
 
@@ -274,9 +370,11 @@ static __must_check struct gh_vm *gh_vm_alloc(struct gh_rm *rm)
 static int gh_vm_start(struct gh_vm *ghvm)
 {
 	struct gh_vm_mem *mapping;
+	struct gh_rm_hyp_resources *resources;
+	struct gh_resource *ghrsc;
 	u64 dtb_offset;
 	u32 mem_handle;
-	int ret;
+	int ret, i, n;
 
 	down_write(&ghvm->status_lock);
 	if (ghvm->vm_status != GH_RM_VM_STATUS_NO_STATE) {
@@ -336,6 +434,22 @@ static int gh_vm_start(struct gh_vm *ghvm)
 	}
 	ghvm->vm_status = GH_RM_VM_STATUS_READY;
 
+	ret = gh_rm_get_hyp_resources(ghvm->rm, ghvm->vmid, &resources);
+	if (ret) {
+		dev_warn(ghvm->parent, "Failed to get hypervisor resources for VM: %d\n", ret);
+		goto err;
+	}
+
+	for (i = 0, n = le32_to_cpu(resources->n_entries); i < n; i++) {
+		ghrsc = gh_rm_alloc_resource(ghvm->rm, &resources->entries[i]);
+		if (!ghrsc) {
+			ret = -ENOMEM;
+			goto err;
+		}
+
+		gh_vm_add_resource(ghvm, ghrsc);
+	}
+
 	ret = gh_rm_vm_start(ghvm->rm, ghvm->vmid);
 	if (ret) {
 		dev_warn(ghvm->parent, "Failed to start VM: %d\n", ret);
@@ -457,6 +571,7 @@ static void gh_vm_free(struct work_struct *work)
 		gh_vm_stop(ghvm);
 
 	gh_vm_remove_functions(ghvm);
+	gh_vm_clean_resources(ghvm);
 
 	if (ghvm->vm_status != GH_RM_VM_STATUS_NO_STATE &&
 	    ghvm->vm_status != GH_RM_VM_STATUS_LOAD &&
diff --git a/drivers/virt/gunyah/vm_mgr.h b/drivers/virt/gunyah/vm_mgr.h
index c4bec1469ae8c..e5e0c92d4cb12 100644
--- a/drivers/virt/gunyah/vm_mgr.h
+++ b/drivers/virt/gunyah/vm_mgr.h
@@ -7,6 +7,7 @@
 #define _GH_VM_MGR_H
 
 #include <linux/gunyah_rsc_mgr.h>
+#include <linux/gunyah_vm_mgr.h>
 #include <linux/list.h>
 #include <linux/kref.h>
 #include <linux/miscdevice.h>
@@ -52,6 +53,9 @@ struct gh_vm {
 	struct list_head memory_mappings;
 	struct mutex fn_lock;
 	struct list_head functions;
+	struct mutex resources_lock;
+	struct list_head resources;
+	struct list_head resource_tickets;
 };
 
 int gh_vm_mem_alloc(struct gh_vm *ghvm, struct gh_userspace_memory_region *region);
diff --git a/include/linux/gunyah_vm_mgr.h b/include/linux/gunyah_vm_mgr.h
index 6e4dd6fa5f96d..af97fec9e2ef5 100644
--- a/include/linux/gunyah_vm_mgr.h
+++ b/include/linux/gunyah_vm_mgr.h
@@ -94,4 +94,35 @@ void gh_vm_function_unregister(struct gh_vm_function *f);
 	module_gh_vm_function(_name);							\
 	MODULE_ALIAS_GH_VM_FUNCTION(_type, _idx)
 
+/**
+ * struct gh_vm_resource_ticket - Represents a ticket to reserve exclusive access to VM resource(s)
+ * @vm_list: for @gh_vm->resource_tickets
+ * @resources: List of resource(s) associated with this ticket(members are from @gh_resource->list)
+ * @resource_type: Type of resource this ticket reserves
+ * @label: Label of the resource from resource manager this ticket reserves.
+ * @owner: owner of the ticket
+ * @populate: callback provided by the ticket owner and called when a resource is found that
+ *            matches @resource_type and @label. Note that this callback could be called
+ *            multiple times if userspace created mutliple resources with the same type/label.
+ *            This callback may also have significant delay after gh_vm_add_resource_ticket()
+ *            since gh_vm_add_resource_ticket() could be called before the VM starts.
+ * @unpopulate: callback provided by the ticket owner and called when the ticket owner should no
+ *              no longer use the resource provided in the argument. When unpopulate() returns,
+ *              the ticket owner should not be able to use the resource any more as the resource
+ *              might being freed.
+ */
+struct gh_vm_resource_ticket {
+	struct list_head vm_list;
+	struct list_head resources;
+	enum gh_resource_type resource_type;
+	u32 label;
+
+	struct module *owner;
+	bool (*populate)(struct gh_vm_resource_ticket *ticket, struct gh_resource *ghrsc);
+	void (*unpopulate)(struct gh_vm_resource_ticket *ticket, struct gh_resource *ghrsc);
+};
+
+int gh_vm_add_resource_ticket(struct gh_vm *ghvm, struct gh_vm_resource_ticket *ticket);
+void gh_vm_remove_resource_ticket(struct gh_vm *ghvm, struct gh_vm_resource_ticket *ticket);
+
 #endif
-- 
2.40.0

[PATCH v14 20/25] virt: gunyah: Add IO handlers

[Elliot Berman]

Add framework for VM functions to handle stage-2 write faults from Gunyah
guest virtual machines. IO handlers have a range of addresses which they
apply to. Optionally, they may apply to only when the value written
matches the IO handler's value.

Reviewed-by: Alex Elder <elder@linaro.org>
Co-developed-by: Prakruthi Deepak Heragu <quic_pheragu@quicinc.com>
Signed-off-by: Prakruthi Deepak Heragu <quic_pheragu@quicinc.com>
Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
---
 drivers/virt/gunyah/vm_mgr.c  | 104 ++++++++++++++++++++++++++++++++++
 drivers/virt/gunyah/vm_mgr.h  |   4 ++
 include/linux/gunyah_vm_mgr.h |  25 ++++++++
 3 files changed, 133 insertions(+)

diff --git a/drivers/virt/gunyah/vm_mgr.c b/drivers/virt/gunyah/vm_mgr.c
index d6aa1731148ae..28da1f95e49ec 100644
--- a/drivers/virt/gunyah/vm_mgr.c
+++ b/drivers/virt/gunyah/vm_mgr.c
@@ -276,6 +276,108 @@ static void gh_vm_clean_resources(struct gh_vm *ghvm)
 	mutex_unlock(&ghvm->resources_lock);
 }
 
+static int _gh_vm_io_handler_compare(const struct rb_node *node, const struct rb_node *parent)
+{
+	struct gh_vm_io_handler *n = container_of(node, struct gh_vm_io_handler, node);
+	struct gh_vm_io_handler *p = container_of(parent, struct gh_vm_io_handler, node);
+
+	if (n->addr < p->addr)
+		return -1;
+	if (n->addr > p->addr)
+		return 1;
+	if ((n->len && !p->len) || (!n->len && p->len))
+		return 0;
+	if (n->len < p->len)
+		return -1;
+	if (n->len > p->len)
+		return 1;
+	/* one of the io handlers doesn't have datamatch and the other does.
+	 * For purposes of comparison, that makes them identical since the
+	 * one that doesn't have datamatch will cover the same handler that
+	 * does.
+	 */
+	if (n->datamatch != p->datamatch)
+		return 0;
+	if (n->data < p->data)
+		return -1;
+	if (n->data > p->data)
+		return 1;
+	return 0;
+}
+
+static int gh_vm_io_handler_compare(struct rb_node *node, const struct rb_node *parent)
+{
+	return _gh_vm_io_handler_compare(node, parent);
+}
+
+static int gh_vm_io_handler_find(const void *key, const struct rb_node *node)
+{
+	const struct gh_vm_io_handler *k = key;
+
+	return _gh_vm_io_handler_compare(&k->node, node);
+}
+
+static struct gh_vm_io_handler *gh_vm_mgr_find_io_hdlr(struct gh_vm *ghvm, u64 addr,
+								u64 len, u64 data)
+{
+	struct gh_vm_io_handler key = {
+		.addr = addr,
+		.len = len,
+		.datamatch = true,
+		.data = data,
+	};
+	struct rb_node *node;
+
+	node = rb_find(&key, &ghvm->mmio_handler_root, gh_vm_io_handler_find);
+	if (!node)
+		return NULL;
+
+	return container_of(node, struct gh_vm_io_handler, node);
+}
+
+int gh_vm_mmio_write(struct gh_vm *ghvm, u64 addr, u32 len, u64 data)
+{
+	struct gh_vm_io_handler *io_hdlr = NULL;
+	int ret;
+
+	down_read(&ghvm->mmio_handler_lock);
+	io_hdlr = gh_vm_mgr_find_io_hdlr(ghvm, addr, len, data);
+	if (!io_hdlr || !io_hdlr->ops || !io_hdlr->ops->write) {
+		ret = -ENODEV;
+		goto out;
+	}
+
+	ret = io_hdlr->ops->write(io_hdlr, addr, len, data);
+
+out:
+	up_read(&ghvm->mmio_handler_lock);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(gh_vm_mmio_write);
+
+int gh_vm_add_io_handler(struct gh_vm *ghvm, struct gh_vm_io_handler *io_hdlr)
+{
+	struct rb_node *found;
+
+	if (io_hdlr->datamatch && (!io_hdlr->len || io_hdlr->len > sizeof(io_hdlr->data)))
+		return -EINVAL;
+
+	down_write(&ghvm->mmio_handler_lock);
+	found = rb_find_add(&io_hdlr->node, &ghvm->mmio_handler_root, gh_vm_io_handler_compare);
+	up_write(&ghvm->mmio_handler_lock);
+
+	return found ? -EEXIST : 0;
+}
+EXPORT_SYMBOL_GPL(gh_vm_add_io_handler);
+
+void gh_vm_remove_io_handler(struct gh_vm *ghvm, struct gh_vm_io_handler *io_hdlr)
+{
+	down_write(&ghvm->mmio_handler_lock);
+	rb_erase(&io_hdlr->node, &ghvm->mmio_handler_root);
+	up_write(&ghvm->mmio_handler_lock);
+}
+EXPORT_SYMBOL_GPL(gh_vm_remove_io_handler);
+
 static int gh_vm_rm_notification_status(struct gh_vm *ghvm, void *data)
 {
 	struct gh_rm_vm_status_payload *payload = data;
@@ -361,6 +463,8 @@ static __must_check struct gh_vm *gh_vm_alloc(struct gh_rm *rm)
 	mutex_init(&ghvm->resources_lock);
 	INIT_LIST_HEAD(&ghvm->resources);
 	INIT_LIST_HEAD(&ghvm->resource_tickets);
+	init_rwsem(&ghvm->mmio_handler_lock);
+	ghvm->mmio_handler_root = RB_ROOT;
 	INIT_LIST_HEAD(&ghvm->functions);
 	ghvm->vm_status = GH_RM_VM_STATUS_NO_STATE;
 
diff --git a/drivers/virt/gunyah/vm_mgr.h b/drivers/virt/gunyah/vm_mgr.h
index e5e0c92d4cb12..3fc0f91dfd1a9 100644
--- a/drivers/virt/gunyah/vm_mgr.h
+++ b/drivers/virt/gunyah/vm_mgr.h
@@ -56,10 +56,14 @@ struct gh_vm {
 	struct mutex resources_lock;
 	struct list_head resources;
 	struct list_head resource_tickets;
+	struct rb_root mmio_handler_root;
+	struct rw_semaphore mmio_handler_lock;
 };
 
 int gh_vm_mem_alloc(struct gh_vm *ghvm, struct gh_userspace_memory_region *region);
 void gh_vm_mem_reclaim(struct gh_vm *ghvm);
 struct gh_vm_mem *gh_vm_mem_find_by_addr(struct gh_vm *ghvm, u64 guest_phys_addr, u32 size);
 
+int gh_vm_mmio_write(struct gh_vm *ghvm, u64 addr, u32 len, u64 data);
+
 #endif
diff --git a/include/linux/gunyah_vm_mgr.h b/include/linux/gunyah_vm_mgr.h
index af97fec9e2ef5..527e946243698 100644
--- a/include/linux/gunyah_vm_mgr.h
+++ b/include/linux/gunyah_vm_mgr.h
@@ -125,4 +125,29 @@ struct gh_vm_resource_ticket {
 int gh_vm_add_resource_ticket(struct gh_vm *ghvm, struct gh_vm_resource_ticket *ticket);
 void gh_vm_remove_resource_ticket(struct gh_vm *ghvm, struct gh_vm_resource_ticket *ticket);
 
+/*
+ * gh_vm_io_handler contains the info about an io device and its associated
+ * addr and the ops associated with the io device.
+ */
+struct gh_vm_io_handler {
+	struct rb_node node;
+	u64 addr;
+
+	bool datamatch;
+	u8 len;
+	u64 data;
+	struct gh_vm_io_handler_ops *ops;
+};
+
+/*
+ * gh_vm_io_handler_ops contains function pointers associated with an iodevice.
+ */
+struct gh_vm_io_handler_ops {
+	int (*read)(struct gh_vm_io_handler *io_dev, u64 addr, u32 len, u64 data);
+	int (*write)(struct gh_vm_io_handler *io_dev, u64 addr, u32 len, u64 data);
+};
+
+int gh_vm_add_io_handler(struct gh_vm *ghvm, struct gh_vm_io_handler *io_dev);
+void gh_vm_remove_io_handler(struct gh_vm *ghvm, struct gh_vm_io_handler *io_dev);
+
 #endif
-- 
2.40.0

[PATCH v14 21/25] virt: gunyah: Add proxy-scheduled vCPUs

[Elliot Berman]

Gunyah allows host virtual machines to schedule guest virtual machines
and handle their MMIO accesses. vCPUs are presented to the host as a
Gunyah resource and represented to userspace as a Gunyah VM function.

Creating the vcpu VM function will create a file descriptor that:
 - can run an ioctl: GH_VCPU_RUN to schedule the guest vCPU until the
   next interrupt occurs on the host or when the guest vCPU can no
   longer be run.
 - can be mmap'd to share a gh_vcpu_run structure which can look up the
   reason why GH_VCPU_RUN returned and provide return values for MMIO
   access.

Acked-by: Alex Elder <elder@linaro.org>
Co-developed-by: Prakruthi Deepak Heragu <quic_pheragu@quicinc.com>
Signed-off-by: Prakruthi Deepak Heragu <quic_pheragu@quicinc.com>
Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
---
 Documentation/virt/gunyah/vm-manager.rst |  46 ++-
 arch/arm64/gunyah/gunyah_hypercall.c     |  28 ++
 drivers/virt/gunyah/Kconfig              |  11 +
 drivers/virt/gunyah/Makefile             |   2 +
 drivers/virt/gunyah/gunyah_vcpu.c        | 470 +++++++++++++++++++++++
 drivers/virt/gunyah/vm_mgr.c             |   4 +
 drivers/virt/gunyah/vm_mgr.h             |   1 +
 include/linux/gunyah.h                   |  24 ++
 include/uapi/linux/gunyah.h              | 128 ++++++
 9 files changed, 712 insertions(+), 2 deletions(-)
 create mode 100644 drivers/virt/gunyah/gunyah_vcpu.c

diff --git a/Documentation/virt/gunyah/vm-manager.rst b/Documentation/virt/gunyah/vm-manager.rst
index cbc79bd8749b4..b0c3bde105ae9 100644
--- a/Documentation/virt/gunyah/vm-manager.rst
+++ b/Documentation/virt/gunyah/vm-manager.rst
@@ -5,8 +5,7 @@ Virtual Machine Manager
 =======================
 
 The Gunyah Virtual Machine Manager is a Linux driver to support launching
-virtual machines using Gunyah. It presently supports launching virtual machines
-scheduled by Gunyah's scheduler.
+virtual machines using Gunyah.
 
