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* [PATCH v3 0/9] CXL 2.0 Support
@ 2021-02-12 22:25 Ben Widawsky
  2021-02-12 22:25 ` [PATCH v3 1/9] cxl/mem: Introduce a driver for CXL-2.0-Type-3 endpoints Ben Widawsky
                   ` (8 more replies)
  0 siblings, 9 replies; 13+ messages in thread
From: Ben Widawsky @ 2021-02-12 22:25 UTC (permalink / raw)
  To: linux-cxl
  Cc: Ben Widawsky, linux-acpi, linux-kernel, linux-nvdimm, linux-pci,
	Bjorn Helgaas, Chris Browy, Christoph Hellwig, Dan Williams,
	David Hildenbrand, David Rientjes, Ira Weiny, Jon Masters,
	Jonathan Cameron, Rafael Wysocki, Randy Dunlap, Vishal Verma,
	John Groves (jgroves),
	Kelley, Sean V

# Changes since v2 [1]

  * s/mbox_lock/mbox_mutex in kdocs (Ben)
  * Remove stray comments about deleted flags (Ben)
  * Remove flags from CXL_CMD (Ben)
  * Rework cxl_mem_enumerate_cmds() to allow more than 2 commands (Ben, Jonathan)
    * I misread the spec and this needed more robust handling.
  * Remove validate_payload() as it no longer is useful (Ben)
  * Remove check that CEL returned reasonable command list (Ben)
    * It is easy enough to figure this out elsewhere.
    * Enable sane set of commands regardless (Ben)
    * Remove now useless cxl_enable_cmd() (Ben)
  * Add payload dump debugging regardless of timeout (Dan)
    * Extracted to separate RFC patch (Ben)
  * Move PCI_DVSEC_HEADER1_LENGTH_MASK back to cxl.h (Jonathan, Bjorn)
  * Drop duplicated PCI_EXT_CAP_ID_DVSEC (Jonathan)
  * Use PCI_DEVICE_CLASS (Jonathan)
  * Create wrapper for kernel mailbox usage (Jonathan)
    * Helps with error conditions
  * Various cosmetic changes (Jonathan)
  * Remove references to removed MUTEX flag (Jonathan)
  * Remove KERNEL flag since not used yet (Jonathan)
  * Remove payload dumping for debug (Jonathan)
  * Show example expansion from macro magic (Jonathan)

---

In addition to the mailing list, please feel free to use #cxl on oftc IRC for
discussion.

---

# Summary

Introduce support for “type-3” memory devices defined in the Compute Express
Link (CXL) 2.0 specification [2]. Specifically, these are the memory devices
defined by section 8.2.8.5 of the CXL 2.0 spec. A reference implementation
emulating these devices has been submitted to the QEMU mailing list [3] and is
available on gitlab [4], but will move to a shared tree on kernel.org after
initial acceptance. “Type-3” is a CXL device that acts as a memory expander for
RAM or Persistent Memory. The device might be interleaved with other CXL devices
in a given physical address range.

In addition to the core functionality of discovering the spec defined registers
and resources, introduce a CXL device model that will be the foundation for
translating CXL capabilities into existing Linux infrastructure for Persistent
Memory and other memory devices. For now, this only includes support for the
management command mailbox the surfacing of type-3 devices. These control
devices fill the role of “DIMMs” / nmemX memory-devices in LIBNVDIMM terms.

## Userspace Interaction

Interaction with the driver and type-3 devices via the CXL drivers is introduced
in this patch series and considered stable ABI. They include

   * sysfs - Documentation/ABI/testing/sysfs-bus-cxl
   * IOCTL - Documentation/driver-api/cxl/memory-devices.rst
   * debugfs - Documentation/ABI/testing/debugfs-debug

Work is in process to add support for CXL interactions to the ndctl project [5]

### Development plans

One of the unique challenges that CXL imposes on the Linux driver model is that
it requires the operating system to perform physical address space management
interleaved across devices and bridges. Whereas LIBNVDIMM handles a list of
established static persistent memory address ranges (for example from the ACPI
NFIT), CXL introduces hotplug and the concept of allocating address space to
instantiate persistent memory ranges. This is similar to PCI in the sense that
the platform establishes the MMIO range for PCI BARs to be allocated, but it is
significantly complicated by the fact that a given device can optionally be
interleaved with other devices and can participate in several interleave-sets at
once. LIBNVDIMM handled something like this with the aliasing between PMEM and
BLOCK-WINDOW mode, but CXL adds flexibility to alias DEVICE MEMORY through up to
10 decoders per device.

All of the above needs to be enabled with respect to PCI hotplug events on
Type-3 memory device which needs hooks to determine if a given device is
contributing to a "System RAM" address range that is unable to be unplugged. In
other words CXL ties PCI hotplug to Memory Hotplug and PCI hotplug needs to be
able to negotiate with memory hotplug.  In the medium term the implications of
CXL hotplug vs ACPI SRAT/SLIT/HMAT need to be reconciled. One capability that
seems to be needed is either the dynamic allocation of new memory nodes, or
default initializing extra pgdat instances beyond what is enumerated in ACPI
SRAT to accommodate hot-added CXL memory.

Patches welcome, questions welcome as the development effort on the post v5.12
capabilities proceeds.

## Running in QEMU

The incantation to get CXL support in QEMU [4] is considered unstable at this
time. Future readers of this cover letter should verify if any changes are
needed. For the novice QEMU user, the following can be copy/pasted into a
working QEMU commandline. It is enough to make the simplest topology possible.
The topology would consist of a single memory window, single type3 device,
single root port, and single host bridge.