 Configuration of a Gunyah virtual machine is done via a devicetree. When the VM
 is launched, memory is provided by the host VM which contains the devictree.
@@ -99,3 +98,46 @@ GH_VM_START
 ~~~~~~~~~~~
 
 This ioctl starts the VM.
+
+GH_VM_ADD_FUNCTION
+~~~~~~~~~~~~~~~~~~
+
+This ioctl registers a Gunyah VM function with the VM manager. The VM function
+is described with a &struct gh_fn_desc.type and some arguments for that type.
+Typically, the function is added before the VM starts, but the function doesn't
+"operate" until the VM starts with `GH_VM_START`_. For example, vCPU ioctls will
+all return an error until the VM starts because the vCPUs don't exist until the
+VM is started. This allows the VMM to set up all the kernel functions needed for
+the VM *before* the VM starts.
+
+.. kernel-doc:: include/uapi/linux/gunyah.h
+   :identifiers: gh_fn_desc gh_fn_type
+
+The argument types are documented below:
+
+.. kernel-doc:: include/uapi/linux/gunyah.h
+   :identifiers: gh_fn_vcpu_arg
+
+Gunyah VCPU API Descriptions
+----------------------------
+
+A vCPU file descriptor is created after calling `GH_VM_ADD_FUNCTION` with the type `GH_FN_VCPU`.
+
+GH_VCPU_RUN
+~~~~~~~~~~~
+
+This ioctl is used to run a guest virtual cpu.  While there are no
+explicit parameters, there is an implicit parameter block that can be
+obtained by mmap()ing the vcpu fd at offset 0, with the size given by
+`GH_VCPU_MMAP_SIZE`_. The parameter block is formatted as a 'struct
+gh_vcpu_run' (see below).
+
+GH_VCPU_MMAP_SIZE
+~~~~~~~~~~~~~~~~~
+
+The `GH_VCPU_RUN`_ ioctl communicates with userspace via a shared
+memory region. This ioctl returns the size of that region. See the
+`GH_VCPU_RUN`_ documentation for details.
+
+.. kernel-doc:: include/uapi/linux/gunyah.h
+   :identifiers: gh_vcpu_exit gh_vcpu_run gh_vm_status gh_vm_exit_info
diff --git a/arch/arm64/gunyah/gunyah_hypercall.c b/arch/arm64/gunyah/gunyah_hypercall.c
index c5bf0dd468ec9..7d96491f84e00 100644
--- a/arch/arm64/gunyah/gunyah_hypercall.c
+++ b/arch/arm64/gunyah/gunyah_hypercall.c
@@ -37,6 +37,7 @@ EXPORT_SYMBOL_GPL(arch_is_gh_guest);
 #define GH_HYPERCALL_HYP_IDENTIFY		GH_HYPERCALL(0x8000)
 #define GH_HYPERCALL_MSGQ_SEND			GH_HYPERCALL(0x801B)
 #define GH_HYPERCALL_MSGQ_RECV			GH_HYPERCALL(0x801C)
+#define GH_HYPERCALL_VCPU_RUN			GH_HYPERCALL(0x8065)
 
 /**
  * gh_hypercall_hyp_identify() - Returns build information and feature flags
@@ -85,5 +86,32 @@ enum gh_error gh_hypercall_msgq_recv(u64 capid, void *buff, size_t size, size_t
 }
 EXPORT_SYMBOL_GPL(gh_hypercall_msgq_recv);
 
+enum gh_error gh_hypercall_vcpu_run(u64 capid, u64 *resume_data,
+					struct gh_hypercall_vcpu_run_resp *resp)
+{
+	struct arm_smccc_1_2_regs args = {
+		.a0 = GH_HYPERCALL_VCPU_RUN,
+		.a1 = capid,
+		.a2 = resume_data[0],
+		.a3 = resume_data[1],
+		.a4 = resume_data[2],
+		/* C language says this will be implictly zero. Gunyah requires 0, so be explicit */
+		.a5 = 0,
+	};
+	struct arm_smccc_1_2_regs res;
+
+	arm_smccc_1_2_hvc(&args, &res);
+
+	if (res.a0 == GH_ERROR_OK) {
+		resp->sized_state = res.a1;
+		resp->state_data[0] = res.a2;
+		resp->state_data[1] = res.a3;
+		resp->state_data[2] = res.a4;
+	}
+
+	return res.a0;
+}
+EXPORT_SYMBOL_GPL(gh_hypercall_vcpu_run);
+
 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("Gunyah Hypervisor Hypercalls");
diff --git a/drivers/virt/gunyah/Kconfig b/drivers/virt/gunyah/Kconfig
index 0421b751aad4f..0a58395f7d2c5 100644
--- a/drivers/virt/gunyah/Kconfig
+++ b/drivers/virt/gunyah/Kconfig
@@ -28,3 +28,14 @@ config GUNYAH_QCOM_PLATFORM
 	  extra platform-specific support.
 
 	  Say Y/M here to use Gunyah on Qualcomm platforms.
+
+config GUNYAH_VCPU
+	tristate "Runnable Gunyah vCPUs"
+	depends on GUNYAH
+	help
+	  Enable kernel support for host-scheduled vCPUs running under Gunyah.
+	  When selecting this option, userspace virtual machine managers (VMM)
+	  can schedule the guest VM's vCPUs instead of using Gunyah's scheduler.
+	  VMMs can also handle stage 2 faults of the vCPUs.
+
+	  Say Y/M here if unsure and you want to support Gunyah VMMs.
diff --git a/drivers/virt/gunyah/Makefile b/drivers/virt/gunyah/Makefile
index 2aa9ff038ed02..cc16b6c19db92 100644
--- a/drivers/virt/gunyah/Makefile
+++ b/drivers/virt/gunyah/Makefile
@@ -5,3 +5,5 @@ obj-$(CONFIG_GUNYAH_QCOM_PLATFORM) += gunyah_qcom.o
 
 gunyah-y += rsc_mgr.o rsc_mgr_rpc.o vm_mgr.o vm_mgr_mm.o
 obj-$(CONFIG_GUNYAH) += gunyah.o
+
+obj-$(CONFIG_GUNYAH_VCPU) += gunyah_vcpu.o
diff --git a/drivers/virt/gunyah/gunyah_vcpu.c b/drivers/virt/gunyah/gunyah_vcpu.c
new file mode 100644
index 0000000000000..82a0cbf55caf6
--- /dev/null
+++ b/drivers/virt/gunyah/gunyah_vcpu.c
@@ -0,0 +1,470 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#include <linux/anon_inodes.h>
+#include <linux/file.h>
+#include <linux/gunyah.h>
+#include <linux/gunyah_vm_mgr.h>
+#include <linux/interrupt.h>
+#include <linux/kref.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/wait.h>
+
+#include "vm_mgr.h"
+
+#include <uapi/linux/gunyah.h>
+
+#define MAX_VCPU_NAME		20 /* gh-vcpu:u32_max+NUL */
+
+struct gh_vcpu {
+	struct gh_vm_function_instance *f;
+	struct gh_resource *rsc;
+	struct mutex run_lock;
+	/* Track why vcpu_run left last time around. */
+	enum {
+		GH_VCPU_UNKNOWN = 0,
+		GH_VCPU_READY,
+		GH_VCPU_MMIO_READ,
+		GH_VCPU_SYSTEM_DOWN,
+	} state;
+	u8 mmio_read_len;
+	struct gh_vcpu_run *vcpu_run;
+	struct completion ready;
+	struct gh_vm *ghvm;
+
+	struct notifier_block nb;
+	struct gh_vm_resource_ticket ticket;
+	struct kref kref;
+};
+
+static void vcpu_release(struct kref *kref)
+{
+	struct gh_vcpu *vcpu = container_of(kref, struct gh_vcpu, kref);
+
+	free_page((unsigned long)vcpu->vcpu_run);
+	kfree(vcpu);
+}
+
+/*
+ * When hypervisor allows us to schedule vCPU again, it gives us an interrupt
+ */
+static irqreturn_t gh_vcpu_irq_handler(int irq, void *data)
+{
+	struct gh_vcpu *vcpu = data;
+
+	complete(&vcpu->ready);
+	return IRQ_HANDLED;
+}
+
+static bool gh_handle_mmio(struct gh_vcpu *vcpu,
+				struct gh_hypercall_vcpu_run_resp *vcpu_run_resp)
+{
+	int ret = 0;
+	u64 addr = vcpu_run_resp->state_data[0],
+	    len  = vcpu_run_resp->state_data[1],
+	    data = vcpu_run_resp->state_data[2];
+
+	if (WARN_ON(len > sizeof(u64)))
+		len = sizeof(u64);
+
+	if (vcpu_run_resp->state == GH_VCPU_ADDRSPACE_VMMIO_READ) {
+		vcpu->vcpu_run->mmio.is_write = 0;
+		/* Record that we need to give vCPU user's supplied value next gh_vcpu_run() */
+		vcpu->state = GH_VCPU_MMIO_READ;
+		vcpu->mmio_read_len = len;
+	} else { /* GH_VCPU_ADDRSPACE_VMMIO_WRITE */
+		/* Try internal handlers first */
+		ret = gh_vm_mmio_write(vcpu->f->ghvm, addr, len, data);
+		if (!ret)
+			return true;
+
+		/* Give userspace the info */
+		vcpu->vcpu_run->mmio.is_write = 1;
+		memcpy(vcpu->vcpu_run->mmio.data, &data, len);
+	}
+
+	vcpu->vcpu_run->mmio.phys_addr = addr;
+	vcpu->vcpu_run->mmio.len = len;
+	vcpu->vcpu_run->exit_reason = GH_VCPU_EXIT_MMIO;
+
+	return false;
+}
+
+static int gh_vcpu_rm_notification(struct notifier_block *nb, unsigned long action, void *data)
+{
+	struct gh_vcpu *vcpu = container_of(nb, struct gh_vcpu, nb);
+	struct gh_rm_vm_exited_payload *exit_payload = data;
+
+	if (action == GH_RM_NOTIFICATION_VM_EXITED &&
+		le16_to_cpu(exit_payload->vmid) == vcpu->ghvm->vmid)
+		complete(&vcpu->ready);
+
+	return NOTIFY_OK;
+}
+
+static inline enum gh_vm_status remap_vm_status(enum gh_rm_vm_status rm_status)
+{
+	switch (rm_status) {
+	case GH_RM_VM_STATUS_INIT_FAILED:
+		return GH_VM_STATUS_LOAD_FAILED;
+	case GH_RM_VM_STATUS_EXITED:
+		return GH_VM_STATUS_EXITED;
+	default:
+		return GH_VM_STATUS_CRASHED;
+	}
+}
+
+/**
+ * gh_vcpu_check_system() - Check whether VM as a whole is running
+ * @vcpu: Pointer to gh_vcpu
+ *
+ * Returns true if the VM is alive.
+ * Returns false if the vCPU is the VM is not alive (can only be that VM is shutting down).
+ */
+static bool gh_vcpu_check_system(struct gh_vcpu *vcpu)
+	__must_hold(&vcpu->run_lock)
+{
+	bool ret = true;
+
+	down_read(&vcpu->ghvm->status_lock);
+	if (likely(vcpu->ghvm->vm_status == GH_RM_VM_STATUS_RUNNING))
+		goto out;
+
+	vcpu->vcpu_run->status.status = remap_vm_status(vcpu->ghvm->vm_status);
+	vcpu->vcpu_run->status.exit_info = vcpu->ghvm->exit_info;
+	vcpu->vcpu_run->exit_reason = GH_VCPU_EXIT_STATUS;
+	vcpu->state = GH_VCPU_SYSTEM_DOWN;
+	ret = false;
+out:
+	up_read(&vcpu->ghvm->status_lock);
+	return ret;
+}
+
+/**
+ * gh_vcpu_run() - Request Gunyah to begin scheduling this vCPU.
+ * @vcpu: The client descriptor that was obtained via gh_vcpu_alloc()
+ */
+static int gh_vcpu_run(struct gh_vcpu *vcpu)
+{
+	struct gh_hypercall_vcpu_run_resp vcpu_run_resp;
+	u64 state_data[3] = { 0 };
+	enum gh_error gh_error;
+	int ret = 0;
+
+	if (!vcpu->f)
+		return -ENODEV;
+
+	if (mutex_lock_interruptible(&vcpu->run_lock))
+		return -ERESTARTSYS;
+
+	if (!vcpu->rsc) {
+		ret = -ENODEV;
+		goto out;
+	}
+
+	switch (vcpu->state) {
+	case GH_VCPU_UNKNOWN:
+		if (vcpu->ghvm->vm_status != GH_RM_VM_STATUS_RUNNING) {
+			/* Check if VM is up. If VM is starting, will block until VM is fully up
+			 * since that thread does down_write.
+			 */
+			if (!gh_vcpu_check_system(vcpu))
+				goto out;
+		}
+		vcpu->state = GH_VCPU_READY;
+		break;
+	case GH_VCPU_MMIO_READ:
+		if (unlikely(vcpu->mmio_read_len > sizeof(state_data[0])))
+			vcpu->mmio_read_len = sizeof(state_data[0]);
+		memcpy(&state_data[0], vcpu->vcpu_run->mmio.data, vcpu->mmio_read_len);
+		vcpu->state = GH_VCPU_READY;
+		break;
+	case GH_VCPU_SYSTEM_DOWN:
+		goto out;
+	default:
+		break;
+	}
+
+	while (!ret && !signal_pending(current)) {
+		if (vcpu->vcpu_run->immediate_exit) {
+			ret = -EINTR;
+			goto out;
+		}
+
+		gh_error = gh_hypercall_vcpu_run(vcpu->rsc->capid, state_data, &vcpu_run_resp);
+		if (gh_error == GH_ERROR_OK) {
+			switch (vcpu_run_resp.state) {
+			case GH_VCPU_STATE_READY:
+				if (need_resched())
+					schedule();
+				break;
+			case GH_VCPU_STATE_POWERED_OFF:
+				/* vcpu might be off because the VM is shut down.
+				 * If so, it won't ever run again: exit back to user
+				 */
+				if (!gh_vcpu_check_system(vcpu))
+					goto out;
+				/* Otherwise, another vcpu will turn it on (e.g. by PSCI)
+				 * and hyp sends an interrupt to wake Linux up.
+				 */
+				fallthrough;
+			case GH_VCPU_STATE_EXPECTS_WAKEUP:
+				ret = wait_for_completion_interruptible(&vcpu->ready);
+				/* reinitialize completion before next hypercall. If we reinitialize
+				 * after the hypercall, interrupt may have already come before
+				 * re-initializing the completion and then end up waiting for
+				 * event that already happened.
+				 */
+				reinit_completion(&vcpu->ready);
+				/* Check system status again. Completion might've
+				 * come from gh_vcpu_rm_notification
+				 */
+				if (!ret && !gh_vcpu_check_system(vcpu))
+					goto out;
+				break;
+			case GH_VCPU_STATE_BLOCKED:
+				schedule();
+				break;
+			case GH_VCPU_ADDRSPACE_VMMIO_READ:
+			case GH_VCPU_ADDRSPACE_VMMIO_WRITE:
+				if (!gh_handle_mmio(vcpu, &vcpu_run_resp))
+					goto out;
+				break;
+			default:
+				pr_warn_ratelimited("Unknown vCPU state: %llx\n",
+							vcpu_run_resp.sized_state);
+				schedule();
+				break;
+			}
+		} else if (gh_error == GH_ERROR_RETRY) {
+			schedule();
+		} else {
+			ret = gh_error_remap(gh_error);
+		}
+	}
+
+out:
+	mutex_unlock(&vcpu->run_lock);
+
+	if (signal_pending(current))
+		return -ERESTARTSYS;
+
+	return ret;
+}
+
+static long gh_vcpu_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
+{
+	struct gh_vcpu *vcpu = filp->private_data;
+	long ret = -EINVAL;
+
+	switch (cmd) {
+	case GH_VCPU_RUN:
+		ret = gh_vcpu_run(vcpu);
+		break;
+	case GH_VCPU_MMAP_SIZE:
+		ret = PAGE_SIZE;
+		break;
+	default:
+		break;
+	}
+	return ret;
+}
+
+static int gh_vcpu_release(struct inode *inode, struct file *filp)
+{
+	struct gh_vcpu *vcpu = filp->private_data;
+
+	gh_vm_put(vcpu->ghvm);
+	kref_put(&vcpu->kref, vcpu_release);
+	return 0;
+}
+
+static vm_fault_t gh_vcpu_fault(struct vm_fault *vmf)
+{
+	struct gh_vcpu *vcpu = vmf->vma->vm_file->private_data;
+	struct page *page = NULL;
+
+	if (vmf->pgoff == 0)
+		page = virt_to_page(vcpu->vcpu_run);
+
+	get_page(page);
+	vmf->page = page;
+	return 0;
+}
+
+static const struct vm_operations_struct gh_vcpu_ops = {
+	.fault = gh_vcpu_fault,
+};
+
+static int gh_vcpu_mmap(struct file *file, struct vm_area_struct *vma)
+{
+	vma->vm_ops = &gh_vcpu_ops;
+	return 0;
+}
+
+static const struct file_operations gh_vcpu_fops = {
+	.owner = THIS_MODULE,
+	.unlocked_ioctl = gh_vcpu_ioctl,
+	.release = gh_vcpu_release,
+	.llseek = noop_llseek,
+	.mmap = gh_vcpu_mmap,
+};
+
+static bool gh_vcpu_populate(struct gh_vm_resource_ticket *ticket, struct gh_resource *ghrsc)
+{
+	struct gh_vcpu *vcpu = container_of(ticket, struct gh_vcpu, ticket);
+	int ret;
+
+	mutex_lock(&vcpu->run_lock);
+	if (vcpu->rsc) {
+		pr_warn("vcpu%d already got a Gunyah resource. Check if multiple resources with same label were configured.\n",
+			vcpu->ticket.label);
+		ret = -EEXIST;
+		goto out;
+	}
+
+	vcpu->rsc = ghrsc;
+	init_completion(&vcpu->ready);
+
+	ret = request_irq(vcpu->rsc->irq, gh_vcpu_irq_handler, IRQF_TRIGGER_RISING, "gh_vcpu",
+			vcpu);
+	if (ret)
+		pr_warn("Failed to request vcpu irq %d: %d", vcpu->rsc->irq, ret);
+
+	enable_irq_wake(vcpu->rsc->irq);
+
+out:
+	mutex_unlock(&vcpu->run_lock);
+	return !ret;
+}
+
+static void gh_vcpu_unpopulate(struct gh_vm_resource_ticket *ticket,
+				   struct gh_resource *ghrsc)
+{
+	struct gh_vcpu *vcpu = container_of(ticket, struct gh_vcpu, ticket);
+
+	vcpu->vcpu_run->immediate_exit = true;
+	complete_all(&vcpu->ready);
+	mutex_lock(&vcpu->run_lock);
+	free_irq(vcpu->rsc->irq, vcpu);
+	vcpu->rsc = NULL;
+	mutex_unlock(&vcpu->run_lock);
+}
+
+static long gh_vcpu_bind(struct gh_vm_function_instance *f)
+{
+	struct gh_fn_vcpu_arg *arg = f->argp;
+	struct gh_vcpu *vcpu;
+	char name[MAX_VCPU_NAME];
+	struct file *file;
+	struct page *page;
+	int fd;
+	long r;
+
+	if (f->arg_size != sizeof(*arg))
+		return -EINVAL;
+
+	vcpu = kzalloc(sizeof(*vcpu), GFP_KERNEL);
+	if (!vcpu)
+		return -ENOMEM;
+
+	vcpu->f = f;
+	f->data = vcpu;
+	mutex_init(&vcpu->run_lock);
+	kref_init(&vcpu->kref);
+
+	page = alloc_page(GFP_KERNEL | __GFP_ZERO);
+	if (!page) {
+		r = -ENOMEM;
+		goto err_destroy_vcpu;
+	}
+	vcpu->vcpu_run = page_address(page);
+
+	vcpu->ticket.resource_type = GH_RESOURCE_TYPE_VCPU;
+	vcpu->ticket.label = arg->id;
+	vcpu->ticket.owner = THIS_MODULE;
+	vcpu->ticket.populate = gh_vcpu_populate;
+	vcpu->ticket.unpopulate = gh_vcpu_unpopulate;
+
+	r = gh_vm_add_resource_ticket(f->ghvm, &vcpu->ticket);
+	if (r)
+		goto err_destroy_page;
+
+	if (!gh_vm_get(f->ghvm)) {
+		r = -ENODEV;
+		goto err_remove_resource_ticket;
+	}
+	vcpu->ghvm = f->ghvm;
+
+	vcpu->nb.notifier_call = gh_vcpu_rm_notification;
+	/* Ensure we run after the vm_mgr handles the notification and does
+	 * any necessary state changes. We wake up to check the new state.
+	 */
+	vcpu->nb.priority = -1;
+	r = gh_rm_notifier_register(f->rm, &vcpu->nb);
+	if (r)
+		goto err_put_gh_vm;
+
+	kref_get(&vcpu->kref);
+
+	fd = get_unused_fd_flags(O_CLOEXEC);
+	if (fd < 0) {
+		r = fd;
+		goto err_notifier;
+	}
+
+	snprintf(name, sizeof(name), "gh-vcpu:%u", vcpu->ticket.label);
+	file = anon_inode_getfile(name, &gh_vcpu_fops, vcpu, O_RDWR);
+	if (IS_ERR(file)) {
+		r = PTR_ERR(file);
+		goto err_put_fd;
+	}
+
+	fd_install(fd, file);
+
+	return fd;
+err_put_fd:
+	put_unused_fd(fd);
+err_notifier:
+	gh_rm_notifier_unregister(f->rm, &vcpu->nb);
+err_put_gh_vm:
+	gh_vm_put(vcpu->ghvm);
+err_remove_resource_ticket:
+	gh_vm_remove_resource_ticket(f->ghvm, &vcpu->ticket);
+err_destroy_page:
+	free_page((unsigned long)vcpu->vcpu_run);
+err_destroy_vcpu:
+	kfree(vcpu);
+	return r;
+}
+
+static void gh_vcpu_unbind(struct gh_vm_function_instance *f)
+{
+	struct gh_vcpu *vcpu = f->data;
+
+	gh_rm_notifier_unregister(f->rm, &vcpu->nb);
+	gh_vm_remove_resource_ticket(vcpu->f->ghvm, &vcpu->ticket);
+	vcpu->f = NULL;
+
+	kref_put(&vcpu->kref, vcpu_release);
+}
+
+static bool gh_vcpu_compare(const struct gh_vm_function_instance *f,
+				const void *arg, size_t size)
+{
+	const struct gh_fn_vcpu_arg *instance = f->argp,
+					 *other = arg;
+
+	if (sizeof(*other) != size)
+		return false;
+
+	return instance->id == other->id;
+}
+
+DECLARE_GH_VM_FUNCTION_INIT(vcpu, GH_FN_VCPU, 1, gh_vcpu_bind, gh_vcpu_unbind, gh_vcpu_compare);
+MODULE_DESCRIPTION("Gunyah vCPU Function");
+MODULE_LICENSE("GPL");
diff --git a/drivers/virt/gunyah/vm_mgr.c b/drivers/virt/gunyah/vm_mgr.c
index 28da1f95e49ec..afea4923847f1 100644
--- a/drivers/virt/gunyah/vm_mgr.c
+++ b/drivers/virt/gunyah/vm_mgr.c
@@ -405,6 +405,10 @@ static int gh_vm_rm_notification_exited(struct gh_vm *ghvm, void *data)
 
 	down_write(&ghvm->status_lock);
 	ghvm->vm_status = GH_RM_VM_STATUS_EXITED;
+	ghvm->exit_info.type = le16_to_cpu(payload->exit_type);
+	ghvm->exit_info.reason_size = le32_to_cpu(payload->exit_reason_size);
+	memcpy(&ghvm->exit_info.reason, payload->exit_reason,
+		min(GH_VM_MAX_EXIT_REASON_SIZE, ghvm->exit_info.reason_size));
 	up_write(&ghvm->status_lock);
 	wake_up(&ghvm->vm_status_wait);
 
diff --git a/drivers/virt/gunyah/vm_mgr.h b/drivers/virt/gunyah/vm_mgr.h
index 3fc0f91dfd1a9..fa2a61e10b57a 100644
--- a/drivers/virt/gunyah/vm_mgr.h
+++ b/drivers/virt/gunyah/vm_mgr.h
@@ -45,6 +45,7 @@ struct gh_vm {
 	enum gh_rm_vm_status vm_status;
 	wait_queue_head_t vm_status_wait;
 	struct rw_semaphore status_lock;
+	struct gh_vm_exit_info exit_info;
 
 	struct work_struct free_work;
 	struct kref kref;
diff --git a/include/linux/gunyah.h b/include/linux/gunyah.h
index 4b398b59c2c5a..cd5704a82c6a5 100644
--- a/include/linux/gunyah.h
+++ b/include/linux/gunyah.h
@@ -177,4 +177,28 @@ enum gh_error gh_hypercall_msgq_send(u64 capid, size_t size, void *buff, u64 tx_
 enum gh_error gh_hypercall_msgq_recv(u64 capid, void *buff, size_t size, size_t *recv_size,
 					bool *ready);
 
+struct gh_hypercall_vcpu_run_resp {
+	union {
+		enum {
+			/* VCPU is ready to run */
+			GH_VCPU_STATE_READY		= 0,
+			/* VCPU is sleeping until an interrupt arrives */
+			GH_VCPU_STATE_EXPECTS_WAKEUP	= 1,
+			/* VCPU is powered off */
+			GH_VCPU_STATE_POWERED_OFF	= 2,
+			/* VCPU is blocked in EL2 for unspecified reason */
+			GH_VCPU_STATE_BLOCKED		= 3,
+			/* VCPU has returned for MMIO READ */
+			GH_VCPU_ADDRSPACE_VMMIO_READ	= 4,
+			/* VCPU has returned for MMIO WRITE */
+			GH_VCPU_ADDRSPACE_VMMIO_WRITE	= 5,
+		} state;
+		u64 sized_state;
+	};
+	u64 state_data[3];
+};
+
+enum gh_error gh_hypercall_vcpu_run(u64 capid, u64 *resume_data,
+					struct gh_hypercall_vcpu_run_resp *resp);
+
 #endif
diff --git a/include/uapi/linux/gunyah.h b/include/uapi/linux/gunyah.h
index bb07118a351fd..434ffa8ffc783 100644
--- a/include/uapi/linux/gunyah.h
+++ b/include/uapi/linux/gunyah.h
@@ -72,8 +72,33 @@ struct gh_vm_dtb_config {
 
 #define GH_VM_START		_IO(GH_IOCTL_TYPE, 0x3)
 
+/**
+ * enum gh_fn_type - Valid types of Gunyah VM functions
+ * @GH_FN_VCPU: create a vCPU instance to control a vCPU
+ *              &struct gh_fn_desc.arg is a pointer to &struct gh_fn_vcpu_arg
+ *              Return: file descriptor to manipulate the vcpu.
+ */
+enum gh_fn_type {
+	GH_FN_VCPU = 1,
+};
+
 #define GH_FN_MAX_ARG_SIZE		256
 
+/**
+ * struct gh_fn_vcpu_arg - Arguments to create a vCPU.
+ * @id: vcpu id
+ *
+ * Create this function with &GH_VM_ADD_FUNCTION using type &GH_FN_VCPU.
+ *
+ * The vcpu type will register with the VM Manager to expect to control
+ * vCPU number `vcpu_id`. It returns a file descriptor allowing interaction with
+ * the vCPU. See the Gunyah vCPU API description sections for interacting with
+ * the Gunyah vCPU file descriptors.
+ */
+struct gh_fn_vcpu_arg {
+	__u32 id;
+};
+
 /**
  * struct gh_fn_desc - Arguments to create a VM function
  * @type: Type of the function. See &enum gh_fn_type.
@@ -90,4 +115,107 @@ struct gh_fn_desc {
 #define GH_VM_ADD_FUNCTION	_IOW(GH_IOCTL_TYPE, 0x4, struct gh_fn_desc)
 #define GH_VM_REMOVE_FUNCTION	_IOW(GH_IOCTL_TYPE, 0x7, struct gh_fn_desc)
 
+/*
+ * ioctls for vCPU fds
+ */
+
+/**
+ * enum gh_vm_status - Stores status reason why VM is not runnable (exited).
+ * @GH_VM_STATUS_LOAD_FAILED: VM didn't start because it couldn't be loaded.
+ * @GH_VM_STATUS_EXITED: VM requested shutdown/reboot.
+ *                       Use &struct gh_vm_exit_info.reason for further details.
+ * @GH_VM_STATUS_CRASHED: VM state is unknown and has crashed.
+ */
+enum gh_vm_status {
+	GH_VM_STATUS_LOAD_FAILED	= 1,
+	GH_VM_STATUS_EXITED		= 2,
+	GH_VM_STATUS_CRASHED		= 3,
+};
+
+/*
+ * Gunyah presently sends max 4 bytes of exit_reason.
+ * If that changes, this macro can be safely increased without breaking
+ * userspace so long as struct gh_vcpu_run < PAGE_SIZE.
+ */
+#define GH_VM_MAX_EXIT_REASON_SIZE	8u
+
+/**
+ * struct gh_vm_exit_info - Reason for VM exit as reported by Gunyah
+ * See Gunyah documentation for values.
+ * @type: Describes how VM exited
+ * @padding: padding bytes
+ * @reason_size: Number of bytes valid for `reason`
+ * @reason: See Gunyah documentation for interpretation. Note: these values are
+ *          not interpreted by Linux and need to be converted from little-endian
+ *          as applicable.
+ */
+struct gh_vm_exit_info {
+	__u16 type;
+	__u16 padding;
+	__u32 reason_size;
+	__u8 reason[GH_VM_MAX_EXIT_REASON_SIZE];
+};
+
+/**
+ * enum gh_vcpu_exit - Stores reason why &GH_VCPU_RUN ioctl recently exited with status 0
+ * @GH_VCPU_EXIT_UNKNOWN: Not used, status != 0
+ * @GH_VCPU_EXIT_MMIO: vCPU performed a read or write that could not be handled
+ *                     by hypervisor or Linux. Use @struct gh_vcpu_run.mmio for
+ *                     details of the read/write.
+ * @GH_VCPU_EXIT_STATUS: vCPU not able to run because the VM has exited.
+ *                       Use @struct gh_vcpu_run.status for why VM has exited.
+ */
+enum gh_vcpu_exit {
+	GH_VCPU_EXIT_UNKNOWN,
+	GH_VCPU_EXIT_MMIO,
+	GH_VCPU_EXIT_STATUS,
+};
+
+/**
+ * struct gh_vcpu_run - Application code obtains a pointer to the gh_vcpu_run
+ *                      structure by mmap()ing a vcpu fd.
+ * @immediate_exit: polled when scheduling the vcpu. If set, immediately returns -EINTR.
+ * @padding: padding bytes
+ * @exit_reason: Set when GH_VCPU_RUN returns successfully and gives reason why
+ *               GH_VCPU_RUN has stopped running the vCPU. See &enum gh_vcpu_exit.
+ * @mmio: Used when exit_reason == GH_VCPU_EXIT_MMIO
+ *        The guest has faulted on an memory-mapped I/O instruction that
+ *        couldn't be satisfied by gunyah.
+ * @mmio.phys_addr: Address guest tried to access
+ * @mmio.data: the value that was written if `is_write == 1`. Filled by
+ *        user for reads (`is_write == 0`).
+ * @mmio.len: Length of write. Only the first `len` bytes of `data`
+ *       are considered by Gunyah.
+ * @mmio.is_write: 1 if VM tried to perform a write, 0 for a read
+ * @status: Used when exit_reason == GH_VCPU_EXIT_STATUS.
+ *          The guest VM is no longer runnable. This struct informs why.
+ * @status.status: See &enum gh_vm_status for possible values
+ * @status.exit_info: Used when status == GH_VM_STATUS_EXITED
+ */
+struct gh_vcpu_run {
+	/* in */
+	__u8 immediate_exit;
+	__u8 padding[7];
+
+	/* out */
+	__u32 exit_reason;
+
+	union {
+		struct {
+			__u64 phys_addr;
+			__u8  data[8];
+			__u32 len;
+			__u8  is_write;
+		} mmio;
+
+		struct {
+			enum gh_vm_status status;
+			struct gh_vm_exit_info exit_info;
+		} status;
+	};
+};
+
+#define GH_VCPU_RUN		_IO(GH_IOCTL_TYPE, 0x5)
+#define GH_VCPU_MMAP_SIZE	_IO(GH_IOCTL_TYPE, 0x6)
+
 #endif
-- 
2.40.0

[PATCH v14 22/25] virt: gunyah: Add hypercalls for sending doorbell

[Elliot Berman]

Gunyah doorbells allow two virtual machines to signal each other using
interrupts. Add the hypercalls needed to assert the interrupt.

Reviewed-by: Alex Elder <elder@linaro.org>
Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
---
 arch/arm64/gunyah/gunyah_hypercall.c | 25 +++++++++++++++++++++++++
 include/linux/gunyah.h               |  3 +++
 2 files changed, 28 insertions(+)

diff --git a/arch/arm64/gunyah/gunyah_hypercall.c b/arch/arm64/gunyah/gunyah_hypercall.c
index 7d96491f84e00..e178b5a0f6917 100644
--- a/arch/arm64/gunyah/gunyah_hypercall.c
+++ b/arch/arm64/gunyah/gunyah_hypercall.c
@@ -35,6 +35,8 @@ EXPORT_SYMBOL_GPL(arch_is_gh_guest);
 						   fn)
 
 #define GH_HYPERCALL_HYP_IDENTIFY		GH_HYPERCALL(0x8000)
+#define GH_HYPERCALL_BELL_SEND			GH_HYPERCALL(0x8012)
+#define GH_HYPERCALL_BELL_SET_MASK		GH_HYPERCALL(0x8015)
 #define GH_HYPERCALL_MSGQ_SEND			GH_HYPERCALL(0x801B)
 #define GH_HYPERCALL_MSGQ_RECV			GH_HYPERCALL(0x801C)
 #define GH_HYPERCALL_VCPU_RUN			GH_HYPERCALL(0x8065)
@@ -57,6 +59,29 @@ void gh_hypercall_hyp_identify(struct gh_hypercall_hyp_identify_resp *hyp_identi
 }
 EXPORT_SYMBOL_GPL(gh_hypercall_hyp_identify);
 
+enum gh_error gh_hypercall_bell_send(u64 capid, u64 new_flags, u64 *old_flags)
+{
+	struct arm_smccc_res res;
+
+	arm_smccc_1_1_hvc(GH_HYPERCALL_BELL_SEND, capid, new_flags, 0, &res);
+
+	if (res.a0 == GH_ERROR_OK && old_flags)
+		*old_flags = res.a1;
+
+	return res.a0;
+}
+EXPORT_SYMBOL_GPL(gh_hypercall_bell_send);
+
+enum gh_error gh_hypercall_bell_set_mask(u64 capid, u64 enable_mask, u64 ack_mask)
+{
+	struct arm_smccc_res res;
+
+	arm_smccc_1_1_hvc(GH_HYPERCALL_BELL_SET_MASK, capid, enable_mask, ack_mask, 0, &res);
+
+	return res.a0;
+}
+EXPORT_SYMBOL_GPL(gh_hypercall_bell_set_mask);
+
 enum gh_error gh_hypercall_msgq_send(u64 capid, size_t size, void *buff, u64 tx_flags, bool *ready)
 {
 	struct arm_smccc_res res;
diff --git a/include/linux/gunyah.h b/include/linux/gunyah.h
index cd5704a82c6a5..1f1685518bf3c 100644
--- a/include/linux/gunyah.h
+++ b/include/linux/gunyah.h
@@ -171,6 +171,9 @@ static inline u16 gh_api_version(const struct gh_hypercall_hyp_identify_resp *gh
 
 void gh_hypercall_hyp_identify(struct gh_hypercall_hyp_identify_resp *hyp_identity);
 
+enum gh_error gh_hypercall_bell_send(u64 capid, u64 new_flags, u64 *old_flags);
+enum gh_error gh_hypercall_bell_set_mask(u64 capid, u64 enable_mask, u64 ack_mask);
+
 #define GH_HYPERCALL_MSGQ_TX_FLAGS_PUSH		BIT(0)
 
 enum gh_error gh_hypercall_msgq_send(u64 capid, size_t size, void *buff, u64 tx_flags, bool *ready);
-- 
2.40.0

[PATCH v14 23/25] virt: gunyah: Add irqfd interface

[Elliot Berman]

Enable support for creating irqfds which can raise an interrupt on a
Gunyah virtual machine. irqfds are exposed to userspace as a Gunyah VM
function with the name "irqfd". If the VM devicetree is not configured
to create a doorbell with the corresponding label, userspace will still
be able to assert the eventfd but no interrupt will be raised on the
guest.

Acked-by: Alex Elder <elder@linaro.org>
Co-developed-by: Prakruthi Deepak Heragu <quic_pheragu@quicinc.com>
Signed-off-by: Prakruthi Deepak Heragu <quic_pheragu@quicinc.com>
Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
---
 Documentation/virt/gunyah/vm-manager.rst |   2 +-
 drivers/virt/gunyah/Kconfig              |   9 ++
 drivers/virt/gunyah/Makefile             |   1 +
 drivers/virt/gunyah/gunyah_irqfd.c       | 180 +++++++++++++++++++++++
 include/uapi/linux/gunyah.h              |  35 +++++
 5 files changed, 226 insertions(+), 1 deletion(-)
 create mode 100644 drivers/virt/gunyah/gunyah_irqfd.c

diff --git a/Documentation/virt/gunyah/vm-manager.rst b/Documentation/virt/gunyah/vm-manager.rst
index b0c3bde105ae9..57a254827be26 100644
--- a/Documentation/virt/gunyah/vm-manager.rst
+++ b/Documentation/virt/gunyah/vm-manager.rst
@@ -116,7 +116,7 @@ the VM *before* the VM starts.
 The argument types are documented below:
 
 .. kernel-doc:: include/uapi/linux/gunyah.h
-   :identifiers: gh_fn_vcpu_arg
+   :identifiers: gh_fn_vcpu_arg gh_fn_irqfd_arg gh_irqfd_flags
 
 Gunyah VCPU API Descriptions
 ----------------------------
diff --git a/drivers/virt/gunyah/Kconfig b/drivers/virt/gunyah/Kconfig
index 0a58395f7d2c5..bc2c46d9df946 100644
--- a/drivers/virt/gunyah/Kconfig
+++ b/drivers/virt/gunyah/Kconfig
@@ -39,3 +39,12 @@ config GUNYAH_VCPU
 	  VMMs can also handle stage 2 faults of the vCPUs.
 
 	  Say Y/M here if unsure and you want to support Gunyah VMMs.
+
+config GUNYAH_IRQFD
+	tristate "Gunyah irqfd interface"
+	depends on GUNYAH
+	help
+	  Enable kernel support for creating irqfds which can raise an interrupt
+	  on Gunyah virtual machine.
+
+	  Say Y/M here if unsure and you want to support Gunyah VMMs.
diff --git a/drivers/virt/gunyah/Makefile b/drivers/virt/gunyah/Makefile
index cc16b6c19db92..ad212a1cf9671 100644
--- a/drivers/virt/gunyah/Makefile
+++ b/drivers/virt/gunyah/Makefile
@@ -7,3 +7,4 @@ gunyah-y += rsc_mgr.o rsc_mgr_rpc.o vm_mgr.o vm_mgr_mm.o
 obj-$(CONFIG_GUNYAH) += gunyah.o
 
 obj-$(CONFIG_GUNYAH_VCPU) += gunyah_vcpu.o
+obj-$(CONFIG_GUNYAH_IRQFD) += gunyah_irqfd.o
diff --git a/drivers/virt/gunyah/gunyah_irqfd.c b/drivers/virt/gunyah/gunyah_irqfd.c
new file mode 100644
index 0000000000000..3e954ebd20297
--- /dev/null
+++ b/drivers/virt/gunyah/gunyah_irqfd.c
@@ -0,0 +1,180 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#include <linux/eventfd.h>
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/gunyah.h>
+#include <linux/gunyah_vm_mgr.h>
+#include <linux/module.h>
+#include <linux/poll.h>
+#include <linux/printk.h>
+
+#include <uapi/linux/gunyah.h>
+
+struct gh_irqfd {
+	struct gh_resource *ghrsc;
+	struct gh_vm_resource_ticket ticket;
+	struct gh_vm_function_instance *f;
+
+	bool level;
+
+	struct eventfd_ctx *ctx;
+	wait_queue_entry_t wait;
+	poll_table pt;
+};
+
+static int irqfd_wakeup(wait_queue_entry_t *wait, unsigned int mode, int sync, void *key)
+{
+	struct gh_irqfd *irqfd = container_of(wait, struct gh_irqfd, wait);
+	__poll_t flags = key_to_poll(key);
+	int ret = 0;
+
+	if (flags & EPOLLIN) {
+		if (irqfd->ghrsc) {
+			ret = gh_hypercall_bell_send(irqfd->ghrsc->capid, 1, NULL);
+			if (ret)
+				pr_err_ratelimited("Failed to inject interrupt %d: %d\n",
+						irqfd->ticket.label, ret);
+		} else
+			pr_err_ratelimited("Premature injection of interrupt\n");
+	}
+
+	return 0;
+}
+
+static void irqfd_ptable_queue_proc(struct file *file, wait_queue_head_t *wqh, poll_table *pt)
+{
+	struct gh_irqfd *irq_ctx = container_of(pt, struct gh_irqfd, pt);
+
+	add_wait_queue(wqh, &irq_ctx->wait);
+}
+
+static bool gh_irqfd_populate(struct gh_vm_resource_ticket *ticket, struct gh_resource *ghrsc)
+{
+	struct gh_irqfd *irqfd = container_of(ticket, struct gh_irqfd, ticket);
+	int ret;
+
+	if (irqfd->ghrsc) {
+		pr_warn("irqfd%d already got a Gunyah resource. Check if multiple resources with same label were configured.\n",
+			irqfd->ticket.label);
+		return false;
+	}
+
+	irqfd->ghrsc = ghrsc;
+	if (irqfd->level) {
+		/* Configure the bell to trigger when bit 0 is asserted (see
+		 * irq_wakeup) and for bell to automatically clear bit 0 once
+		 * received by the VM (ack_mask).  need to make sure bit 0 is cleared right away,
+		 * otherwise the line will never be deasserted. Emulating edge
+		 * trigger interrupt does not need to set either mask
+		 * because irq is listed only once per gh_hypercall_bell_send
+		 */
+		ret = gh_hypercall_bell_set_mask(irqfd->ghrsc->capid, 1, 1);
+		if (ret)
+			pr_warn("irq %d couldn't be set as level triggered. Might cause IRQ storm if asserted\n",
+				irqfd->ticket.label);
+	}
+
+	return true;
+}
+
+static void gh_irqfd_unpopulate(struct gh_vm_resource_ticket *ticket, struct gh_resource *ghrsc)
+{
+	struct gh_irqfd *irqfd = container_of(ticket, struct gh_irqfd, ticket);
+	u64 cnt;
+
+	eventfd_ctx_remove_wait_queue(irqfd->ctx, &irqfd->wait, &cnt);
+}
+
+static long gh_irqfd_bind(struct gh_vm_function_instance *f)
+{
+	struct gh_fn_irqfd_arg *args = f->argp;
+	struct gh_irqfd *irqfd;
+	__poll_t events;
+	struct fd fd;
+	long r;
+
+	if (f->arg_size != sizeof(*args))
+		return -EINVAL;
+
+	/* All other flag bits are reserved for future use */
+	if (args->flags & ~GH_IRQFD_FLAGS_LEVEL)
+		return -EINVAL;
+
+	irqfd = kzalloc(sizeof(*irqfd), GFP_KERNEL);
+	if (!irqfd)
+		return -ENOMEM;
+
+	irqfd->f = f;
+	f->data = irqfd;
+
+	fd = fdget(args->fd);
+	if (!fd.file) {
+		kfree(irqfd);
+		return -EBADF;
+	}
+
+	irqfd->ctx = eventfd_ctx_fileget(fd.file);
+	if (IS_ERR(irqfd->ctx)) {
+		r = PTR_ERR(irqfd->ctx);
+		goto err_fdput;
+	}
+
+	if (args->flags & GH_IRQFD_FLAGS_LEVEL)
+		irqfd->level = true;
+
+	init_waitqueue_func_entry(&irqfd->wait, irqfd_wakeup);
+	init_poll_funcptr(&irqfd->pt, irqfd_ptable_queue_proc);
+
+	irqfd->ticket.resource_type = GH_RESOURCE_TYPE_BELL_TX;
+	irqfd->ticket.label = args->label;
+	irqfd->ticket.owner = THIS_MODULE;
+	irqfd->ticket.populate = gh_irqfd_populate;
+	irqfd->ticket.unpopulate = gh_irqfd_unpopulate;
+
+	r = gh_vm_add_resource_ticket(f->ghvm, &irqfd->ticket);
+	if (r)
+		goto err_ctx;
+
+	events = vfs_poll(fd.file, &irqfd->pt);
+	if (events & EPOLLIN)
+		pr_warn("Premature injection of interrupt\n");
+	fdput(fd);
+
+	return 0;
+err_ctx:
+	eventfd_ctx_put(irqfd->ctx);
+err_fdput:
+	fdput(fd);
+	kfree(irqfd);
+	return r;
+}
+
+static void gh_irqfd_unbind(struct gh_vm_function_instance *f)
+{
+	struct gh_irqfd *irqfd = f->data;
+
+	gh_vm_remove_resource_ticket(irqfd->f->ghvm, &irqfd->ticket);
+	eventfd_ctx_put(irqfd->ctx);
+	kfree(irqfd);
+}
+
+static bool gh_irqfd_compare(const struct gh_vm_function_instance *f,
+				const void *arg, size_t size)
+{
+	const struct gh_fn_irqfd_arg *instance = f->argp,
+					 *other = arg;
+
+	if (sizeof(*other) != size)
+		return false;
+
+	return instance->label == other->label;
+}
+
+DECLARE_GH_VM_FUNCTION_INIT(irqfd, GH_FN_IRQFD, 2, gh_irqfd_bind, gh_irqfd_unbind,
+				gh_irqfd_compare);
+MODULE_DESCRIPTION("Gunyah irqfd VM Function");
+MODULE_LICENSE("GPL");
diff --git a/include/uapi/linux/gunyah.h b/include/uapi/linux/gunyah.h
index 434ffa8ffc783..0c480c622686a 100644
--- a/include/uapi/linux/gunyah.h
+++ b/include/uapi/linux/gunyah.h
@@ -77,9 +77,12 @@ struct gh_vm_dtb_config {
  * @GH_FN_VCPU: create a vCPU instance to control a vCPU
  *              &struct gh_fn_desc.arg is a pointer to &struct gh_fn_vcpu_arg
  *              Return: file descriptor to manipulate the vcpu.
+ * @GH_FN_IRQFD: register eventfd to assert a Gunyah doorbell
+ *               &struct gh_fn_desc.arg is a pointer to &struct gh_fn_irqfd_arg
  */
 enum gh_fn_type {
 	GH_FN_VCPU = 1,
+	GH_FN_IRQFD,
 };
 
 #define GH_FN_MAX_ARG_SIZE		256
@@ -99,6 +102,38 @@ struct gh_fn_vcpu_arg {
 	__u32 id;
 };
 
+/**
+ * enum gh_irqfd_flags - flags for use in gh_fn_irqfd_arg
+ * @GH_IRQFD_FLAGS_LEVEL: make the interrupt operate like a level triggered
+ *                        interrupt on guest side. Triggering IRQFD before
+ *                        guest handles the interrupt causes interrupt to
+ *                        stay asserted.
+ */
+enum gh_irqfd_flags {
+	GH_IRQFD_FLAGS_LEVEL		= 1UL << 0,
+};
+
+/**
+ * struct gh_fn_irqfd_arg - Arguments to create an irqfd function.