    +-------------+
    |   CXL PXB   |
    |             |
    |  +-------+  |<----------+
    |  |CXL RP |  |           |
    +--+-------+--+           v
           |            +----------+
           |            | "window" |
           |            +----------+
           v                  ^
    +-------------+           |
    |  CXL Type 3 |           |
    |   Device    |<----------+
    +-------------+

// Memory backend for "window"
-object memory-backend-file,id=cxl-mem1,share,mem-path=cxl-type3,size=512M

// Memory backend for LSA
-object memory-backend-file,id=cxl-mem1-lsa,share,mem-path=cxl-mem1-lsa,size=1K

// Host Bridge
-device pxb-cxl id=cxl.0,bus=pcie.0,bus_nr=52,uid=0 len-window-base=1,window-base[0]=0x4c0000000 memdev[0]=cxl-mem1

// Single root port
-device cxl rp,id=rp0,bus=cxl.0,addr=0.0,chassis=0,slot=0,memdev=cxl-mem1

// Single type3 device
-device cxl-type3,bus=rp0,memdev=cxl-mem1,id=cxl-pmem0,size=256M -device cxl-type3,bus=rp1,memdev=cxl-mem1,id=cxl-pmem1,size=256M,lsa=cxl-mem1-lsa

---

[1]: https://lore.kernel.org/linux-cxl/20210210000259.635748-1-ben.widawsky@intel.com/
[2]: https://www.computeexpresslink.org/](https://www.computeexpresslink.org/)
[3]: https://lore.kernel.org/qemu-devel/20210202005948.241655-1-ben.widawsky@intel.com/
[4]: https://gitlab.com/bwidawsk/qemu/-/tree/cxl-2.0v4
[5]: https://github.com/pmem/ndctl/tree/cxl-2.0v2

Ben Widawsky (7):
  cxl/mem: Find device capabilities
  cxl/mem: Add basic IOCTL interface
  cxl/mem: Add a "RAW" send command
  cxl/mem: Enable commands via CEL
  cxl/mem: Add set of informational commands
  MAINTAINERS: Add maintainers of the CXL driver
  cxl/mem: Add payload dumping for debug

Dan Williams (2):
  cxl/mem: Introduce a driver for CXL-2.0-Type-3 endpoints
  cxl/mem: Register CXL memX devices

 .clang-format                                 |    1 +
 Documentation/ABI/testing/sysfs-bus-cxl       |   26 +
 Documentation/driver-api/cxl/index.rst        |   12 +
 .../driver-api/cxl/memory-devices.rst         |   46 +
 Documentation/driver-api/index.rst            |    1 +
 .../userspace-api/ioctl/ioctl-number.rst      |    1 +
 MAINTAINERS                                   |   11 +
 drivers/Kconfig                               |    1 +
 drivers/Makefile                              |    1 +
 drivers/cxl/Kconfig                           |   66 +
 drivers/cxl/Makefile                          |    7 +
 drivers/cxl/bus.c                             |   29 +
 drivers/cxl/cxl.h                             |   93 +
 drivers/cxl/mem.c                             | 1531 +++++++++++++++++
 drivers/cxl/pci.h                             |   31 +
 include/linux/pci_ids.h                       |    1 +
 include/uapi/linux/cxl_mem.h                  |  170 ++
 17 files changed, 2028 insertions(+)
 create mode 100644 Documentation/ABI/testing/sysfs-bus-cxl
 create mode 100644 Documentation/driver-api/cxl/index.rst
 create mode 100644 Documentation/driver-api/cxl/memory-devices.rst
 create mode 100644 drivers/cxl/Kconfig
 create mode 100644 drivers/cxl/Makefile
 create mode 100644 drivers/cxl/bus.c
 create mode 100644 drivers/cxl/cxl.h
 create mode 100644 drivers/cxl/mem.c
 create mode 100644 drivers/cxl/pci.h
 create mode 100644 include/uapi/linux/cxl_mem.h

---

Cc: linux-acpi@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-nvdimm@lists.01.org
Cc: linux-pci@vger.kernel.org
Cc: Bjorn Helgaas <helgaas@kernel.org>
Cc: Chris Browy <cbrowy@avery-design.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jon Masters <jcm@jonmasters.org>
Cc: Jonathan Cameron <Jonathan.Cameron@Huawei.com>
Cc: Rafael Wysocki <rafael.j.wysocki@intel.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: "John Groves (jgroves)" <jgroves@micron.com>
Cc: "Kelley, Sean V" <sean.v.kelley@intel.com>

-- 
2.30.0


^ permalink raw reply	[flat|nested] 13+ messages in thread

* [PATCH v3 1/9] cxl/mem: Introduce a driver for CXL-2.0-Type-3 endpoints
  2021-02-12 22:25 [PATCH v3 0/9] CXL 2.0 Support Ben Widawsky
@ 2021-02-12 22:25 ` Ben Widawsky
  2021-02-12 22:25 ` [PATCH v3 2/9] cxl/mem: Find device capabilities Ben Widawsky
                   ` (7 subsequent siblings)
  8 siblings, 0 replies; 13+ messages in thread
From: Ben Widawsky @ 2021-02-12 22:25 UTC (permalink / raw)
  To: linux-cxl
  Cc: Ben Widawsky, linux-acpi, linux-kernel, linux-nvdimm, linux-pci,
	Bjorn Helgaas, Chris Browy, Christoph Hellwig, Dan Williams,
	David Hildenbrand, David Rientjes, Ira Weiny, Jon Masters,
	Jonathan Cameron, Rafael Wysocki, Randy Dunlap, Vishal Verma,
	John Groves (jgroves),
	Kelley, Sean V, Jonathan Corbet, Jonathan Cameron

From: Dan Williams <dan.j.williams@intel.com>

The CXL.mem protocol allows a device to act as a provider of "System
RAM" and/or "Persistent Memory" that is fully coherent as if the memory
was attached to the typical CPU memory controller.

With the CXL-2.0 specification a PCI endpoint can implement a "Type-3"
device interface and give the operating system control over "Host
Managed Device Memory". See section 2.3 Type 3 CXL Device.

The memory range exported by the device may optionally be described by
the platform firmware memory map, or by infrastructure like LIBNVDIMM to
provision persistent memory capacity from one, or more, CXL.mem devices.

A pre-requisite for Linux-managed memory-capacity provisioning is this
cxl_mem driver that can speak the mailbox protocol defined in section
8.2.8.4 Mailbox Registers.

For now just land the initial driver boiler-plate and Documentation/
infrastructure.

Link: https://www.computeexpresslink.org/download-the-specification
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Acked-by: David Rientjes <rientjes@google.com> (v1)
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---
 Documentation/driver-api/cxl/index.rst        | 12 ++++
 .../driver-api/cxl/memory-devices.rst         | 29 +++++++++
 Documentation/driver-api/index.rst            |  1 +
 drivers/Kconfig                               |  1 +
 drivers/Makefile                              |  1 +
 drivers/cxl/Kconfig                           | 35 +++++++++++
 drivers/cxl/Makefile                          |  4 ++
 drivers/cxl/mem.c                             | 62 +++++++++++++++++++
 drivers/cxl/pci.h                             | 17 +++++
 include/linux/pci_ids.h                       |  1 +
 10 files changed, 163 insertions(+)
 create mode 100644 Documentation/driver-api/cxl/index.rst
 create mode 100644 Documentation/driver-api/cxl/memory-devices.rst
 create mode 100644 drivers/cxl/Kconfig
 create mode 100644 drivers/cxl/Makefile
 create mode 100644 drivers/cxl/mem.c
 create mode 100644 drivers/cxl/pci.h

diff --git a/Documentation/driver-api/cxl/index.rst b/Documentation/driver-api/cxl/index.rst
new file mode 100644
index 000000000000..036e49553542
--- /dev/null
+++ b/Documentation/driver-api/cxl/index.rst
@@ -0,0 +1,12 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+====================
+Compute Express Link
+====================
+
+.. toctree::
+   :maxdepth: 1
+
+   memory-devices
+
+.. only::  subproject and html
diff --git a/Documentation/driver-api/cxl/memory-devices.rst b/Documentation/driver-api/cxl/memory-devices.rst
new file mode 100644
index 000000000000..43177e700d62
--- /dev/null
+++ b/Documentation/driver-api/cxl/memory-devices.rst
@@ -0,0 +1,29 @@
+.. SPDX-License-Identifier: GPL-2.0
+.. include:: <isonum.txt>
+
+===================================
+Compute Express Link Memory Devices
+===================================
+
+A Compute Express Link Memory Device is a CXL component that implements the
+CXL.mem protocol. It contains some amount of volatile memory, persistent memory,
+or both. It is enumerated as a PCI device for configuration and passing
+messages over an MMIO mailbox. Its contribution to the System Physical
+Address space is handled via HDM (Host Managed Device Memory) decoders
+that optionally define a device's contribution to an interleaved address
+range across multiple devices underneath a host-bridge or interleaved
+across host-bridges.
+
+Driver Infrastructure
+=====================
+
+This section covers the driver infrastructure for a CXL memory device.
+
+CXL Memory Device
+-----------------
+
+.. kernel-doc:: drivers/cxl/mem.c
+   :doc: cxl mem
+
+.. kernel-doc:: drivers/cxl/mem.c
+   :internal:
diff --git a/Documentation/driver-api/index.rst b/Documentation/driver-api/index.rst
index 2456d0a97ed8..d246a18fd78f 100644
--- a/Documentation/driver-api/index.rst
+++ b/Documentation/driver-api/index.rst
@@ -35,6 +35,7 @@ available subsections can be seen below.
    usb/index
    firewire
    pci/index
+   cxl/index
    spi
    i2c
    ipmb
diff --git a/drivers/Kconfig b/drivers/Kconfig
index dcecc9f6e33f..62c753a73651 100644
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -6,6 +6,7 @@ menu "Device Drivers"
 source "drivers/amba/Kconfig"
 source "drivers/eisa/Kconfig"
 source "drivers/pci/Kconfig"
+source "drivers/cxl/Kconfig"
 source "drivers/pcmcia/Kconfig"
 source "drivers/rapidio/Kconfig"
 