+ *
+ * Create this function with &GH_VM_ADD_FUNCTION using type &GH_FN_IRQFD.
+ *
+ * Allows setting an eventfd to directly trigger a guest interrupt.
+ * irqfd.fd specifies the file descriptor to use as the eventfd.
+ * irqfd.label corresponds to the doorbell label used in the guest VM's devicetree.
+ *
+ * @fd: an eventfd which when written to will raise a doorbell
+ * @label: Label of the doorbell created on the guest VM
+ * @flags: see &enum gh_irqfd_flags
+ * @padding: padding bytes
+ */
+struct gh_fn_irqfd_arg {
+	__u32 fd;
+	__u32 label;
+	__u32 flags;
+	__u32 padding;
+};
+
 /**
  * struct gh_fn_desc - Arguments to create a VM function
  * @type: Type of the function. See &enum gh_fn_type.
-- 
2.40.0

[PATCH v14 24/25] virt: gunyah: Add ioeventfd

[Elliot Berman]

Allow userspace to attach an ioeventfd to an mmio address within the guest.

Reviewed-by: Alex Elder <elder@linaro.org>
Co-developed-by: Prakruthi Deepak Heragu <quic_pheragu@quicinc.com>
Signed-off-by: Prakruthi Deepak Heragu <quic_pheragu@quicinc.com>
Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
---
 Documentation/virt/gunyah/vm-manager.rst |   2 +-
 drivers/virt/gunyah/Kconfig              |   9 ++
 drivers/virt/gunyah/Makefile             |   1 +
 drivers/virt/gunyah/gunyah_ioeventfd.c   | 130 +++++++++++++++++++++++
 include/uapi/linux/gunyah.h              |  37 +++++++
 5 files changed, 178 insertions(+), 1 deletion(-)
 create mode 100644 drivers/virt/gunyah/gunyah_ioeventfd.c

diff --git a/Documentation/virt/gunyah/vm-manager.rst b/Documentation/virt/gunyah/vm-manager.rst
index 57a254827be26..415b11248e00b 100644
--- a/Documentation/virt/gunyah/vm-manager.rst
+++ b/Documentation/virt/gunyah/vm-manager.rst
@@ -116,7 +116,7 @@ the VM *before* the VM starts.
 The argument types are documented below:
 
 .. kernel-doc:: include/uapi/linux/gunyah.h
-   :identifiers: gh_fn_vcpu_arg gh_fn_irqfd_arg gh_irqfd_flags
+   :identifiers: gh_fn_vcpu_arg gh_fn_irqfd_arg gh_irqfd_flags gh_fn_ioeventfd_arg gh_ioeventfd_flags
 
 Gunyah VCPU API Descriptions
 ----------------------------
diff --git a/drivers/virt/gunyah/Kconfig b/drivers/virt/gunyah/Kconfig
index bc2c46d9df946..63bebc5b9f825 100644
--- a/drivers/virt/gunyah/Kconfig
+++ b/drivers/virt/gunyah/Kconfig
@@ -48,3 +48,12 @@ config GUNYAH_IRQFD
 	  on Gunyah virtual machine.
 
 	  Say Y/M here if unsure and you want to support Gunyah VMMs.
+
+config GUNYAH_IOEVENTFD
+	tristate "Gunyah ioeventfd interface"
+	depends on GUNYAH
+	help
+	  Enable kernel support for creating ioeventfds which can alert userspace
+	  when a Gunyah virtual machine accesses a memory address.
+
+	  Say Y/M here if unsure and you want to support Gunyah VMMs.
diff --git a/drivers/virt/gunyah/Makefile b/drivers/virt/gunyah/Makefile
index ad212a1cf9671..63ca11e747961 100644
--- a/drivers/virt/gunyah/Makefile
+++ b/drivers/virt/gunyah/Makefile
@@ -8,3 +8,4 @@ obj-$(CONFIG_GUNYAH) += gunyah.o
 
 obj-$(CONFIG_GUNYAH_VCPU) += gunyah_vcpu.o
 obj-$(CONFIG_GUNYAH_IRQFD) += gunyah_irqfd.o
+obj-$(CONFIG_GUNYAH_IOEVENTFD) += gunyah_ioeventfd.o
diff --git a/drivers/virt/gunyah/gunyah_ioeventfd.c b/drivers/virt/gunyah/gunyah_ioeventfd.c
new file mode 100644
index 0000000000000..5b1b9fd9ac3aa
--- /dev/null
+++ b/drivers/virt/gunyah/gunyah_ioeventfd.c
@@ -0,0 +1,130 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#include <linux/eventfd.h>
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/gunyah.h>
+#include <linux/gunyah_vm_mgr.h>
+#include <linux/module.h>
+#include <linux/printk.h>
+
+#include <uapi/linux/gunyah.h>
+
+struct gh_ioeventfd {
+	struct gh_vm_function_instance *f;
+	struct gh_vm_io_handler io_handler;
+
+	struct eventfd_ctx *ctx;
+};
+
+static int gh_write_ioeventfd(struct gh_vm_io_handler *io_dev, u64 addr, u32 len, u64 data)
+{
+	struct gh_ioeventfd *iofd = container_of(io_dev, struct gh_ioeventfd, io_handler);
+
+	eventfd_signal(iofd->ctx, 1);
+	return 0;
+}
+
+static struct gh_vm_io_handler_ops io_ops = {
+	.write = gh_write_ioeventfd,
+};
+
+static long gh_ioeventfd_bind(struct gh_vm_function_instance *f)
+{
+	const struct gh_fn_ioeventfd_arg *args = f->argp;
+	struct gh_ioeventfd *iofd;
+	struct eventfd_ctx *ctx;
+	int ret;
+
+	if (f->arg_size != sizeof(*args))
+		return -EINVAL;
+
+	/* All other flag bits are reserved for future use */
+	if (args->flags & ~GH_IOEVENTFD_FLAGS_DATAMATCH)
+		return -EINVAL;
+
+	/* must be natural-word sized, or 0 to ignore length */
+	switch (args->len) {
+	case 0:
+	case 1:
+	case 2:
+	case 4:
+	case 8:
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	/* check for range overflow */
+	if (overflows_type(args->addr + args->len, u64))
+		return -EINVAL;
+
+	/* ioeventfd with no length can't be combined with DATAMATCH */
+	if (!args->len && (args->flags & GH_IOEVENTFD_FLAGS_DATAMATCH))
+		return -EINVAL;
+
+	ctx = eventfd_ctx_fdget(args->fd);
+	if (IS_ERR(ctx))
+		return PTR_ERR(ctx);
+
+	iofd = kzalloc(sizeof(*iofd), GFP_KERNEL);
+	if (!iofd) {
+		ret = -ENOMEM;
+		goto err_eventfd;
+	}
+
+	f->data = iofd;
+	iofd->f = f;
+
+	iofd->ctx = ctx;
+
+	if (args->flags & GH_IOEVENTFD_FLAGS_DATAMATCH) {
+		iofd->io_handler.datamatch = true;
+		iofd->io_handler.len = args->len;
+		iofd->io_handler.data = args->datamatch;
+	}
+	iofd->io_handler.addr = args->addr;
+	iofd->io_handler.ops = &io_ops;
+
+	ret = gh_vm_add_io_handler(f->ghvm, &iofd->io_handler);
+	if (ret)
+		goto err_io_dev_add;
+
+	return 0;
+
+err_io_dev_add:
+	kfree(iofd);
+err_eventfd:
+	eventfd_ctx_put(ctx);
+	return ret;
+}
+
+static void gh_ioevent_unbind(struct gh_vm_function_instance *f)
+{
+	struct gh_ioeventfd *iofd = f->data;
+
+	eventfd_ctx_put(iofd->ctx);
+	gh_vm_remove_io_handler(iofd->f->ghvm, &iofd->io_handler);
+	kfree(iofd);
+}
+
+static bool gh_ioevent_compare(const struct gh_vm_function_instance *f,
+				const void *arg, size_t size)
+{
+	const struct gh_fn_ioeventfd_arg *instance = f->argp,
+					 *other = arg;
+
+	if (sizeof(*other) != size)
+		return false;
+
+	return instance->addr == other->addr;
+}
+
+DECLARE_GH_VM_FUNCTION_INIT(ioeventfd, GH_FN_IOEVENTFD, 3,
+				gh_ioeventfd_bind, gh_ioevent_unbind,
+				gh_ioevent_compare);
+MODULE_DESCRIPTION("Gunyah ioeventfd VM Function");
+MODULE_LICENSE("GPL");
diff --git a/include/uapi/linux/gunyah.h b/include/uapi/linux/gunyah.h
index 0c480c622686a..fa1cae7419d2b 100644
--- a/include/uapi/linux/gunyah.h
+++ b/include/uapi/linux/gunyah.h
@@ -79,10 +79,13 @@ struct gh_vm_dtb_config {
  *              Return: file descriptor to manipulate the vcpu.
  * @GH_FN_IRQFD: register eventfd to assert a Gunyah doorbell
  *               &struct gh_fn_desc.arg is a pointer to &struct gh_fn_irqfd_arg
+ * @GH_FN_IOEVENTFD: register ioeventfd to trigger when VM faults on parameter
+ *                   &struct gh_fn_desc.arg is a pointer to &struct gh_fn_ioeventfd_arg
  */
 enum gh_fn_type {
 	GH_FN_VCPU = 1,
 	GH_FN_IRQFD,
+	GH_FN_IOEVENTFD,
 };
 
 #define GH_FN_MAX_ARG_SIZE		256
@@ -134,6 +137,40 @@ struct gh_fn_irqfd_arg {
 	__u32 padding;
 };
 
+/**
+ * enum gh_ioeventfd_flags - flags for use in gh_fn_ioeventfd_arg
+ * @GH_IOEVENTFD_FLAGS_DATAMATCH: the event will be signaled only if the
+ *                                written value to the registered address is
+ *                                equal to &struct gh_fn_ioeventfd_arg.datamatch
+ */
+enum gh_ioeventfd_flags {
+	GH_IOEVENTFD_FLAGS_DATAMATCH	= 1UL << 0,
+};
+
+/**
+ * struct gh_fn_ioeventfd_arg - Arguments to create an ioeventfd function
+ * @datamatch: data used when GH_IOEVENTFD_DATAMATCH is set
+ * @addr: Address in guest memory
+ * @len: Length of access
+ * @fd: When ioeventfd is matched, this eventfd is written
+ * @flags: See &enum gh_ioeventfd_flags
+ * @padding: padding bytes
+ *
+ * Create this function with &GH_VM_ADD_FUNCTION using type &GH_FN_IOEVENTFD.
+ *
+ * Attaches an ioeventfd to a legal mmio address within the guest. A guest write
+ * in the registered address will signal the provided event instead of triggering
+ * an exit on the GH_VCPU_RUN ioctl.
+ */
+struct gh_fn_ioeventfd_arg {
+	__u64 datamatch;
+	__u64 addr;        /* legal mmio address */
+	__u32 len;         /* 1, 2, 4, or 8 bytes; or 0 to ignore length */
+	__s32 fd;
+	__u32 flags;
+	__u32 padding;
+};
+
 /**
  * struct gh_fn_desc - Arguments to create a VM function
  * @type: Type of the function. See &enum gh_fn_type.
-- 
2.40.0

[PATCH v14 25/25] MAINTAINERS: Add Gunyah hypervisor drivers section

[Elliot Berman]

Add myself and Prakruthi as maintainers of Gunyah hypervisor drivers.

Reviewed-by: Alex Elder <elder@linaro.org>
Signed-off-by: Prakruthi Deepak Heragu <quic_pheragu@quicinc.com>
Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
---
 MAINTAINERS | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index f794002a192e2..b25e20c871827 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -8973,6 +8973,19 @@ L:	linux-efi@vger.kernel.org
 S:	Maintained
 F:	block/partitions/efi.*
 
+GUNYAH HYPERVISOR DRIVER
+M:	Elliot Berman <quic_eberman@quicinc.com>
+M:	Prakruthi Deepak Heragu <quic_pheragu@quicinc.com>
+L:	linux-arm-msm@vger.kernel.org
+S:	Supported
+F:	Documentation/devicetree/bindings/firmware/gunyah-hypervisor.yaml
+F:	Documentation/virt/gunyah/
+F:	arch/arm64/gunyah/
+F:	drivers/mailbox/gunyah-msgq.c
+F:	drivers/virt/gunyah/
+F:	include/linux/gunyah*.h
+F:	samples/gunyah/
+
 HABANALABS PCI DRIVER
 M:	Oded Gabbay <ogabbay@kernel.org>
 L:	dri-devel@lists.freedesktop.org
-- 
2.40.0

Re: [PATCH v14 01/25] docs: gunyah: Introduce Gunyah Hypervisor

[Alex Elder]

On 6/13/23 12:20 PM, Elliot Berman wrote:
> Gunyah is an open-source Type-1 hypervisor developed by Qualcomm. It
> does not depend on any lower-privileged OS/kernel code for its core
> functionality. This increases its security and can support a smaller
> trusted computing based when compared to Type-2 hypervisors.

s/based/base/

> 
> Add documentation describing the Gunyah hypervisor and the main
> components of the Gunyah hypervisor which are of interest to Linux
> virtualization development.
> 
> Reviewed-by: Bagas Sanjaya <bagasdotme@gmail.com>
> Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>

I have some questions and comments.  But I trust that you
can answer them and update your patch in a reasonable way
to address what I say.  So... please consider these things,
and update as you see fit.

Reviewed-by: Alex Elder <elder@linaro.org>

> ---
>   Documentation/virt/gunyah/index.rst         | 113 ++++++++++++++++++++
>   Documentation/virt/gunyah/message-queue.rst |  63 +++++++++++
>   Documentation/virt/index.rst                |   1 +
>   3 files changed, 177 insertions(+)
>   create mode 100644 Documentation/virt/gunyah/index.rst
>   create mode 100644 Documentation/virt/gunyah/message-queue.rst
> 
> diff --git a/Documentation/virt/gunyah/index.rst b/Documentation/virt/gunyah/index.rst
> new file mode 100644
> index 0000000000000..74aa345e0a144
> --- /dev/null
> +++ b/Documentation/virt/gunyah/index.rst
> @@ -0,0 +1,113 @@
> +.. SPDX-License-Identifier: GPL-2.0
> +
> +=================
> +Gunyah Hypervisor
> +=================
> +
> +.. toctree::
> +   :maxdepth: 1
> +
> +   message-queue
> +
> +Gunyah is a Type-1 hypervisor which is independent of any OS kernel, and runs in
> +a higher CPU privilege level. It does not depend on any lower-privileged operating system
> +for its core functionality. This increases its security and can support a much smaller
> +trusted computing base than a Type-2 hypervisor.
> +
> +Gunyah is an open source hypervisor. The source repo is available at
> +https://github.com/quic/gunyah-hypervisor.
> +
> +Gunyah provides these following features.
> +
> +- Scheduling:
> +
> +  A scheduler for virtual CPUs (vCPUs) on physical CPUs enables time-sharing
> +  of the CPUs. Gunyah supports two models of scheduling:
> +
> +    1. "Behind the back" scheduling in which Gunyah hypervisor schedules vCPUS on its own.

s/VCPUS/VCPUs/

> +    2. "Proxy" scheduling in which a delegated VM can donate part of one of its vCPU slice
> +       to another VM's vCPU via a hypercall.

This might sound dumb, but can there be more vCPUs than there
are physical CPUs?  Is a vCPU *tied* to a particular physical
CPU, or does it just indicate that a VM has one abstracted CPU
available to use--and any available physical CPU core can
implement it (possibly changing between time slices)?

> +
> +- Memory Management:
> +
> +  APIs handling memory, abstracted as objects, limiting direct use of physical
> +  addresses. Memory ownership and usage tracking of all memory under its control.
> +  Memory partitioning between VMs is a fundamental security feature.
> +
> +- Interrupt Virtualization:
> +
> +  Uses CPU hardware interrupt virtualization capabilities. Interrupts are handled
> +  in the hypervisor and routed to the assigned VM.
> +
> +- Inter-VM Communication:
> +
> +  There are several different mechanisms provided for communicating between VMs.
> +
> +- Virtual platform:
> +
> +  Architectural devices such as interrupt controllers and CPU timers are directly provided
> +  by the hypervisor as well as core virtual platform devices and system APIs such as ARM PSCI.
> +
> +- Device Virtualization:
> +
> +  Para-virtualization of devices is supported using inter-VM communication.
> +
> +Architectures supported
> +=======================
> +AArch64 with a GIC
> +
> +Resources and Capabilities
> +==========================
> +
> +Some services or resources provided by the Gunyah hypervisor are described to a virtual machine by
> +capability IDs. For instance, inter-VM communication is performed with doorbells and message queues.
> +Gunyah allows access to manipulate that doorbell via the capability ID. These resources are
> +described in Linux as a struct gh_resource.
> +
> +High level management of these resources is performed by the resource manager VM. RM informs a
> +guest VM about resources it can access through either the device tree or via guest-initiated RPC.
> +
> +For each virtual machine, Gunyah maintains a table of resources which can be accessed by that VM.
> +An entry in this table is called a "capability" and VMs can only access resources via this
> +capability table. Hence, virtual Gunyah resources are referenced by a "capability IDs" and not
> +"resource IDs". If 2 VMs have access to the same resource, they might not be using the same
> +capability ID to access that resource since the capability tables are independent per VM.
> +
> +Resource Manager
> +================
> +
> +The resource manager (RM) is a privileged application VM supporting the Gunyah Hypervisor.
> +It provides policy enforcement aspects of the virtualization system. The resource manager can
> +be treated as an extension of the Hypervisor but is separated to its own partition to ensure
> +that the hypervisor layer itself remains small and secure and to maintain a separation of policy
> +and mechanism in the platform. RM runs at arm64 NS-EL1 similar to other virtual machines.
> +
> +Communication with the resource manager from each guest VM happens with message-queue.rst. Details
> +about the specific messages can be found in drivers/virt/gunyah/rsc_mgr.c
> +
> +::
> +
> +  +-------+   +--------+   +--------+
> +  |  RM   |   |  VM_A  |   |  VM_B  |
> +  +-.-.-.-+   +---.----+   +---.----+
> +    | |           |            |
> +  +-.-.-----------.------------.----+
> +  | | \==========/             |    |
> +  |  \========================/     |
> +  |            Gunyah               |
> +  +---------------------------------+
> +
> +The source for the resource manager is available at https://github.com/quic/gunyah-resource-manager.
> +
> +The resource manager provides the following features:
> +
> +- VM lifecycle management: allocating a VM, starting VMs, destruction of VMs
> +- VM access control policy, including memory sharing and lending
> +- Interrupt routing configuration
> +- Forwarding of system-level events (e.g. VM shutdown) to owner VM
> +
> +When booting a virtual machine which uses a devicetree such as Linux, resource manager overlays a
> +/hypervisor node. This node can let Linux know it is running as a Gunyah guest VM,
> +how to communicate with resource manager, and basic description and capabilities of

Maybe:

This node lets Linux know it is running as a Gunyah guest VM.
It provides a basic description and capabilities of the VM,
as well as information required to communicate with the resource
manager.

> +this VM. See Documentation/devicetree/bindings/firmware/gunyah-hypervisor.yaml for a description
> +of this node.
> diff --git a/Documentation/virt/gunyah/message-queue.rst b/Documentation/virt/gunyah/message-queue.rst
> new file mode 100644
> index 0000000000000..b352918ae54b4
> --- /dev/null
> +++ b/Documentation/virt/gunyah/message-queue.rst
> @@ -0,0 +1,63 @@
> +.. SPDX-License-Identifier: GPL-2.0
> +
> +Message Queues
> +==============
> +Message queue is a simple low-capacity IPC channel between two VMs. It is

I don't know what the "capacity" of an IPC channel is.  But
that's OK I guess; it's sort of descriptive.

> +intended for sending small control and configuration messages. Each message
> +queue is unidirectional, so a full-duplex IPC channel requires a pair of queues.
> +
> +Messages can be up to 240 bytes in length. Longer messages require a further
> +protocol on top of the message queue messages themselves. For instance, communication
> +with the resource manager adds a header field for sending longer messages via multiple
> +message fragments.
> +
> +The diagram below shows how message queue works. A typical configuration involves
> +2 message queues. Message queue 1 allows VM_A to send messages to VM_B. Message
> +queue 2 allows VM_B to send messages to VM_A.
> +
> +1. VM_A sends a message of up to 240 bytes in length. It raises a hypercall
> +   with the message to inform the hypervisor to add the message to
> +   message queue 1's queue. The hypervisor copies memory into the internal
> +   message queue representation; the memory doesn't need to be shared between
> +   VM_A and VM_B.
> +
> +2. Gunyah raises the corresponding interrupt for VM_B (Rx vIRQ) when any of
> +   these happens:
> +
> +   a. gh_msgq_send() has PUSH flag. Queue is immediately flushed. This is the typical case.
> +   b. Explicility with gh_msgq_push command from VM_A.

s/Explicility/Explicitly/

Is gh_msgq_send() a function and gh_msgq_push a "command" or
something?  Why the difference in parentheses?  (Pick a
convention and follow it.)

Does "Queue is flushed" mean "VM_B is interrupted"?

VM_A calls gh_msgq_push, and that causes the VM_B interrupt to
be signaled?

I'm being a little picky but I think these descriptions could be
improved a bit.

> +   c. Message queue has reached a threshold depth.
> +
> +3. VM_B calls gh_msgq_recv() and Gunyah copies message to requested buffer.

It sure would be nice if all this didn't have to be copied
twice.  But I recognize the copies ensure isolation.

> +
> +4. Gunyah buffers messages in the queue. If the queue became full when VM_A added a message,
> +   the return values for gh_msgq_send() include a flag that indicates the queue is full.
> +   Once VM_B receives the message and, thus, there is space in the queue, Gunyah
> +   will raise the Tx vIRQ on VM_A to indicate it can continue sending messages.

Does the Tx vIRQ on VM_A fire after *every* message is sent,
or only when the state of the queue goes from "full" to "not"?
(Looking at patch 6 it looks like the latter.)

If it's signaled after every message is sent, does it
indicate that the message has been *received* by VM_B
(versus just received and copied by Gunyah)?

> +
> +For VM_B to send a message to VM_A, the process is identical, except that hypercalls
> +reference message queue 2's capability ID. Each message queue has its own independent
> +vIRQ: two TX message queues will have two vIRQs (and two capability IDs).
> +
> +::
> +
> +      +---------------+         +-----------------+         +---------------+
> +      |      VM_A     |         |Gunyah hypervisor|         |      VM_B     |
> +      |               |         |                 |         |               |
> +      |               |         |                 |         |               |
> +      |               |   Tx    |                 |         |               |
> +      |               |-------->|                 | Rx vIRQ |               |
> +      |gh_msgq_send() | Tx vIRQ |Message queue 1  |-------->|gh_msgq_recv() |
> +      |               |<------- |                 |         |               |
> +      |               |         |                 |         |               |
> +      | Message Queue |         |                 |         | Message Queue |
> +      | driver        |         |                 |         | driver        |
> +      |               |         |                 |         |               |
> +      |               |         |                 |         |               |
> +      |               |         |                 |   Tx    |               |
> +      |               | Rx vIRQ |                 |<--------|               |
> +      |gh_msgq_recv() |<--------|Message queue 2  | Tx vIRQ |gh_msgq_send() |
> +      |               |         |                 |-------->|               |
> +      |               |         |                 |         |               |
> +      |               |         |                 |         |               |
> +      +---------------+         +-----------------+         +---------------+
> diff --git a/Documentation/virt/index.rst b/Documentation/virt/index.rst
> index 7fb55ae08598d..15869ee059b35 100644
> --- a/Documentation/virt/index.rst
> +++ b/Documentation/virt/index.rst
> @@ -16,6 +16,7 @@ Virtualization Support
>      coco/sev-guest
>      coco/tdx-guest
>      hyperv/index
> +   gunyah/index
>   
>   .. only:: html and subproject
>   

Re: [PATCH v14 02/25] dt-bindings: Add binding for gunyah hypervisor

[Alex Elder]

On 6/13/23 12:20 PM, Elliot Berman wrote:
> When Linux is booted as a guest under the Gunyah hypervisor, the Gunyah
> Resource Manager applies a devicetree overlay describing the virtual
> platform configuration of the guest VM, such as the message queue
> capability IDs for communicating with the Resource Manager. This
> information is not otherwise discoverable by a VM: the Gunyah hypervisor
> core does not provide a direct interface to discover capability IDs nor
> a way to communicate with RM without having already known the
> corresponding message queue capability ID. Add the DT bindings that
> Gunyah adheres for the hypervisor node and message queues.

Isn't the resource-manager property required?  And there
is exactly one of them?  (Maybe those constraints are
represented here; I learn something every time I try to
write a YAML binding...)

Anyway, this otherwise looks good to me.

Reviewed-by: Alex Elder <elder@linaro.org>

> Reviewed-by: Rob Herring <robh@kernel.org>
> Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
> ---
>   .../bindings/firmware/gunyah-hypervisor.yaml  | 82 +++++++++++++++++++
>   1 file changed, 82 insertions(+)
>   create mode 100644 Documentation/devicetree/bindings/firmware/gunyah-hypervisor.yaml
> 
> diff --git a/Documentation/devicetree/bindings/firmware/gunyah-hypervisor.yaml b/Documentation/devicetree/bindings/firmware/gunyah-hypervisor.yaml
> new file mode 100644
> index 0000000000000..3fc0b043ac3cf
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/firmware/gunyah-hypervisor.yaml
> @@ -0,0 +1,82 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/firmware/gunyah-hypervisor.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Gunyah Hypervisor
> +
> +maintainers:
> +  - Prakruthi Deepak Heragu <quic_pheragu@quicinc.com>
> +  - Elliot Berman <quic_eberman@quicinc.com>
> +
> +description: |+
> +  Gunyah virtual machines use this information to determine the capability IDs
> +  of the message queues used to communicate with the Gunyah Resource Manager.
> +  See also: https://github.com/quic/gunyah-resource-manager/blob/develop/src/vm_creation/dto_construct.c
> +
> +properties:
> +  compatible:
> +    const: gunyah-hypervisor
> +
> +  "#address-cells":
> +    description: Number of cells needed to represent 64-bit capability IDs.
> +    const: 2
> +
> +  "#size-cells":
> +    description: must be 0, because capability IDs are not memory address
> +                  ranges and do not have a size.
> +    const: 0
> +
> +patternProperties:
> +  "^gunyah-resource-mgr(@.*)?":
> +    type: object
> +    description:
> +      Resource Manager node which is required to communicate to Resource
> +      Manager VM using Gunyah Message Queues.
> +
> +    properties:
> +      compatible:
> +        const: gunyah-resource-manager
> +
> +      reg:
> +        items:
> +          - description: Gunyah capability ID of the TX message queue
> +          - description: Gunyah capability ID of the RX message queue
> +
> +      interrupts:
> +        items:
> +          - description: Interrupt for the TX message queue
> +          - description: Interrupt for the RX message queue
> +
> +    additionalProperties: false
> +
> +    required:
> +      - compatible
> +      - reg
> +      - interrupts
> +
> +additionalProperties: false
> +
> +required:
> +  - compatible
> +  - "#address-cells"
> +  - "#size-cells"
> +
> +examples:
> +  - |
> +    #include <dt-bindings/interrupt-controller/arm-gic.h>
> +
> +    hypervisor {
> +        #address-cells = <2>;
> +        #size-cells = <0>;
> +        compatible = "gunyah-hypervisor";
> +
> +        gunyah-resource-mgr@0 {
> +            compatible = "gunyah-resource-manager";
> +            interrupts = <GIC_SPI 3 IRQ_TYPE_EDGE_RISING>, /* TX full IRQ */
> +                         <GIC_SPI 4 IRQ_TYPE_EDGE_RISING>; /* RX empty IRQ */
> +            reg = <0x00000000 0x00000000>, <0x00000000 0x00000001>;
> +                  /* TX, RX cap ids */
> +        };
> +    };

Re: [PATCH v14 06/25] mailbox: Add Gunyah message queue mailbox

[Alex Elder]

On 6/13/23 12:20 PM, Elliot Berman wrote:
> Gunyah message queues are a unidirectional inter-VM pipe for messages up
> to 1024 bytes. This driver supports pairing a receiver message queue and
> a transmitter message queue to expose a single mailbox channel.
> 
> Reviewed-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
> Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>

Despite a small gripe this looks good.

Reviewed-by: Alex Elder <elder@linaro.org>

> ---
>   Documentation/virt/gunyah/message-queue.rst |   8 +
>   drivers/mailbox/Makefile                    |   2 +
>   drivers/mailbox/gunyah-msgq.c               | 219 ++++++++++++++++++++
>   include/linux/gunyah.h                      |  57 +++++
>   4 files changed, 286 insertions(+)
>   create mode 100644 drivers/mailbox/gunyah-msgq.c
> 
> diff --git a/Documentation/virt/gunyah/message-queue.rst b/Documentation/virt/gunyah/message-queue.rst
> index b352918ae54b4..70d82a4ef32d7 100644
> --- a/Documentation/virt/gunyah/message-queue.rst
> +++ b/Documentation/virt/gunyah/message-queue.rst
> @@ -61,3 +61,11 @@ vIRQ: two TX message queues will have two vIRQs (and two capability IDs).
>         |               |         |                 |         |               |
>         |               |         |                 |         |               |
>         +---------------+         +-----------------+         +---------------+
> +
> +Gunyah message queues are exposed as mailboxes. To create the mailbox, create
> +a mbox_client and call `gh_msgq_init()`. On receipt of the RX_READY interrupt,
> +all messages in the RX message queue are read and pushed via the `rx_callback`
> +of the registered mbox_client.
> +
> +.. kernel-doc:: drivers/mailbox/gunyah-msgq.c
> +   :identifiers: gh_msgq_init
> diff --git a/drivers/mailbox/Makefile b/drivers/mailbox/Makefile
> index fc93761171113..5f929bb55e9a5 100644
> --- a/drivers/mailbox/Makefile
> +++ b/drivers/mailbox/Makefile
> @@ -55,6 +55,8 @@ obj-$(CONFIG_MTK_CMDQ_MBOX)	+= mtk-cmdq-mailbox.o
>   
>   obj-$(CONFIG_ZYNQMP_IPI_MBOX)	+= zynqmp-ipi-mailbox.o
>   
> +obj-$(CONFIG_GUNYAH)		+= gunyah-msgq.o
> +
>   obj-$(CONFIG_SUN6I_MSGBOX)	+= sun6i-msgbox.o
>   
>   obj-$(CONFIG_SPRD_MBOX)		+= sprd-mailbox.o
> diff --git a/drivers/mailbox/gunyah-msgq.c b/drivers/mailbox/gunyah-msgq.c
> new file mode 100644
> index 0000000000000..7f777339278eb
> --- /dev/null
> +++ b/drivers/mailbox/gunyah-msgq.c
> @@ -0,0 +1,219 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All rights reserved.
> + */
> +
> +#include <linux/mailbox_controller.h>
> +#include <linux/module.h>
> +#include <linux/interrupt.h>
> +#include <linux/gunyah.h>
> +#include <linux/printk.h>
> +#include <linux/init.h>
> +#include <linux/slab.h>
> +#include <linux/wait.h>
> +
> +#define mbox_chan_to_msgq(chan) (container_of(chan->mbox, struct gh_msgq, mbox))
> +
> +static irqreturn_t gh_msgq_rx_irq_handler(int irq, void *data)
> +{
> +	struct gh_msgq *msgq = data;
> +	struct gh_msgq_rx_data rx_data;
> +	enum gh_error gh_error;
> +	bool ready = true;

Since ready is true initially, you could use do...while ()
and not bother pre-initializing it.

> +
> +	while (ready) {
> +		gh_error = gh_hypercall_msgq_recv(msgq->rx_ghrsc->capid,
> +				&rx_data.data, sizeof(rx_data.data),
> +				&rx_data.length, &ready);
> +		if (gh_error != GH_ERROR_OK) {
> +			if (gh_error != GH_ERROR_MSGQUEUE_EMPTY)
> +				dev_warn(msgq->mbox.dev, "Failed to receive data: %d\n", gh_error);
> +			break;
> +		}
> +		if (likely(gh_msgq_chan(msgq)->cl))
> +			mbox_chan_received_data(gh_msgq_chan(msgq), &rx_data);
> +	}
> +
> +	return IRQ_HANDLED;
> +}
> +
> +/* Fired when message queue transitions from "full" to "space available" to send messages */
> +static irqreturn_t gh_msgq_tx_irq_handler(int irq, void *data)
> +{
> +	struct gh_msgq *msgq = data;
> +
> +	mbox_chan_txdone(gh_msgq_chan(msgq), 0);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +/* Fired after sending message and hypercall told us there was more space available. */
> +static void gh_msgq_txdone_tasklet(struct tasklet_struct *tasklet)
> +{
> +	struct gh_msgq *msgq = container_of(tasklet, struct gh_msgq, txdone_tasklet);
> +
> +	mbox_chan_txdone(gh_msgq_chan(msgq), msgq->last_ret);
> +}
> +
> +static int gh_msgq_send_data(struct mbox_chan *chan, void *data)
> +{
> +	struct gh_msgq *msgq = mbox_chan_to_msgq(chan);
> +	struct gh_msgq_tx_data *msgq_data = data;
> +	u64 tx_flags = 0;
> +	enum gh_error gh_error;
> +	bool ready;
> +
> +	if (!msgq->tx_ghrsc)
> +		return -EOPNOTSUPP;
> +
> +	if (msgq_data->push)
> +		tx_flags |= GH_HYPERCALL_MSGQ_TX_FLAGS_PUSH;
> +
> +	gh_error = gh_hypercall_msgq_send(msgq->tx_ghrsc->capid, msgq_data->length, msgq_data->data,
> +						tx_flags, &ready);
> +
> +	/**
> +	 * unlikely because Linux tracks state of msgq and should not try to
> +	 * send message when msgq is full.
> +	 */
> +	if (unlikely(gh_error == GH_ERROR_MSGQUEUE_FULL))
> +		return -EAGAIN;
> +
> +	/**
> +	 * Propagate all other errors to client. If we return error to mailbox
> +	 * framework, then no other messages can be sent and nobody will know
> +	 * to retry this message.
> +	 */
> +	msgq->last_ret = gh_error_remap(gh_error);
> +
> +	/**
> +	 * This message was successfully sent, but message queue isn't ready to
> +	 * accept more messages because it's now full. Mailbox framework
> +	 * requires that we only report that message was transmitted when
> +	 * we're ready to transmit another message. We'll get that in the form
> +	 * of tx IRQ once the other side starts to drain the msgq.
> +	 */

I really dislike this mismatch between Gunyah and mailbox
semantics.  Oh well.

> +	if (gh_error == GH_ERROR_OK) {
> +		if (!ready)
> +			return 0;
> +	} else {
> +		dev_err(msgq->mbox.dev, "Failed to send data: %d (%d)\n", gh_error, msgq->last_ret);
> +	}
> +
> +	/**
> +	 * We can send more messages. Mailbox framework requires that tx done
> +	 * happens asynchronously to sending the message. Gunyah message queues
> +	 * tell us right away on the hypercall return whether we can send more
> +	 * messages. To work around this, defer the txdone to a tasklet.
> +	 */

This mismatch too...

> +	tasklet_schedule(&msgq->txdone_tasklet);
> +
> +	return 0;
> +}
> +
> +static struct mbox_chan_ops gh_msgq_ops = {
> +	.send_data = gh_msgq_send_data,
> +};
> +
> +/**
> + * gh_msgq_init() - Initialize a Gunyah message queue with an mbox_client
> + * @parent: device parent used for the mailbox controller
> + * @msgq: Pointer to the gh_msgq to initialize
> + * @cl: A mailbox client to bind to the mailbox channel that the message queue creates
> + * @tx_ghrsc: optional, the transmission side of the message queue
> + * @rx_ghrsc: optional, the receiving side of the message queue
> + *
> + * At least one of tx_ghrsc and rx_ghrsc must be not NULL. Most message queue use cases come with
> + * a pair of message queues to facilitate bidirectional communication. When tx_ghrsc is set,
> + * the client can send messages with mbox_send_message(gh_msgq_chan(msgq), msg). When rx_ghrsc
> + * is set, the mbox_client must register an .rx_callback() and the message queue driver will
> + * deliver all available messages upon receiving the RX ready interrupt. The messages should be
> + * consumed or copied by the client right away as the gh_msgq_rx_data will be replaced/destroyed
> + * after the callback.
> + *
> + * Returns - 0 on success, negative otherwise
> + */
> +int gh_msgq_init(struct device *parent, struct gh_msgq *msgq, struct mbox_client *cl,
> +		 struct gh_resource *tx_ghrsc, struct gh_resource *rx_ghrsc)
> +{
> +	int ret;
> +
> +	/* Must have at least a tx_ghrsc or rx_ghrsc and that they are the right device types */
> +	if ((!tx_ghrsc && !rx_ghrsc) ||
> +	    (tx_ghrsc && tx_ghrsc->type != GH_RESOURCE_TYPE_MSGQ_TX) ||
> +	    (rx_ghrsc && rx_ghrsc->type != GH_RESOURCE_TYPE_MSGQ_RX))
> +		return -EINVAL;
> +
> +	msgq->mbox.dev = parent;
> +	msgq->mbox.ops = &gh_msgq_ops;
> +	msgq->mbox.num_chans = 1;
> +	msgq->mbox.txdone_irq = true;
> +	msgq->mbox.chans = &msgq->mbox_chan;
> +
> +	ret = mbox_controller_register(&msgq->mbox);
> +	if (ret)
> +		return ret;
> +
> +	ret = mbox_bind_client(gh_msgq_chan(msgq), cl);
> +	if (ret)
> +		goto err_mbox;
> +
> +	if (tx_ghrsc) {
> +		msgq->tx_ghrsc = tx_ghrsc;
> +
> +		ret = request_irq(msgq->tx_ghrsc->irq, gh_msgq_tx_irq_handler, 0, "gh_msgq_tx",
> +				msgq);
> +		if (ret)
> +			goto err_tx_ghrsc;
> +
> +		enable_irq_wake(msgq->tx_ghrsc->irq);
> +
> +		tasklet_setup(&msgq->txdone_tasklet, gh_msgq_txdone_tasklet);
> +	}
> +
> +	if (rx_ghrsc) {
> +		msgq->rx_ghrsc = rx_ghrsc;
> +
> +		ret = request_threaded_irq(msgq->rx_ghrsc->irq, NULL, gh_msgq_rx_irq_handler,
> +						IRQF_ONESHOT, "gh_msgq_rx", msgq);
> +		if (ret)
> +			goto err_tx_irq;
> +