diff --git a/drivers/Makefile b/drivers/Makefile
index fd11b9ac4cc3..678ea810410f 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -73,6 +73,7 @@ obj-$(CONFIG_NVM)		+= lightnvm/
 obj-y				+= base/ block/ misc/ mfd/ nfc/
 obj-$(CONFIG_LIBNVDIMM)		+= nvdimm/
 obj-$(CONFIG_DAX)		+= dax/
+obj-$(CONFIG_CXL_BUS)		+= cxl/
 obj-$(CONFIG_DMA_SHARED_BUFFER) += dma-buf/
 obj-$(CONFIG_NUBUS)		+= nubus/
 obj-y				+= macintosh/
diff --git a/drivers/cxl/Kconfig b/drivers/cxl/Kconfig
new file mode 100644
index 000000000000..9e80b311e928
--- /dev/null
+++ b/drivers/cxl/Kconfig
@@ -0,0 +1,35 @@
+# SPDX-License-Identifier: GPL-2.0-only
+menuconfig CXL_BUS
+	tristate "CXL (Compute Express Link) Devices Support"
+	depends on PCI
+	help
+	  CXL is a bus that is electrically compatible with PCI Express, but
+	  layers three protocols on that signalling (CXL.io, CXL.cache, and
+	  CXL.mem). The CXL.cache protocol allows devices to hold cachelines
+	  locally, the CXL.mem protocol allows devices to be fully coherent
+	  memory targets, the CXL.io protocol is equivalent to PCI Express.
+	  Say 'y' to enable support for the configuration and management of
+	  devices supporting these protocols.
+
+if CXL_BUS
+
+config CXL_MEM
+	tristate "CXL.mem: Memory Devices"
+	help
+	  The CXL.mem protocol allows a device to act as a provider of
+	  "System RAM" and/or "Persistent Memory" that is fully coherent
+	  as if the memory was attached to the typical CPU memory
+	  controller.
+
+	  Say 'y/m' to enable a driver (named "cxl_mem.ko" when built as
+	  a module) that will attach to CXL.mem devices for
+	  configuration, provisioning, and health monitoring. This
+	  driver is required for dynamic provisioning of CXL.mem
+	  attached memory which is a prerequisite for persistent memory
+	  support. Typically volatile memory is mapped by platform
+	  firmware and included in the platform memory map, but in some
+	  cases the OS is responsible for mapping that memory. See
+	  Chapter 2.3 Type 3 CXL Device in the CXL 2.0 specification.
+
+	  If unsure say 'm'.
+endif
diff --git a/drivers/cxl/Makefile b/drivers/cxl/Makefile
new file mode 100644
index 000000000000..4a30f7c3fc4a
--- /dev/null
+++ b/drivers/cxl/Makefile
@@ -0,0 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_CXL_MEM) += cxl_mem.o
+
+cxl_mem-y := mem.o
diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c
new file mode 100644
index 000000000000..ce33c5ee77c9
--- /dev/null
+++ b/drivers/cxl/mem.c
@@ -0,0 +1,62 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright(c) 2020 Intel Corporation. All rights reserved. */
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/io.h>
+#include "pci.h"
+
+static int cxl_mem_dvsec(struct pci_dev *pdev, int dvsec)
+{
+	int pos;
+
+	pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_DVSEC);
+	if (!pos)
+		return 0;
+
+	while (pos) {
+		u16 vendor, id;
+
+		pci_read_config_word(pdev, pos + PCI_DVSEC_HEADER1, &vendor);
+		pci_read_config_word(pdev, pos + PCI_DVSEC_HEADER2, &id);
+		if (vendor == PCI_DVSEC_VENDOR_ID_CXL && dvsec == id)
+			return pos;
+
+		pos = pci_find_next_ext_capability(pdev, pos,
+						   PCI_EXT_CAP_ID_DVSEC);
+	}
+
+	return 0;
+}
+
+static int cxl_mem_probe(struct pci_dev *pdev, const struct pci_device_id *id)
+{
+	struct device *dev = &pdev->dev;
+	int regloc;
+
+	regloc = cxl_mem_dvsec(pdev, PCI_DVSEC_ID_CXL_REGLOC_OFFSET);
+	if (!regloc) {
+		dev_err(dev, "register location dvsec not found\n");
+		return -ENXIO;
+	}
+
+	return 0;
+}
+
+static const struct pci_device_id cxl_mem_pci_tbl[] = {
+	/* PCI class code for CXL.mem Type-3 Devices */
+	{ PCI_DEVICE_CLASS((PCI_CLASS_MEMORY_CXL << 8 | CXL_MEMORY_PROGIF), ~0)},
+	{ /* terminate list */ },
+};
+MODULE_DEVICE_TABLE(pci, cxl_mem_pci_tbl);
+
+static struct pci_driver cxl_mem_driver = {
+	.name			= KBUILD_MODNAME,
+	.id_table		= cxl_mem_pci_tbl,
+	.probe			= cxl_mem_probe,
+	.driver	= {
+		.probe_type	= PROBE_PREFER_ASYNCHRONOUS,
+	},
+};
+
+MODULE_LICENSE("GPL v2");
+module_pci_driver(cxl_mem_driver);
diff --git a/drivers/cxl/pci.h b/drivers/cxl/pci.h
new file mode 100644
index 000000000000..e464bea3f4d3
--- /dev/null
+++ b/drivers/cxl/pci.h
@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/* Copyright(c) 2020 Intel Corporation. All rights reserved. */
+#ifndef __CXL_PCI_H__
+#define __CXL_PCI_H__
+
+#define CXL_MEMORY_PROGIF	0x10
+
+/*
+ * See section 8.1 Configuration Space Registers in the CXL 2.0
+ * Specification
+ */
+#define PCI_DVSEC_VENDOR_ID_CXL		0x1E98
+#define PCI_DVSEC_ID_CXL		0x0
+
+#define PCI_DVSEC_ID_CXL_REGLOC_OFFSET		0x8
+
+#endif /* __CXL_PCI_H__ */
diff --git a/include/linux/pci_ids.h b/include/linux/pci_ids.h
index d8156a5dbee8..766260a9b247 100644
--- a/include/linux/pci_ids.h
+++ b/include/linux/pci_ids.h
@@ -51,6 +51,7 @@
 #define PCI_BASE_CLASS_MEMORY		0x05
 #define PCI_CLASS_MEMORY_RAM		0x0500
 #define PCI_CLASS_MEMORY_FLASH		0x0501
+#define PCI_CLASS_MEMORY_CXL		0x0502
 #define PCI_CLASS_MEMORY_OTHER		0x0580
 
 #define PCI_BASE_CLASS_BRIDGE		0x06
-- 
2.30.0


^ permalink raw reply related	[flat|nested] 13+ messages in thread

* [PATCH v3 2/9] cxl/mem: Find device capabilities
  2021-02-12 22:25 [PATCH v3 0/9] CXL 2.0 Support Ben Widawsky
  2021-02-12 22:25 ` [PATCH v3 1/9] cxl/mem: Introduce a driver for CXL-2.0-Type-3 endpoints Ben Widawsky
@ 2021-02-12 22:25 ` Ben Widawsky
  2021-02-12 22:25 ` [PATCH v3 3/9] cxl/mem: Register CXL memX devices Ben Widawsky
                   ` (6 subsequent siblings)
  8 siblings, 0 replies; 13+ messages in thread
From: Ben Widawsky @ 2021-02-12 22:25 UTC (permalink / raw)
  To: linux-cxl
  Cc: Ben Widawsky, linux-acpi, linux-kernel, linux-nvdimm, linux-pci,
	Bjorn Helgaas, Chris Browy, Christoph Hellwig, Dan Williams,
	David Hildenbrand, David Rientjes, Ira Weiny, Jon Masters,
	Jonathan Cameron, Rafael Wysocki, Randy Dunlap, Vishal Verma,
	John Groves (jgroves),
	Kelley, Sean V

Provide enough functionality to utilize the mailbox of a memory device.
The mailbox is used to interact with the firmware running on the memory
device. The flow is proven with one implemented command, "identify".
Because the class code has already told the driver this is a memory
device and the identify command is mandatory.

CXL devices contain an array of capabilities that describe the
interactions software can have with the device or firmware running on
the device. A CXL compliant device must implement the device status and
the mailbox capability. Additionally, a CXL compliant memory device must
implement the memory device capability. Each of the capabilities can
[will] provide an offset within the MMIO region for interacting with the
CXL device.

The capabilities tell the driver how to find and map the register space
for CXL Memory Devices. The registers are required to utilize the CXL
spec defined mailbox interface. The spec outlines two mailboxes, primary
and secondary. The secondary mailbox is earmarked for system firmware,
and not handled in this driver.

Primary mailboxes are capable of generating an interrupt when submitting
a background command. That implementation is saved for a later time.

Link: https://www.computeexpresslink.org/download-the-specification
Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com> (v2)
---
 drivers/cxl/cxl.h |  88 ++++++++
 drivers/cxl/mem.c | 542 +++++++++++++++++++++++++++++++++++++++++++++-
 drivers/cxl/pci.h |  14 ++
 3 files changed, 642 insertions(+), 2 deletions(-)
 create mode 100644 drivers/cxl/cxl.h

diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
new file mode 100644
index 000000000000..9cd9bc79fc48
--- /dev/null
+++ b/drivers/cxl/cxl.h
@@ -0,0 +1,88 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/* Copyright(c) 2020 Intel Corporation. */
+
+#ifndef __CXL_H__
+#define __CXL_H__
+
+#include <linux/bitfield.h>
+#include <linux/bitops.h>
+#include <linux/io.h>
+
+/* CXL 2.0 8.2.8.1 Device Capabilities Array Register */
+#define CXLDEV_CAP_ARRAY_OFFSET 0x0
+#define   CXLDEV_CAP_ARRAY_CAP_ID 0
+#define   CXLDEV_CAP_ARRAY_ID_MASK GENMASK(15, 0)
+#define   CXLDEV_CAP_ARRAY_COUNT_MASK GENMASK(47, 32)
+/* CXL 2.0 8.2.8.2.1 CXL Device Capabilities */
+#define CXLDEV_CAP_CAP_ID_DEVICE_STATUS 0x1
+#define CXLDEV_CAP_CAP_ID_PRIMARY_MAILBOX 0x2
+#define CXLDEV_CAP_CAP_ID_SECONDARY_MAILBOX 0x3
+#define CXLDEV_CAP_CAP_ID_MEMDEV 0x4000
+
+/* CXL 2.0 8.2.8.4 Mailbox Registers */
+#define CXLDEV_MBOX_CAPS_OFFSET 0x00
+#define   CXLDEV_MBOX_CAP_PAYLOAD_SIZE_MASK GENMASK(4, 0)
+#define CXLDEV_MBOX_CTRL_OFFSET 0x04
+#define   CXLDEV_MBOX_CTRL_DOORBELL BIT(0)
+#define CXLDEV_MBOX_CMD_OFFSET 0x08
+#define   CXLDEV_MBOX_CMD_COMMAND_OPCODE_MASK GENMASK(15, 0)
+#define   CXLDEV_MBOX_CMD_PAYLOAD_LENGTH_MASK GENMASK(36, 16)
+#define CXLDEV_MBOX_STATUS_OFFSET 0x10
+#define   CXLDEV_MBOX_STATUS_RET_CODE_MASK GENMASK(47, 32)
+#define CXLDEV_MBOX_BG_CMD_STATUS_OFFSET 0x18
+#define CXLDEV_MBOX_PAYLOAD_OFFSET 0x20
+
+/* CXL 2.0 8.2.8.5.1.1 Memory Device Status Register */
+#define CXLMDEV_STATUS_OFFSET 0x0
+#define   CXLMDEV_DEV_FATAL BIT(0)
+#define   CXLMDEV_FW_HALT BIT(1)
+#define   CXLMDEV_STATUS_MEDIA_STATUS_MASK GENMASK(3, 2)
+#define     CXLMDEV_MS_NOT_READY 0
+#define     CXLMDEV_MS_READY 1
+#define     CXLMDEV_MS_ERROR 2
+#define     CXLMDEV_MS_DISABLED 3
+#define CXLMDEV_READY(status)                                                  \
+	(FIELD_GET(CXLMDEV_STATUS_MEDIA_STATUS_MASK, status) ==                \
+	 CXLMDEV_MS_READY)
+#define   CXLMDEV_MBOX_IF_READY BIT(4)
+#define   CXLMDEV_RESET_NEEDED_MASK GENMASK(7, 5)
+#define     CXLMDEV_RESET_NEEDED_NOT 0
+#define     CXLMDEV_RESET_NEEDED_COLD 1
+#define     CXLMDEV_RESET_NEEDED_WARM 2
+#define     CXLMDEV_RESET_NEEDED_HOT 3
+#define     CXLMDEV_RESET_NEEDED_CXL 4
+#define CXLMDEV_RESET_NEEDED(status)                                           \
+	(FIELD_GET(CXLMDEV_RESET_NEEDED_MASK, status) !=                       \
+	 CXLMDEV_RESET_NEEDED_NOT)
+
+/**
+ * struct cxl_mem - A CXL memory device
+ * @pdev: The PCI device associated with this CXL device.
+ * @regs: IO mappings to the device's MMIO
+ * @status_regs: CXL 2.0 8.2.8.3 Device Status Registers
+ * @mbox_regs: CXL 2.0 8.2.8.4 Mailbox Registers
+ * @memdev_regs: CXL 2.0 8.2.8.5 Memory Device Registers
+ * @payload_size: Size of space for payload
+ *                (CXL 2.0 8.2.8.4.3 Mailbox Capabilities Register)
+ * @mbox_mutex: Mutex to synchronize mailbox access.
+ * @firmware_version: Firmware version for the memory device.
+ * @pmem: Persistent memory capacity information.
+ * @ram: Volatile memory capacity information.
+ */
+struct cxl_mem {
+	struct pci_dev *pdev;
+	void __iomem *regs;
+
+	void __iomem *status_regs;
+	void __iomem *mbox_regs;
+	void __iomem *memdev_regs;
+
+	size_t payload_size;
+	struct mutex mbox_mutex; /* Protects device mailbox and firmware */
+	char firmware_version[0x10];
+
+	struct range pmem_range;
+	struct range ram_range;
+};
+
+#endif /* __CXL_H__ */
diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c
index ce33c5ee77c9..2b289a311f27 100644
--- a/drivers/cxl/mem.c
+++ b/drivers/cxl/mem.c
@@ -4,6 +4,456 @@
 #include <linux/pci.h>
 #include <linux/io.h>
 #include "pci.h"
+#include "cxl.h"
+
+#define cxl_doorbell_busy(cxlm)                                                \
+	(readl((cxlm)->mbox_regs + CXLDEV_MBOX_CTRL_OFFSET) &                  \
+	 CXLDEV_MBOX_CTRL_DOORBELL)
+
+/* CXL 2.0 - 8.2.8.4 */
+#define CXL_MAILBOX_TIMEOUT_MS (2 * HZ)
+
+enum opcode {
+	CXL_MBOX_OP_IDENTIFY		= 0x4000,
+	CXL_MBOX_OP_MAX			= 0x10000
+};
+
+/**
+ * struct mbox_cmd - A command to be submitted to hardware.
+ * @opcode: (input) The command set and command submitted to hardware.
+ * @payload_in: (input) Pointer to the input payload.
+ * @payload_out: (output) Pointer to the output payload. Must be allocated by
+ *		 the caller.
+ * @size_in: (input) Number of bytes to load from @payload.