> +		enable_irq_wake(msgq->rx_ghrsc->irq);
> +	}
> +
> +	return 0;
> +err_tx_irq:
> +	if (msgq->tx_ghrsc)
> +		free_irq(msgq->tx_ghrsc->irq, msgq);
> +
> +	msgq->rx_ghrsc = NULL;
> +err_tx_ghrsc:
> +	msgq->tx_ghrsc = NULL;
> +err_mbox:
> +	mbox_controller_unregister(&msgq->mbox);
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(gh_msgq_init);
> +
> +void gh_msgq_remove(struct gh_msgq *msgq)
> +{
> +	mbox_free_channel(gh_msgq_chan(msgq));
> +
> +	if (msgq->rx_ghrsc)
> +		free_irq(msgq->rx_ghrsc->irq, msgq);
> +
> +	if (msgq->tx_ghrsc) {
> +		tasklet_kill(&msgq->txdone_tasklet);
> +		free_irq(msgq->tx_ghrsc->irq, msgq);
> +	}
> +
> +	mbox_controller_unregister(&msgq->mbox);
> +
> +	msgq->rx_ghrsc = NULL;
> +	msgq->tx_ghrsc = NULL;
> +}
> +EXPORT_SYMBOL_GPL(gh_msgq_remove);
> +
> +MODULE_LICENSE("GPL");
> +MODULE_DESCRIPTION("Gunyah Message Queue Driver");
> diff --git a/include/linux/gunyah.h b/include/linux/gunyah.h
> index 01a6f202d037e..982e27d10d57f 100644
> --- a/include/linux/gunyah.h
> +++ b/include/linux/gunyah.h
> @@ -8,11 +8,68 @@
>   
>   #include <linux/bitfield.h>
>   #include <linux/errno.h>
> +#include <linux/interrupt.h>
>   #include <linux/limits.h>
> +#include <linux/mailbox_controller.h>
> +#include <linux/mailbox_client.h>
>   #include <linux/types.h>
>   
> +/* Matches resource manager's resource types for VM_GET_HYP_RESOURCES RPC */
> +enum gh_resource_type {
> +	GH_RESOURCE_TYPE_BELL_TX	= 0,
> +	GH_RESOURCE_TYPE_BELL_RX	= 1,
> +	GH_RESOURCE_TYPE_MSGQ_TX	= 2,
> +	GH_RESOURCE_TYPE_MSGQ_RX	= 3,
> +	GH_RESOURCE_TYPE_VCPU		= 4,
> +};
> +
> +struct gh_resource {
> +	enum gh_resource_type type;
> +	u64 capid;
> +	unsigned int irq;
> +};
> +
> +/**
> + * Gunyah Message Queues
> + */
> +
> +#define GH_MSGQ_MAX_MSG_SIZE		240
> +
> +struct gh_msgq_tx_data {
> +	size_t length;
> +	bool push;
> +	char data[];
> +};
> +
> +struct gh_msgq_rx_data {
> +	size_t length;
> +	char data[GH_MSGQ_MAX_MSG_SIZE];
> +};
> +
> +struct gh_msgq {
> +	struct gh_resource *tx_ghrsc;
> +	struct gh_resource *rx_ghrsc;
> +
> +	/* msgq private */
> +	int last_ret; /* Linux error, not GH_STATUS_* */
> +	struct mbox_chan mbox_chan;
> +	struct mbox_controller mbox;
> +	struct tasklet_struct txdone_tasklet;
> +};
> +
> +
> +int gh_msgq_init(struct device *parent, struct gh_msgq *msgq, struct mbox_client *cl,
> +		     struct gh_resource *tx_ghrsc, struct gh_resource *rx_ghrsc);
> +void gh_msgq_remove(struct gh_msgq *msgq);
> +
> +static inline struct mbox_chan *gh_msgq_chan(struct gh_msgq *msgq)
> +{
> +	return &msgq->mbox.chans[0];
> +}
> +
>   /******************************************************************************/
>   /* Common arch-independent definitions for Gunyah hypercalls                  */
> +
>   #define GH_CAPID_INVAL	U64_MAX
>   #define GH_VMID_ROOT_VM	0xff
>   

Re: [PATCH v14 11/25] gunyah: vm_mgr: Add/remove user memory regions

[Alex Elder]

On 6/13/23 12:20 PM, Elliot Berman wrote:
> When launching a virtual machine, Gunyah userspace allocates memory for
> the guest and informs Gunyah about these memory regions through
> SET_USER_MEMORY_REGION ioctl.
> 
> Co-developed-by: Prakruthi Deepak Heragu <quic_pheragu@quicinc.com>
> Signed-off-by: Prakruthi Deepak Heragu <quic_pheragu@quicinc.com>
> Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>

I have one trivial comment below.  This patch adds some complexity
but this time around I'm going to assume I checked those things
in some detail previously.  This time I'm doing more of a scan
through the patch and I find it looks good.  (If you want me to
spend more time on this, say so.)

Reviewed-by: Alex Elder <elder@linaro.org>

> ---
>   drivers/virt/gunyah/Makefile    |   2 +-
>   drivers/virt/gunyah/vm_mgr.c    |  59 +++++++-
>   drivers/virt/gunyah/vm_mgr.h    |  26 ++++
>   drivers/virt/gunyah/vm_mgr_mm.c | 232 ++++++++++++++++++++++++++++++++
>   include/uapi/linux/gunyah.h     |  37 +++++
>   5 files changed, 352 insertions(+), 4 deletions(-)
>   create mode 100644 drivers/virt/gunyah/vm_mgr_mm.c
> 
> diff --git a/drivers/virt/gunyah/Makefile b/drivers/virt/gunyah/Makefile
> index e47e25895299c..bacf78b8fa337 100644
> --- a/drivers/virt/gunyah/Makefile
> +++ b/drivers/virt/gunyah/Makefile
> @@ -1,4 +1,4 @@
>   # SPDX-License-Identifier: GPL-2.0
>   
> -gunyah-y += rsc_mgr.o rsc_mgr_rpc.o vm_mgr.o
> +gunyah-y += rsc_mgr.o rsc_mgr_rpc.o vm_mgr.o vm_mgr_mm.o
>   obj-$(CONFIG_GUNYAH) += gunyah.o
> diff --git a/drivers/virt/gunyah/vm_mgr.c b/drivers/virt/gunyah/vm_mgr.c
> index a43401cb34f7d..297427952b8c7 100644
> --- a/drivers/virt/gunyah/vm_mgr.c
> +++ b/drivers/virt/gunyah/vm_mgr.c
> @@ -15,6 +15,8 @@
>   
>   #include "vm_mgr.h"
>   
> +static void gh_vm_free(struct work_struct *work);
> +
>   static __must_check struct gh_vm *gh_vm_alloc(struct gh_rm *rm)
>   {
>   	struct gh_vm *ghvm;
> @@ -26,20 +28,72 @@ static __must_check struct gh_vm *gh_vm_alloc(struct gh_rm *rm)
>   	ghvm->parent = gh_rm_get(rm);
>   	ghvm->rm = rm;
>   
> +	mmgrab(current->mm);
> +	ghvm->mm = current->mm;
> +	mutex_init(&ghvm->mm_lock);
> +	INIT_LIST_HEAD(&ghvm->memory_mappings);
> +	INIT_WORK(&ghvm->free_work, gh_vm_free);
> +
>   	return ghvm;
>   }
>   
> -static int gh_vm_release(struct inode *inode, struct file *filp)
> +static long gh_vm_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
>   {
>   	struct gh_vm *ghvm = filp->private_data;
> +	void __user *argp = (void __user *)arg;
> +	long r;

Don't you use "ret" for return values most of the time?
(Not a big deal, maybe there's another reason you used
"r" here.)

> +
> +	switch (cmd) {
> +	case GH_VM_SET_USER_MEM_REGION: {
> +		struct gh_userspace_memory_region region;
> +
> +		/* only allow owner task to add memory */
> +		if (ghvm->mm != current->mm)
> +			return -EPERM;
> +
> +		if (copy_from_user(&region, argp, sizeof(region)))
> +			return -EFAULT;
> +
> +		/* All other flag bits are reserved for future use */
> +		if (region.flags & ~(GH_MEM_ALLOW_READ | GH_MEM_ALLOW_WRITE | GH_MEM_ALLOW_EXEC))
> +			return -EINVAL;
> +
> +		r = gh_vm_mem_alloc(ghvm, &region);
> +		break;
> +	}
> +	default:
> +		r = -ENOTTY;
> +		break;
> +	}
>   
> +	return r;
> +}
> +
> +static void gh_vm_free(struct work_struct *work)
> +{
> +	struct gh_vm *ghvm = container_of(work, struct gh_vm, free_work);
> +
> +	gh_vm_mem_reclaim(ghvm);
>   	gh_rm_put(ghvm->rm);
> +	mmdrop(ghvm->mm);
>   	kfree(ghvm);
> +}
> +
> +static int gh_vm_release(struct inode *inode, struct file *filp)
> +{
> +	struct gh_vm *ghvm = filp->private_data;
> +
> +	/* VM will be reset and make RM calls which can interruptible sleep.
> +	 * Defer to a work so this thread can receive signal.
> +	 */
> +	schedule_work(&ghvm->free_work);
>   	return 0;
>   }
>   
>   static const struct file_operations gh_vm_fops = {
>   	.owner = THIS_MODULE,
> +	.unlocked_ioctl = gh_vm_ioctl,
> +	.compat_ioctl	= compat_ptr_ioctl,
>   	.release = gh_vm_release,
>   	.llseek = noop_llseek,
>   };
> @@ -77,8 +131,7 @@ static long gh_dev_ioctl_create_vm(struct gh_rm *rm, unsigned long arg)
>   err_put_fd:
>   	put_unused_fd(fd);
>   err_destroy_vm:
> -	gh_rm_put(ghvm->rm);
> -	kfree(ghvm);
> +	gh_vm_free(&ghvm->free_work);
>   	return err;
>   }
>   
> diff --git a/drivers/virt/gunyah/vm_mgr.h b/drivers/virt/gunyah/vm_mgr.h
> index 1e94b58d7d34d..434ef9f662a7a 100644
> --- a/drivers/virt/gunyah/vm_mgr.h
> +++ b/drivers/virt/gunyah/vm_mgr.h
> @@ -7,14 +7,40 @@
>   #define _GH_VM_MGR_H
>   
>   #include <linux/gunyah_rsc_mgr.h>
> +#include <linux/list.h>
> +#include <linux/miscdevice.h>
> +#include <linux/mutex.h>
>   
>   #include <uapi/linux/gunyah.h>
>   
>   long gh_dev_vm_mgr_ioctl(struct gh_rm *rm, unsigned int cmd, unsigned long arg);
>   
> +enum gh_vm_mem_share_type {
> +	VM_MEM_SHARE,
> +	VM_MEM_LEND,
> +};
> +
> +struct gh_vm_mem {
> +	struct list_head list;
> +	enum gh_vm_mem_share_type share_type;
> +	struct gh_rm_mem_parcel parcel;
> +
> +	__u64 guest_phys_addr;
> +	struct page **pages;
> +	unsigned long npages;
> +};
> +
>   struct gh_vm {
>   	struct gh_rm *rm;
>   	struct device *parent;
> +
> +	struct work_struct free_work;
> +	struct mm_struct *mm; /* userspace tied to this vm */
> +	struct mutex mm_lock;
> +	struct list_head memory_mappings;
>   };
>   
> +int gh_vm_mem_alloc(struct gh_vm *ghvm, struct gh_userspace_memory_region *region);
> +void gh_vm_mem_reclaim(struct gh_vm *ghvm);
> +
>   #endif
> diff --git a/drivers/virt/gunyah/vm_mgr_mm.c b/drivers/virt/gunyah/vm_mgr_mm.c
> new file mode 100644
> index 0000000000000..6974607f02edd
> --- /dev/null
> +++ b/drivers/virt/gunyah/vm_mgr_mm.c
> @@ -0,0 +1,232 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All rights reserved.
> + */
> +
> +#define pr_fmt(fmt) "gh_vm_mgr: " fmt
> +
> +#include <linux/gunyah_rsc_mgr.h>
> +#include <linux/mm.h>
> +
> +#include <uapi/linux/gunyah.h>
> +
> +#include "vm_mgr.h"
> +
> +static bool pages_are_mergeable(struct page *a, struct page *b)
> +{
> +	return page_to_pfn(a) + 1 == page_to_pfn(b);
> +}
> +
> +static bool gh_vm_mem_overlap(struct gh_vm_mem *a, u64 addr, u64 size)
> +{
> +	u64 a_end = a->guest_phys_addr + (a->npages << PAGE_SHIFT);
> +	u64 end = addr + size;
> +
> +	return a->guest_phys_addr < end && addr < a_end;
> +}
> +
> +static struct gh_vm_mem *__gh_vm_mem_find_by_label(struct gh_vm *ghvm, u32 label)
> +	__must_hold(&ghvm->mm_lock)
> +{
> +	struct gh_vm_mem *mapping;
> +
> +	list_for_each_entry(mapping, &ghvm->memory_mappings, list)
> +		if (mapping->parcel.label == label)
> +			return mapping;
> +
> +	return NULL;
> +}
> +
> +static void gh_vm_mem_reclaim_mapping(struct gh_vm *ghvm, struct gh_vm_mem *mapping)
> +	__must_hold(&ghvm->mm_lock)
> +{
> +	int ret = 0;
> +
> +	if (mapping->parcel.mem_handle != GH_MEM_HANDLE_INVAL) {
> +		ret = gh_rm_mem_reclaim(ghvm->rm, &mapping->parcel);
> +		if (ret)
> +			pr_warn("Failed to reclaim memory parcel for label %d: %d\n",
> +				mapping->parcel.label, ret);
> +	}
> +
> +	if (!ret) {
> +		unpin_user_pages(mapping->pages, mapping->npages);
> +		account_locked_vm(ghvm->mm, mapping->npages, false);
> +	}
> +
> +	kfree(mapping->pages);
> +	kfree(mapping->parcel.acl_entries);
> +	kfree(mapping->parcel.mem_entries);
> +
> +	list_del(&mapping->list);
> +}
> +
> +void gh_vm_mem_reclaim(struct gh_vm *ghvm)
> +{
> +	struct gh_vm_mem *mapping, *tmp;
> +
> +	mutex_lock(&ghvm->mm_lock);
> +
> +	list_for_each_entry_safe(mapping, tmp, &ghvm->memory_mappings, list) {
> +		gh_vm_mem_reclaim_mapping(ghvm, mapping);
> +		kfree(mapping);
> +	}
> +
> +	mutex_unlock(&ghvm->mm_lock);
> +}
> +
> +int gh_vm_mem_alloc(struct gh_vm *ghvm, struct gh_userspace_memory_region *region)
> +{
> +	struct gh_vm_mem *mapping, *tmp_mapping;
> +	struct page *curr_page, *prev_page;
> +	struct gh_rm_mem_parcel *parcel;
> +	int i, j, pinned, ret = 0;
> +	unsigned int gup_flags;
> +	size_t entry_size;
> +	u16 vmid;
> +
> +	if (!region->memory_size || !PAGE_ALIGNED(region->memory_size) ||
> +		!PAGE_ALIGNED(region->userspace_addr) ||
> +		!PAGE_ALIGNED(region->guest_phys_addr))
> +		return -EINVAL;
> +
> +	if (overflows_type(region->guest_phys_addr + region->memory_size, u64))
> +		return -EOVERFLOW;
> +
> +	ret = mutex_lock_interruptible(&ghvm->mm_lock);
> +	if (ret)
> +		return ret;
> +
> +	mapping = __gh_vm_mem_find_by_label(ghvm, region->label);
> +	if (mapping) {
> +		ret = -EEXIST;
> +		goto unlock;
> +	}
> +
> +	list_for_each_entry(tmp_mapping, &ghvm->memory_mappings, list) {
> +		if (gh_vm_mem_overlap(tmp_mapping, region->guest_phys_addr,
> +					region->memory_size)) {
> +			ret = -EEXIST;
> +			goto unlock;
> +		}
> +	}
> +
> +	mapping = kzalloc(sizeof(*mapping), GFP_KERNEL_ACCOUNT);
> +	if (!mapping) {
> +		ret = -ENOMEM;
> +		goto unlock;
> +	}
> +
> +	mapping->guest_phys_addr = region->guest_phys_addr;
> +	mapping->npages = region->memory_size >> PAGE_SHIFT;
> +	parcel = &mapping->parcel;
> +	parcel->label = region->label;
> +	parcel->mem_handle = GH_MEM_HANDLE_INVAL; /* to be filled later by mem_share/mem_lend */
> +	parcel->mem_type = GH_RM_MEM_TYPE_NORMAL;
> +
> +	ret = account_locked_vm(ghvm->mm, mapping->npages, true);
> +	if (ret)
> +		goto free_mapping;
> +
> +	mapping->pages = kcalloc(mapping->npages, sizeof(*mapping->pages), GFP_KERNEL_ACCOUNT);
> +	if (!mapping->pages) {
> +		ret = -ENOMEM;
> +		mapping->npages = 0; /* update npages for reclaim */
> +		goto unlock_pages;
> +	}
> +
> +	gup_flags = FOLL_LONGTERM;
> +	if (region->flags & GH_MEM_ALLOW_WRITE)
> +		gup_flags |= FOLL_WRITE;
> +
> +	pinned = pin_user_pages_fast(region->userspace_addr, mapping->npages,
> +					gup_flags, mapping->pages);
> +	if (pinned < 0) {
> +		ret = pinned;
> +		goto free_pages;
> +	} else if (pinned != mapping->npages) {
> +		ret = -EFAULT;
> +		mapping->npages = pinned; /* update npages for reclaim */
> +		goto unpin_pages;
> +	}
> +
> +	parcel->n_acl_entries = 2;
> +	mapping->share_type = VM_MEM_SHARE;
> +	parcel->acl_entries = kcalloc(parcel->n_acl_entries, sizeof(*parcel->acl_entries),
> +					GFP_KERNEL);
> +	if (!parcel->acl_entries) {
> +		ret = -ENOMEM;
> +		goto unpin_pages;
> +	}
> +
> +	/* acl_entries[0].vmid will be this VM's vmid. We'll fill it when the
> +	 * VM is starting and we know the VM's vmid.
> +	 */
> +	if (region->flags & GH_MEM_ALLOW_READ)
> +		parcel->acl_entries[0].perms |= GH_RM_ACL_R;
> +	if (region->flags & GH_MEM_ALLOW_WRITE)
> +		parcel->acl_entries[0].perms |= GH_RM_ACL_W;
> +	if (region->flags & GH_MEM_ALLOW_EXEC)
> +		parcel->acl_entries[0].perms |= GH_RM_ACL_X;
> +
> +	ret = gh_rm_get_vmid(ghvm->rm, &vmid);
> +	if (ret)
> +		goto free_acl;
> +
> +	parcel->acl_entries[1].vmid = cpu_to_le16(vmid);
> +	/* Host assumed to have all these permissions. Gunyah will not
> +	 * grant new permissions if host actually had less than RWX
> +	 */
> +	parcel->acl_entries[1].perms = GH_RM_ACL_R | GH_RM_ACL_W | GH_RM_ACL_X;
> +
> +	parcel->n_mem_entries = 1;
> +	for (i = 1; i < mapping->npages; i++) {
> +		if (!pages_are_mergeable(mapping->pages[i - 1], mapping->pages[i]))
> +			parcel->n_mem_entries++;
> +	}
> +
> +	parcel->mem_entries = kcalloc(parcel->n_mem_entries,
> +					sizeof(parcel->mem_entries[0]),
> +					GFP_KERNEL_ACCOUNT);
> +	if (!parcel->mem_entries) {
> +		ret = -ENOMEM;
> +		goto free_acl;
> +	}
> +
> +	/* reduce number of entries by combining contiguous pages into single memory entry */
> +	prev_page = mapping->pages[0];
> +	parcel->mem_entries[0].phys_addr = cpu_to_le64(page_to_phys(prev_page));
> +	entry_size = PAGE_SIZE;
> +	for (i = 1, j = 0; i < mapping->npages; i++) {
> +		curr_page = mapping->pages[i];
> +		if (pages_are_mergeable(prev_page, curr_page)) {
> +			entry_size += PAGE_SIZE;
> +		} else {
> +			parcel->mem_entries[j].size = cpu_to_le64(entry_size);
> +			j++;
> +			parcel->mem_entries[j].phys_addr =
> +				cpu_to_le64(page_to_phys(curr_page));
> +			entry_size = PAGE_SIZE;
> +		}
> +
> +		prev_page = curr_page;
> +	}
> +	parcel->mem_entries[j].size = cpu_to_le64(entry_size);
> +
> +	list_add(&mapping->list, &ghvm->memory_mappings);
> +	mutex_unlock(&ghvm->mm_lock);
> +	return 0;
> +free_acl:
> +	kfree(parcel->acl_entries);
> +unpin_pages:
> +	unpin_user_pages(mapping->pages, pinned);
> +free_pages:
> +	kfree(mapping->pages);
> +unlock_pages:
> +	account_locked_vm(ghvm->mm, mapping->npages, false);
> +free_mapping:
> +	kfree(mapping);
> +unlock:
> +	mutex_unlock(&ghvm->mm_lock);
> +	return ret;
> +}
> diff --git a/include/uapi/linux/gunyah.h b/include/uapi/linux/gunyah.h
> index 86b9cb60118dd..91d6dd26fcc89 100644
> --- a/include/uapi/linux/gunyah.h
> +++ b/include/uapi/linux/gunyah.h
> @@ -20,4 +20,41 @@
>    */
>   #define GH_CREATE_VM			_IO(GH_IOCTL_TYPE, 0x0) /* Returns a Gunyah VM fd */
>   
> +/*
> + * ioctls for VM fds
> + */
> +
> +/**
> + * enum gh_mem_flags - Possible flags on &struct gh_userspace_memory_region
> + * @GH_MEM_ALLOW_READ: Allow guest to read the memory
> + * @GH_MEM_ALLOW_WRITE: Allow guest to write to the memory
> + * @GH_MEM_ALLOW_EXEC: Allow guest to execute instructions in the memory
> + */
> +enum gh_mem_flags {
> +	GH_MEM_ALLOW_READ	= 1UL << 0,
> +	GH_MEM_ALLOW_WRITE	= 1UL << 1,
> +	GH_MEM_ALLOW_EXEC	= 1UL << 2,
> +};
> +
> +/**
> + * struct gh_userspace_memory_region - Userspace memory descripion for GH_VM_SET_USER_MEM_REGION
> + * @label: Identifer to the region which is unique to the VM.
> + * @flags: Flags for memory parcel behavior. See &enum gh_mem_flags.
> + * @guest_phys_addr: Location of the memory region in guest's memory space (page-aligned)
> + * @memory_size: Size of the region (page-aligned)
> + * @userspace_addr: Location of the memory region in caller (userspace)'s memory
> + *
> + * See Documentation/virt/gunyah/vm-manager.rst for further details.
> + */
> +struct gh_userspace_memory_region {
> +	__u32 label;
> +	__u32 flags;
> +	__u64 guest_phys_addr;
> +	__u64 memory_size;
> +	__u64 userspace_addr;
> +};
> +
> +#define GH_VM_SET_USER_MEM_REGION	_IOW(GH_IOCTL_TYPE, 0x1, \
> +						struct gh_userspace_memory_region)
> +
>   #endif

Re: [PATCH v14 16/25] docs: gunyah: Document Gunyah VM Manager

[Alex Elder]

On 6/13/23 12:20 PM, Elliot Berman wrote:
> Document the ioctls and usage of Gunyah VM Manager driver.
> 
> Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>

A few minor comments below, but regardless:

Reviewed-by: Alex Elder <elder@linaro.org>

> ---
>   Documentation/virt/gunyah/index.rst      |  1 +
>   Documentation/virt/gunyah/vm-manager.rst | 83 ++++++++++++++++++++++++
>   2 files changed, 84 insertions(+)
>   create mode 100644 Documentation/virt/gunyah/vm-manager.rst
> 
> diff --git a/Documentation/virt/gunyah/index.rst b/Documentation/virt/gunyah/index.rst
> index 74aa345e0a144..7058249825b16 100644
> --- a/Documentation/virt/gunyah/index.rst
> +++ b/Documentation/virt/gunyah/index.rst
> @@ -7,6 +7,7 @@ Gunyah Hypervisor
>   .. toctree::
>      :maxdepth: 1
>   
> +   vm-manager
>      message-queue
>   
>   Gunyah is a Type-1 hypervisor which is independent of any OS kernel, and runs in
> diff --git a/Documentation/virt/gunyah/vm-manager.rst b/Documentation/virt/gunyah/vm-manager.rst
> new file mode 100644
> index 0000000000000..df0e1a8279bf5
> --- /dev/null
> +++ b/Documentation/virt/gunyah/vm-manager.rst
> @@ -0,0 +1,83 @@
> +.. SPDX-License-Identifier: GPL-2.0
> +
> +=======================
> +Virtual Machine Manager
> +=======================
> +
> +The Gunyah Virtual Machine Manager is a Linux driver to support launching
> +virtual machines using Gunyah. It presently supports launching virtual machines
> +scheduled by Gunyah's scheduler.

You referred to this as "behind-the-back" scheduling in patch 1.
(I don't know if this terminology is important to use.)

> +
> +Configuration of a Gunyah virtual machine is done via a devicetree. When the VM
> +is launched, memory is provided by the host VM which contains the devictree.
> +Gunyah reads the devicetree to configure the memory map and create resources
> +such as vCPUs for the VM. Memory can be shared with the VM with
> +`GH_VM_SET_USER_MEM_REGION`_. Userspace can interact with the resources in Linux
> +by adding "functions" to the VM.
> +
> +Sample Userspace VMM
> +====================
> +
> +A sample userspace VMM is included in samples/gunyah/ along with a minimal
> +devicetree that can be used to launch a VM. To build this sample, enable
> +CONFIG_SAMPLE_GUNYAH.
> +
> +IOCTLs and userspace VMM flows
> +==============================
> +
> +The kernel exposes a char device interface at /dev/gunyah.
> +
> +To create a VM, use the `GH_CREATE_VM`_ ioctl. A successful call will return a
> +"Gunyah VM" file descriptor.

Maybe reword this a bit so it's clearer that the IOCTL calls
are performed on the file descriptor resulting from opening
/dev/gunyah?

> +
> +/dev/gunyah API Descriptions
> +----------------------------
> +
> +GH_CREATE_VM
> +~~~~~~~~~~~~
> +
> +Creates a Gunyah VM. The argument is reserved for future use and must be 0.
> +A successful call will return a Gunyah VM file descriptor. See
> +`Gunyah VM API Descriptions`_ for list of IOCTLs that can be made on this file

Maybe "the next section" rather than an explicit reference.
But it's fine as-is.

Also (because you duplicate "file"):

s/on this file/on this/

> +file descriptor.
> +
> +Gunyah VM API Descriptions
> +--------------------------
> +
> +GH_VM_SET_USER_MEM_REGION
> +~~~~~~~~~~~~~~~~~~~~~~~~~
> +
> +This ioctl allows the user to create or delete a memory parcel for a guest

How are memory parcels deleted?  (Maybe add a sentence at the end
of this section.)

> +virtual machine. Each memory region is uniquely identified by a label;
> +attempting to create two regions with the same label is not allowed. Labels are
> +unique per virtual machine.
> +
> +While VMM is guest-agnostic and allows runtime addition of memory regions,
> +Linux guest virtual machines do not support accepting memory regions at runtime.
> +Thus, for Linux guests, memory regions should be provided before starting the VM
> +and the VM must be configured via the devicetree to accept these at boot-up.
> +
> +The guest physical address is used by Linux kernel to check that the requested
> +user regions do not overlap and to help find the corresponding memory region
> +for calls like `GH_VM_SET_DTB_CONFIG`_. It must be page aligned.
> +
> +To add a memory region, call `GH_VM_SET_USER_MEM_REGION`_ with fields set as
> +described above.
> +
> +.. kernel-doc:: include/uapi/linux/gunyah.h
> +   :identifiers: gh_userspace_memory_region gh_mem_flags
> +
> +GH_VM_SET_DTB_CONFIG
> +~~~~~~~~~~~~~~~~~~~~
> +
> +This ioctl sets the location of the VM's devicetree blob and is used by Gunyah
> +Resource Manager to allocate resources. The guest physical memory must be part
> +of the primary memory parcel provided to the VM prior to GH_VM_START.
> +
> +.. kernel-doc:: include/uapi/linux/gunyah.h
> +   :identifiers: gh_vm_dtb_config
> +
> +GH_VM_START
> +~~~~~~~~~~~
> +
> +This ioctl starts the VM.

Re: [PATCH v14 18/25] gunyah: vm_mgr: Add framework for VM Functions

[Alex Elder]

On 6/13/23 12:20 PM, Elliot Berman wrote:
> Introduce a framework for Gunyah userspace to install VM functions. VM
> functions are optional interfaces to the virtual machine. vCPUs,
> ioeventfs, and irqfds are examples of such VM functions and are

s/ioventfs/ioeventfds/

> implemented in subsequent patches.
> 
> A generic framework is implemented instead of individual ioctls to
> create vCPUs, irqfds, etc., in order to simplify the VM manager core
> implementation and allow dynamic loading of VM function modules.

I have some comments, and one question about the user space
argument passed during function instance removal.  Assuming
you explain/address that:

Reviewed-by: Alex Elder <elder@linaro.org>

> 
> Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
> ---
>   Documentation/virt/gunyah/vm-manager.rst |  18 ++
>   drivers/virt/gunyah/vm_mgr.c             | 213 ++++++++++++++++++++++-
>   drivers/virt/gunyah/vm_mgr.h             |   4 +
>   include/linux/gunyah_vm_mgr.h            |  97 +++++++++++
>   include/uapi/linux/gunyah.h              |  18 ++
>   5 files changed, 347 insertions(+), 3 deletions(-)
>   create mode 100644 include/linux/gunyah_vm_mgr.h
> 
> diff --git a/Documentation/virt/gunyah/vm-manager.rst b/Documentation/virt/gunyah/vm-manager.rst
> index df0e1a8279bf5..cbc79bd8749b4 100644
> --- a/Documentation/virt/gunyah/vm-manager.rst
> +++ b/Documentation/virt/gunyah/vm-manager.rst
> @@ -15,6 +15,24 @@ such as vCPUs for the VM. Memory can be shared with the VM with
>   `GH_VM_SET_USER_MEM_REGION`_. Userspace can interact with the resources in Linux
>   by adding "functions" to the VM.
>   
> +Gunyah Functions
> +================
> +
> +Components of a Gunyah VM's configuration that need kernel configuration are
> +called "functions" and are built on top of a framework. Functions are identified
> +by a string and have some argument(s) to configure them. They are typically
> +created by the `GH_VM_ADD_FUNCTION`_ ioctl.

Regarding "typically": when are they not aded by this IOCTL?

> +
> +Functions typically will always do at least one of these operations:

Again, "typically" or "always"?  I just find using both of those
in the same sentence a little odd.

> +
> +1. Create resource ticket(s). Resource tickets allow a function to register
> +   itself as the client for a Gunyah resource (e.g. doorbell or vCPU) and
> +   the function is given the pointer to the &struct gh_resource when the

s/when the/when a/

> +   VM is starting.
> +
> +2. Register IO handler(s). IO handlers allow a function to handle stage-2 faults
> +   from the virtual machine.
> +
>   Sample Userspace VMM
>   ====================
>   
> diff --git a/drivers/virt/gunyah/vm_mgr.c b/drivers/virt/gunyah/vm_mgr.c
> index 562ae6ed4a5f1..cfd79bc9900fd 100644
> --- a/drivers/virt/gunyah/vm_mgr.c
> +++ b/drivers/virt/gunyah/vm_mgr.c
> @@ -6,10 +6,13 @@
>   #define pr_fmt(fmt) "gh_vm_mgr: " fmt
>   
>   #include <linux/anon_inodes.h>
> +#include <linux/compat.h>
>   #include <linux/file.h>
>   #include <linux/gunyah_rsc_mgr.h>
> +#include <linux/gunyah_vm_mgr.h>
>   #include <linux/miscdevice.h>
>   #include <linux/module.h>
> +#include <linux/xarray.h>
>   
>   #include <uapi/linux/gunyah.h>
>   
> @@ -17,6 +20,169 @@
>   
>   static void gh_vm_free(struct work_struct *work);
>   
> +static DEFINE_XARRAY(gh_vm_functions);
> +
> +static void gh_vm_put_function(struct gh_vm_function *fn)
> +{
> +	module_put(fn->mod);
> +}
> +
> +static struct gh_vm_function *gh_vm_get_function(u32 type)
> +{
> +	struct gh_vm_function *fn;
> +
> +	fn = xa_load(&gh_vm_functions, type);
> +	if (!fn) {
> +		request_module("ghfunc:%d", type);
> +
> +		fn = xa_load(&gh_vm_functions, type);
> +	}
> +
> +	if (!fn || !try_module_get(fn->mod))
> +		fn = ERR_PTR(-ENOENT);
> +
> +	return fn;
> +}
> +
> +static void gh_vm_remove_function_instance(struct gh_vm_function_instance *inst)
> +	__must_hold(&inst->ghvm->fn_lock)
> +{
> +	inst->fn->unbind(inst);
> +	list_del(&inst->vm_list);
> +	gh_vm_put_function(inst->fn);
> +	kfree(inst->argp);
> +	kfree(inst);
> +}
> +
> +static void gh_vm_remove_functions(struct gh_vm *ghvm)
> +{
> +	struct gh_vm_function_instance *inst, *iiter;
> +
> +	mutex_lock(&ghvm->fn_lock);
> +	list_for_each_entry_safe(inst, iiter, &ghvm->functions, vm_list) {
> +		gh_vm_remove_function_instance(inst);
> +	}
> +	mutex_unlock(&ghvm->fn_lock);
> +}
> +
> +static long gh_vm_add_function_instance(struct gh_vm *ghvm, struct gh_fn_desc *f)
> +{
> +	struct gh_vm_function_instance *inst;
> +	void __user *argp;
> +	long r = 0;
> +
> +	if (f->arg_size > GH_FN_MAX_ARG_SIZE) {
> +		dev_err_ratelimited(ghvm->parent, "%s: arg_size > %d\n",
> +					__func__, GH_FN_MAX_ARG_SIZE);
> +		return -EINVAL;
> +	}
> +
> +	inst = kzalloc(sizeof(*inst), GFP_KERNEL);
> +	if (!inst)
> +		return -ENOMEM;
> +
> +	inst->arg_size = f->arg_size;
> +	if (inst->arg_size) {
> +		inst->argp = kzalloc(inst->arg_size, GFP_KERNEL);
> +		if (!inst->argp) {
> +			r = -ENOMEM;
> +			goto free;
> +		}
> +
> +		argp = u64_to_user_ptr(f->arg);
> +		if (copy_from_user(inst->argp, argp, f->arg_size)) {
> +			r = -EFAULT;
> +			goto free_arg;
> +		}
> +	}
> +
> +	inst->fn = gh_vm_get_function(f->type);
> +	if (IS_ERR(inst->fn)) {
> +		r = PTR_ERR(inst->fn);
> +		goto free_arg;
> +	}
> +
> +	inst->ghvm = ghvm;
> +	inst->rm = ghvm->rm;
> +
> +	mutex_lock(&ghvm->fn_lock);
> +	r = inst->fn->bind(inst);
> +	if (r < 0) {
> +		mutex_unlock(&ghvm->fn_lock);
> +		gh_vm_put_function(inst->fn);
> +		goto free_arg;
> +	}
> +
> +	list_add(&inst->vm_list, &ghvm->functions);
> +	mutex_unlock(&ghvm->fn_lock);
> +
> +	return r;
> +free_arg:
> +	kfree(inst->argp);
> +free:
> +	kfree(inst);
> +	return r;
> +}
> +
> +static long gh_vm_rm_function_instance(struct gh_vm *ghvm, struct gh_fn_desc *f)
> +{
> +	struct gh_vm_function_instance *inst, *iter;
> +	void __user *user_argp;
> +	void *argp;
> +	long r = 0;
> +
> +	r = mutex_lock_interruptible(&ghvm->fn_lock);
> +	if (r)
> +		return r;
> +
> +	if (f->arg_size) {
> +		argp = kzalloc(f->arg_size, GFP_KERNEL);
> +		if (!argp) {
> +			r = -ENOMEM;
> +			goto out;
> +		}
> +
> +		user_argp = u64_to_user_ptr(f->arg);

What is the user pointer even needed for here?  What
is the purpose of copying it into the local buffer?
You never reference it after this point.

I could envision it being usable (and so it makes
some sense being part of the user space API), but
at least at this time it serves no purpose.

> +		if (copy_from_user(argp, user_argp, f->arg_size)) {
> +			r = -EFAULT;
> +			kfree(argp);
> +			goto out;
> +		}
> +
> +		r = -ENOENT;
> +		list_for_each_entry_safe(inst, iter, &ghvm->functions, vm_list) {
> +			if (inst->fn->type == f->type &&
> +				inst->fn->compare(inst, argp, f->arg_size)) {
> +				gh_vm_remove_function_instance(inst);
> +				r = 0;
> +			}
> +		}
> +
> +		kfree(argp);
> +	}
> +
> +out:
> +	mutex_unlock(&ghvm->fn_lock);
> +	return r;
> +}
> +
> +int gh_vm_function_register(struct gh_vm_function *fn)
> +{
> +	if (!fn->bind || !fn->unbind)
> +		return -EINVAL;
> +
> +	return xa_err(xa_store(&gh_vm_functions, fn->type, fn, GFP_KERNEL));
> +}
> +EXPORT_SYMBOL_GPL(gh_vm_function_register);
> +
> +void gh_vm_function_unregister(struct gh_vm_function *fn)
> +{
> +	/* Expecting unregister to only come when unloading a module */
> +	WARN_ON(fn->mod && module_refcount(fn->mod));
> +	xa_erase(&gh_vm_functions, fn->type);
> +}
> +EXPORT_SYMBOL_GPL(gh_vm_function_unregister);
> +
>   static int gh_vm_rm_notification_status(struct gh_vm *ghvm, void *data)
>   {
>   	struct gh_rm_vm_status_payload *payload = data;
> @@ -98,6 +264,8 @@ static __must_check struct gh_vm *gh_vm_alloc(struct gh_rm *rm)
>   	init_rwsem(&ghvm->status_lock);
>   	init_waitqueue_head(&ghvm->vm_status_wait);
>   	INIT_WORK(&ghvm->free_work, gh_vm_free);
> +	kref_init(&ghvm->kref);
> +	INIT_LIST_HEAD(&ghvm->functions);
>   	ghvm->vm_status = GH_RM_VM_STATUS_NO_STATE;
>   
>   	return ghvm;
> @@ -254,6 +422,24 @@ static long gh_vm_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
>   		r = gh_vm_ensure_started(ghvm);
>   		break;
>   	}
> +	case GH_VM_ADD_FUNCTION: {
> +		struct gh_fn_desc f;
> +
> +		if (copy_from_user(&f, argp, sizeof(f)))
> +			return -EFAULT;
> +
> +		r = gh_vm_add_function_instance(ghvm, &f);
> +		break;
> +	}
> +	case GH_VM_REMOVE_FUNCTION: {
> +		struct gh_fn_desc f;
> +
> +		if (copy_from_user(&f, argp, sizeof(f)))
> +			return -EFAULT;
> +
> +		r = gh_vm_rm_function_instance(ghvm, &f);
> +		break;
> +	}
>   	default:
>   		r = -ENOTTY;
>   		break;
> @@ -270,6 +456,8 @@ static void gh_vm_free(struct work_struct *work)
>   	if (ghvm->vm_status == GH_RM_VM_STATUS_RUNNING)
>   		gh_vm_stop(ghvm);
>   
> +	gh_vm_remove_functions(ghvm);
> +
>   	if (ghvm->vm_status != GH_RM_VM_STATUS_NO_STATE &&
>   	    ghvm->vm_status != GH_RM_VM_STATUS_LOAD &&
>   	    ghvm->vm_status != GH_RM_VM_STATUS_RESET) {
> @@ -294,14 +482,33 @@ static void gh_vm_free(struct work_struct *work)
>   	kfree(ghvm);
>   }
>   
> -static int gh_vm_release(struct inode *inode, struct file *filp)
> +int __must_check gh_vm_get(struct gh_vm *ghvm)
>   {
> -	struct gh_vm *ghvm = filp->private_data;
> +	return kref_get_unless_zero(&ghvm->kref);
> +}
> +EXPORT_SYMBOL_GPL(gh_vm_get);
> +
> +static void _gh_vm_put(struct kref *kref)
> +{
> +	struct gh_vm *ghvm = container_of(kref, struct gh_vm, kref);
>   
>   	/* VM will be reset and make RM calls which can interruptible sleep.
>   	 * Defer to a work so this thread can receive signal.
>   	 */
>   	schedule_work(&ghvm->free_work);
> +}
> +
> +void gh_vm_put(struct gh_vm *ghvm)
> +{
> +	kref_put(&ghvm->kref, _gh_vm_put);
> +}
> +EXPORT_SYMBOL_GPL(gh_vm_put);
> +
> +static int gh_vm_release(struct inode *inode, struct file *filp)
> +{
> +	struct gh_vm *ghvm = filp->private_data;
> +
> +	gh_vm_put(ghvm);
>   	return 0;
>   }
>   
> @@ -346,7 +553,7 @@ static long gh_dev_ioctl_create_vm(struct gh_rm *rm, unsigned long arg)
>   err_put_fd:
>   	put_unused_fd(fd);
>   err_destroy_vm:
> -	gh_vm_free(&ghvm->free_work);
> +	gh_vm_put(ghvm);
>   	return err;
>   }
>   
> diff --git a/drivers/virt/gunyah/vm_mgr.h b/drivers/virt/gunyah/vm_mgr.h
> index 4173bd51f83fe..c4bec1469ae8c 100644
> --- a/drivers/virt/gunyah/vm_mgr.h
> +++ b/drivers/virt/gunyah/vm_mgr.h
> @@ -8,6 +8,7 @@
>   
>   #include <linux/gunyah_rsc_mgr.h>
>   #include <linux/list.h>
> +#include <linux/kref.h>
>   #include <linux/miscdevice.h>
>   #include <linux/mutex.h>
>   #include <linux/rwsem.h>
> @@ -45,9 +46,12 @@ struct gh_vm {
>   	struct rw_semaphore status_lock;
>   
>   	struct work_struct free_work;
> +	struct kref kref;
>   	struct mm_struct *mm; /* userspace tied to this vm */
>   	struct mutex mm_lock;
>   	struct list_head memory_mappings;
> +	struct mutex fn_lock;
> +	struct list_head functions;
>   };
>   
>   int gh_vm_mem_alloc(struct gh_vm *ghvm, struct gh_userspace_memory_region *region);
> diff --git a/include/linux/gunyah_vm_mgr.h b/include/linux/gunyah_vm_mgr.h
> new file mode 100644
> index 0000000000000..6e4dd6fa5f96d
> --- /dev/null
> +++ b/include/linux/gunyah_vm_mgr.h
> @@ -0,0 +1,97 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All rights reserved.
> + */
> +
> +#ifndef _GUNYAH_VM_MGR_H
> +#define _GUNYAH_VM_MGR_H
> +
> +#include <linux/compiler_types.h>
> +#include <linux/gunyah.h>
> +#include <linux/gunyah_rsc_mgr.h>
> +#include <linux/list.h>
> +#include <linux/mod_devicetable.h>
> +#include <linux/notifier.h>
> +
> +#include <uapi/linux/gunyah.h>
> +
> +struct gh_vm;
> +
> +int __must_check gh_vm_get(struct gh_vm *ghvm);
> +void gh_vm_put(struct gh_vm *ghvm);
> +
> +struct gh_vm_function_instance;
> +/**
> + * struct gh_vm_function - Represents a function type
> + * @type: value from &enum gh_fn_type
> + * @name: friendly name for debug purposes
> + * @mod: owner of the function type
> + * @bind: Called when a new function of this type has been allocated.
> + * @unbind: Called when the function instance is being destroyed.
> + * @compare: Compare function instance @f's argument to the provided arg.
> + *           Return true if they are equivalent. Used on GH_VM_REMOVE_FUNCTION.
> + */
> +struct gh_vm_function {
> +	u32 type;
> +	const char *name;
> +	struct module *mod;
> +	long (*bind)(struct gh_vm_function_instance *f);
> +	void (*unbind)(struct gh_vm_function_instance *f);
> +	bool (*compare)(const struct gh_vm_function_instance *f, const void *arg, size_t size);
> +};
> +
> +/**
> + * struct gh_vm_function_instance - Represents one function instance
> + * @arg_size: size of user argument
> + * @argp: pointer to user argument
> + * @ghvm: Pointer to VM instance
> + * @rm: Pointer to resource manager for the VM instance
> + * @fn: The ops for the function
> + * @data: Private data for function
> + * @vm_list: for gh_vm's functions list
> + * @fn_list: for gh_vm_function's instances list
> + */