+ * @size_out: (output) Number of bytes loaded into @payload.
+ * @return_code: (output) Error code returned from hardware.
+ *
+ * This is the primary mechanism used to send commands to the hardware.
+ * All the fields except @payload_* correspond exactly to the fields described in
+ * Command Register section of the CXL 2.0 8.2.8.4.5. @payload_in and
+ * @payload_out are written to, and read from the Command Payload Registers
+ * defined in CXL 2.0 8.2.8.4.8.
+ */
+struct mbox_cmd {
+	u16 opcode;
+	void *payload_in;
+	void *payload_out;
+	size_t size_in;
+	size_t size_out;
+	u16 return_code;
+#define CXL_MBOX_SUCCESS 0
+};
+
+static int cxl_mem_wait_for_doorbell(struct cxl_mem *cxlm)
+{
+	const unsigned long start = jiffies;
+	unsigned long end = start;
+
+	while (cxl_doorbell_busy(cxlm)) {
+		end = jiffies;
+
+		if (time_after(end, start + CXL_MAILBOX_TIMEOUT_MS)) {
+			/* Check again in case preempted before timeout test */
+			if (!cxl_doorbell_busy(cxlm))
+				break;
+			return -ETIMEDOUT;
+		}
+		cpu_relax();
+	}
+
+	dev_dbg(&cxlm->pdev->dev, "Doorbell wait took %dms",
+		jiffies_to_msecs(end) - jiffies_to_msecs(start));
+	return 0;
+}
+
+static void cxl_mem_mbox_timeout(struct cxl_mem *cxlm,
+				 struct mbox_cmd *mbox_cmd)
+{
+	struct device *dev = &cxlm->pdev->dev;
+
+	dev_dbg(dev, "Mailbox command (opcode: %#x size: %zub) timed out\n",
+		mbox_cmd->opcode, mbox_cmd->size_in);
+}
+
+/**
+ * __cxl_mem_mbox_send_cmd() - Execute a mailbox command
+ * @cxlm: The CXL memory device to communicate with.
+ * @mbox_cmd: Command to send to the memory device.
+ *
+ * Context: Any context. Expects mbox_mutex to be held.
+ * Return: -ETIMEDOUT if timeout occurred waiting for completion. 0 on success.
+ *         Caller should check the return code in @mbox_cmd to make sure it
+ *         succeeded.
+ *
+ * This is a generic form of the CXL mailbox send command thus only using the
+ * registers defined by the mailbox capability ID - CXL 2.0 8.2.8.4. Memory
+ * devices, and perhaps other types of CXL devices may have further information
+ * available upon error conditions. Driver facilities wishing to send mailbox
+ * commands should use the wrapper command.
+ *
+ * The CXL spec allows for up to two mailboxes. The intention is for the primary
+ * mailbox to be OS controlled and the secondary mailbox to be used by system
+ * firmware. This allows the OS and firmware to communicate with the device and
+ * not need to coordinate with each other. The driver only uses the primary
+ * mailbox.
+ */
+static int __cxl_mem_mbox_send_cmd(struct cxl_mem *cxlm,
+				   struct mbox_cmd *mbox_cmd)
+{
+	void __iomem *payload = cxlm->mbox_regs + CXLDEV_MBOX_PAYLOAD_OFFSET;
+	u64 cmd_reg, status_reg;
+	size_t out_len;
+	int rc;
+
+	lockdep_assert_held(&cxlm->mbox_mutex);
+
+	/*
+	 * Here are the steps from 8.2.8.4 of the CXL 2.0 spec.
+	 *   1. Caller reads MB Control Register to verify doorbell is clear
+	 *   2. Caller writes Command Register
+	 *   3. Caller writes Command Payload Registers if input payload is non-empty
+	 *   4. Caller writes MB Control Register to set doorbell
+	 *   5. Caller either polls for doorbell to be clear or waits for interrupt if configured
+	 *   6. Caller reads MB Status Register to fetch Return code
+	 *   7. If command successful, Caller reads Command Register to get Payload Length
+	 *   8. If output payload is non-empty, host reads Command Payload Registers
+	 *
+	 * Hardware is free to do whatever it wants before the doorbell is rung,
+	 * and isn't allowed to change anything after it clears the doorbell. As
+	 * such, steps 2 and 3 can happen in any order, and steps 6, 7, 8 can
+	 * also happen in any order (though some orders might not make sense).
+	 */
+
+	/* #1 */
+	if (cxl_doorbell_busy(cxlm)) {
+		dev_err_ratelimited(&cxlm->pdev->dev,
+				    "Mailbox re-busy after acquiring\n");
+		return -EBUSY;
+	}
+
+	cmd_reg = FIELD_PREP(CXLDEV_MBOX_CMD_COMMAND_OPCODE_MASK,
+			     mbox_cmd->opcode);
+	if (mbox_cmd->size_in) {
+		if (WARN_ON(!mbox_cmd->payload_in))
+			return -EINVAL;
+
+		cmd_reg |= FIELD_PREP(CXLDEV_MBOX_CMD_PAYLOAD_LENGTH_MASK,
+				      mbox_cmd->size_in);
+		memcpy_toio(payload, mbox_cmd->payload_in, mbox_cmd->size_in);
+	}
+
+	/* #2, #3 */
+	writeq(cmd_reg, cxlm->mbox_regs + CXLDEV_MBOX_CMD_OFFSET);
+
+	/* #4 */
+	dev_dbg(&cxlm->pdev->dev, "Sending command\n");
+	writel(CXLDEV_MBOX_CTRL_DOORBELL,
+	       cxlm->mbox_regs + CXLDEV_MBOX_CTRL_OFFSET);
+
+	/* #5 */
+	rc = cxl_mem_wait_for_doorbell(cxlm);
+	if (rc == -ETIMEDOUT) {
+		cxl_mem_mbox_timeout(cxlm, mbox_cmd);
+		return rc;
+	}
+
+	/* #6 */
+	status_reg = readq(cxlm->mbox_regs + CXLDEV_MBOX_STATUS_OFFSET);
+	mbox_cmd->return_code =
+		FIELD_GET(CXLDEV_MBOX_STATUS_RET_CODE_MASK, status_reg);
+
+	if (mbox_cmd->return_code != 0) {
+		dev_dbg(&cxlm->pdev->dev, "Mailbox operation had an error\n");
+		return 0;
+	}
+
+	/* #7 */
+	cmd_reg = readq(cxlm->mbox_regs + CXLDEV_MBOX_CMD_OFFSET);
+	out_len = FIELD_GET(CXLDEV_MBOX_CMD_PAYLOAD_LENGTH_MASK, cmd_reg);
+
+	/* #8 */
+	if (out_len && mbox_cmd->payload_out) {
+		size_t n = min_t(size_t, cxlm->payload_size, out_len);
+
+		memcpy_fromio(mbox_cmd->payload_out, payload, n);
+		mbox_cmd->size_out = n;
+	} else {
+		mbox_cmd->size_out = 0;
+	}
+
+	return 0;
+}
+
+/**
+ * cxl_mem_mbox_get() - Acquire exclusive access to the mailbox.
+ * @cxlm: The memory device to gain access to.
+ *
+ * Context: Any context. Takes the mbox_mutex.
+ * Return: 0 if exclusive access was acquired.
+ */
+static int cxl_mem_mbox_get(struct cxl_mem *cxlm)
+{
+	struct device *dev = &cxlm->pdev->dev;
+	int rc = -EBUSY;
+	u64 md_status;
+
+	mutex_lock_io(&cxlm->mbox_mutex);
+
+	/*
+	 * XXX: There is some amount of ambiguity in the 2.0 version of the spec
+	 * around the mailbox interface ready (8.2.8.5.1.1).  The purpose of the
+	 * bit is to allow firmware running on the device to notify the driver
+	 * that it's ready to receive commands. It is unclear if the bit needs
+	 * to be read for each transaction mailbox, ie. the firmware can switch
+	 * it on and off as needed. Second, there is no defined timeout for
+	 * mailbox ready, like there is for the doorbell interface.
+	 *
+	 * Assumptions:
+	 * 1. The firmware might toggle the Mailbox Interface Ready bit, check
+	 *    it for every command.
+	 *
+	 * 2. If the doorbell is clear, the firmware should have first set the
+	 *    Mailbox Interface Ready bit. Therefore, waiting for the doorbell
+	 *    to be ready is sufficient.
+	 */
+	rc = cxl_mem_wait_for_doorbell(cxlm);
+	if (rc) {
+		dev_warn(dev, "Mailbox interface not ready\n");
+		goto out;
+	}
+
+	md_status = readq(cxlm->memdev_regs + CXLMDEV_STATUS_OFFSET);
+	if (!(md_status & CXLMDEV_MBOX_IF_READY && CXLMDEV_READY(md_status))) {
+		dev_err(dev, "mbox: reported doorbell ready, but not mbox ready\n");
+		goto out;
+	}
+
+	/*
+	 * Hardware shouldn't allow a ready status but also have failure bits
+	 * set. Spit out an error, this should be a bug report
+	 */
+	rc = -EFAULT;
+	if (md_status & CXLMDEV_DEV_FATAL) {
+		dev_err(dev, "mbox: reported ready, but fatal\n");
+		goto out;
+	}
+	if (md_status & CXLMDEV_FW_HALT) {
+		dev_err(dev, "mbox: reported ready, but halted\n");
+		goto out;
+	}
+	if (CXLMDEV_RESET_NEEDED(md_status)) {
+		dev_err(dev, "mbox: reported ready, but reset needed\n");
+		goto out;
+	}
+
+	/* with lock held */
+	return 0;
+
+out:
+	mutex_unlock(&cxlm->mbox_mutex);
+	return rc;
+}
+
+/**
+ * cxl_mem_mbox_put() - Release exclusive access to the mailbox.
+ * @cxlm: The CXL memory device to communicate with.
+ *
+ * Context: Any context. Expects mbox_mutex to be held.
+ */
+static void cxl_mem_mbox_put(struct cxl_mem *cxlm)
+{
+	mutex_unlock(&cxlm->mbox_mutex);
+}
+
+/**
+ * cxl_mem_mbox_send_cmd() - Send a mailbox command to a memory device.
+ * @cxlm: The CXL memory device to communicate with.
+ * @opcode: Opcode for the mailbox command.
+ * @in: The input payload for the mailbox command.
+ * @in_size: The length of the input payload
+ * @out: Caller allocated buffer for the output.
+ * @out_min_size: Minimum expected size of output.
+ *
+ * Context: Any context. Will acquire and release mbox_mutex.
+ * Return:
+ *  * %>=0	- Number of bytes returned in @out.
+ *  * %-E2BIG	- Payload is too large for hardware.
+ *  * %-EBUSY	- Couldn't acquire exclusive mailbox access.
+ *  * %-EFAULT	- Hardware error occurred.
+ *  * %-ENXIO	- Command completed, but device reported an error.
+ *  * %-ENODATA	- Not enough payload data returned by hardware.
+ *
+ * Mailbox commands may execute successfully yet the device itself reported an
+ * error. While this distinction can be useful for commands from userspace, the
+ * kernel will only be able to use results when both are successful.
+ *
+ * See __cxl_mem_mbox_send_cmd()
+ */
+static int cxl_mem_mbox_send_cmd(struct cxl_mem *cxlm, u16 opcode, u8 *in,
+				 size_t in_size, u8 *out, size_t out_min_size)
+{
+	struct mbox_cmd mbox_cmd = {
+		.opcode = opcode,
+		.payload_in = in,
+		.size_in = in_size,
+		.payload_out = out,
+	};
+	int rc;
+
+	if (out_min_size > cxlm->payload_size)
+		return -E2BIG;
+
+	rc = cxl_mem_mbox_get(cxlm);
+	if (rc)
+		return rc;
+
+	rc = __cxl_mem_mbox_send_cmd(cxlm, &mbox_cmd);
+	cxl_mem_mbox_put(cxlm);
+	if (rc)
+		return rc;
+
+	/* TODO: Map return code to proper kernel style errno */
+	if (mbox_cmd.return_code != CXL_MBOX_SUCCESS)
+		return -ENXIO;
+
+	if (mbox_cmd.size_out < out_min_size)
+		return -ENODATA;
+
+	return mbox_cmd.size_out;