> +struct gh_vm_function_instance {
> +	size_t arg_size;
> +	void *argp;
> +	struct gh_vm *ghvm;
> +	struct gh_rm *rm;
> +	struct gh_vm_function *fn;
> +	void *data;
> +	struct list_head vm_list;
> +};
> +
> +int gh_vm_function_register(struct gh_vm_function *f);
> +void gh_vm_function_unregister(struct gh_vm_function *f);
> +
> +/* Since the function identifiers were setup in a uapi header as an
> + * enum and we do no want to change that, the user must supply the expanded
> + * constant as well and the compiler checks they are the same.
> + * See also MODULE_ALIAS_RDMA_NETLINK.
> + */
> +#define MODULE_ALIAS_GH_VM_FUNCTION(_type, _idx)			\
> +	static inline void __maybe_unused __chk##_idx(void)		\
> +	{								\
> +		BUILD_BUG_ON(_type != _idx);				\
> +	}								\
> +	MODULE_ALIAS("ghfunc:" __stringify(_idx))
> +
> +#define DECLARE_GH_VM_FUNCTION(_name, _type, _bind, _unbind, _compare)	\
> +	static struct gh_vm_function _name = {				\
> +		.type = _type,						\
> +		.name = __stringify(_name),				\
> +		.mod = THIS_MODULE,					\
> +		.bind = _bind,						\
> +		.unbind = _unbind,					\
> +		.compare = _compare,					\
> +	}
> +
> +#define module_gh_vm_function(__gf)					\
> +	module_driver(__gf, gh_vm_function_register, gh_vm_function_unregister)
> +
> +#define DECLARE_GH_VM_FUNCTION_INIT(_name, _type, _idx, _bind, _unbind, _compare)	\
> +	DECLARE_GH_VM_FUNCTION(_name, _type, _bind, _unbind, _compare);			\
> +	module_gh_vm_function(_name);							\
> +	MODULE_ALIAS_GH_VM_FUNCTION(_type, _idx)
> +
> +#endif
> diff --git a/include/uapi/linux/gunyah.h b/include/uapi/linux/gunyah.h
> index 4b63d0b9b8ba7..bb07118a351fd 100644
> --- a/include/uapi/linux/gunyah.h
> +++ b/include/uapi/linux/gunyah.h
> @@ -72,4 +72,22 @@ struct gh_vm_dtb_config {
>   
>   #define GH_VM_START		_IO(GH_IOCTL_TYPE, 0x3)
>   
> +#define GH_FN_MAX_ARG_SIZE		256
> +
> +/**
> + * struct gh_fn_desc - Arguments to create a VM function
> + * @type: Type of the function. See &enum gh_fn_type.
> + * @arg_size: Size of argument to pass to the function. arg_size <= GH_FN_MAX_ARG_SIZE
> + * @arg: Pointer to argument given to the function. See &enum gh_fn_type for expected
> + *       arguments for a function type.
> + */
> +struct gh_fn_desc {
> +	__u32 type;
> +	__u32 arg_size;
> +	__u64 arg;
> +};
> +
> +#define GH_VM_ADD_FUNCTION	_IOW(GH_IOCTL_TYPE, 0x4, struct gh_fn_desc)
> +#define GH_VM_REMOVE_FUNCTION	_IOW(GH_IOCTL_TYPE, 0x7, struct gh_fn_desc)
> +
>   #endif

Re: [PATCH v14 23/25] virt: gunyah: Add irqfd interface

[Alex Elder]

On 6/13/23 12:20 PM, Elliot Berman wrote:
> Enable support for creating irqfds which can raise an interrupt on a
> Gunyah virtual machine. irqfds are exposed to userspace as a Gunyah VM
> function with the name "irqfd". If the VM devicetree is not configured
> to create a doorbell with the corresponding label, userspace will still
> be able to assert the eventfd but no interrupt will be raised on the
> guest.
> 
> Acked-by: Alex Elder <elder@linaro.org>

I guess I don't mind upgrading this.  It looks good to me.

Reviewed-by: Alex Elder <elder@linaro.org>

> Co-developed-by: Prakruthi Deepak Heragu <quic_pheragu@quicinc.com>
> Signed-off-by: Prakruthi Deepak Heragu <quic_pheragu@quicinc.com>
> Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
> ---
>   Documentation/virt/gunyah/vm-manager.rst |   2 +-
>   drivers/virt/gunyah/Kconfig              |   9 ++
>   drivers/virt/gunyah/Makefile             |   1 +
>   drivers/virt/gunyah/gunyah_irqfd.c       | 180 +++++++++++++++++++++++
>   include/uapi/linux/gunyah.h              |  35 +++++
>   5 files changed, 226 insertions(+), 1 deletion(-)
>   create mode 100644 drivers/virt/gunyah/gunyah_irqfd.c
> 
> diff --git a/Documentation/virt/gunyah/vm-manager.rst b/Documentation/virt/gunyah/vm-manager.rst
> index b0c3bde105ae9..57a254827be26 100644
> --- a/Documentation/virt/gunyah/vm-manager.rst
> +++ b/Documentation/virt/gunyah/vm-manager.rst
> @@ -116,7 +116,7 @@ the VM *before* the VM starts.
>   The argument types are documented below:
>   
>   .. kernel-doc:: include/uapi/linux/gunyah.h
> -   :identifiers: gh_fn_vcpu_arg
> +   :identifiers: gh_fn_vcpu_arg gh_fn_irqfd_arg gh_irqfd_flags
>   
>   Gunyah VCPU API Descriptions
>   ----------------------------
> diff --git a/drivers/virt/gunyah/Kconfig b/drivers/virt/gunyah/Kconfig
> index 0a58395f7d2c5..bc2c46d9df946 100644
> --- a/drivers/virt/gunyah/Kconfig
> +++ b/drivers/virt/gunyah/Kconfig
> @@ -39,3 +39,12 @@ config GUNYAH_VCPU
>   	  VMMs can also handle stage 2 faults of the vCPUs.
>   
>   	  Say Y/M here if unsure and you want to support Gunyah VMMs.
> +
> +config GUNYAH_IRQFD
> +	tristate "Gunyah irqfd interface"
> +	depends on GUNYAH
> +	help
> +	  Enable kernel support for creating irqfds which can raise an interrupt
> +	  on Gunyah virtual machine.
> +
> +	  Say Y/M here if unsure and you want to support Gunyah VMMs.
> diff --git a/drivers/virt/gunyah/Makefile b/drivers/virt/gunyah/Makefile
> index cc16b6c19db92..ad212a1cf9671 100644
> --- a/drivers/virt/gunyah/Makefile
> +++ b/drivers/virt/gunyah/Makefile
> @@ -7,3 +7,4 @@ gunyah-y += rsc_mgr.o rsc_mgr_rpc.o vm_mgr.o vm_mgr_mm.o
>   obj-$(CONFIG_GUNYAH) += gunyah.o
>   
>   obj-$(CONFIG_GUNYAH_VCPU) += gunyah_vcpu.o
> +obj-$(CONFIG_GUNYAH_IRQFD) += gunyah_irqfd.o
> diff --git a/drivers/virt/gunyah/gunyah_irqfd.c b/drivers/virt/gunyah/gunyah_irqfd.c
> new file mode 100644
> index 0000000000000..3e954ebd20297
> --- /dev/null
> +++ b/drivers/virt/gunyah/gunyah_irqfd.c
> @@ -0,0 +1,180 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All rights reserved.
> + */
> +
> +#include <linux/eventfd.h>
> +#include <linux/file.h>
> +#include <linux/fs.h>
> +#include <linux/gunyah.h>
> +#include <linux/gunyah_vm_mgr.h>
> +#include <linux/module.h>
> +#include <linux/poll.h>
> +#include <linux/printk.h>
> +
> +#include <uapi/linux/gunyah.h>
> +
> +struct gh_irqfd {
> +	struct gh_resource *ghrsc;
> +	struct gh_vm_resource_ticket ticket;
> +	struct gh_vm_function_instance *f;
> +
> +	bool level;
> +
> +	struct eventfd_ctx *ctx;
> +	wait_queue_entry_t wait;
> +	poll_table pt;
> +};
> +
> +static int irqfd_wakeup(wait_queue_entry_t *wait, unsigned int mode, int sync, void *key)
> +{
> +	struct gh_irqfd *irqfd = container_of(wait, struct gh_irqfd, wait);
> +	__poll_t flags = key_to_poll(key);
> +	int ret = 0;
> +
> +	if (flags & EPOLLIN) {
> +		if (irqfd->ghrsc) {
> +			ret = gh_hypercall_bell_send(irqfd->ghrsc->capid, 1, NULL);
> +			if (ret)
> +				pr_err_ratelimited("Failed to inject interrupt %d: %d\n",
> +						irqfd->ticket.label, ret);
> +		} else
> +			pr_err_ratelimited("Premature injection of interrupt\n");
> +	}
> +
> +	return 0;
> +}
> +
> +static void irqfd_ptable_queue_proc(struct file *file, wait_queue_head_t *wqh, poll_table *pt)
> +{
> +	struct gh_irqfd *irq_ctx = container_of(pt, struct gh_irqfd, pt);
> +
> +	add_wait_queue(wqh, &irq_ctx->wait);
> +}
> +
> +static bool gh_irqfd_populate(struct gh_vm_resource_ticket *ticket, struct gh_resource *ghrsc)
> +{
> +	struct gh_irqfd *irqfd = container_of(ticket, struct gh_irqfd, ticket);
> +	int ret;
> +
> +	if (irqfd->ghrsc) {
> +		pr_warn("irqfd%d already got a Gunyah resource. Check if multiple resources with same label were configured.\n",
> +			irqfd->ticket.label);
> +		return false;
> +	}
> +
> +	irqfd->ghrsc = ghrsc;
> +	if (irqfd->level) {
> +		/* Configure the bell to trigger when bit 0 is asserted (see
> +		 * irq_wakeup) and for bell to automatically clear bit 0 once
> +		 * received by the VM (ack_mask).  need to make sure bit 0 is cleared right away,
> +		 * otherwise the line will never be deasserted. Emulating edge
> +		 * trigger interrupt does not need to set either mask
> +		 * because irq is listed only once per gh_hypercall_bell_send
> +		 */
> +		ret = gh_hypercall_bell_set_mask(irqfd->ghrsc->capid, 1, 1);
> +		if (ret)
> +			pr_warn("irq %d couldn't be set as level triggered. Might cause IRQ storm if asserted\n",
> +				irqfd->ticket.label);
> +	}
> +
> +	return true;
> +}
> +
> +static void gh_irqfd_unpopulate(struct gh_vm_resource_ticket *ticket, struct gh_resource *ghrsc)
> +{
> +	struct gh_irqfd *irqfd = container_of(ticket, struct gh_irqfd, ticket);
> +	u64 cnt;
> +
> +	eventfd_ctx_remove_wait_queue(irqfd->ctx, &irqfd->wait, &cnt);
> +}
> +
> +static long gh_irqfd_bind(struct gh_vm_function_instance *f)
> +{
> +	struct gh_fn_irqfd_arg *args = f->argp;
> +	struct gh_irqfd *irqfd;
> +	__poll_t events;
> +	struct fd fd;
> +	long r;
> +
> +	if (f->arg_size != sizeof(*args))
> +		return -EINVAL;
> +
> +	/* All other flag bits are reserved for future use */
> +	if (args->flags & ~GH_IRQFD_FLAGS_LEVEL)
> +		return -EINVAL;
> +
> +	irqfd = kzalloc(sizeof(*irqfd), GFP_KERNEL);
> +	if (!irqfd)
> +		return -ENOMEM;
> +
> +	irqfd->f = f;
> +	f->data = irqfd;
> +
> +	fd = fdget(args->fd);
> +	if (!fd.file) {
> +		kfree(irqfd);
> +		return -EBADF;
> +	}
> +
> +	irqfd->ctx = eventfd_ctx_fileget(fd.file);
> +	if (IS_ERR(irqfd->ctx)) {
> +		r = PTR_ERR(irqfd->ctx);
> +		goto err_fdput;
> +	}
> +
> +	if (args->flags & GH_IRQFD_FLAGS_LEVEL)
> +		irqfd->level = true;
> +
> +	init_waitqueue_func_entry(&irqfd->wait, irqfd_wakeup);
> +	init_poll_funcptr(&irqfd->pt, irqfd_ptable_queue_proc);
> +
> +	irqfd->ticket.resource_type = GH_RESOURCE_TYPE_BELL_TX;
> +	irqfd->ticket.label = args->label;
> +	irqfd->ticket.owner = THIS_MODULE;
> +	irqfd->ticket.populate = gh_irqfd_populate;
> +	irqfd->ticket.unpopulate = gh_irqfd_unpopulate;
> +
> +	r = gh_vm_add_resource_ticket(f->ghvm, &irqfd->ticket);
> +	if (r)
> +		goto err_ctx;
> +
> +	events = vfs_poll(fd.file, &irqfd->pt);
> +	if (events & EPOLLIN)
> +		pr_warn("Premature injection of interrupt\n");
> +	fdput(fd);
> +
> +	return 0;
> +err_ctx:
> +	eventfd_ctx_put(irqfd->ctx);
> +err_fdput:
> +	fdput(fd);
> +	kfree(irqfd);
> +	return r;
> +}
> +
> +static void gh_irqfd_unbind(struct gh_vm_function_instance *f)
> +{
> +	struct gh_irqfd *irqfd = f->data;
> +
> +	gh_vm_remove_resource_ticket(irqfd->f->ghvm, &irqfd->ticket);
> +	eventfd_ctx_put(irqfd->ctx);
> +	kfree(irqfd);
> +}
> +
> +static bool gh_irqfd_compare(const struct gh_vm_function_instance *f,
> +				const void *arg, size_t size)
> +{
> +	const struct gh_fn_irqfd_arg *instance = f->argp,
> +					 *other = arg;
> +
> +	if (sizeof(*other) != size)
> +		return false;
> +
> +	return instance->label == other->label;
> +}
> +
> +DECLARE_GH_VM_FUNCTION_INIT(irqfd, GH_FN_IRQFD, 2, gh_irqfd_bind, gh_irqfd_unbind,
> +				gh_irqfd_compare);
> +MODULE_DESCRIPTION("Gunyah irqfd VM Function");
> +MODULE_LICENSE("GPL");
> diff --git a/include/uapi/linux/gunyah.h b/include/uapi/linux/gunyah.h
> index 434ffa8ffc783..0c480c622686a 100644
> --- a/include/uapi/linux/gunyah.h
> +++ b/include/uapi/linux/gunyah.h
> @@ -77,9 +77,12 @@ struct gh_vm_dtb_config {
>    * @GH_FN_VCPU: create a vCPU instance to control a vCPU
>    *              &struct gh_fn_desc.arg is a pointer to &struct gh_fn_vcpu_arg
>    *              Return: file descriptor to manipulate the vcpu.
> + * @GH_FN_IRQFD: register eventfd to assert a Gunyah doorbell
> + *               &struct gh_fn_desc.arg is a pointer to &struct gh_fn_irqfd_arg
>    */
>   enum gh_fn_type {
>   	GH_FN_VCPU = 1,
> +	GH_FN_IRQFD,
>   };
>   
>   #define GH_FN_MAX_ARG_SIZE		256
> @@ -99,6 +102,38 @@ struct gh_fn_vcpu_arg {
>   	__u32 id;
>   };
>   
> +/**
> + * enum gh_irqfd_flags - flags for use in gh_fn_irqfd_arg
> + * @GH_IRQFD_FLAGS_LEVEL: make the interrupt operate like a level triggered
> + *                        interrupt on guest side. Triggering IRQFD before
> + *                        guest handles the interrupt causes interrupt to
> + *                        stay asserted.
> + */
> +enum gh_irqfd_flags {
> +	GH_IRQFD_FLAGS_LEVEL		= 1UL << 0,
> +};
> +
> +/**
> + * struct gh_fn_irqfd_arg - Arguments to create an irqfd function.
> + *
> + * Create this function with &GH_VM_ADD_FUNCTION using type &GH_FN_IRQFD.
> + *
> + * Allows setting an eventfd to directly trigger a guest interrupt.
> + * irqfd.fd specifies the file descriptor to use as the eventfd.
> + * irqfd.label corresponds to the doorbell label used in the guest VM's devicetree.
> + *
> + * @fd: an eventfd which when written to will raise a doorbell
> + * @label: Label of the doorbell created on the guest VM
> + * @flags: see &enum gh_irqfd_flags
> + * @padding: padding bytes
> + */
> +struct gh_fn_irqfd_arg {
> +	__u32 fd;
> +	__u32 label;
> +	__u32 flags;
> +	__u32 padding;
> +};
> +
>   /**
>    * struct gh_fn_desc - Arguments to create a VM function
>    * @type: Type of the function. See &enum gh_fn_type.

Re: [PATCH v14 00/25] Drivers for Gunyah hypervisor

[Alex Elder]

On 6/13/23 12:20 PM, Elliot Berman wrote:
> Gunyah is a Type-1 hypervisor independent of any
> high-level OS kernel, and runs in a higher CPU privilege level. It does
> not depend on any lower-privileged OS kernel/code for its core
> functionality. This increases its security and can support a much smaller
> trusted computing base than a Type-2 hypervisor.

I believe I have marked "Reviewed-by" on this entire series
now.  If I'm mistaken about that, or if you make a change
that you think warrants me taking another look, please call
that to my attention.

Thanks for being very responsive to my review comments.  My
greatest hope is that we've prevented some bugs from getting
accepted, but I also hope you have found my feedback helpful.

					-Alex

> Gunyah is an open source hypervisor. The source repo is available at
> https://github.com/quic/gunyah-hypervisor.
> 
> The diagram below shows the architecture.
> 
> ::
> 
>           VM A                    VM B
>       +-----+ +-----+  | +-----+ +-----+ +-----+
>       |     | |     |  | |     | |     | |     |
>   EL0 | APP | | APP |  | | APP | | APP | | APP |
>       |     | |     |  | |     | |     | |     |
>       +-----+ +-----+  | +-----+ +-----+ +-----+
>   ---------------------|-------------------------
>       +--------------+ | +----------------------+
>       |              | | |                      |
>   EL1 | Linux Kernel | | |Linux kernel/Other OS |   ...
>       |              | | |                      |
>       +--------------+ | +----------------------+
>   --------hvc/smc------|------hvc/smc------------
>       +----------------------------------------+
>       |                                        |
>   EL2 |            Gunyah Hypervisor           |
>       |                                        |
>       +----------------------------------------+
> 
> Gunyah provides these following features.
> 
> - Threads and Scheduling: The scheduler schedules virtual CPUs (VCPUs) on
> physical CPUs and enables time-sharing of the CPUs.
> - Memory Management: Gunyah tracks memory ownership and use of all memory
> under its control. Memory partitioning between VMs is a fundamental
> security feature.
> - Interrupt Virtualization: All interrupts are handled in the hypervisor
> and routed to the assigned VM.
> - Inter-VM Communication: There are several different mechanisms provided
> for communicating between VMs.
> - Device Virtualization: Para-virtualization of devices is supported using
> inter-VM communication. Low level system features and devices such as
> interrupt controllers are supported with emulation where required.
> 
> This series adds the basic framework for detecting that Linux is running
> under Gunyah as a virtual machine, communication with the Gunyah Resource
> Manager, and a sample virtual machine manager capable of launching virtual machines.
> 
> The series relies on two other patches posted separately:
>   - https://lore.kernel.org/all/20230213181832.3489174-1-quic_eberman@quicinc.com/
>   - https://lore.kernel.org/all/20230213232537.2040976-2-quic_eberman@quicinc.com/
> 
> 
> Changes in v14:
>   - Coding/cosmetic tweaks suggested by Alex
>   - Mark IRQs as wake-up capable
> 
> Changes in v13: https://lore.kernel.org/all/20230509204801.2824351-1-quic_eberman@quicinc.com/
>   - Tweaks to message queue driver to address race condition between IRQ and mailbox registration
>   - Allow removal of VM functions by function-specific comparison -- specifically to allow
>     removing irqfd by label only and not requiring original FD to be provided.
> 
> Changes in v12: https://lore.kernel.org/all/20230424231558.70911-1-quic_eberman@quicinc.com/
>   - Stylistic/cosmetic tweaks suggested by Alex
>   - Remove patch "virt: gunyah: Identify hypervisor version" and squash the
>     check that we're running under a reasonable Gunyah hypervisor into RM driver
>   - Refactor platform hooks into a separate module per suggestion from Srini
>   - GFP_KERNEL_ACCOUNT and account_locked_vm() for page pinning
>   - enum-ify related constants
> 
> Changes in v11: https://lore.kernel.org/all/20230304010632.2127470-1-quic_eberman@quicinc.com/
>   - Rename struct gh_vm_dtb_config:gpa -> guest_phys_addr & overflow checks for this
>   - More docstrings throughout
>   - Make resp_buf and resp_buf_size optional
>   - Replace deprecated idr with xarray
>   - Refconting on misc device instead of RM's platform device
>   - Renaming variables, structs, etc. from gunyah_ -> gh_
>   - Drop removal of user mem regions
>   - Drop mem_lend functionality; to converge with restricted_memfd later
> 
> Changes in v10: https://lore.kernel.org/all/20230214211229.3239350-1-quic_eberman@quicinc.com/
>   - Fix bisectability (end result of series is same, --fixups applied to wrong commits)
>   - Convert GH_ERROR_* and GH_RM_ERROR_* to enums
>   - Correct race condition between allocating/freeing user memory
>   - Replace offsetof with struct_size
>   - Series-wide renaming of functions to be more consistent
>   - VM shutdown & restart support added in vCPU and VM Manager patches
>   - Convert VM function name (string) to type (number)
>   - Convert VM function argument to value (which could be a pointer) to remove memory wastage for arguments
>   - Remove defensive checks of hypervisor correctness
>   - Clean ups to ioeventfd as suggested by Srivatsa
> 
> Changes in v9: https://lore.kernel.org/all/20230120224627.4053418-1-quic_eberman@quicinc.com/
>   - Refactor Gunyah API flags to be exposed as feature flags at kernel level
>   - Move mbox client cleanup into gunyah_msgq_remove()
>   - Simplify gh_rm_call return value and response payload
>   - Missing clean-up/error handling/little endian fixes as suggested by Srivatsa and Alex in v8 series
> 
> Changes in v8: https://lore.kernel.org/all/20221219225850.2397345-1-quic_eberman@quicinc.com/
>   - Treat VM manager as a library of RM
>   - Add patches 21-28 as RFC to support proxy-scheduled vCPUs and necessary bits to support virtio
>     from Gunyah userspace
> 
> Changes in v7: https://lore.kernel.org/all/20221121140009.2353512-1-quic_eberman@quicinc.com/
>   - Refactor to remove gunyah RM bus
>   - Refactor allow multiple RM device instances
>   - Bump UAPI to start at 0x0
>   - Refactor QCOM SCM's platform hooks to allow CONFIG_QCOM_SCM=Y/CONFIG_GUNYAH=M combinations
> 
> Changes in v6: https://lore.kernel.org/all/20221026185846.3983888-1-quic_eberman@quicinc.com/
>   - *Replace gunyah-console with gunyah VM Manager*
>   - Move include/asm-generic/gunyah.h into include/linux/gunyah.h
>   - s/gunyah_msgq/gh_msgq/
>   - Minor tweaks and documentation tidying based on comments from Jiri, Greg, Arnd, Dmitry, and Bagas.
> 
> Changes in v5: https://lore.kernel.org/all/20221011000840.289033-1-quic_eberman@quicinc.com/
>   - Dropped sysfs nodes
>   - Switch from aux bus to Gunyah RM bus for the subdevices
>   - Cleaning up RM console
> 
> Changes in v4: https://lore.kernel.org/all/20220928195633.2348848-1-quic_eberman@quicinc.com/
>   - Tidied up documentation throughout based on questions/feedback received
>   - Switched message queue implementation to use mailboxes
>   - Renamed "gunyah_device" as "gunyah_resource"
> 
> Changes in v3: https://lore.kernel.org/all/20220811214107.1074343-1-quic_eberman@quicinc.com/
>   - /Maintained/Supported/ in MAINTAINERS
>   - Tidied up documentation throughout based on questions/feedback received
>   - Moved hypercalls into arch/arm64/gunyah/; following hyper-v's implementation
>   - Drop opaque typedefs
>   - Move sysfs nodes under /sys/hypervisor/gunyah/
>   - Moved Gunyah console driver to drivers/tty/
>   - Reworked gh_device design to drop the Gunyah bus.
> 
> Changes in v2: https://lore.kernel.org/all/20220801211240.597859-1-quic_eberman@quicinc.com/
>   - DT bindings clean up
>   - Switch hypercalls to follow SMCCC
> 
> v1: https://lore.kernel.org/all/20220223233729.1571114-1-quic_eberman@quicinc.com/
> 
> Elliot Berman (25):
>    docs: gunyah: Introduce Gunyah Hypervisor
>    dt-bindings: Add binding for gunyah hypervisor
>    gunyah: Common types and error codes for Gunyah hypercalls
>    virt: gunyah: Add hypercalls to identify Gunyah
>    virt: gunyah: msgq: Add hypercalls to send and receive messages
>    mailbox: Add Gunyah message queue mailbox
>    gunyah: rsc_mgr: Add resource manager RPC core
>    gunyah: rsc_mgr: Add VM lifecycle RPC
>    gunyah: vm_mgr: Introduce basic VM Manager
>    gunyah: rsc_mgr: Add RPC for sharing memory
>    gunyah: vm_mgr: Add/remove user memory regions
>    gunyah: vm_mgr: Add ioctls to support basic non-proxy VM boot
>    samples: Add sample userspace Gunyah VM Manager
>    gunyah: rsc_mgr: Add platform ops on mem_lend/mem_reclaim
>    virt: gunyah: Add Qualcomm Gunyah platform ops
>    docs: gunyah: Document Gunyah VM Manager
>    virt: gunyah: Translate gh_rm_hyp_resource into gunyah_resource
>    gunyah: vm_mgr: Add framework for VM Functions
>    virt: gunyah: Add resource tickets
>    virt: gunyah: Add IO handlers
>    virt: gunyah: Add proxy-scheduled vCPUs
>    virt: gunyah: Add hypercalls for sending doorbell
>    virt: gunyah: Add irqfd interface
>    virt: gunyah: Add ioeventfd
>    MAINTAINERS: Add Gunyah hypervisor drivers section
> 
>   .../bindings/firmware/gunyah-hypervisor.yaml  |  82 ++
>   .../userspace-api/ioctl/ioctl-number.rst      |   1 +
>   Documentation/virt/gunyah/index.rst           | 114 +++
>   Documentation/virt/gunyah/message-queue.rst   |  71 ++
>   Documentation/virt/gunyah/vm-manager.rst      | 143 +++
>   Documentation/virt/index.rst                  |   1 +
>   MAINTAINERS                                   |  13 +
>   arch/arm64/Kbuild                             |   1 +
>   arch/arm64/gunyah/Makefile                    |   3 +
>   arch/arm64/gunyah/gunyah_hypercall.c          | 142 +++
>   arch/arm64/include/asm/gunyah.h               |  24 +
>   drivers/mailbox/Makefile                      |   2 +
>   drivers/mailbox/gunyah-msgq.c                 | 219 +++++
>   drivers/virt/Kconfig                          |   2 +
>   drivers/virt/Makefile                         |   1 +
>   drivers/virt/gunyah/Kconfig                   |  59 ++
>   drivers/virt/gunyah/Makefile                  |  11 +
>   drivers/virt/gunyah/gunyah_ioeventfd.c        | 130 +++
>   drivers/virt/gunyah/gunyah_irqfd.c            | 180 ++++
>   drivers/virt/gunyah/gunyah_platform_hooks.c   |  80 ++
>   drivers/virt/gunyah/gunyah_qcom.c             | 153 +++
>   drivers/virt/gunyah/gunyah_vcpu.c             | 470 +++++++++
>   drivers/virt/gunyah/rsc_mgr.c                 | 909 ++++++++++++++++++
>   drivers/virt/gunyah/rsc_mgr.h                 |  19 +
>   drivers/virt/gunyah/rsc_mgr_rpc.c             | 500 ++++++++++
>   drivers/virt/gunyah/vm_mgr.c                  | 791 +++++++++++++++
>   drivers/virt/gunyah/vm_mgr.h                  |  70 ++
>   drivers/virt/gunyah/vm_mgr_mm.c               | 252 +++++
>   include/linux/gunyah.h                        | 207 ++++
>   include/linux/gunyah_rsc_mgr.h                | 162 ++++
>   include/linux/gunyah_vm_mgr.h                 | 153 +++
>   include/uapi/linux/gunyah.h                   | 293 ++++++
>   samples/Kconfig                               |  10 +
>   samples/Makefile                              |   1 +
>   samples/gunyah/.gitignore                     |   2 +
>   samples/gunyah/Makefile                       |   6 +
>   samples/gunyah/gunyah_vmm.c                   | 266 +++++
>   samples/gunyah/sample_vm.dts                  |  68 ++
>   38 files changed, 5611 insertions(+)
>   create mode 100644 Documentation/devicetree/bindings/firmware/gunyah-hypervisor.yaml
>   create mode 100644 Documentation/virt/gunyah/index.rst
>   create mode 100644 Documentation/virt/gunyah/message-queue.rst
>   create mode 100644 Documentation/virt/gunyah/vm-manager.rst
>   create mode 100644 arch/arm64/gunyah/Makefile
>   create mode 100644 arch/arm64/gunyah/gunyah_hypercall.c
>   create mode 100644 arch/arm64/include/asm/gunyah.h
>   create mode 100644 drivers/mailbox/gunyah-msgq.c
>   create mode 100644 drivers/virt/gunyah/Kconfig
>   create mode 100644 drivers/virt/gunyah/Makefile
>   create mode 100644 drivers/virt/gunyah/gunyah_ioeventfd.c
>   create mode 100644 drivers/virt/gunyah/gunyah_irqfd.c
>   create mode 100644 drivers/virt/gunyah/gunyah_platform_hooks.c
>   create mode 100644 drivers/virt/gunyah/gunyah_qcom.c
>   create mode 100644 drivers/virt/gunyah/gunyah_vcpu.c
>   create mode 100644 drivers/virt/gunyah/rsc_mgr.c
>   create mode 100644 drivers/virt/gunyah/rsc_mgr.h
>   create mode 100644 drivers/virt/gunyah/rsc_mgr_rpc.c
>   create mode 100644 drivers/virt/gunyah/vm_mgr.c
>   create mode 100644 drivers/virt/gunyah/vm_mgr.h
>   create mode 100644 drivers/virt/gunyah/vm_mgr_mm.c
>   create mode 100644 include/linux/gunyah.h
>   create mode 100644 include/linux/gunyah_rsc_mgr.h
>   create mode 100644 include/linux/gunyah_vm_mgr.h
>   create mode 100644 include/uapi/linux/gunyah.h
>   create mode 100644 samples/gunyah/.gitignore
>   create mode 100644 samples/gunyah/Makefile
>   create mode 100644 samples/gunyah/gunyah_vmm.c
>   create mode 100644 samples/gunyah/sample_vm.dts
> 
> 
> base-commit: 858fd168a95c5b9669aac8db6c14a9aeab446375

Re: [PATCH v14 01/25] docs: gunyah: Introduce Gunyah Hypervisor

[Elliot Berman]

On 6/16/2023 9:32 AM, Alex Elder wrote:
> On 6/13/23 12:20 PM, Elliot Berman wrote:
>> Gunyah is an open-source Type-1 hypervisor developed by Qualcomm. It
>> does not depend on any lower-privileged OS/kernel code for its core
>> functionality. This increases its security and can support a smaller
>> trusted computing based when compared to Type-2 hypervisors.
> 
> s/based/base/
> 
>>
>> Add documentation describing the Gunyah hypervisor and the main
>> components of the Gunyah hypervisor which are of interest to Linux
>> virtualization development.
>>
>> Reviewed-by: Bagas Sanjaya <bagasdotme@gmail.com>
>> Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
> 
> I have some questions and comments.  But I trust that you
> can answer them and update your patch in a reasonable way
> to address what I say.  So... please consider these things,
> and update as you see fit.
> 
> Reviewed-by: Alex Elder <elder@linaro.org>
> 
>> ---
>>   Documentation/virt/gunyah/index.rst         | 113 ++++++++++++++++++++
>>   Documentation/virt/gunyah/message-queue.rst |  63 +++++++++++
>>   Documentation/virt/index.rst                |   1 +
>>   3 files changed, 177 insertions(+)
>>   create mode 100644 Documentation/virt/gunyah/index.rst
>>   create mode 100644 Documentation/virt/gunyah/message-queue.rst
>>
>> diff --git a/Documentation/virt/gunyah/index.rst 
>> b/Documentation/virt/gunyah/index.rst
>> new file mode 100644
>> index 0000000000000..74aa345e0a144
>> --- /dev/null
>> +++ b/Documentation/virt/gunyah/index.rst
>> @@ -0,0 +1,113 @@
>> +.. SPDX-License-Identifier: GPL-2.0
>> +
>> +=================
>> +Gunyah Hypervisor
>> +=================
>> +
>> +.. toctree::
>> +   :maxdepth: 1
>> +
>> +   message-queue
>> +
>> +Gunyah is a Type-1 hypervisor which is independent of any OS kernel, 
>> and runs in
>> +a higher CPU privilege level. It does not depend on any 
>> lower-privileged operating system
>> +for its core functionality. This increases its security and can 
>> support a much smaller
>> +trusted computing base than a Type-2 hypervisor.
>> +
>> +Gunyah is an open source hypervisor. The source repo is available at
>> +https://github.com/quic/gunyah-hypervisor.
>> +
>> +Gunyah provides these following features.
>> +
>> +- Scheduling:
>> +
>> +  A scheduler for virtual CPUs (vCPUs) on physical CPUs enables 
>> time-sharing
>> +  of the CPUs. Gunyah supports two models of scheduling:
>> +
>> +    1. "Behind the back" scheduling in which Gunyah hypervisor 
>> schedules vCPUS on its own.
> 
> s/VCPUS/VCPUs/
> 
>> +    2. "Proxy" scheduling in which a delegated VM can donate part of 
>> one of its vCPU slice
>> +       to another VM's vCPU via a hypercall.
> 
> This might sound dumb, but can there be more vCPUs than there
> are physical CPUs?  Is a vCPU *tied* to a particular physical
> CPU, or does it just indicate that a VM has one abstracted CPU
> available to use--and any available physical CPU core can
> implement it (possibly changing between time slices)?
> 

There can be more vCPUs than physical CPUs. If someone wanted to 
hard-code their VM to use 16 vCPUs, they could (I picked 16 arbitrarily).

The latter -- the physical CPU that makes the "vcpu_run" hypercall will 
be the one to run the vCPU. The userspace thread triggers the hypercall 
via GH_VCPU_RUN ioctl and is dependent on the host's task placement for 
which physical cpu that userspace thread runs on.

>> +
>> +- Memory Management:
>> +
>> +  APIs handling memory, abstracted as objects, limiting direct use of 
>> physical
>> +  addresses. Memory ownership and usage tracking of all memory under 
>> its control.
>> +  Memory partitioning between VMs is a fundamental security feature.
>> +
>> +- Interrupt Virtualization:
>> +
>> +  Uses CPU hardware interrupt virtualization capabilities. Interrupts 
>> are handled
>> +  in the hypervisor and routed to the assigned VM.
>> +
>> +- Inter-VM Communication:
>> +
>> +  There are several different mechanisms provided for communicating 
>> between VMs.
>> +
>> +- Virtual platform:
>> +
>> +  Architectural devices such as interrupt controllers and CPU timers 
>> are directly provided
>> +  by the hypervisor as well as core virtual platform devices and 
>> system APIs such as ARM PSCI.
>> +
>> +- Device Virtualization:
>> +
>> +  Para-virtualization of devices is supported using inter-VM 
>> communication.
>> +
>> +Architectures supported
>> +=======================
>> +AArch64 with a GIC
>> +
>> +Resources and Capabilities
>> +==========================
>> +
>> +Some services or resources provided by the Gunyah hypervisor are 
>> described to a virtual machine by
>> +capability IDs. For instance, inter-VM communication is performed 
>> with doorbells and message queues.
>> +Gunyah allows access to manipulate that doorbell via the capability 
>> ID. These resources are
>> +described in Linux as a struct gh_resource.
>> +
>> +High level management of these resources is performed by the resource 
>> manager VM. RM informs a
>> +guest VM about resources it can access through either the device tree 
>> or via guest-initiated RPC.
>> +
>> +For each virtual machine, Gunyah maintains a table of resources which 
>> can be accessed by that VM.
>> +An entry in this table is called a "capability" and VMs can only 
>> access resources via this
>> +capability table. Hence, virtual Gunyah resources are referenced by a 
>> "capability IDs" and not
>> +"resource IDs". If 2 VMs have access to the same resource, they might 
>> not be using the same
>> +capability ID to access that resource since the capability tables are 
>> independent per VM.
>> +
>> +Resource Manager
>> +================
>> +
>> +The resource manager (RM) is a privileged application VM supporting 
>> the Gunyah Hypervisor.
>> +It provides policy enforcement aspects of the virtualization system. 
>> The resource manager can
>> +be treated as an extension of the Hypervisor but is separated to its 
>> own partition to ensure
>> +that the hypervisor layer itself remains small and secure and to 
>> maintain a separation of policy
>> +and mechanism in the platform. RM runs at arm64 NS-EL1 similar to 
>> other virtual machines.
>> +
>> +Communication with the resource manager from each guest VM happens 
>> with message-queue.rst. Details
>> +about the specific messages can be found in 
>> drivers/virt/gunyah/rsc_mgr.c
>> +
>> +::
>> +
>> +  +-------+   +--------+   +--------+
>> +  |  RM   |   |  VM_A  |   |  VM_B  |
>> +  +-.-.-.-+   +---.----+   +---.----+
>> +    | |           |            |
>> +  +-.-.-----------.------------.----+
>> +  | | \==========/             |    |
>> +  |  \========================/     |
>> +  |            Gunyah               |
>> +  +---------------------------------+
>> +
>> +The source for the resource manager is available at 
>> https://github.com/quic/gunyah-resource-manager.
>> +
>> +The resource manager provides the following features:
>> +
>> +- VM lifecycle management: allocating a VM, starting VMs, destruction 
>> of VMs
>> +- VM access control policy, including memory sharing and lending
>> +- Interrupt routing configuration
>> +- Forwarding of system-level events (e.g. VM shutdown) to owner VM
>> +
>> +When booting a virtual machine which uses a devicetree such as Linux, 
>> resource manager overlays a
>> +/hypervisor node. This node can let Linux know it is running as a 
>> Gunyah guest VM,
>> +how to communicate with resource manager, and basic description and 
>> capabilities of
> 
> Maybe:
> 
> This node lets Linux know it is running as a Gunyah guest VM.
> It provides a basic description and capabilities of the VM,
> as well as information required to communicate with the resource
> manager.
> 
>> +this VM. See 
>> Documentation/devicetree/bindings/firmware/gunyah-hypervisor.yaml for 
>> a description
>> +of this node.
>> diff --git a/Documentation/virt/gunyah/message-queue.rst 
>> b/Documentation/virt/gunyah/message-queue.rst
>> new file mode 100644
>> index 0000000000000..b352918ae54b4
>> --- /dev/null
>> +++ b/Documentation/virt/gunyah/message-queue.rst
>> @@ -0,0 +1,63 @@
>> +.. SPDX-License-Identifier: GPL-2.0
>> +
>> +Message Queues
>> +==============
>> +Message queue is a simple low-capacity IPC channel between two VMs. 
>> It is
> 
> I don't know what the "capacity" of an IPC channel is.  But
> that's OK I guess; it's sort of descriptive.
> 
>> +intended for sending small control and configuration messages. Each 
>> message
>> +queue is unidirectional, so a full-duplex IPC channel requires a pair 
>> of queues.
>> +
>> +Messages can be up to 240 bytes in length. Longer messages require a 
>> further
>> +protocol on top of the message queue messages themselves. For 
>> instance, communication
>> +with the resource manager adds a header field for sending longer 
>> messages via multiple
>> +message fragments.
>> +
>> +The diagram below shows how message queue works. A typical 
>> configuration involves
>> +2 message queues. Message queue 1 allows VM_A to send messages to 
>> VM_B. Message
>> +queue 2 allows VM_B to send messages to VM_A.
>> +
>> +1. VM_A sends a message of up to 240 bytes in length. It raises a 
>> hypercall
>> +   with the message to inform the hypervisor to add the message to
>> +   message queue 1's queue. The hypervisor copies memory into the 
>> internal
>> +   message queue representation; the memory doesn't need to be shared 
>> between
>> +   VM_A and VM_B.
>> +
>> +2. Gunyah raises the corresponding interrupt for VM_B (Rx vIRQ) when 
>> any of
>> +   these happens:
>> +
>> +   a. gh_msgq_send() has PUSH flag. Queue is immediately flushed. 
>> This is the typical case.
>> +   b. Explicility with gh_msgq_push command from VM_A.
> 
> s/Explicility/Explicitly/
> 
> Is gh_msgq_send() a function and gh_msgq_push a "command" or
> something?  Why the difference in parentheses?  (Pick a
> convention and follow it.)

Will fix.

> 
> Does "Queue is flushed" mean "VM_B is interrupted"?

Yes, I'll clarify that's what it means. VM_B could get the interrupt and 
still decide not to read from the queue.

> 
> VM_A calls gh_msgq_push, and that causes the VM_B interrupt to
> be signaled?
> 

Yes.

> I'm being a little picky but I think these descriptions could be
> improved a bit.
> 
>> +   c. Message queue has reached a threshold depth.
>> +
>> +3. VM_B calls gh_msgq_recv() and Gunyah copies message to requested 
>> buffer.
> 
> It sure would be nice if all this didn't have to be copied
> twice.  But I recognize the copies ensure isolation.
> 
>> +
>> +4. Gunyah buffers messages in the queue. If the queue became full 
>> when VM_A added a message,
>> +   the return values for gh_msgq_send() include a flag that indicates 
>> the queue is full.
>> +   Once VM_B receives the message and, thus, there is space in the 
>> queue, Gunyah
>> +   will raise the Tx vIRQ on VM_A to indicate it can continue sending 
>> messages.
> 
> Does the Tx vIRQ on VM_A fire after *every* message is sent,
> or only when the state of the queue goes from "full" to "not"?
> (Looking at patch 6 it looks like the latter.)

Tx vIRQ only fires when state of queue goes from "full" to "not".

This may not be very relevant, but Gunyah allows the "not full" 
threshold to be less than the queue depth. For instance, the Tx vIRQ 
could be configured to only fire once there are no pending messages in 
the queue. Linux doesn't presently configure this threshold.

> 
> If it's signaled after every message is sent, does it
> indicate that the message has been *received* by VM_B
> (versus just received and copied by Gunyah)?
> 

To connect some dots: the Tx vIRQ is fired when the reader reads a 
message and the number of messages still in the queue decrements to the 
"not full" threshold.

https://github.com/quic/gunyah-hypervisor/blob/3d4014404993939f898018cfb1935c2d9bfc2830/hyp/ipc/msgqueue/src/msgqueue_common.c#L142-L148

>> +
>> +For VM_B to send a message to VM_A, the process is identical, except 
>> that hypercalls
>> +reference message queue 2's capability ID. Each message queue has its 
>> own independent
>> +vIRQ: two TX message queues will have two vIRQs (and two capability 
>> IDs).
>> +
>> +::
>> +
>> +      +---------------+         +-----------------+         
>> +---------------+
>> +      |      VM_A     |         |Gunyah hypervisor|         |      
>> VM_B     |
>> +      |               |         |                 |         
>> |               |
>> +      |               |         |                 |         
>> |               |
>> +      |               |   Tx    |                 |         
>> |               |
>> +      |               |-------->|                 | Rx vIRQ 
>> |               |
>> +      |gh_msgq_send() | Tx vIRQ |Message queue 1  
>> |-------->|gh_msgq_recv() |
>> +      |               |<------- |                 |         
>> |               |
>> +      |               |         |                 |         
>> |               |
>> +      | Message Queue |         |                 |         | Message 
>> Queue |
>> +      | driver        |         |                 |         | 
>> driver        |
>> +      |               |         |                 |         
>> |               |
>> +      |               |         |                 |         
>> |               |
>> +      |               |         |                 |   Tx    
>> |               |
>> +      |               | Rx vIRQ |                 
>> |<--------|               |
>> +      |gh_msgq_recv() |<--------|Message queue 2  | Tx vIRQ 
>> |gh_msgq_send() |
>> +      |               |         |                 
>> |-------->|               |
>> +      |               |         |                 |         
>> |               |
>> +      |               |         |                 |         
>> |               |
>> +      +---------------+         +-----------------+         
>> +---------------+
>> diff --git a/Documentation/virt/index.rst b/Documentation/virt/index.rst
>> index 7fb55ae08598d..15869ee059b35 100644
>> --- a/Documentation/virt/index.rst
>> +++ b/Documentation/virt/index.rst
>> @@ -16,6 +16,7 @@ Virtualization Support
>>      coco/sev-guest
>>      coco/tdx-guest
>>      hyperv/index
>> +   gunyah/index
>>   .. only:: html and subproject
> 

Re: [PATCH v14 01/25] docs: gunyah: Introduce Gunyah Hypervisor

[Alex Elder]

On 7/3/23 5:41 PM, Elliot Berman wrote:
>> If it's signaled after every message is sent, does it
>> indicate that the message has been *received* by VM_B
>> (versus just received and copied by Gunyah)?
>>
> 
> To connect some dots: the Tx vIRQ is fired when the reader reads a 
> message and the number of messages still in the queue decrements to the 
> "not full" threshold.
> 
> https://github.com/quic/gunyah-hypervisor/blob/3d4014404993939f898018cfb1935c2d9bfc2830/hyp/ipc/msgqueue/src/msgqueue_common.c#L142-L148

So the Tx vIRQ on the sender is only fired when the state of the
receiver's Rx queue goes from "full" to "not full".

Normally there is no signal sent, and a sender sends messages
until it gets a "queue full" flag back from a gh_msgq_send()
call.  At that point it should stop sending, until the Tx vIRQ
fires to indicate the receiver queue has "room" (fewer than
the "full threshold" messages are consumed).

There is no way (at this layer of the protocol) to tell whether
a given message has been *received*, only that it has been *sent*
(meaning the hypervisor has accepted it).  And Gunyah provides
reliable delivery (each message received in send order, exactly
once).

Now that I re-read what you said it makes sense and I guess I
just misunderstood.  There *might* be a way to reword slightly
to prevent any misinterpretation.

Thanks.

					-Alex

Re: [PATCH v14 06/25] mailbox: Add Gunyah message queue mailbox

[Jassi Brar]

On Tue, Jun 13, 2023 at 12:21 PM Elliot Berman <quic_eberman@quicinc.com> wrote:
......

> diff --git a/drivers/mailbox/gunyah-msgq.c b/drivers/mailbox/gunyah-msgq.c
> new file mode 100644
> index 0000000000000..7f777339278eb
> --- /dev/null
> +++ b/drivers/mailbox/gunyah-msgq.c
> @@ -0,0 +1,219 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All rights reserved.
> + */
> +
> +#include <linux/mailbox_controller.h>
> +#include <linux/module.h>
> +#include <linux/interrupt.h>
> +#include <linux/gunyah.h>
> +#include <linux/printk.h>
> +#include <linux/init.h>
> +#include <linux/slab.h>
> +#include <linux/wait.h>
> +
I believe some includes could be removed without issue.

>
> +#define mbox_chan_to_msgq(chan) (container_of(chan->mbox, struct gh_msgq, mbox))
> +
container_of need not be in brackets.

> +static irqreturn_t gh_msgq_rx_irq_handler(int irq, void *data)
> +{
> +       struct gh_msgq *msgq = data;
> +       struct gh_msgq_rx_data rx_data;
> +       enum gh_error gh_error;
> +       bool ready = true;
> +
Please limit the scope of rx_data and gh_error by moving them inside
the while() body.

> +       while (ready) {
> +               gh_error = gh_hypercall_msgq_recv(msgq->rx_ghrsc->capid,
> +                               &rx_data.data, sizeof(rx_data.data),
> +                               &rx_data.length, &ready);
> +               if (gh_error != GH_ERROR_OK) {
> +                       if (gh_error != GH_ERROR_MSGQUEUE_EMPTY)
> +                               dev_warn(msgq->mbox.dev, "Failed to receive data: %d\n", gh_error);
> +                       break;
> +               }
> +               if (likely(gh_msgq_chan(msgq)->cl))
> +                       mbox_chan_received_data(gh_msgq_chan(msgq), &rx_data);
> +       }
> +
> +       return IRQ_HANDLED;
> +}
> +


> +static int gh_msgq_send_data(struct mbox_chan *chan, void *data)
> +{
> +       struct gh_msgq *msgq = mbox_chan_to_msgq(chan);
> +       struct gh_msgq_tx_data *msgq_data = data;
> +       u64 tx_flags = 0;
> +       enum gh_error gh_error;
> +       bool ready;
> +
> +       if (!msgq->tx_ghrsc)
> +               return -EOPNOTSUPP;
> +
If we hit this error, the fix will still be in the upper layer.
So please drop the check and, if needed, add one in the client driver.


> +       if (msgq_data->push)
> +               tx_flags |= GH_HYPERCALL_MSGQ_TX_FLAGS_PUSH;
> +
> +       gh_error = gh_hypercall_msgq_send(msgq->tx_ghrsc->capid, msgq_data->length, msgq_data->data,
> +                                               tx_flags, &ready);
> +
> +       /**
> +        * unlikely because Linux tracks state of msgq and should not try to
> +        * send message when msgq is full.
> +        */
> +       if (unlikely(gh_error == GH_ERROR_MSGQUEUE_FULL))
> +               return -EAGAIN;
> +
If it is not expected to hit, please remove the check.
If there can be a 'race' like situation, still remove this and try to
find an appropriate place to avoid the race.

> +       /**
> +        * Propagate all other errors to client. If we return error to mailbox
> +        * framework, then no other messages can be sent and nobody will know
> +        * to retry this message.
> +        */
> +       msgq->last_ret = gh_error_remap(gh_error);
> +
> +       /**
> +        * This message was successfully sent, but message queue isn't ready to
> +        * accept more messages because it's now full. Mailbox framework
> +        * requires that we only report that message was transmitted when
> +        * we're ready to transmit another message. We'll get that in the form
> +        * of tx IRQ once the other side starts to drain the msgq.
> +        */
> +       if (gh_error == GH_ERROR_OK) {
> +               if (!ready)
> +                       return 0;
> +       } else {
> +               dev_err(msgq->mbox.dev, "Failed to send data: %d (%d)\n", gh_error, msgq->last_ret);
> +       }
> +
> +       /**
> +        * We can send more messages.
>
            ... until we can not (when the platform specific queue is full).

>             Mailbox framework requires that tx done
> +        * happens asynchronously to sending the message.
>
hence the mailbox api needs to track each transfer's stage.

>             Gunyah message queues
> +        * tell us right away on the hypercall return whether we can send more
> +        * messages. To work around this, defer the txdone to a tasklet.
> +        */
>
If not here, you would still have to put the 'defer' somewhere in the
upper layer.
So it is not exactly a "workaround".

> +       tasklet_schedule(&msgq->txdone_tasklet);
> +
> +       return 0;
> +}
> +


> diff --git a/include/linux/gunyah.h b/include/linux/gunyah.h
> index 01a6f202d037e..982e27d10d57f 100644
> --- a/include/linux/gunyah.h
> +++ b/include/linux/gunyah.h
> @@ -8,11 +8,68 @@
>
>  #include <linux/bitfield.h>
>  #include <linux/errno.h>
> +#include <linux/interrupt.h>
>  #include <linux/limits.h>
> +#include <linux/mailbox_controller.h>
> +#include <linux/mailbox_client.h>
>  #include <linux/types.h>
>
controller.h and client.h aren't supposed to be in the same header.
The Client and the Controller driver could include them respectively
before this header.

Cheers.

Re: [PATCH v14 02/25] dt-bindings: Add binding for gunyah hypervisor

[Bjorn Andersson]

On Tue, Jun 13, 2023 at 10:20:30AM -0700, Elliot Berman wrote:
> When Linux is booted as a guest under the Gunyah hypervisor, the Gunyah

Is this unique to the case of booting Linux?

> Resource Manager applies a devicetree overlay describing the virtual
> platform configuration of the guest VM, such as the message queue
> capability IDs for communicating with the Resource Manager. This
> information is not otherwise discoverable by a VM: the Gunyah hypervisor
> core does not provide a direct interface to discover capability IDs nor
> a way to communicate with RM without having already known the
> corresponding message queue capability ID. Add the DT bindings that
> Gunyah adheres for the hypervisor node and message queues.
> 
> Reviewed-by: Rob Herring <robh@kernel.org>
> Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
> ---
>  .../bindings/firmware/gunyah-hypervisor.yaml  | 82 +++++++++++++++++++
>  1 file changed, 82 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/firmware/gunyah-hypervisor.yaml
> 
> diff --git a/Documentation/devicetree/bindings/firmware/gunyah-hypervisor.yaml b/Documentation/devicetree/bindings/firmware/gunyah-hypervisor.yaml
> new file mode 100644
> index 0000000000000..3fc0b043ac3cf
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/firmware/gunyah-hypervisor.yaml
> @@ -0,0 +1,82 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/firmware/gunyah-hypervisor.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Gunyah Hypervisor
> +
> +maintainers:
> +  - Prakruthi Deepak Heragu <quic_pheragu@quicinc.com>
> +  - Elliot Berman <quic_eberman@quicinc.com>
> +
> +description: |+
> +  Gunyah virtual machines use this information to determine the capability IDs
> +  of the message queues used to communicate with the Gunyah Resource Manager.
> +  See also: https://github.com/quic/gunyah-resource-manager/blob/develop/src/vm_creation/dto_construct.c
> +
> +properties:
> +  compatible:
> +    const: gunyah-hypervisor
> +
> +  "#address-cells":
> +    description: Number of cells needed to represent 64-bit capability IDs.
> +    const: 2
> +
> +  "#size-cells":
> +    description: must be 0, because capability IDs are not memory address
> +                  ranges and do not have a size.
> +    const: 0
> +
> +patternProperties:
> +  "^gunyah-resource-mgr(@.*)?":
> +    type: object
> +    description:
> +      Resource Manager node which is required to communicate to Resource
> +      Manager VM using Gunyah Message Queues.
> +
> +    properties:
> +      compatible:
> +        const: gunyah-resource-manager
> +
> +      reg:
> +        items:
> +          - description: Gunyah capability ID of the TX message queue
> +          - description: Gunyah capability ID of the RX message queue
> +
> +      interrupts:
> +        items:
> +          - description: Interrupt for the TX message queue
> +          - description: Interrupt for the RX message queue
> +
> +    additionalProperties: false
> +
> +    required:
> +      - compatible
> +      - reg
> +      - interrupts
> +
> +additionalProperties: false
> +
> +required:
> +  - compatible
> +  - "#address-cells"
> +  - "#size-cells"
> +
> +examples:
> +  - |
> +    #include <dt-bindings/interrupt-controller/arm-gic.h>
> +
> +    hypervisor {
> +        #address-cells = <2>;
> +        #size-cells = <0>;
> +        compatible = "gunyah-hypervisor";

It's typical to carry the compatible first among the properties.

Unrelated to the binding itself, I don't see any code that matches this
compatible, and as such will probe the resource manager. What am I
missing?

> +
> +        gunyah-resource-mgr@0 {
> +            compatible = "gunyah-resource-manager";
> +            interrupts = <GIC_SPI 3 IRQ_TYPE_EDGE_RISING>, /* TX full IRQ */

This is the "Tx no longer full IRQ", so the comment is misleading.

> +                         <GIC_SPI 4 IRQ_TYPE_EDGE_RISING>; /* RX empty IRQ */

And this irq seems to fire when there's data in the RX queue, not when
it's empty...

> +            reg = <0x00000000 0x00000000>, <0x00000000 0x00000001>;
> +                  /* TX, RX cap ids */

Wrapping this differently will make the comments more useful.

Regards,
Bjorn

> +        };
> +    };
> -- 
> 2.40.0
> 

Re: [PATCH v14 03/25] gunyah: Common types and error codes for Gunyah hypercalls

[Bjorn Andersson]

On Tue, Jun 13, 2023 at 10:20:31AM -0700, Elliot Berman wrote:
> diff --git a/include/linux/gunyah.h b/include/linux/gunyah.h
[..]
> +/******************************************************************************/
> +/* Common arch-independent definitions for Gunyah hypercalls                  */
> +#define GH_CAPID_INVAL	U64_MAX
> +#define GH_VMID_ROOT_VM	0xff
> +
> +enum gh_error {

"gh_" happens to be an unused prefix in the Linux kernel, but I find it
to be an unnatural abbreviation of "gunyah".

I would therefor prefer to have it expanded to "gunyah" for all
functions, macros and data types throughout the implementation.

Regards,
Bjorn

Re: [PATCH v14 05/25] virt: gunyah: msgq: Add hypercalls to send and receive messages

[Bjorn Andersson]

On Tue, Jun 13, 2023 at 10:20:33AM -0700, Elliot Berman wrote:
> Add hypercalls to send and receive messages on a Gunyah message queue.
> 
> Reviewed-by: Alex Elder <elder@linaro.org>
> Reviewed-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
> Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
> ---
>  arch/arm64/gunyah/gunyah_hypercall.c | 31 ++++++++++++++++++++++++++++
>  include/linux/gunyah.h               |  6 ++++++
>  2 files changed, 37 insertions(+)
> 
> diff --git a/arch/arm64/gunyah/gunyah_hypercall.c b/arch/arm64/gunyah/gunyah_hypercall.c
> index ef48e0b8b5448..c5bf0dd468ec9 100644
> --- a/arch/arm64/gunyah/gunyah_hypercall.c
> +++ b/arch/arm64/gunyah/gunyah_hypercall.c
> @@ -35,6 +35,8 @@ EXPORT_SYMBOL_GPL(arch_is_gh_guest);
>  						   fn)
>  
>  #define GH_HYPERCALL_HYP_IDENTIFY		GH_HYPERCALL(0x8000)
> +#define GH_HYPERCALL_MSGQ_SEND			GH_HYPERCALL(0x801B)
> +#define GH_HYPERCALL_MSGQ_RECV			GH_HYPERCALL(0x801C)
>  
>  /**
>   * gh_hypercall_hyp_identify() - Returns build information and feature flags
> @@ -54,5 +56,34 @@ void gh_hypercall_hyp_identify(struct gh_hypercall_hyp_identify_resp *hyp_identi
>  }
>  EXPORT_SYMBOL_GPL(gh_hypercall_hyp_identify);
>  
> +enum gh_error gh_hypercall_msgq_send(u64 capid, size_t size, void *buff, u64 tx_flags, bool *ready)

I find the name "ready" unclear, I believe it will be true to indicate
that the message queue is not full (i.e. Gunyah is ready to receive
another message?)

Naming it "full" and reversing the values would make this immediately
obvious.

> +{
> +	struct arm_smccc_res res;
> +
> +	arm_smccc_1_1_hvc(GH_HYPERCALL_MSGQ_SEND, capid, size, (uintptr_t)buff, tx_flags, 0, &res);
> +
> +	if (res.a0 == GH_ERROR_OK)
> +		*ready = !!res.a1;
> +
> +	return res.a0;
> +}
> +EXPORT_SYMBOL_GPL(gh_hypercall_msgq_send);
> +
> +enum gh_error gh_hypercall_msgq_recv(u64 capid, void *buff, size_t size, size_t *recv_size,
> +					bool *ready)

And this "ready" seems to be "more data available". Naming it "empty",
and reversing the values, would make this obvious.


Perhaps when working with the hypercalls on a regular basis it makes
sense to not invert the value space...renaming the two "ready" would be
beneficial regardless.

> +{
> +	struct arm_smccc_res res;
> +
> +	arm_smccc_1_1_hvc(GH_HYPERCALL_MSGQ_RECV, capid, (uintptr_t)buff, size, 0, &res);
> +
> +	if (res.a0 == GH_ERROR_OK) {
> +		*recv_size = res.a1;
> +		*ready = !!res.a2;
> +	}
> +
> +	return res.a0;
> +}
> +EXPORT_SYMBOL_GPL(gh_hypercall_msgq_recv);
> +
>  MODULE_LICENSE("GPL");
>  MODULE_DESCRIPTION("Gunyah Hypervisor Hypercalls");
> diff --git a/include/linux/gunyah.h b/include/linux/gunyah.h
> index 6b36cf4787efb..01a6f202d037e 100644
> --- a/include/linux/gunyah.h
> +++ b/include/linux/gunyah.h
> @@ -111,4 +111,10 @@ static inline u16 gh_api_version(const struct gh_hypercall_hyp_identify_resp *gh
>  
>  void gh_hypercall_hyp_identify(struct gh_hypercall_hyp_identify_resp *hyp_identity);
>  
> +#define GH_HYPERCALL_MSGQ_TX_FLAGS_PUSH		BIT(0)

Unless the flags are growing, passing this as a bool push instead of a
flag field seems reasonable.

> +
> +enum gh_error gh_hypercall_msgq_send(u64 capid, size_t size, void *buff, u64 tx_flags, bool *ready);
> +enum gh_error gh_hypercall_msgq_recv(u64 capid, void *buff, size_t size, size_t *recv_size,
> +					bool *ready);

Please wrap things to 80 characters, unless going a little bit over
makes things more readable.

Regards,
Bjorn

Re: [PATCH v14 06/25] mailbox: Add Gunyah message queue mailbox

[Bjorn Andersson]

On Tue, Jun 13, 2023 at 10:20:34AM -0700, Elliot Berman wrote:
> Gunyah message queues are a unidirectional inter-VM pipe for messages up
> to 1024 bytes. This driver supports pairing a receiver message queue and
> a transmitter message queue to expose a single mailbox channel.
> 

I don't find value in using the mailbox framework to abstract the
message queues. You've split the resource-manager code in two separate
subsystems, with the complexities introduced by the abstraction, while
still being one implementation. Every message sent requires a tasklet
to be scheduled before continuing and you're unnecessarily waiting for
the tx fifo when you're filling the message queue.

You can effectively implement the same functionality, with 10% of the
code if not involving the mailbox framework.

> Reviewed-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
> Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
> ---
>  Documentation/virt/gunyah/message-queue.rst |   8 +
>  drivers/mailbox/Makefile                    |   2 +
>  drivers/mailbox/gunyah-msgq.c               | 219 ++++++++++++++++++++
>  include/linux/gunyah.h                      |  57 +++++
>  4 files changed, 286 insertions(+)
>  create mode 100644 drivers/mailbox/gunyah-msgq.c
> 
> diff --git a/Documentation/virt/gunyah/message-queue.rst b/Documentation/virt/gunyah/message-queue.rst
> index b352918ae54b4..70d82a4ef32d7 100644
> --- a/Documentation/virt/gunyah/message-queue.rst
> +++ b/Documentation/virt/gunyah/message-queue.rst
> @@ -61,3 +61,11 @@ vIRQ: two TX message queues will have two vIRQs (and two capability IDs).
>        |               |         |                 |         |               |
>        |               |         |                 |         |               |
>        +---------------+         +-----------------+         +---------------+
> +
> +Gunyah message queues are exposed as mailboxes. To create the mailbox, create
> +a mbox_client and call `gh_msgq_init()`. On receipt of the RX_READY interrupt,
> +all messages in the RX message queue are read and pushed via the `rx_callback`
> +of the registered mbox_client.
> +
> +.. kernel-doc:: drivers/mailbox/gunyah-msgq.c
> +   :identifiers: gh_msgq_init
> diff --git a/drivers/mailbox/Makefile b/drivers/mailbox/Makefile
> index fc93761171113..5f929bb55e9a5 100644
> --- a/drivers/mailbox/Makefile
> +++ b/drivers/mailbox/Makefile
> @@ -55,6 +55,8 @@ obj-$(CONFIG_MTK_CMDQ_MBOX)	+= mtk-cmdq-mailbox.o
>  
>  obj-$(CONFIG_ZYNQMP_IPI_MBOX)	+= zynqmp-ipi-mailbox.o
>  
> +obj-$(CONFIG_GUNYAH)		+= gunyah-msgq.o
> +
>  obj-$(CONFIG_SUN6I_MSGBOX)	+= sun6i-msgbox.o
>  
>  obj-$(CONFIG_SPRD_MBOX)		+= sprd-mailbox.o
> diff --git a/drivers/mailbox/gunyah-msgq.c b/drivers/mailbox/gunyah-msgq.c
> new file mode 100644
> index 0000000000000..7f777339278eb
> --- /dev/null
> +++ b/drivers/mailbox/gunyah-msgq.c
> @@ -0,0 +1,219 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All rights reserved.
> + */
> +
> +#include <linux/mailbox_controller.h>
> +#include <linux/module.h>
> +#include <linux/interrupt.h>
> +#include <linux/gunyah.h>
> +#include <linux/printk.h>
> +#include <linux/init.h>
> +#include <linux/slab.h>
> +#include <linux/wait.h>
> +
> +#define mbox_chan_to_msgq(chan) (container_of(chan->mbox, struct gh_msgq, mbox))
> +
> +static irqreturn_t gh_msgq_rx_irq_handler(int irq, void *data)
> +{
> +	struct gh_msgq *msgq = data;
> +	struct gh_msgq_rx_data rx_data;
> +	enum gh_error gh_error;

err would be sufficient

> +	bool ready = true;

s/read/more_data/ perhaps?

> +
> +	while (ready) {

Doesn't really matter logically, but what you really mean is:

do {
	...
} while (more_data);

So perhaps reasonable to type that.

> +		gh_error = gh_hypercall_msgq_recv(msgq->rx_ghrsc->capid,
> +				&rx_data.data, sizeof(rx_data.data),
> +				&rx_data.length, &ready);
> +		if (gh_error != GH_ERROR_OK) {
> +			if (gh_error != GH_ERROR_MSGQUEUE_EMPTY)
> +				dev_warn(msgq->mbox.dev, "Failed to receive data: %d\n", gh_error);
> +			break;
> +		}

		if (err == GH_ERROR_MSGQUEUE_EMPTY) {
			break;
		} else if (err != GH_ERROR_OK) {
			dev_warn(...)
			break;
		}

		handle_message();

> +		if (likely(gh_msgq_chan(msgq)->cl))
> +			mbox_chan_received_data(gh_msgq_chan(msgq), &rx_data);
> +	}
> +
> +	return IRQ_HANDLED;
> +}
> +
> +/* Fired when message queue transitions from "full" to "space available" to send messages */
> +static irqreturn_t gh_msgq_tx_irq_handler(int irq, void *data)
> +{
> +	struct gh_msgq *msgq = data;
> +
> +	mbox_chan_txdone(gh_msgq_chan(msgq), 0);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +/* Fired after sending message and hypercall told us there was more space available. */
> +static void gh_msgq_txdone_tasklet(struct tasklet_struct *tasklet)
> +{
> +	struct gh_msgq *msgq = container_of(tasklet, struct gh_msgq, txdone_tasklet);
> +
> +	mbox_chan_txdone(gh_msgq_chan(msgq), msgq->last_ret);
> +}
> +
> +static int gh_msgq_send_data(struct mbox_chan *chan, void *data)
> +{
> +	struct gh_msgq *msgq = mbox_chan_to_msgq(chan);
> +	struct gh_msgq_tx_data *msgq_data = data;
> +	u64 tx_flags = 0;
> +	enum gh_error gh_error;
> +	bool ready;

s/ready/not_full/ or invert the values in gh_hypercall_msgq_send()

> +
> +	if (!msgq->tx_ghrsc)
> +		return -EOPNOTSUPP;
> +
> +	if (msgq_data->push)
> +		tx_flags |= GH_HYPERCALL_MSGQ_TX_FLAGS_PUSH;
> +
> +	gh_error = gh_hypercall_msgq_send(msgq->tx_ghrsc->capid, msgq_data->length, msgq_data->data,
> +						tx_flags, &ready);
> +
> +	/**
> +	 * unlikely because Linux tracks state of msgq and should not try to
> +	 * send message when msgq is full.
> +	 */
> +	if (unlikely(gh_error == GH_ERROR_MSGQUEUE_FULL))
> +		return -EAGAIN;

You're propagating this all the way up to the application.

> +
> +	/**
> +	 * Propagate all other errors to client. If we return error to mailbox
> +	 * framework, then no other messages can be sent and nobody will know
> +	 * to retry this message.
> +	 */
> +	msgq->last_ret = gh_error_remap(gh_error);
> +
> +	/**
> +	 * This message was successfully sent, but message queue isn't ready to
> +	 * accept more messages because it's now full. Mailbox framework
> +	 * requires that we only report that message was transmitted when
> +	 * we're ready to transmit another message. We'll get that in the form
> +	 * of tx IRQ once the other side starts to drain the msgq.
> +	 */
> +	if (gh_error == GH_ERROR_OK) {
> +		if (!ready)
> +			return 0;

The message was committed successfully to the queue, there's no reason
for this VM to wait for the receiving VM to start consuming the queue
before returning from mbox_send_message().

As mentioned above, if you move away from the mailbox framework you can
instead keep track of when gh_hypercall_msgq_send() returned "the
message queue was filled up" and wait for the tx interrupt before making
the next call.

This will allow this instance to continue executing to some natural
point of waiting for resources.

> +	} else {
> +		dev_err(msgq->mbox.dev, "Failed to send data: %d (%d)\n", gh_error, msgq->last_ret);
> +	}
> +
> +	/**
> +	 * We can send more messages. Mailbox framework requires that tx done
> +	 * happens asynchronously to sending the message. Gunyah message queues
> +	 * tell us right away on the hypercall return whether we can send more
> +	 * messages. To work around this, defer the txdone to a tasklet.
> +	 */
> +	tasklet_schedule(&msgq->txdone_tasklet);

Ick.

> +
> +	return 0;
> +}
> +
> +static struct mbox_chan_ops gh_msgq_ops = {
> +	.send_data = gh_msgq_send_data,
> +};
> +
> +/**
> + * gh_msgq_init() - Initialize a Gunyah message queue with an mbox_client
> + * @parent: device parent used for the mailbox controller
> + * @msgq: Pointer to the gh_msgq to initialize
> + * @cl: A mailbox client to bind to the mailbox channel that the message queue creates
> + * @tx_ghrsc: optional, the transmission side of the message queue
> + * @rx_ghrsc: optional, the receiving side of the message queue
> + *
> + * At least one of tx_ghrsc and rx_ghrsc must be not NULL. Most message queue use cases come with
> + * a pair of message queues to facilitate bidirectional communication. When tx_ghrsc is set,
> + * the client can send messages with mbox_send_message(gh_msgq_chan(msgq), msg). When rx_ghrsc
> + * is set, the mbox_client must register an .rx_callback() and the message queue driver will
> + * deliver all available messages upon receiving the RX ready interrupt. The messages should be
> + * consumed or copied by the client right away as the gh_msgq_rx_data will be replaced/destroyed
> + * after the callback.
> + *
> + * Returns - 0 on success, negative otherwise
> + */
> +int gh_msgq_init(struct device *parent, struct gh_msgq *msgq, struct mbox_client *cl,
> +		 struct gh_resource *tx_ghrsc, struct gh_resource *rx_ghrsc)
> +{
> +	int ret;
> +
> +	/* Must have at least a tx_ghrsc or rx_ghrsc and that they are the right device types */
> +	if ((!tx_ghrsc && !rx_ghrsc) ||
> +	    (tx_ghrsc && tx_ghrsc->type != GH_RESOURCE_TYPE_MSGQ_TX) ||
> +	    (rx_ghrsc && rx_ghrsc->type != GH_RESOURCE_TYPE_MSGQ_RX))
> +		return -EINVAL;
> +
> +	msgq->mbox.dev = parent;
> +	msgq->mbox.ops = &gh_msgq_ops;
> +	msgq->mbox.num_chans = 1;
> +	msgq->mbox.txdone_irq = true;
> +	msgq->mbox.chans = &msgq->mbox_chan;
> +
> +	ret = mbox_controller_register(&msgq->mbox);
> +	if (ret)
> +		return ret;
> +
> +	ret = mbox_bind_client(gh_msgq_chan(msgq), cl);
> +	if (ret)
> +		goto err_mbox;
> +
> +	if (tx_ghrsc) {
> +		msgq->tx_ghrsc = tx_ghrsc;
> +
> +		ret = request_irq(msgq->tx_ghrsc->irq, gh_msgq_tx_irq_handler, 0, "gh_msgq_tx",

Wrap your lines to 80 characters, unless there's a good reason. You
don't have a good reason here.

> +				msgq);
> +		if (ret)
> +			goto err_tx_ghrsc;
> +
> +		enable_irq_wake(msgq->tx_ghrsc->irq);
> +
> +		tasklet_setup(&msgq->txdone_tasklet, gh_msgq_txdone_tasklet);
> +	}
> +
> +	if (rx_ghrsc) {
> +		msgq->rx_ghrsc = rx_ghrsc;
> +
> +		ret = request_threaded_irq(msgq->rx_ghrsc->irq, NULL, gh_msgq_rx_irq_handler,
> +						IRQF_ONESHOT, "gh_msgq_rx", msgq);
> +		if (ret)
> +			goto err_tx_irq;
> +
> +		enable_irq_wake(msgq->rx_ghrsc->irq);
> +	}
> +
> +	return 0;
> +err_tx_irq:
> +	if (msgq->tx_ghrsc)
> +		free_irq(msgq->tx_ghrsc->irq, msgq);
> +
> +	msgq->rx_ghrsc = NULL;
> +err_tx_ghrsc:
> +	msgq->tx_ghrsc = NULL;
> +err_mbox:
> +	mbox_controller_unregister(&msgq->mbox);
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(gh_msgq_init);
> +
> +void gh_msgq_remove(struct gh_msgq *msgq)
> +{
> +	mbox_free_channel(gh_msgq_chan(msgq));
> +
> +	if (msgq->rx_ghrsc)
> +		free_irq(msgq->rx_ghrsc->irq, msgq);
> +
> +	if (msgq->tx_ghrsc) {
> +		tasklet_kill(&msgq->txdone_tasklet);
> +		free_irq(msgq->tx_ghrsc->irq, msgq);
> +	}
> +
> +	mbox_controller_unregister(&msgq->mbox);
> +
> +	msgq->rx_ghrsc = NULL;
> +	msgq->tx_ghrsc = NULL;
> +}
> +EXPORT_SYMBOL_GPL(gh_msgq_remove);
> +
> +MODULE_LICENSE("GPL");
> +MODULE_DESCRIPTION("Gunyah Message Queue Driver");
> diff --git a/include/linux/gunyah.h b/include/linux/gunyah.h
> index 01a6f202d037e..982e27d10d57f 100644
> --- a/include/linux/gunyah.h
> +++ b/include/linux/gunyah.h
> @@ -8,11 +8,68 @@
>  
>  #include <linux/bitfield.h>
>  #include <linux/errno.h>
> +#include <linux/interrupt.h>
>  #include <linux/limits.h>
> +#include <linux/mailbox_controller.h>
> +#include <linux/mailbox_client.h>
>  #include <linux/types.h>
>  
> +/* Matches resource manager's resource types for VM_GET_HYP_RESOURCES RPC */
> +enum gh_resource_type {
> +	GH_RESOURCE_TYPE_BELL_TX	= 0,
> +	GH_RESOURCE_TYPE_BELL_RX	= 1,
> +	GH_RESOURCE_TYPE_MSGQ_TX	= 2,
> +	GH_RESOURCE_TYPE_MSGQ_RX	= 3,
> +	GH_RESOURCE_TYPE_VCPU		= 4,
> +};
> +
> +struct gh_resource {
> +	enum gh_resource_type type;
> +	u64 capid;
> +	unsigned int irq;
> +};
> +
> +/**
> + * Gunyah Message Queues
> + */
> +
> +#define GH_MSGQ_MAX_MSG_SIZE		240
> +
> +struct gh_msgq_tx_data {
> +	size_t length;
> +	bool push;
> +	char data[];
> +};
> +
> +struct gh_msgq_rx_data {
> +	size_t length;
> +	char data[GH_MSGQ_MAX_MSG_SIZE];
> +};
> +
> +struct gh_msgq {

This is just private data, exposed so that it can be intertwined with
the resource manager implementation.

> +	struct gh_resource *tx_ghrsc;
> +	struct gh_resource *rx_ghrsc;
> +
> +	/* msgq private */
> +	int last_ret; /* Linux error, not GH_STATUS_* */
> +	struct mbox_chan mbox_chan;
> +	struct mbox_controller mbox;
> +	struct tasklet_struct txdone_tasklet;
> +};
> +

Double newlines.

> +
> +int gh_msgq_init(struct device *parent, struct gh_msgq *msgq, struct mbox_client *cl,
> +		     struct gh_resource *tx_ghrsc, struct gh_resource *rx_ghrsc);
> +void gh_msgq_remove(struct gh_msgq *msgq);
> +
> +static inline struct mbox_chan *gh_msgq_chan(struct gh_msgq *msgq)
> +{
> +	return &msgq->mbox.chans[0];
> +}
> +
>  /******************************************************************************/
>  /* Common arch-independent definitions for Gunyah hypercalls                  */
> +

Unrelated change.

Regards,
Bjorn

>  #define GH_CAPID_INVAL	U64_MAX
>  #define GH_VMID_ROOT_VM	0xff
>  
> -- 
> 2.40.0
> 

Re: [PATCH v14 07/25] gunyah: rsc_mgr: Add resource manager RPC core

[Bjorn Andersson]

On Tue, Jun 13, 2023 at 10:20:35AM -0700, Elliot Berman wrote:
> The resource manager is a special virtual machine which is always
> running on a Gunyah system. It provides APIs for creating and destroying
> VMs, secure memory management, sharing/lending of memory between VMs,
> and setup of inter-VM communication. Calls to the resource manager are
> made via message queues.
> 
> This patch implements the basic probing and RPC mechanism to make those
> API calls. Request/response calls can be made with gh_rm_call.
> Drivers can also register to notifications pushed by RM via
> gh_rm_register_notifier
> 
> Specific API calls that resource manager supports will be implemented in
> subsequent patches.
> 
> Reviewed-by: Alex Elder <elder@linaro.org>
> Reviewed-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
> Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
> ---
>  drivers/virt/Makefile          |   1 +
>  drivers/virt/gunyah/Makefile   |   4 +
>  drivers/virt/gunyah/rsc_mgr.c  | 700 +++++++++++++++++++++++++++++++++
>  drivers/virt/gunyah/rsc_mgr.h  |  16 +
>  include/linux/gunyah_rsc_mgr.h |  21 +
>  5 files changed, 742 insertions(+)
>  create mode 100644 drivers/virt/gunyah/Makefile
>  create mode 100644 drivers/virt/gunyah/rsc_mgr.c
>  create mode 100644 drivers/virt/gunyah/rsc_mgr.h
>  create mode 100644 include/linux/gunyah_rsc_mgr.h
> 
> diff --git a/drivers/virt/Makefile b/drivers/virt/Makefile
> index e9aa6fc96fab7..a5817e2d7d718 100644
> --- a/drivers/virt/Makefile
> +++ b/drivers/virt/Makefile
> @@ -12,3 +12,4 @@ obj-$(CONFIG_ACRN_HSM)		+= acrn/
>  obj-$(CONFIG_EFI_SECRET)	+= coco/efi_secret/
>  obj-$(CONFIG_SEV_GUEST)		+= coco/sev-guest/
>  obj-$(CONFIG_INTEL_TDX_GUEST)	+= coco/tdx-guest/
> +obj-y				+= gunyah/
> diff --git a/drivers/virt/gunyah/Makefile b/drivers/virt/gunyah/Makefile
> new file mode 100644
> index 0000000000000..0f5aec8346988
> --- /dev/null
> +++ b/drivers/virt/gunyah/Makefile
> @@ -0,0 +1,4 @@
> +# SPDX-License-Identifier: GPL-2.0
> +
> +gunyah-y += rsc_mgr.o
> +obj-$(CONFIG_GUNYAH) += gunyah.o
> diff --git a/drivers/virt/gunyah/rsc_mgr.c b/drivers/virt/gunyah/rsc_mgr.c
> new file mode 100644
> index 0000000000000..04c8e131d259f
> --- /dev/null
> +++ b/drivers/virt/gunyah/rsc_mgr.c
> @@ -0,0 +1,700 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All rights reserved.
> + */
> +
> +#include <linux/of.h>
> +#include <linux/slab.h>
> +#include <linux/mutex.h>
> +#include <linux/sched.h>
> +#include <linux/gunyah.h>
> +#include <linux/module.h>
> +#include <linux/of_irq.h>
> +#include <linux/notifier.h>
> +#include <linux/workqueue.h>
> +#include <linux/completion.h>
> +#include <linux/gunyah_rsc_mgr.h>
> +#include <linux/platform_device.h>
> +
> +#include "rsc_mgr.h"
> +
> +#define RM_RPC_API_VERSION_MASK		GENMASK(3, 0)
> +#define RM_RPC_HEADER_WORDS_MASK	GENMASK(7, 4)
> +#define RM_RPC_API_VERSION		FIELD_PREP(RM_RPC_API_VERSION_MASK, 1)
> +#define RM_RPC_HEADER_WORDS		FIELD_PREP(RM_RPC_HEADER_WORDS_MASK, \
> +						(sizeof(struct gh_rm_rpc_hdr) / sizeof(u32)))
> +#define RM_RPC_API			(RM_RPC_API_VERSION | RM_RPC_HEADER_WORDS)
> +
> +#define RM_RPC_TYPE_CONTINUATION	0x0
> +#define RM_RPC_TYPE_REQUEST		0x1
> +#define RM_RPC_TYPE_REPLY		0x2
> +#define RM_RPC_TYPE_NOTIF		0x3
> +#define RM_RPC_TYPE_MASK		GENMASK(1, 0)
> +
> +#define GH_RM_MAX_NUM_FRAGMENTS		62
> +#define RM_RPC_FRAGMENTS_MASK		GENMASK(7, 2)
> +
> +struct gh_rm_rpc_hdr {
> +	u8 api;
> +	u8 type;
> +	__le16 seq;
> +	__le32 msg_id;
> +} __packed;
> +
> +struct gh_rm_rpc_reply_hdr {
> +	struct gh_rm_rpc_hdr hdr;
> +	__le32 err_code; /* GH_RM_ERROR_* */
> +} __packed;
> +
> +#define GH_RM_MAX_MSG_SIZE	(GH_MSGQ_MAX_MSG_SIZE - sizeof(struct gh_rm_rpc_hdr))
> +
> +/* RM Error codes */
> +enum gh_rm_error {
> +	GH_RM_ERROR_OK			= 0x0,
> +	GH_RM_ERROR_UNIMPLEMENTED	= 0xFFFFFFFF,
> +	GH_RM_ERROR_NOMEM		= 0x1,
> +	GH_RM_ERROR_NORESOURCE		= 0x2,
> +	GH_RM_ERROR_DENIED		= 0x3,
> +	GH_RM_ERROR_INVALID		= 0x4,
> +	GH_RM_ERROR_BUSY		= 0x5,
> +	GH_RM_ERROR_ARGUMENT_INVALID	= 0x6,
> +	GH_RM_ERROR_HANDLE_INVALID	= 0x7,
> +	GH_RM_ERROR_VALIDATE_FAILED	= 0x8,
> +	GH_RM_ERROR_MAP_FAILED		= 0x9,
> +	GH_RM_ERROR_MEM_INVALID		= 0xA,
> +	GH_RM_ERROR_MEM_INUSE		= 0xB,
> +	GH_RM_ERROR_MEM_RELEASED	= 0xC,
> +	GH_RM_ERROR_VMID_INVALID	= 0xD,
> +	GH_RM_ERROR_LOOKUP_FAILED	= 0xE,
> +	GH_RM_ERROR_IRQ_INVALID		= 0xF,
> +	GH_RM_ERROR_IRQ_INUSE		= 0x10,
> +	GH_RM_ERROR_IRQ_RELEASED	= 0x11,
> +};
> +
> +/**
> + * struct gh_rm_connection - Represents a complete message from resource manager
> + * @payload: Combined payload of all the fragments (msg headers stripped off).
> + * @size: Size of the payload received so far.
> + * @msg_id: Message ID from the header.
> + * @type: RM_RPC_TYPE_REPLY or RM_RPC_TYPE_NOTIF.
> + * @num_fragments: total number of fragments expected to be received.
> + * @fragments_received: fragments received so far.
> + * @reply: Fields used for request/reply sequences
> + * @notification: Fields used for notifiations
> + */
> +struct gh_rm_connection {

Is there a good reason why this is called a connection, when it's
actually a message (specifically a response or notification)?

> +	void *payload;
> +	size_t size;
> +	__le32 msg_id;

Everything else in this struct is native endian, I don't think you loose
much from keeping this native and moving your
cpu_to_le32()/le32_to_cpu() calls around the implementation.

> +	u8 type;
> +
> +	u8 num_fragments;
> +	u8 fragments_received;
> +
> +	union {
> +		/**
> +		 * @ret: Linux return code, there was an error processing connection
> +		 * @seq: Sequence ID for the main message.
> +		 * @rm_error: For request/reply sequences with standard replies
> +		 * @seq_done: Signals caller that the RM reply has been received
> +		 */
> +		struct {
> +			int ret;
> +			u16 seq;
> +			enum gh_rm_error rm_error;
> +			struct completion seq_done;
> +		} reply;
> +
> +		/**
> +		 * @rm: Pointer to the RM that launched the connection
> +		 * @work: Triggered when all fragments of a notification received
> +		 */
> +		struct {
> +			struct gh_rm *rm;
> +			struct work_struct work;
> +		} notification;
> +	};
> +};
> +
> +/**
> + * struct gh_rm - private data for communicating w/Gunyah resource manager
> + * @dev: pointer to RM platform device
> + * @tx_ghrsc: message queue resource to TX to RM
> + * @rx_ghrsc: message queue resource to RX from RM
> + * @msgq: mailbox instance of TX/RX resources above
> + * @msgq_client: mailbox client of above msgq
> + * @active_rx_connection: ongoing gh_rm_connection for which we're receiving fragments
> + * @last_tx_ret: return value of last mailbox tx
> + * @call_xarray: xarray to allocate & lookup sequence IDs for Request/Response flows
> + * @next_seq: next ID to allocate (for xa_alloc_cyclic)
> + * @cache: cache for allocating Tx messages
> + * @send_lock: synchronization to allow only one request to be sent at a time
> + * @nh: notifier chain for clients interested in RM notification messages
> + */
> +struct gh_rm {
> +	struct device *dev;
> +	struct gh_resource tx_ghrsc;
> +	struct gh_resource rx_ghrsc;
> +	struct gh_msgq msgq;
> +	struct mbox_client msgq_client;
> +	struct gh_rm_connection *active_rx_connection;
> +	int last_tx_ret;
> +
> +	struct xarray call_xarray;
> +	u32 next_seq;
> +
> +	struct kmem_cache *cache;
> +	struct mutex send_lock;
> +	struct blocking_notifier_head nh;
> +};
> +
> +/**
> + * gh_rm_error_remap() - Remap Gunyah resource manager errors into a Linux error code
> + * @rm_error: "Standard" return value from Gunyah resource manager
> + */
> +static inline int gh_rm_error_remap(enum gh_rm_error rm_error)
> +{
> +	switch (rm_error) {
> +	case GH_RM_ERROR_OK:
> +		return 0;
> +	case GH_RM_ERROR_UNIMPLEMENTED:
> +		return -EOPNOTSUPP;
> +	case GH_RM_ERROR_NOMEM:
> +		return -ENOMEM;
> +	case GH_RM_ERROR_NORESOURCE:
> +		return -ENODEV;
> +	case GH_RM_ERROR_DENIED:
> +		return -EPERM;
> +	case GH_RM_ERROR_BUSY:
> +		return -EBUSY;
> +	case GH_RM_ERROR_INVALID:
> +	case GH_RM_ERROR_ARGUMENT_INVALID:
> +	case GH_RM_ERROR_HANDLE_INVALID:
> +	case GH_RM_ERROR_VALIDATE_FAILED:
> +	case GH_RM_ERROR_MAP_FAILED:
> +	case GH_RM_ERROR_MEM_INVALID:
> +	case GH_RM_ERROR_MEM_INUSE:
> +	case GH_RM_ERROR_MEM_RELEASED:
> +	case GH_RM_ERROR_VMID_INVALID:
> +	case GH_RM_ERROR_LOOKUP_FAILED:
> +	case GH_RM_ERROR_IRQ_INVALID:
> +	case GH_RM_ERROR_IRQ_INUSE:
> +	case GH_RM_ERROR_IRQ_RELEASED:
> +		return -EINVAL;
> +	default:
> +		return -EBADMSG;
> +	}
> +}
> +
> +static int gh_rm_init_connection_payload(struct gh_rm_connection *connection, void *msg,
> +					size_t hdr_size, size_t msg_size)
> +{
> +	size_t max_buf_size, payload_size;
> +	struct gh_rm_rpc_hdr *hdr = msg;
> +
> +	if (msg_size < hdr_size)
> +		return -EINVAL;
> +
> +	payload_size = msg_size - hdr_size;
> +
> +	connection->num_fragments = FIELD_GET(RM_RPC_FRAGMENTS_MASK, hdr->type);
> +	connection->fragments_received = 0;
> +
> +	/* There's not going to be any payload, no need to allocate buffer. */
> +	if (!payload_size && !connection->num_fragments)
> +		return 0;
> +
> +	if (connection->num_fragments > GH_RM_MAX_NUM_FRAGMENTS)
> +		return -EINVAL;
> +
> +	max_buf_size = payload_size + (connection->num_fragments * GH_RM_MAX_MSG_SIZE);
> +
> +	connection->payload = kzalloc(max_buf_size, GFP_KERNEL);
> +	if (!connection->payload)
> +		return -ENOMEM;
> +
> +	memcpy(connection->payload, msg + hdr_size, payload_size);
> +	connection->size = payload_size;
> +	return 0;
> +}
> +
> +static void gh_rm_abort_connection(struct gh_rm *rm)
> +{
> +	switch (rm->active_rx_connection->type) {
> +	case RM_RPC_TYPE_REPLY:
> +		rm->active_rx_connection->reply.ret = -EIO;
> +		complete(&rm->active_rx_connection->reply.seq_done);
> +		break;
> +	case RM_RPC_TYPE_NOTIF:
> +		fallthrough;

Don't you need to cancel the work here as well?

> +	default:
> +		kfree(rm->active_rx_connection->payload);
> +		kfree(rm->active_rx_connection);
> +	}
> +
> +	rm->active_rx_connection = NULL;
> +}
> +
> +static void gh_rm_notif_work(struct work_struct *work)
> +{
> +	struct gh_rm_connection *connection = container_of(work, struct gh_rm_connection,
> +								notification.work);
> +	struct gh_rm *rm = connection->notification.rm;
> +
> +	blocking_notifier_call_chain(&rm->nh, le32_to_cpu(connection->msg_id), connection->payload);
> +
> +	put_device(rm->dev);
> +	kfree(connection->payload);
> +	kfree(connection);
> +}
> +
> +static void gh_rm_process_notif(struct gh_rm *rm, void *msg, size_t msg_size)
> +{
> +	struct gh_rm_connection *connection;
> +	struct gh_rm_rpc_hdr *hdr = msg;
> +	int ret;
> +
> +	if (rm->active_rx_connection)
> +		gh_rm_abort_connection(rm);

So every notification or reply is always expected to be sent in full, or
it should be thrown away?

I do find this logic a little bit odd, can you confirm that this is
defined by the hypervisor?

> +
> +	connection = kzalloc(sizeof(*connection), GFP_KERNEL);
> +	if (!connection)
> +		return;
> +
> +	connection->type = RM_RPC_TYPE_NOTIF;
> +	connection->msg_id = hdr->msg_id;
> +
> +	get_device(rm->dev);
> +	connection->notification.rm = rm;
> +	INIT_WORK(&connection->notification.work, gh_rm_notif_work);

I tend to dislike work in allocated objects, in particularly when they
are scheduled on the global work queues...

I'd prefer a list of outstanding notifications associated with the rm
and a worker that traverses that list. That saves you from carrying the
rm back-pointer in the "connection" and you don't need to refcount the
rm->dev.

> +
> +	ret = gh_rm_init_connection_payload(connection, msg, sizeof(*hdr), msg_size);
> +	if (ret) {
> +		dev_err(rm->dev, "Failed to initialize connection for notification: %d\n", ret);
> +		put_device(rm->dev);
> +		kfree(connection);
> +		return;
> +	}
> +
> +	rm->active_rx_connection = connection;
> +}
> +
> +static void gh_rm_process_reply(struct gh_rm *rm, void *msg, size_t msg_size)
> +{
> +	struct gh_rm_rpc_reply_hdr *reply_hdr = msg;
> +	struct gh_rm_connection *connection;
> +	u16 seq_id;
> +
> +	seq_id = le16_to_cpu(reply_hdr->hdr.seq);
> +	connection = xa_load(&rm->call_xarray, seq_id);
> +
> +	if (!connection || connection->msg_id != reply_hdr->hdr.msg_id)

Wouldn't it be bad if a response is received with the wrong msg_id?
Please confirm that this should be silently ignored.

> +		return;
> +
> +	if (rm->active_rx_connection)
> +		gh_rm_abort_connection(rm);
> +
> +	if (gh_rm_init_connection_payload(connection, msg, sizeof(*reply_hdr), msg_size)) {
> +		dev_err(rm->dev, "Failed to alloc connection buffer for sequence %d\n", seq_id);
> +		/* Send connection complete and error the client. */
> +		connection->reply.ret = -ENOMEM;
> +		complete(&connection->reply.seq_done);
> +		return;
> +	}
> +
> +	connection->reply.rm_error = le32_to_cpu(reply_hdr->err_code);
> +	rm->active_rx_connection = connection;
> +}
> +
> +static void gh_rm_process_cont(struct gh_rm *rm, struct gh_rm_connection *connection,
> +				void *msg, size_t msg_size)
> +{
> +	struct gh_rm_rpc_hdr *hdr = msg;
> +	size_t payload_size = msg_size - sizeof(*hdr);
> +
> +	if (!rm->active_rx_connection)

Perhaps reasonable to be consistent and complain if the hypervisor gives
you a continuation when you have no active response? Seems like this
would result in a silent hang...

> +		return;
> +
> +	/*
> +	 * hdr->fragments and hdr->msg_id preserves the value from first reply
> +	 * or notif message. To detect mishandling, check it's still intact.
> +	 */
> +	if (connection->msg_id != hdr->msg_id ||
> +		connection->num_fragments != FIELD_GET(RM_RPC_FRAGMENTS_MASK, hdr->type)) {

When breaking an expression, align all lines under each other. Here it
looks like connection->num_fragments.. is part of the conditional block,
rather than the expression.

> +		gh_rm_abort_connection(rm);
> +		return;
> +	}
> +
> +	memcpy(connection->payload + connection->size, msg + sizeof(*hdr), payload_size);
> +	connection->size += payload_size;
> +	connection->fragments_received++;
> +}
> +
> +static void gh_rm_try_complete_connection(struct gh_rm *rm)
> +{
> +	struct gh_rm_connection *connection = rm->active_rx_connection;
> +
> +	if (!connection || connection->fragments_received != connection->num_fragments)
> +		return;
> +
> +	switch (connection->type) {
> +	case RM_RPC_TYPE_REPLY:
> +		complete(&connection->reply.seq_done);
> +		break;
> +	case RM_RPC_TYPE_NOTIF:
> +		schedule_work(&connection->notification.work);
> +		break;
> +	default:
> +		dev_err_ratelimited(rm->dev, "Invalid message type (%u) received\n",
> +					connection->type);
> +		gh_rm_abort_connection(rm);
> +		break;
> +	}
> +
> +	rm->active_rx_connection = NULL;
> +}
> +
> +static void gh_rm_msgq_rx_data(struct mbox_client *cl, void *mssg)
> +{
> +	struct gh_rm *rm = container_of(cl, struct gh_rm, msgq_client);
> +	struct gh_msgq_rx_data *rx_data = mssg;
> +	size_t msg_size = rx_data->length;
> +	void *msg = rx_data->data;
> +	struct gh_rm_rpc_hdr *hdr;
> +
> +	if (msg_size < sizeof(*hdr) || msg_size > GH_MSGQ_MAX_MSG_SIZE)
> +		return;
> +
> +	hdr = msg;
> +	if (hdr->api != RM_RPC_API) {
> +		dev_err(rm->dev, "Unknown RM RPC API version: %x\n", hdr->api);
> +		return;
> +	}
> +
> +	switch (FIELD_GET(RM_RPC_TYPE_MASK, hdr->type)) {
> +	case RM_RPC_TYPE_NOTIF:
> +		gh_rm_process_notif(rm, msg, msg_size);
> +		break;
> +	case RM_RPC_TYPE_REPLY:
> +		gh_rm_process_reply(rm, msg, msg_size);
> +		break;
> +	case RM_RPC_TYPE_CONTINUATION:
> +		gh_rm_process_cont(rm, rm->active_rx_connection, msg, msg_size);
> +		break;
> +	default:
> +		dev_err(rm->dev, "Invalid message type (%lu) received\n",
> +			FIELD_GET(RM_RPC_TYPE_MASK, hdr->type));
> +		return;
> +	}
> +
> +	gh_rm_try_complete_connection(rm);

I stared at this logic for quite a while, I think it would be clearer if
you moved the "now check if we did get all the data and if so handle it"
to each f the process functions.

> +}
> +
> +static void gh_rm_msgq_tx_done(struct mbox_client *cl, void *mssg, int r)
> +{
> +	struct gh_rm *rm = container_of(cl, struct gh_rm, msgq_client);
> +
> +	kmem_cache_free(rm->cache, mssg);
> +	rm->last_tx_ret = r;
> +}
> +
> +static int gh_rm_send_request(struct gh_rm *rm, u32 message_id,
> +			      const void *req_buf, size_t req_buf_size,
> +			      struct gh_rm_connection *connection)
> +{
> +	size_t buf_size_remaining = req_buf_size;
> +	const void *req_buf_curr = req_buf;
> +	struct gh_msgq_tx_data *msg;
> +	struct gh_rm_rpc_hdr *hdr, hdr_template;
> +	u32 cont_fragments = 0;
> +	size_t payload_size;
> +	void *payload;
> +	int ret;
> +
> +	if (req_buf_size > GH_RM_MAX_NUM_FRAGMENTS * GH_RM_MAX_MSG_SIZE) {
> +		dev_warn(rm->dev, "Limit (%lu bytes) exceeded for the maximum message size: %lu\n",
> +			GH_RM_MAX_NUM_FRAGMENTS * GH_RM_MAX_MSG_SIZE, req_buf_size);
> +		dump_stack();
> +		return -E2BIG;
> +	}
> +
> +	if (req_buf_size)
> +		cont_fragments = (req_buf_size - 1) / GH_RM_MAX_MSG_SIZE;
> +
> +	hdr_template.api = RM_RPC_API;
> +	hdr_template.type = FIELD_PREP(RM_RPC_TYPE_MASK, RM_RPC_TYPE_REQUEST) |
> +				FIELD_PREP(RM_RPC_FRAGMENTS_MASK, cont_fragments);
> +	hdr_template.seq = cpu_to_le16(connection->reply.seq);
> +	hdr_template.msg_id = cpu_to_le32(message_id);
> +
> +	ret = mutex_lock_interruptible(&rm->send_lock);
> +	if (ret)
> +		return ret;
> +
> +	do {
> +		msg = kmem_cache_zalloc(rm->cache, GFP_KERNEL);

Per the rm->send_lock() we can only have one msg outstanding at any
point in time. So you should be able to allocate one of those at probe
time and be done with it.

> +		if (!msg) {
> +			ret = -ENOMEM;
> +			goto out;
> +		}
> +
> +		/* Fill header */
> +		hdr = (struct gh_rm_rpc_hdr *)&msg->data[0];
> +		*hdr = hdr_template;
> +
> +		/* Copy payload */
> +		payload = &msg->data[0] + sizeof(*hdr);
> +		payload_size = min(buf_size_remaining, GH_RM_MAX_MSG_SIZE);
> +		memcpy(payload, req_buf_curr, payload_size);
> +		req_buf_curr += payload_size;
> +		buf_size_remaining -= payload_size;
> +
> +		/* Force the last fragment to immediately alert the receiver */
> +		msg->push = !buf_size_remaining;
> +		msg->length = sizeof(*hdr) + payload_size;
> +
> +		ret = mbox_send_message(gh_msgq_chan(&rm->msgq), msg);

This would be much cleaner if it was just an optional wait for pending
tx irq and a synchronous call to gh_hypercall_msgq_send().

> +		if (ret < 0) {
> +			kmem_cache_free(rm->cache, msg);
> +			break;
> +		}
> +
> +		if (rm->last_tx_ret) {
> +			ret = rm->last_tx_ret;
> +			break;
> +		}
> +
> +		hdr_template.type = FIELD_PREP(RM_RPC_TYPE_MASK, RM_RPC_TYPE_CONTINUATION) |
> +					FIELD_PREP(RM_RPC_FRAGMENTS_MASK, cont_fragments);
> +	} while (buf_size_remaining);
> +
> +out:
> +	mutex_unlock(&rm->send_lock);
> +	return ret < 0 ? ret : 0;
> +}
> +
> +/**
> + * gh_rm_call: Achieve request-response type communication with RPC
> + * @rm: Pointer to Gunyah resource manager internal data
> + * @message_id: The RM RPC message-id
> + * @req_buf: Request buffer that contains the payload
> + * @req_buf_size: Total size of the payload
> + * @resp_buf: Pointer to a response buffer
> + * @resp_buf_size: Size of the response buffer
> + *
> + * Make a request to the Resource Manager and wait for reply back. For a successful
> + * response, the function returns the payload. The size of the payload is set in
> + * resp_buf_size. The resp_buf must be freed by the caller when 0 is returned
> + * and resp_buf_size != 0.
> + *
> + * req_buf should be not NULL for req_buf_size >0. If req_buf_size == 0,
> + * req_buf *can* be NULL and no additional payload is sent.
> + *
> + * Context: Process context. Will sleep waiting for reply.
> + * Return: 0 on success. <0 if error.
> + */
> +int gh_rm_call(struct gh_rm *rm, u32 message_id, const void *req_buf, size_t req_buf_size,
> +		void **resp_buf, size_t *resp_buf_size)
> +{
> +	struct gh_rm_connection *connection;
> +	u32 seq_id;
> +	int ret;
> +
> +	/* message_id 0 is reserved. req_buf_size implies req_buf is not NULL */
> +	if (!rm || !message_id || (!req_buf && req_buf_size))
> +		return -EINVAL;
> +
> +
> +	connection = kzalloc(sizeof(*connection), GFP_KERNEL);

No matter how many times I read this code, this isn't "a connection" it
is the response message.

sizeof(*connection) doesn't seem too bad either, so you should be able
to just store it on the stack.

> +	if (!connection)
> +		return -ENOMEM;
> +
> +	connection->type = RM_RPC_TYPE_REPLY;
> +	connection->msg_id = cpu_to_le32(message_id);
> +
> +	init_completion(&connection->reply.seq_done);
> +
> +	/* Allocate a new seq number for this connection */
> +	ret = xa_alloc_cyclic(&rm->call_xarray, &seq_id, connection, xa_limit_16b, &rm->next_seq,
> +				GFP_KERNEL);
> +	if (ret < 0)
> +		goto free;
> +	connection->reply.seq = lower_16_bits(seq_id);

You use connection->reply.seq for two things; 1) as a local variable, 2)
to pass the sequence id as an argument to gh_rm_send_request().

Further more, reply.seq is the only thing extracted from "connection" in
gh_rm_send_request(), so if you passed that directly instead of the
"connection" #2 is gone and you're down to duplicating the variable
already on the stack...

So you can remove "seq" from struct gh_rm_connection...

> +
> +	/* Send the request to the Resource Manager */
> +	ret = gh_rm_send_request(rm, message_id, req_buf, req_buf_size, connection);
> +	if (ret < 0)
> +		goto out;
> +
> +	/* Wait for response. Uninterruptible because rollback based on what RM did to VM

/*
 * Multi-line comments should generally be started on the second line.
 */

> +	 * requires us to know how RM handled the call.
> +	 */
> +	wait_for_completion(&connection->reply.seq_done);
> +
> +	/* Check for internal (kernel) error waiting for the response */
> +	if (connection->reply.ret) {
> +		ret = connection->reply.ret;
> +		if (ret != -ENOMEM)
> +			kfree(connection->payload);
> +		goto out;
> +	}
> +
> +	/* Got a response, did resource manager give us an error? */
> +	if (connection->reply.rm_error != GH_RM_ERROR_OK) {
> +		dev_warn(rm->dev, "RM rejected message %08x. Error: %d\n", message_id,
> +			connection->reply.rm_error);
> +		ret = gh_rm_error_remap(connection->reply.rm_error);
> +		kfree(connection->payload);
> +		goto out;
> +	}
> +
> +	/* Everything looks good, return the payload */
> +	if (resp_buf_size)
> +		*resp_buf_size = connection->size;
> +	if (connection->size && resp_buf)

Keep {} around all blocks if anyone of them need it.

> +		*resp_buf = connection->payload;
> +	else {
> +		/* kfree in case RM sent us multiple fragments but never any data in
> +		 * those fragments. We would've allocated memory for it, but connection->size == 0
> +		 */
> +		kfree(connection->payload);
> +	}
> +
> +out:
> +	xa_erase(&rm->call_xarray, connection->reply.seq);
> +free:
> +	kfree(connection);
> +	return ret;
> +}
> +
> +
> +int gh_rm_notifier_register(struct gh_rm *rm, struct notifier_block *nb)
> +{
> +	return blocking_notifier_chain_register(&rm->nh, nb);
> +}
> +EXPORT_SYMBOL_GPL(gh_rm_notifier_register);
> +
> +int gh_rm_notifier_unregister(struct gh_rm *rm, struct notifier_block *nb)
> +{
> +	return blocking_notifier_chain_unregister(&rm->nh, nb);
> +}
> +EXPORT_SYMBOL_GPL(gh_rm_notifier_unregister);
> +
> +static int gh_msgq_platform_probe_direction(struct platform_device *pdev, bool tx,
> +					    struct gh_resource *ghrsc)
> +{
> +	struct device_node *node = pdev->dev.of_node;
> +	int ret;
> +	int idx = tx ? 0 : 1;
> +
> +	ghrsc->type = tx ? GH_RESOURCE_TYPE_MSGQ_TX : GH_RESOURCE_TYPE_MSGQ_RX;
> +
> +	ghrsc->irq = platform_get_irq(pdev, idx);
> +	if (ghrsc->irq < 0) {
> +		dev_err(&pdev->dev, "Failed to get irq%d: %d\n", idx, ghrsc->irq);

"irq0"/"irq1" won't help the reader much.

... "Failed to get %s irq: %d\n", tx ? "tx" : "rx", ghrsc->irq);

> +		return ghrsc->irq;
> +	}
> +
> +	ret = of_property_read_u64_index(node, "reg", idx, &ghrsc->capid);
> +	if (ret) {
> +		dev_err(&pdev->dev, "Failed to get capid%d: %d\n", idx, ret);
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static int gh_identify(void)
> +{
> +	struct gh_hypercall_hyp_identify_resp gh_api;
> +
> +	if (!arch_is_gh_guest())
> +		return -ENODEV;
> +
> +	gh_hypercall_hyp_identify(&gh_api);
> +
> +	pr_info("Running under Gunyah hypervisor %llx/v%u\n",
> +		FIELD_GET(GH_API_INFO_VARIANT_MASK, gh_api.api_info),
> +		gh_api_version(&gh_api));
> +
> +	/* We might move this out to individual drivers if there's ever an API version bump */
> +	if (gh_api_version(&gh_api) != GH_API_V1) {
> +		pr_info("Unsupported Gunyah version: %u\n", gh_api_version(&gh_api));

Is this just an informational statement?

> +		return -ENODEV;
> +	}
> +
> +	return 0;
> +}
> +
> +static int gh_rm_drv_probe(struct platform_device *pdev)

Does "_drv_" add value to this function name?

> +{
> +	struct gh_msgq_tx_data *msg;
> +	struct gh_rm *rm;
> +	int ret;
> +
> +	ret = gh_identify();
> +	if (ret)
> +		return ret;
> +
> +	rm = devm_kzalloc(&pdev->dev, sizeof(*rm), GFP_KERNEL);
> +	if (!rm)
> +		return -ENOMEM;
> +
> +	platform_set_drvdata(pdev, rm);
> +	rm->dev = &pdev->dev;
> +
> +	mutex_init(&rm->send_lock);
> +	BLOCKING_INIT_NOTIFIER_HEAD(&rm->nh);
> +	xa_init_flags(&rm->call_xarray, XA_FLAGS_ALLOC);
> +	rm->cache = kmem_cache_create("gh_rm", struct_size(msg, data, GH_MSGQ_MAX_MSG_SIZE), 0,
> +		SLAB_HWCACHE_ALIGN, NULL);
> +	if (!rm->cache)
> +		return -ENOMEM;
> +
> +	ret = gh_msgq_platform_probe_direction(pdev, true, &rm->tx_ghrsc);
> +	if (ret)
> +		goto err_cache;
> +
> +	ret = gh_msgq_platform_probe_direction(pdev, false, &rm->rx_ghrsc);
> +	if (ret)
> +		goto err_cache;
> +
> +	rm->msgq_client.dev = &pdev->dev;
> +	rm->msgq_client.tx_block = true;
> +	rm->msgq_client.rx_callback = gh_rm_msgq_rx_data;
> +	rm->msgq_client.tx_done = gh_rm_msgq_tx_done;
> +
> +	return gh_msgq_init(&pdev->dev, &rm->msgq, &rm->msgq_client, &rm->tx_ghrsc, &rm->rx_ghrsc);
> +err_cache:
> +	kmem_cache_destroy(rm->cache);
> +	return ret;
> +}
> +
> +static int gh_rm_drv_remove(struct platform_device *pdev)
> +{
> +	struct gh_rm *rm = platform_get_drvdata(pdev);
> +
> +	gh_msgq_remove(&rm->msgq);
> +	kmem_cache_destroy(rm->cache);
> +

As soon as you return here, "rm" will be freed by devres (it's not tied
to the refcount of the struct device). If you have any outstanding
notification work, that will result in a use-after-free.

> +	return 0;
> +}
> +
> +static const struct of_device_id gh_rm_of_match[] = {
> +	{ .compatible = "gunyah-resource-manager" },
> +	{}
> +};
> +MODULE_DEVICE_TABLE(of, gh_rm_of_match);
> +
> +static struct platform_driver gh_rm_driver = {
> +	.probe = gh_rm_drv_probe,
> +	.remove = gh_rm_drv_remove,
> +	.driver = {
> +		.name = "gh_rsc_mgr",
> +		.of_match_table = gh_rm_of_match,
> +	},
> +};
> +module_platform_driver(gh_rm_driver);
> +
> +MODULE_LICENSE("GPL");
> +MODULE_DESCRIPTION("Gunyah Resource Manager Driver");
> diff --git a/drivers/virt/gunyah/rsc_mgr.h b/drivers/virt/gunyah/rsc_mgr.h
> new file mode 100644
> index 0000000000000..8309b7bf46683
> --- /dev/null
> +++ b/drivers/virt/gunyah/rsc_mgr.h
> @@ -0,0 +1,16 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All rights reserved.
> + */
> +#ifndef __GH_RSC_MGR_PRIV_H
> +#define __GH_RSC_MGR_PRIV_H
> +
> +#include <linux/gunyah.h>
> +#include <linux/gunyah_rsc_mgr.h>

You declare struct gh_rm below, so do you really need these two
includes?

> +#include <linux/types.h>
> +
> +struct gh_rm;

Would be nice with an empty line here.

> +int gh_rm_call(struct gh_rm *rsc_mgr, u32 message_id, const void *req_buf, size_t req_buf_size,
> +		void **resp_buf, size_t *resp_buf_size);
> +
> +#endif
> diff --git a/include/linux/gunyah_rsc_mgr.h b/include/linux/gunyah_rsc_mgr.h
> new file mode 100644
> index 0000000000000..f2a312e80af52
> --- /dev/null
> +++ b/include/linux/gunyah_rsc_mgr.h
> @@ -0,0 +1,21 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All rights reserved.
> + */
> +
> +#ifndef _GUNYAH_RSC_MGR_H
> +#define _GUNYAH_RSC_MGR_H
> +
> +#include <linux/list.h>

Unused?

> +#include <linux/notifier.h>
> +#include <linux/gunyah.h>
> +
> +#define GH_VMID_INVAL		U16_MAX

Unused in this patch.

> +
> +struct gh_rm;

Would be nice with an empty line here.

> +int gh_rm_notifier_register(struct gh_rm *rm, struct notifier_block *nb);
> +int gh_rm_notifier_unregister(struct gh_rm *rm, struct notifier_block *nb);
> +struct device *gh_rm_get(struct gh_rm *rm);
> +void gh_rm_put(struct gh_rm *rm);
> +

Regards,
Bjorn

Re: [PATCH v14 01/25] docs: gunyah: Introduce Gunyah Hypervisor

[Bjorn Andersson]

On Tue, Jun 13, 2023 at 10:20:29AM -0700, Elliot Berman wrote:
> Gunyah is an open-source Type-1 hypervisor developed by Qualcomm. It
> does not depend on any lower-privileged OS/kernel code for its core
> functionality. This increases its security and can support a smaller
> trusted computing based when compared to Type-2 hypervisors.
> 
> Add documentation describing the Gunyah hypervisor and the main
> components of the Gunyah hypervisor which are of interest to Linux
> virtualization development.
> 
> Reviewed-by: Bagas Sanjaya <bagasdotme@gmail.com>
> Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
> ---
>  Documentation/virt/gunyah/index.rst         | 113 ++++++++++++++++++++
>  Documentation/virt/gunyah/message-queue.rst |  63 +++++++++++
>  Documentation/virt/index.rst                |   1 +
>  3 files changed, 177 insertions(+)
>  create mode 100644 Documentation/virt/gunyah/index.rst
>  create mode 100644 Documentation/virt/gunyah/message-queue.rst
> 
> diff --git a/Documentation/virt/gunyah/index.rst b/Documentation/virt/gunyah/index.rst
> new file mode 100644
> index 0000000000000..74aa345e0a144
> --- /dev/null
> +++ b/Documentation/virt/gunyah/index.rst
> @@ -0,0 +1,113 @@
> +.. SPDX-License-Identifier: GPL-2.0
> +
> +=================
> +Gunyah Hypervisor
> +=================
> +
> +.. toctree::
> +   :maxdepth: 1
> +
> +   message-queue
> +
> +Gunyah is a Type-1 hypervisor which is independent of any OS kernel, and runs in
> +a higher CPU privilege level. It does not depend on any lower-privileged operating system
> +for its core functionality. This increases its security and can support a much smaller
> +trusted computing base than a Type-2 hypervisor.

Wrap your lines at 80 characters please.

> +
> +Gunyah is an open source hypervisor. The source repo is available at
> +https://github.com/quic/gunyah-hypervisor.
> +
> +Gunyah provides these following features.
> +
> +- Scheduling:
> +
> +  A scheduler for virtual CPUs (vCPUs) on physical CPUs enables time-sharing
> +  of the CPUs. Gunyah supports two models of scheduling:
> +
> +    1. "Behind the back" scheduling in which Gunyah hypervisor schedules vCPUS on its own.
> +    2. "Proxy" scheduling in which a delegated VM can donate part of one of its vCPU slice
> +       to another VM's vCPU via a hypercall.
> +
> +- Memory Management:
> +
> +  APIs handling memory, abstracted as objects, limiting direct use of physical
> +  addresses. Memory ownership and usage tracking of all memory under its control.
> +  Memory partitioning between VMs is a fundamental security feature.
> +
> +- Interrupt Virtualization:
> +
> +  Uses CPU hardware interrupt virtualization capabilities. Interrupts are handled
> +  in the hypervisor and routed to the assigned VM.
> +
> +- Inter-VM Communication:
> +
> +  There are several different mechanisms provided for communicating between VMs.
> +
> +- Virtual platform:
> +
> +  Architectural devices such as interrupt controllers and CPU timers are directly provided
> +  by the hypervisor as well as core virtual platform devices and system APIs such as ARM PSCI.
> +
> +- Device Virtualization:
> +
> +  Para-virtualization of devices is supported using inter-VM communication.
> +
> +Architectures supported
> +=======================
> +AArch64 with a GIC
> +
> +Resources and Capabilities
> +==========================
> +
> +Some services or resources provided by the Gunyah hypervisor are described to a virtual machine by

To my understanding neither resources, nor services are "described", but
rather "exposed through capability IDs"

Is it really "some services or resource", isn't everything in Gunyah
exposed to the VMs as a capability?

> +capability IDs. For instance, inter-VM communication is performed with doorbells and message queues.
> +Gunyah allows access to manipulate that doorbell via the capability ID. These resources are

s/manipulate/interact with/ ?

> +described in Linux as a struct gh_resource.
> +
> +High level management of these resources is performed by the resource manager VM. RM informs a
> +guest VM about resources it can access through either the device tree or via guest-initiated RPC.
> +
> +For each virtual machine, Gunyah maintains a table of resources which can be accessed by that VM.
> +An entry in this table is called a "capability" and VMs can only access resources via this
> +capability table. Hence, virtual Gunyah resources are referenced by a "capability IDs" and not
> +"resource IDs". If 2 VMs have access to the same resource, they might not be using the same
> +capability ID to access that resource since the capability tables are independent per VM.

I think you can rewrite this section more succinctly by saying that Gunyah
handles resources, which are selectively exposed to each VM through
VM-specific capability ids.

> +
> +Resource Manager
> +================
> +
> +The resource manager (RM) is a privileged application VM supporting the Gunyah Hypervisor.
> +It provides policy enforcement aspects of the virtualization system. The resource manager can
> +be treated as an extension of the Hypervisor but is separated to its own partition to ensure
> +that the hypervisor layer itself remains small and secure and to maintain a separation of policy
> +and mechanism in the platform. RM runs at arm64 NS-EL1 similar to other virtual machines.

s/RM/The resource manager/ and a ',' after EL1, please.

> +
> +Communication with the resource manager from each guest VM happens with message-queue.rst. Details

s/each guest VM/other VMs/ or perhaps even spell out virtual machines.

> +about the specific messages can be found in drivers/virt/gunyah/rsc_mgr.c
> +
> +::
> +
> +  +-------+   +--------+   +--------+
> +  |  RM   |   |  VM_A  |   |  VM_B  |
> +  +-.-.-.-+   +---.----+   +---.----+
> +    | |           |            |
> +  +-.-.-----------.------------.----+
> +  | | \==========/             |    |
> +  |  \========================/     |
> +  |            Gunyah               |
> +  +---------------------------------+
> +
> +The source for the resource manager is available at https://github.com/quic/gunyah-resource-manager.
> +
> +The resource manager provides the following features:
> +
> +- VM lifecycle management: allocating a VM, starting VMs, destruction of VMs
> +- VM access control policy, including memory sharing and lending
> +- Interrupt routing configuration
> +- Forwarding of system-level events (e.g. VM shutdown) to owner VM
> +
> +When booting a virtual machine which uses a devicetree such as Linux, resource manager overlays a

You can omit "such as Linux" without loosing information. Also, "the
resource manager".

> +/hypervisor node. This node can let Linux know it is running as a Gunyah guest VM,

"can"? Looking at the implementation that doesn't seem to be how you
detect that you're running under Gunyah.

> +how to communicate with resource manager, and basic description and capabilities of

When it comes to RM, it doesn't seem to be "can" anymore. Here it _is_
the way you inform the OS about how to communicate with the resource
manager.

> +this VM. See Documentation/devicetree/bindings/firmware/gunyah-hypervisor.yaml for a description
> +of this node.
> diff --git a/Documentation/virt/gunyah/message-queue.rst b/Documentation/virt/gunyah/message-queue.rst
> new file mode 100644
> index 0000000000000..b352918ae54b4
> --- /dev/null
> +++ b/Documentation/virt/gunyah/message-queue.rst
> @@ -0,0 +1,63 @@
> +.. SPDX-License-Identifier: GPL-2.0
> +
> +Message Queues
> +==============
> +Message queue is a simple low-capacity IPC channel between two VMs. It is

s/VMs/virtual machines/

> +intended for sending small control and configuration messages. Each message
> +queue is unidirectional, so a full-duplex IPC channel requires a pair of queues.
> +
> +Messages can be up to 240 bytes in length. Longer messages require a further
> +protocol on top of the message queue messages themselves. For instance, communication
> +with the resource manager adds a header field for sending longer messages via multiple
> +message fragments.
> +
> +The diagram below shows how message queue works. A typical configuration involves
> +2 message queues. Message queue 1 allows VM_A to send messages to VM_B. Message
> +queue 2 allows VM_B to send messages to VM_A.

What is described below all relates to one message queue, I think it
would be clearer if you remove the second message queue from the example
below and simply state that each direction need its own queue (as you
do here).

> +
> +1. VM_A sends a message of up to 240 bytes in length. It raises a hypercall
> +   with the message to inform the hypervisor to add the message to
> +   message queue 1's queue. The hypervisor copies memory into the internal
> +   message queue representation; the memory doesn't need to be shared between
> +   VM_A and VM_B.
> +
> +2. Gunyah raises the corresponding interrupt for VM_B (Rx vIRQ) when any of
> +   these happens:
> +
> +   a. gh_msgq_send() has PUSH flag. Queue is immediately flushed. This is the typical case.

Funny when the description of the unusual word "push" directly grabs the
word "flush" which everyone understands the meaning of. But I guess this
is Gunyah nomenclature.

On the other hand, if you consider the PUSH flag to just mean "push a RX
interrupt", then the naming isn't so strange. But it wouldn't
necessarily imply that "the queue is flushed", it's simply raising the
rx irq for the receiving side to drain the queue - at it's own pace.

I wouldn't be surprised to see that pushed messages denotes the "typical
case", but I don't think it's relevant details for the rx irq
description.


> +   b. Explicility with gh_msgq_push command from VM_A.

There's no function named gh_msgq_send(), and the gh_msgq_push is
lacking parenthesis. Please refer to these consistently with references
to functions, or perhaps capitalize them to refer to the hypercall?

> +   c. Message queue has reached a threshold depth.
> +
> +3. VM_B calls gh_msgq_recv() and Gunyah copies message to requested buffer.

s/requested/a provided/

> +
> +4. Gunyah buffers messages in the queue. If the queue became full when VM_A added a message,

s/the/a/

> +   the return values for gh_msgq_send() include a flag that indicates the queue is full.
> +   Once VM_B receives the message and, thus, there is space in the queue, Gunyah

"Once messages are drained from the queue, Gunyah will raise the..."

> +   will raise the Tx vIRQ on VM_A to indicate it can continue sending messages.
> +
> +For VM_B to send a message to VM_A, the process is identical, except that hypercalls
> +reference message queue 2's capability ID. Each message queue has its own independent
> +vIRQ: two TX message queues will have two vIRQs (and two capability IDs).
> +
> +::
> +
> +      +---------------+         +-----------------+         +---------------+
> +      |      VM_A     |         |Gunyah hypervisor|         |      VM_B     |
> +      |               |         |                 |         |               |
> +      |               |         |                 |         |               |
> +      |               |   Tx    |                 |         |               |
> +      |               |-------->|                 | Rx vIRQ |               |
> +      |gh_msgq_send() | Tx vIRQ |Message queue 1  |-------->|gh_msgq_recv() |
> +      |               |<------- |                 |         |               |
> +      |               |         |                 |         |               |
> +      | Message Queue |         |                 |         | Message Queue |
> +      | driver        |         |                 |         | driver        |
> +      |               |         |                 |         |               |
> +      |               |         |                 |         |               |
> +      |               |         |                 |   Tx    |               |
> +      |               | Rx vIRQ |                 |<--------|               |
> +      |gh_msgq_recv() |<--------|Message queue 2  | Tx vIRQ |gh_msgq_send() |
> +      |               |         |                 |-------->|               |
> +      |               |         |                 |         |               |
> +      |               |         |                 |         |               |
> +      +---------------+         +-----------------+         +---------------+
> diff --git a/Documentation/virt/index.rst b/Documentation/virt/index.rst
> index 7fb55ae08598d..15869ee059b35 100644
> --- a/Documentation/virt/index.rst
> +++ b/Documentation/virt/index.rst
> @@ -16,6 +16,7 @@ Virtualization Support
>     coco/sev-guest
>     coco/tdx-guest
>     hyperv/index
> +   gunyah/index

'g' < 'h'

Regards,
Bjorn

Re: [PATCH v14 08/25] gunyah: rsc_mgr: Add VM lifecycle RPC

[Bjorn Andersson]

On Tue, Jun 13, 2023 at 10:20:36AM -0700, Elliot Berman wrote:
> diff --git a/drivers/virt/gunyah/rsc_mgr_rpc.c b/drivers/virt/gunyah/rsc_mgr_rpc.c
[..]
> +/**
> + * gh_rm_alloc_vmid() - Allocate a new VM in Gunyah. Returns the VM identifier.
> + * @rm: Handle to a Gunyah resource manager
> + * @vmid: Use 0 to dynamically allocate a VM. A reserved VMID can be supplied
> + *        to request allocation of a platform-defined VM.
> + *
> + * Returns - the allocated VMID or negative value on error

kernel-doc Return:

> + */
> +int gh_rm_alloc_vmid(struct gh_rm *rm, u16 vmid)
> +{
> +	struct gh_rm_vm_common_vmid_req req_payload = {
> +		.vmid = cpu_to_le16(vmid),
> +	};
> +	struct gh_rm_vm_alloc_vmid_resp *resp_payload;
> +	size_t resp_size;
> +	void *resp;
> +	int ret;
> +
> +	ret = gh_rm_call(rm, GH_RM_RPC_VM_ALLOC_VMID, &req_payload, sizeof(req_payload), &resp,

Wrap lines at 80 characters, unless it improves readability, which is
doesn't here as you wrap it later anyways.

(The gh_rm_call() in gh_rm_common_vmid_call() above is a good example of
where going above 80 characters looks good)

> +			&resp_size);
> +	if (ret)
> +		return ret;
> +
> +	if (!vmid) {
> +		resp_payload = resp;
> +		ret = le16_to_cpu(resp_payload->vmid);
> +		kfree(resp);
> +	}

With vmid specified, will the call somehow not return a response buffer?
If this is the case please document it here with a comment.

Otherwise, you're leaking resp.

> +
> +	return ret;
> +}
> +
> +/**
> + * gh_rm_dealloc_vmid() - Dispose of a VMID
> + * @rm: Handle to a Gunyah resource manager
> + * @vmid: VM identifier allocated with gh_rm_alloc_vmid

Doesn't hurt to define the return value of all these apis.

> + */
> +int gh_rm_dealloc_vmid(struct gh_rm *rm, u16 vmid)
> +{
> +	return gh_rm_common_vmid_call(rm, GH_RM_RPC_VM_DEALLOC_VMID, vmid);
> +}
> +
> +/**
> + * gh_rm_vm_reset() - Reset a VM's resources
> + * @rm: Handle to a Gunyah resource manager
> + * @vmid: VM identifier allocated with gh_rm_alloc_vmid
> + *
> + * As part of tearing down the VM, request RM to clean up all the VM resources
> + * associated with the VM. Only after this, Linux can clean up all the

s/, Linux can/can Linux/

> + * references it maintains to resources.
> + */
> +int gh_rm_vm_reset(struct gh_rm *rm, u16 vmid)
> +{
> +	return gh_rm_common_vmid_call(rm, GH_RM_RPC_VM_RESET, vmid);
> +}
[..]
> +int gh_rm_get_hyp_resources(struct gh_rm *rm, u16 vmid,
> +				struct gh_rm_hyp_resources **resources)
> +{
> +	struct gh_rm_vm_common_vmid_req req_payload = {
> +		.vmid = cpu_to_le16(vmid),
> +	};
> +	struct gh_rm_hyp_resources *resp;
> +	size_t resp_size;
> +	int ret;
> +
> +	ret = gh_rm_call(rm, GH_RM_RPC_VM_GET_HYP_RESOURCES,
> +			 &req_payload, sizeof(req_payload),
> +			 (void **)&resp, &resp_size);
> +	if (ret)
> +		return ret;
> +
> +	if (!resp_size)
> +		return -EBADMSG;
> +
> +	if (resp_size < struct_size(resp, entries, 0) ||
> +		resp_size != struct_size(resp, entries, le32_to_cpu(resp->n_entries))) {

Indent wrapped expressions to match the previous start of that
expression.

> +		kfree(resp);
> +		return -EBADMSG;
> +	}
> +
> +	*resources = resp;
> +	return 0;
> +}
> +
> +/**
> + * gh_rm_get_vmid() - Retrieve VMID of this virtual machine
> + * @rm: Handle to a Gunyah resource manager
> + * @vmid: Filled with the VMID of this VM

In gh_rm_alloc_vmid() you return the vmid (or a errno), here you return
the value by reference. Pick one please. (Preferably return vmid)

> + */
> +int gh_rm_get_vmid(struct gh_rm *rm, u16 *vmid)
> +{
> +	static u16 cached_vmid = GH_VMID_INVAL;
> +	size_t resp_size;
> +	__le32 *resp;
> +	int ret;
> +
> +	if (cached_vmid != GH_VMID_INVAL) {
> +		*vmid = cached_vmid;
> +		return 0;
> +	}

Regards,
Bjorn

Re: [PATCH v14 09/25] gunyah: vm_mgr: Introduce basic VM Manager

[Bjorn Andersson]

On Tue, Jun 13, 2023 at 10:20:37AM -0700, Elliot Berman wrote:
> diff --git a/drivers/virt/gunyah/rsc_mgr.c b/drivers/virt/gunyah/rsc_mgr.c
> index 04c8e131d259f..a0faf126ee56e 100644
> --- a/drivers/virt/gunyah/rsc_mgr.c
> +++ b/drivers/virt/gunyah/rsc_mgr.c
> @@ -15,8 +15,10 @@
>  #include <linux/completion.h>
>  #include <linux/gunyah_rsc_mgr.h>
>  #include <linux/platform_device.h>
> +#include <linux/miscdevice.h>

'm' < 'p'

>  
>  #include "rsc_mgr.h"
> +#include "vm_mgr.h"
>  
>  #define RM_RPC_API_VERSION_MASK		GENMASK(3, 0)
>  #define RM_RPC_HEADER_WORDS_MASK	GENMASK(7, 4)
> @@ -130,6 +132,7 @@ struct gh_rm_connection {
>   * @cache: cache for allocating Tx messages
>   * @send_lock: synchronization to allow only one request to be sent at a time
>   * @nh: notifier chain for clients interested in RM notification messages
> + * @miscdev: /dev/gunyah
>   */
>  struct gh_rm {
>  	struct device *dev;
> @@ -146,6 +149,8 @@ struct gh_rm {
>  	struct kmem_cache *cache;
>  	struct mutex send_lock;
>  	struct blocking_notifier_head nh;
> +
> +	struct miscdevice miscdev;
>  };
>  
>  /**
> @@ -580,6 +585,33 @@ int gh_rm_notifier_unregister(struct gh_rm *rm, struct notifier_block *nb)
>  }
>  EXPORT_SYMBOL_GPL(gh_rm_notifier_unregister);
>  
> +struct device *gh_rm_get(struct gh_rm *rm)
> +{
> +	return get_device(rm->miscdev.this_device);

Please add a comment to why the VM is parented off the miscdevice and
not the RM itself, when the function name indicates that you're
acquiring a reference to the rm...

> +}
> +EXPORT_SYMBOL_GPL(gh_rm_get);
> +
[..]
> diff --git a/drivers/virt/gunyah/vm_mgr.c b/drivers/virt/gunyah/vm_mgr.c
> new file mode 100644
> index 0000000000000..a43401cb34f7d
> --- /dev/null
> +++ b/drivers/virt/gunyah/vm_mgr.c
> @@ -0,0 +1,93 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All rights reserved.
> + */
> +
> +#define pr_fmt(fmt) "gh_vm_mgr: " fmt

Unused?

Regards,
Bjorn

Re: [PATCH v14 10/25] gunyah: rsc_mgr: Add RPC for sharing memory

[Bjorn Andersson]

On Tue, Jun 13, 2023 at 10:20:38AM -0700, Elliot Berman wrote:
> Gunyah resource manager provides API to manipulate stage 2 page tables.
> Manipulations are represented as a memory parcel. Memory parcels
> describe a list of memory regions (intermediate physical address--IPA--and
> size), a list of new permissions for VMs, and the memory type (DDR or
> MMIO). Each memory parcel is uniquely identified by a handle allocated by
> Gunyah. There are a few types of memory parcel sharing which Gunyah
> supports:
> 
>  - Sharing: the guest and host VM both have access
>  - Lending: only the guest has access; host VM loses access
>  - Donating: Permanently lent (not reclaimed even if guest shuts down)
> 
> Memory parcels that have been shared or lent can be reclaimed by the
> host via an additional call. The reclaim operation restores the original
> access the host VM had to the memory parcel and removes the access to
> other VM.
> 
> One point to note that memory parcels don't describe where in the guest
> VM the memory parcel should reside. The guest VM must accept the memory
> parcel either explicitly via a "gh_rm_mem_accept" call (not introduced
> here) or be configured to accept it automatically at boot. When the guest
> VM accepts the memory parcel, it also mentions the IPA it wants to place
> memory parcel. Although the region might be discontiguous on the host,
> the memory parcel is place contiguously in the guest memory at the
> specified IPA.
> 
> Reviewed-by: Alex Elder <elder@linaro.org>
> Reviewed-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
> Co-developed-by: Prakruthi Deepak Heragu <quic_pheragu@quicinc.com>
> Signed-off-by: Prakruthi Deepak Heragu <quic_pheragu@quicinc.com>
> Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
> ---
>  drivers/virt/gunyah/rsc_mgr_rpc.c | 227 ++++++++++++++++++++++++++++++
>  include/linux/gunyah_rsc_mgr.h    |  48 +++++++
>  2 files changed, 275 insertions(+)
> 
> diff --git a/drivers/virt/gunyah/rsc_mgr_rpc.c b/drivers/virt/gunyah/rsc_mgr_rpc.c
> index a4a9f0ba4e1fc..25064123a31c3 100644
> --- a/drivers/virt/gunyah/rsc_mgr_rpc.c
> +++ b/drivers/virt/gunyah/rsc_mgr_rpc.c
> @@ -6,6 +6,12 @@
>  #include <linux/gunyah_rsc_mgr.h>
>  #include "rsc_mgr.h"
>  
> +/* Message IDs: Memory Management */
> +#define GH_RM_RPC_MEM_LEND			0x51000012
> +#define GH_RM_RPC_MEM_SHARE			0x51000013
> +#define GH_RM_RPC_MEM_RECLAIM			0x51000015
> +#define GH_RM_RPC_MEM_APPEND			0x51000018
> +
>  /* Message IDs: VM Management */
>  #define GH_RM_RPC_VM_ALLOC_VMID			0x56000001
>  #define GH_RM_RPC_VM_DEALLOC_VMID		0x56000002
> @@ -22,6 +28,46 @@ struct gh_rm_vm_common_vmid_req {
>  	__le16 _padding;
>  } __packed;
>  
> +/* Call: MEM_LEND, MEM_SHARE */
> +#define GH_MEM_SHARE_REQ_FLAGS_APPEND		BIT(1)
> +
> +struct gh_rm_mem_share_req_header {
> +	u8 mem_type;
> +	u8 _padding0;
> +	u8 flags;
> +	u8 _padding1;
> +	__le32 label;
> +} __packed;
> +
> +struct gh_rm_mem_share_req_acl_section {
> +	__le32 n_entries;
> +	struct gh_rm_mem_acl_entry entries[];
> +};
> +
> +struct gh_rm_mem_share_req_mem_section {
> +	__le16 n_entries;
> +	__le16 _padding;
> +	struct gh_rm_mem_entry entries[];
> +};

Any reason why these two are not explicitly packed?

> +
> +/* Call: MEM_RELEASE */
> +struct gh_rm_mem_release_req {
> +	__le32 mem_handle;
> +	u8 flags; /* currently not used */
> +	u8 _padding0;
> +	__le16 _padding1;
> +} __packed;
> +
> +/* Call: MEM_APPEND */
> +#define GH_MEM_APPEND_REQ_FLAGS_END		BIT(0)
> +
> +struct gh_rm_mem_append_req_header {
> +	__le32 mem_handle;
> +	u8 flags;
> +	u8 _padding0;
> +	__le16 _padding1;
> +} __packed;
> +
>  /* Call: VM_ALLOC */
>  struct gh_rm_vm_alloc_vmid_resp {
>  	__le16 vmid;
> @@ -51,6 +97,8 @@ struct gh_rm_vm_config_image_req {
>  	__le64 dtb_size;
>  } __packed;
>  
> +#define GH_RM_MAX_MEM_ENTRIES	512
> +
>  /*
>   * Several RM calls take only a VMID as a parameter and give only standard
>   * response back. Deduplicate boilerplate code by using this common call.
> @@ -64,6 +112,185 @@ static int gh_rm_common_vmid_call(struct gh_rm *rm, u32 message_id, u16 vmid)
>  	return gh_rm_call(rm, message_id, &req_payload, sizeof(req_payload), NULL, NULL);
>  }
>  
> +static int _gh_rm_mem_append(struct gh_rm *rm, u32 mem_handle, bool end_append,
> +			struct gh_rm_mem_entry *mem_entries, size_t n_mem_entries)
> +{
> +	struct gh_rm_mem_share_req_mem_section *mem_section;

"sections" is sufficient.

> +	struct gh_rm_mem_append_req_header *req_header;
> +	size_t msg_size = 0;
> +	void *msg;
> +	int ret;
> +
> +	msg_size += sizeof(struct gh_rm_mem_append_req_header);

msg_size is sizeof(header) + sizeof(sections), but written this way you
state that it's:

msg_size is X + sizeof(header),
and msg_size is also sizeof(sections)


It's the same thing, but you're forcing the reader to look for the
initial value of msg_size.

> +	msg_size += struct_size(mem_section, entries, n_mem_entries);
> +
> +	msg = kzalloc(msg_size, GFP_KERNEL);
> +	if (!msg)
> +		return -ENOMEM;
> +
> +	req_header = msg;

Can't you just make msg a strcut gh_rm_mem_append_req_header?

> +	mem_section = (void *)(req_header + 1);
> +
> +	req_header->mem_handle = cpu_to_le32(mem_handle);
> +	if (end_append)
> +		req_header->flags |= GH_MEM_APPEND_REQ_FLAGS_END;
> +
> +	mem_section->n_entries = cpu_to_le16(n_mem_entries);
> +	memcpy(mem_section->entries, mem_entries, sizeof(*mem_entries) * n_mem_entries);
> +
> +	ret = gh_rm_call(rm, GH_RM_RPC_MEM_APPEND, msg, msg_size, NULL, NULL);
> +	kfree(msg);
> +
> +	return ret;
> +}
> +
> +static int gh_rm_mem_append(struct gh_rm *rm, u32 mem_handle,
> +			struct gh_rm_mem_entry *mem_entries, size_t n_mem_entries)

You can name these arguments "entries" and "n_entries" (or num_entries)
without loosing any infromation, but saving a whole bunch of characters
that people have to read.

> +{
> +	bool end_append;

Iiuc this means "is this the last entry", perhaps calling it "last"
would make its purpose immediately obvious.

> +	int ret = 0;
> +	size_t n;
> +
> +	while (n_mem_entries) {
> +		if (n_mem_entries > GH_RM_MAX_MEM_ENTRIES) {
> +			end_append = false;
> +			n = GH_RM_MAX_MEM_ENTRIES;
> +		} else {
> +			end_append = true;
> +			n = n_mem_entries;
> +		}
> +
> +		ret = _gh_rm_mem_append(rm, mem_handle, end_append, mem_entries, n);

Every loop here you kzallc() and kfree() the same chunk of scratch
memory. If you inline _gh_rm_mem_append() here and do the allocation
once based on GH_RM_MAX_MEM_ENTRIES this would be faster and seemingly
easier to read/follow.

> +		if (ret)
> +			break;
> +
> +		mem_entries += n;
> +		n_mem_entries -= n;
> +	}
> +
> +	return ret;
> +}
> +
> +static int gh_rm_mem_lend_common(struct gh_rm *rm, u32 message_id, struct gh_rm_mem_parcel *p)
> +{
> +	size_t msg_size = 0, initial_mem_entries = p->n_mem_entries, resp_size;
> +	size_t acl_section_size, mem_section_size;

You keep all other variables one per line, and in reverse x-mas style.
Please do the same for this.

Naming these acl_size and mem_size would be beneficial.

> +	struct gh_rm_mem_share_req_acl_section *acl_section;
> +	struct gh_rm_mem_share_req_mem_section *mem_section;

Naming these acl and mem will make below easier to read.

> +	struct gh_rm_mem_share_req_header *req_header;
> +	u32 *attr_section;
> +	__le32 *resp;
> +	void *msg;
> +	int ret;
> +
> +	if (!p->acl_entries || !p->n_acl_entries || !p->mem_entries || !p->n_mem_entries ||
> +	    p->n_acl_entries > U8_MAX || p->mem_handle != GH_MEM_HANDLE_INVAL)
> +		return -EINVAL;
> +
> +	if (initial_mem_entries > GH_RM_MAX_MEM_ENTRIES)
> +		initial_mem_entries = GH_RM_MAX_MEM_ENTRIES;
> +
> +	acl_section_size = struct_size(acl_section, entries, p->n_acl_entries);
> +	mem_section_size = struct_size(mem_section, entries, initial_mem_entries);

An empty line here seems reasonable.

> +	/* The format of the message goes:
> +	 * request header
> +	 * ACL entries (which VMs get what kind of access to this memory parcel)
> +	 * Memory entries (list of memory regions to share)
> +	 * Memory attributes (currently unused, we'll hard-code the size to 0)
> +	 */
> +	msg_size += sizeof(struct gh_rm_mem_share_req_header);

Hidden above is the confirmation that msg_size was initialized to 0,
drop the '+' here to make it clear.

> +	msg_size += acl_section_size;
> +	msg_size += mem_section_size;
> +	msg_size += sizeof(u32); /* for memory attributes, currently unused */
> +
> +	msg = kzalloc(msg_size, GFP_KERNEL);
> +	if (!msg)
> +		return -ENOMEM;
> +
> +	req_header = msg;

I don't think you need to keep req_header and msg separately.

> +	acl_section = (void *)req_header + sizeof(*req_header);
> +	mem_section = (void *)acl_section + acl_section_size;
> +	attr_section = (void *)mem_section + mem_section_size;
> +
> +	req_header->mem_type = p->mem_type;
> +	if (initial_mem_entries != p->n_mem_entries)

I think this will only happen if p->n_mem_entries >
GH_RM_MAX_MEM_ENTRIES, for which you already have a condition earlier.
Set the flag in that condition rather than spreading it over two (three)
code paths.

> +		req_header->flags |= GH_MEM_SHARE_REQ_FLAGS_APPEND;
> +	req_header->label = cpu_to_le32(p->label);
> +
> +	acl_section->n_entries = cpu_to_le32(p->n_acl_entries);
> +	memcpy(acl_section->entries, p->acl_entries,
> +		flex_array_size(acl_section, entries, p->n_acl_entries));
> +
> +	mem_section->n_entries = cpu_to_le16(initial_mem_entries);
> +	memcpy(mem_section->entries, p->mem_entries,
> +		flex_array_size(mem_section, entries, initial_mem_entries));
> +
> +	/* Set n_entries for memory attribute section to 0 */
> +	*attr_section = 0;
> +
> +	ret = gh_rm_call(rm, message_id, msg, msg_size, (void **)&resp, &resp_size);
> +	kfree(msg);
> +
> +	if (ret)
> +		return ret;
> +
> +	p->mem_handle = le32_to_cpu(*resp);
> +	kfree(resp);
> +
> +	if (initial_mem_entries != p->n_mem_entries) {

Another "we took that conditional path above", please make it obvious.


Can you please also write a comment describing that this operation is
split in a main one, followed by one of more appended operations as
necessary. This took me too long time to realize...

In particular I was wondering why "initial" didn't mean "the original
value", but now I see that it probably means "the value relevant for the
initial request".

> +		ret = gh_rm_mem_append(rm, p->mem_handle,
> +					&p->mem_entries[initial_mem_entries],
> +					p->n_mem_entries - initial_mem_entries);
> +		if (ret) {
> +			gh_rm_mem_reclaim(rm, p);
> +			p->mem_handle = GH_MEM_HANDLE_INVAL;

What happens to the entries that was already lended or shared?

Regards,
Bjorn

Re: [PATCH v14 13/25] samples: Add sample userspace Gunyah VM Manager

[Bjorn Andersson]

On Tue, Jun 13, 2023 at 10:20:41AM -0700, Elliot Berman wrote:
> diff --git a/samples/gunyah/gunyah_vmm.c b/samples/gunyah/gunyah_vmm.c
> new file mode 100644
> index 0000000000000..6f636ac227c69
> --- /dev/null
> +++ b/samples/gunyah/gunyah_vmm.c
> @@ -0,0 +1,266 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All rights reserved.
> + */
> +
> +#include <stdlib.h>
> +#include <stdio.h>
> +#include <unistd.h>
> +#include <sys/types.h>
> +#include <sys/stat.h>
> +#include <fcntl.h>
> +#include <sys/ioctl.h>
> +#include <getopt.h>
> +#include <limits.h>
> +#include <stdint.h>
> +#include <fcntl.h>
> +#include <string.h>
> +#include <sys/sysmacros.h>
> +#define __USE_GNU
> +#include <sys/mman.h>
> +
> +#include <linux/gunyah.h>
> +
> +#define DEFAULT_GUEST_BASE	0x80000000
> +#define DEFAULT_GUEST_SIZE	0x6400000 /* 100 MiB */
> +#define DEFAULT_DTB_OFFSET	0x45f0000 /* 70MiB - 64 KiB */
> +#define DEFAULT_RAMDISK_OFFSET	0x4600000 /* 70MiB */

Would be nice if the default ramdisk offset was close to accounting for
the kernel modules produced in an upstream defconfig build... Perhaps
just bumping the default guest size to facilitate this?

[..]
> diff --git a/samples/gunyah/sample_vm.dts b/samples/gunyah/sample_vm.dts
> new file mode 100644
> index 0000000000000..293bbc0469c8f
> --- /dev/null
> +++ b/samples/gunyah/sample_vm.dts
> @@ -0,0 +1,68 @@
> +// SPDX-License-Identifier: BSD-3-Clause
> +/*
> + * Copyright (c) 2022 Qualcomm Innovation Center, Inc. All rights reserved.
> + */
> +
> +/dts-v1/;
> +
> +/ {
> +	#address-cells = <2>;
> +	#size-cells = <2>;
> +	interrupt-parent = <&intc>;
> +
> +	chosen {
> +		bootargs = "nokaslr";

Is this required?

> +	};
> +
> +	cpus {
> +		#address-cells = <0x2>;
> +		#size-cells = <0>;
> +
> +		cpu@0 {
> +			device_type = "cpu";
> +			compatible = "arm,armv8";
> +			reg = <0 0>;
> +		};
> +	};
> +
> +	intc: interrupt-controller@3FFF0000 {
> +		compatible = "arm,gic-v3";
> +		#interrupt-cells = <3>;
> +		#address-cells = <2>;
> +		#size-cells = <2>;
> +		interrupt-controller;
> +		reg = <0 0x3FFF0000 0 0x10000>,
> +		      <0 0x3FFD0000 0 0x20000>;

Lowercase hex digits please.

> +	};
> +
> +	timer {
> +		compatible = "arm,armv8-timer";
> +		always-on;
> +		interrupts = <1 13 0x108>,
> +			     <1 14 0x108>,
> +			     <1 11 0x108>,
> +			     <1 10 0x108>;
> +		clock-frequency = <19200000>;
> +	};
> +
> +	gunyah-vm-config {

Is this node documented somewhere?

Regards,
Bjorn

> +		image-name = "linux_vm_0";
> +
> +		memory {
> +			#address-cells = <2>;
> +			#size-cells = <2>;
> +
> +			base-address = <0 0x80000000>;
> +		};
> +
> +		interrupts {
> +			config = <&intc>;
> +		};
> +
> +		vcpus {
> +			affinity-map = < 0 >;
> +			sched-priority = < (-1) >;
> +			sched-timeslice = < 2000 >;
> +		};
> +	};
> +};
> -- 
> 2.40.0
> 

Re: [PATCH v14 14/25] gunyah: rsc_mgr: Add platform ops on mem_lend/mem_reclaim

[Bjorn Andersson]

On Tue, Jun 13, 2023 at 10:20:42AM -0700, Elliot Berman wrote:
> On Qualcomm platforms, there is a firmware entity which controls access
> to physical pages. In order to share memory with another VM, this entity
> needs to be informed that the guest VM should have access to the memory.
> 

Why isn't this handled by the system above us?

> Reviewed-by: Alex Elder <elder@linaro.org>
> Co-developed-by: Prakruthi Deepak Heragu <quic_pheragu@quicinc.com>
> Signed-off-by: Prakruthi Deepak Heragu <quic_pheragu@quicinc.com>
> Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
> ---
>  drivers/virt/gunyah/Kconfig                 |  4 ++
>  drivers/virt/gunyah/Makefile                |  2 +
>  drivers/virt/gunyah/gunyah_platform_hooks.c | 80 +++++++++++++++++++++
>  drivers/virt/gunyah/rsc_mgr.h               |  3 +
>  drivers/virt/gunyah/rsc_mgr_rpc.c           | 18 ++++-
>  include/linux/gunyah_rsc_mgr.h              | 17 +++++
>  6 files changed, 122 insertions(+), 2 deletions(-)
>  create mode 100644 drivers/virt/gunyah/gunyah_platform_hooks.c
> 
> diff --git a/drivers/virt/gunyah/Kconfig b/drivers/virt/gunyah/Kconfig
> index 1a737694c333d..de815189dab6c 100644
> --- a/drivers/virt/gunyah/Kconfig
> +++ b/drivers/virt/gunyah/Kconfig
> @@ -4,6 +4,7 @@ config GUNYAH
>  	tristate "Gunyah Virtualization drivers"
>  	depends on ARM64
>  	depends on MAILBOX
> +	select GUNYAH_PLATFORM_HOOKS
>  	help
>  	  The Gunyah drivers are the helper interfaces that run in a guest VM
>  	  such as basic inter-VM IPC and signaling mechanisms, and higher level
> @@ -11,3 +12,6 @@ config GUNYAH
>  
>  	  Say Y/M here to enable the drivers needed to interact in a Gunyah
>  	  virtual environment.
> +
> +config GUNYAH_PLATFORM_HOOKS

Automatically selected by GUNYAH and the only platform so far, no need
to keep this as a separate Kconfig.

> +	tristate
> diff --git a/drivers/virt/gunyah/Makefile b/drivers/virt/gunyah/Makefile
> index bacf78b8fa337..4fbeee521d60a 100644
> --- a/drivers/virt/gunyah/Makefile
> +++ b/drivers/virt/gunyah/Makefile
> @@ -1,4 +1,6 @@
>  # SPDX-License-Identifier: GPL-2.0
>  
> +obj-$(CONFIG_GUNYAH_PLATFORM_HOOKS) += gunyah_platform_hooks.o
> +

Why is this added before the core gunyah components?

>  gunyah-y += rsc_mgr.o rsc_mgr_rpc.o vm_mgr.o vm_mgr_mm.o
>  obj-$(CONFIG_GUNYAH) += gunyah.o

Regards,
Bjorn

Re: [PATCH v14 15/25] virt: gunyah: Add Qualcomm Gunyah platform ops

[Bjorn Andersson]

On Tue, Jun 13, 2023 at 10:20:43AM -0700, Elliot Berman wrote:
> Qualcomm platforms have a firmware entity which performs access control
> to physical pages. Dynamically started Gunyah virtual machines use the
> QCOM_SCM_RM_MANAGED_VMID for access. Linux thus needs to assign access
> to the memory used by guest VMs. Gunyah doesn't do this operation for us
> since it is the current VM (typically VMID_HLOS) delegating the access
> and not Gunyah itself. Use the Gunyah platform ops to achieve this so
> that only Qualcomm platforms attempt to make the needed SCM calls.
> 
> Reviewed-by: Alex Elder <elder@linaro.org>
> Co-developed-by: Prakruthi Deepak Heragu <quic_pheragu@quicinc.com>
> Signed-off-by: Prakruthi Deepak Heragu <quic_pheragu@quicinc.com>
> Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
> ---
>  drivers/virt/gunyah/Kconfig       |  13 +++
>  drivers/virt/gunyah/Makefile      |   1 +
>  drivers/virt/gunyah/gunyah_qcom.c | 153 ++++++++++++++++++++++++++++++
>  3 files changed, 167 insertions(+)
>  create mode 100644 drivers/virt/gunyah/gunyah_qcom.c
> 
> diff --git a/drivers/virt/gunyah/Kconfig b/drivers/virt/gunyah/Kconfig
> index de815189dab6c..0421b751aad4f 100644
> --- a/drivers/virt/gunyah/Kconfig
> +++ b/drivers/virt/gunyah/Kconfig
> @@ -5,6 +5,7 @@ config GUNYAH
>  	depends on ARM64
>  	depends on MAILBOX
>  	select GUNYAH_PLATFORM_HOOKS
> +	imply GUNYAH_QCOM_PLATFORM if ARCH_QCOM
>  	help
>  	  The Gunyah drivers are the helper interfaces that run in a guest VM
>  	  such as basic inter-VM IPC and signaling mechanisms, and higher level
> @@ -15,3 +16,15 @@ config GUNYAH
>  
>  config GUNYAH_PLATFORM_HOOKS
>  	tristate
> +
> +config GUNYAH_QCOM_PLATFORM
> +	tristate "Support for Gunyah on Qualcomm platforms"
> +	depends on GUNYAH
> +	select GUNYAH_PLATFORM_HOOKS
> +	select QCOM_SCM
> +	help
> +	  Enable support for interacting with Gunyah on Qualcomm
> +	  platforms. Interaction with Qualcomm firmware requires
> +	  extra platform-specific support.
> +
> +	  Say Y/M here to use Gunyah on Qualcomm platforms.
> diff --git a/drivers/virt/gunyah/Makefile b/drivers/virt/gunyah/Makefile
> index 4fbeee521d60a..2aa9ff038ed02 100644
> --- a/drivers/virt/gunyah/Makefile
> +++ b/drivers/virt/gunyah/Makefile
> @@ -1,6 +1,7 @@
>  # SPDX-License-Identifier: GPL-2.0
>  
>  obj-$(CONFIG_GUNYAH_PLATFORM_HOOKS) += gunyah_platform_hooks.o
> +obj-$(CONFIG_GUNYAH_QCOM_PLATFORM) += gunyah_qcom.o
>  
>  gunyah-y += rsc_mgr.o rsc_mgr_rpc.o vm_mgr.o vm_mgr_mm.o
>  obj-$(CONFIG_GUNYAH) += gunyah.o
> diff --git a/drivers/virt/gunyah/gunyah_qcom.c b/drivers/virt/gunyah/gunyah_qcom.c
> new file mode 100644
> index 0000000000000..f06a598f2e1b3
> --- /dev/null
> +++ b/drivers/virt/gunyah/gunyah_qcom.c
> @@ -0,0 +1,153 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (c) 2023 Qualcomm Innovation Center, Inc. All rights reserved.
> + */
> +
> +#include <linux/arm-smccc.h>
> +#include <linux/gunyah_rsc_mgr.h>
> +#include <linux/module.h>
> +#include <linux/firmware/qcom/qcom_scm.h>
> +#include <linux/types.h>
> +#include <linux/uuid.h>
> +
> +#define QCOM_SCM_RM_MANAGED_VMID	0x3A
> +#define QCOM_SCM_MAX_MANAGED_VMID	0x3F
> +
> +static int qcom_scm_gh_rm_pre_mem_share(struct gh_rm *rm, struct gh_rm_mem_parcel *mem_parcel)
> +{
> +	struct qcom_scm_vmperm *new_perms;
> +	u64 src, src_cpy;
> +	int ret = 0, i, n;
> +	u16 vmid;
> +
> +	new_perms = kcalloc(mem_parcel->n_acl_entries, sizeof(*new_perms), GFP_KERNEL);
> +	if (!new_perms)
> +		return -ENOMEM;
> +
> +	for (n = 0; n < mem_parcel->n_acl_entries; n++) {
> +		vmid = le16_to_cpu(mem_parcel->acl_entries[n].vmid);
> +		if (vmid <= QCOM_SCM_MAX_MANAGED_VMID)
> +			new_perms[n].vmid = vmid;
> +		else
> +			new_perms[n].vmid = QCOM_SCM_RM_MANAGED_VMID;
> +		if (mem_parcel->acl_entries[n].perms & GH_RM_ACL_X)
> +			new_perms[n].perm |= QCOM_SCM_PERM_EXEC;
> +		if (mem_parcel->acl_entries[n].perms & GH_RM_ACL_W)
> +			new_perms[n].perm |= QCOM_SCM_PERM_WRITE;
> +		if (mem_parcel->acl_entries[n].perms & GH_RM_ACL_R)
> +			new_perms[n].perm |= QCOM_SCM_PERM_READ;
> +	}
> +
> +	src = BIT_ULL(QCOM_SCM_VMID_HLOS);
> +
> +	for (i = 0; i < mem_parcel->n_mem_entries; i++) {
> +		src_cpy = src;
> +		ret = qcom_scm_assign_mem(le64_to_cpu(mem_parcel->mem_entries[i].phys_addr),
> +						le64_to_cpu(mem_parcel->mem_entries[i].size),
> +						&src_cpy, new_perms, mem_parcel->n_acl_entries);
> +		if (ret)
> +			break;
> +	}
> +
> +	if (!ret)
> +		goto out;

I was going to complain that you don't unroll the assignments on
failure, but now realized that this "error handling" is backwards and
actually represents the success case.

Please don't do that, goto error_handling || kfree(new_perms); return 0;
here instead.


That also means that you don't need to zero-initialize ret, because you
would goto err_reclaim inside the loop.

> +
> +	src = 0;
> +	for (n = 0; n < mem_parcel->n_acl_entries; n++) {
> +		vmid = le16_to_cpu(mem_parcel->acl_entries[n].vmid);
> +		if (vmid <= QCOM_SCM_MAX_MANAGED_VMID)
> +			src |= BIT_ULL(vmid);
> +		else
> +			src |= BIT_ULL(QCOM_SCM_RM_MANAGED_VMID);
> +	}
> +
> +	new_perms[0].vmid = QCOM_SCM_VMID_HLOS;
> +
> +	for (i--; i >= 0; i--) {
> +		src_cpy = src;
> +		WARN_ON_ONCE(qcom_scm_assign_mem(
> +				le64_to_cpu(mem_parcel->mem_entries[i].phys_addr),
> +				le64_to_cpu(mem_parcel->mem_entries[i].size),
> +				&src_cpy, new_perms, 1));
> +	}
> +
> +out:
> +	kfree(new_perms);
> +	return ret;
> +}

Regards,
Bjorn

Re: [PATCH v14 17/25] virt: gunyah: Translate gh_rm_hyp_resource into gunyah_resource

[Bjorn Andersson]

On Tue, Jun 13, 2023 at 10:20:45AM -0700, Elliot Berman wrote:
> diff --git a/drivers/virt/gunyah/rsc_mgr.c b/drivers/virt/gunyah/rsc_mgr.c
[..]
> +struct gh_resource *gh_rm_alloc_resource(struct gh_rm *rm, struct gh_rm_hyp_resource *hyp_resource)
> +{
> +	struct gh_resource *ghrsc;
> +	int ret;
> +
> +	ghrsc = kzalloc(sizeof(*ghrsc), GFP_KERNEL);
> +	if (!ghrsc)
> +		return NULL;
> +
> +	ghrsc->type = hyp_resource->type;
> +	ghrsc->capid = le64_to_cpu(hyp_resource->cap_id);
> +	ghrsc->irq = IRQ_NOTCONNECTED;
> +	ghrsc->rm_label = le32_to_cpu(hyp_resource->resource_label);
> +	if (hyp_resource->virq) {
> +		struct gh_irq_chip_data irq_data = {
> +			.gh_virq = le32_to_cpu(hyp_resource->virq),
> +		};
> +
> +		ret = irq_domain_alloc_irqs(rm->irq_domain, 1, NUMA_NO_NODE, &irq_data);
> +		if (ret < 0) {
> +			dev_err(rm->dev,
> +				"Failed to allocate interrupt for resource %d label: %d: %d\n",
> +				ghrsc->type, ghrsc->rm_label, ret);
> +			kfree(ghrsc);
> +			return NULL;
> +		} else {

No need for the else here, the failure case has already returned.

> +			ghrsc->irq = ret;
> +		}
> +	}
> +
> +	return ghrsc;
> +}
[..]
> diff --git a/include/linux/gunyah.h b/include/linux/gunyah.h
> index 982e27d10d57f..4b398b59c2c5a 100644
> --- a/include/linux/gunyah.h
> +++ b/include/linux/gunyah.h
> @@ -27,6 +27,9 @@ struct gh_resource {
>  	enum gh_resource_type type;
>  	u64 capid;
>  	unsigned int irq;
> +
> +	struct list_head list;

This is unused.

Regards,
Bjorn

Re: [PATCH v14 25/25] MAINTAINERS: Add Gunyah hypervisor drivers section

[Bjorn Andersson]

On Tue, Jun 13, 2023 at 10:20:53AM -0700, Elliot Berman wrote:
> Add myself and Prakruthi as maintainers of Gunyah hypervisor drivers.
> 
> Reviewed-by: Alex Elder <elder@linaro.org>
> Signed-off-by: Prakruthi Deepak Heragu <quic_pheragu@quicinc.com>
> Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>

Reviewed-by: Bjorn Andersson <andersson@kernel.org>

Regards,
Bjorn