+}
+
+/**
+ * cxl_mem_setup_regs() - Setup necessary MMIO.
+ * @cxlm: The CXL memory device to communicate with.
+ *
+ * Return: 0 if all necessary registers mapped.
+ *
+ * A memory device is required by spec to implement a certain set of MMIO
+ * regions. The purpose of this function is to enumerate and map those
+ * registers.
+ */
+static int cxl_mem_setup_regs(struct cxl_mem *cxlm)
+{
+	struct device *dev = &cxlm->pdev->dev;
+	int cap, cap_count;
+	u64 cap_array;
+
+	cap_array = readq(cxlm->regs + CXLDEV_CAP_ARRAY_OFFSET);
+	if (FIELD_GET(CXLDEV_CAP_ARRAY_ID_MASK, cap_array) !=
+	    CXLDEV_CAP_ARRAY_CAP_ID)
+		return -ENODEV;
+
+	cap_count = FIELD_GET(CXLDEV_CAP_ARRAY_COUNT_MASK, cap_array);
+
+	for (cap = 1; cap <= cap_count; cap++) {
+		void __iomem *register_block;
+		u32 offset;
+		u16 cap_id;
+
+		cap_id = readl(cxlm->regs + cap * 0x10) & 0xffff;
+		offset = readl(cxlm->regs + cap * 0x10 + 0x4);
+		register_block = cxlm->regs + offset;
+
+		switch (cap_id) {
+		case CXLDEV_CAP_CAP_ID_DEVICE_STATUS:
+			dev_dbg(dev, "found Status capability (0x%x)\n", offset);
+			cxlm->status_regs = register_block;
+			break;
+		case CXLDEV_CAP_CAP_ID_PRIMARY_MAILBOX:
+			dev_dbg(dev, "found Mailbox capability (0x%x)\n", offset);
+			cxlm->mbox_regs = register_block;
+			break;
+		case CXLDEV_CAP_CAP_ID_SECONDARY_MAILBOX:
+			dev_dbg(dev, "found Secondary Mailbox capability (0x%x)\n", offset);
+			break;
+		case CXLDEV_CAP_CAP_ID_MEMDEV:
+			dev_dbg(dev, "found Memory Device capability (0x%x)\n", offset);
+			cxlm->memdev_regs = register_block;
+			break;
+		default:
+			dev_dbg(dev, "Unknown cap ID: %d (0x%x)\n", cap_id, offset);
+			break;
+		}
+	}
+
+	if (!cxlm->status_regs || !cxlm->mbox_regs || !cxlm->memdev_regs) {
+		dev_err(dev, "registers not found: %s%s%s\n",
+			!cxlm->status_regs ? "status " : "",
+			!cxlm->mbox_regs ? "mbox " : "",
+			!cxlm->memdev_regs ? "memdev" : "");
+		return -ENXIO;
+	}
+
+	return 0;
+}
+
+static int cxl_mem_setup_mailbox(struct cxl_mem *cxlm)
+{
+	const int cap = readl(cxlm->mbox_regs + CXLDEV_MBOX_CAPS_OFFSET);
+
+	cxlm->payload_size =
+		1 << FIELD_GET(CXLDEV_MBOX_CAP_PAYLOAD_SIZE_MASK, cap);
+
+	/*
+	 * CXL 2.0 8.2.8.4.3 Mailbox Capabilities Register
+	 *
+	 * If the size is too small, mandatory commands will not work and so
+	 * there's no point in going forward. If the size is too large, there's
+	 * no harm is soft limiting it.
+	 */
+	cxlm->payload_size = min_t(size_t, cxlm->payload_size, SZ_1M);
+	if (cxlm->payload_size < 256) {
+		dev_err(&cxlm->pdev->dev, "Mailbox is too small (%zub)",
+			cxlm->payload_size);
+		return -ENXIO;
+	}
+
+	dev_dbg(&cxlm->pdev->dev, "Mailbox payload sized %zu",
+		cxlm->payload_size);
+
+	return 0;
+}
+
+static struct cxl_mem *cxl_mem_create(struct pci_dev *pdev, u32 reg_lo,
+				      u32 reg_hi)
+{
+	struct device *dev = &pdev->dev;
+	struct cxl_mem *cxlm;
+	void __iomem *regs;
+	u64 offset;
+	u8 bar;
+	int rc;
+
+	cxlm = devm_kzalloc(&pdev->dev, sizeof(*cxlm), GFP_KERNEL);
+	if (!cxlm) {
+		dev_err(dev, "No memory available\n");
+		return NULL;
+	}
+
+	offset = ((u64)reg_hi << 32) | FIELD_GET(CXL_REGLOC_ADDR_MASK, reg_lo);
+	bar = FIELD_GET(CXL_REGLOC_BIR_MASK, reg_lo);
+
+	/* Basic sanity check that BAR is big enough */
+	if (pci_resource_len(pdev, bar) < offset) {
+		dev_err(dev, "BAR%d: %pr: too small (offset: %#llx)\n", bar,
+			&pdev->resource[bar], (unsigned long long)offset);
+		return NULL;
+	}
+
+	rc = pcim_iomap_regions(pdev, BIT(bar), pci_name(pdev));
+	if (rc) {
+		dev_err(dev, "failed to map registers\n");
+		return NULL;
+	}
+	regs = pcim_iomap_table(pdev)[bar];
+
+	mutex_init(&cxlm->mbox_mutex);
+	cxlm->pdev = pdev;
+	cxlm->regs = regs + offset;
+
+	dev_dbg(dev, "Mapped CXL Memory Device resource\n");
+	return cxlm;
+}
 
 static int cxl_mem_dvsec(struct pci_dev *pdev, int dvsec)
 {
@@ -28,10 +478,65 @@ static int cxl_mem_dvsec(struct pci_dev *pdev, int dvsec)
 	return 0;
 }
 
+/**
+ * cxl_mem_identify() - Send the IDENTIFY command to the device.
+ * @cxlm: The device to identify.
+ *
+ * Return: 0 if identify was executed successfully.
+ *
+ * This will dispatch the identify command to the device and on success populate
+ * structures to be exported to sysfs.
+ */
+static int cxl_mem_identify(struct cxl_mem *cxlm)
+{
+	struct cxl_mbox_identify {
+		char fw_revision[0x10];
+		__le64 total_capacity;
+		__le64 volatile_capacity;
+		__le64 persistent_capacity;
+		__le64 partition_align;
+		__le16 info_event_log_size;
+		__le16 warning_event_log_size;
+		__le16 failure_event_log_size;
+		__le16 fatal_event_log_size;
+		__le32 lsa_size;
+		u8 poison_list_max_mer[3];
+		__le16 inject_poison_limit;
+		u8 poison_caps;
+		u8 qos_telemetry_caps;
+	} __packed id;
+	int rc;
+
+	rc = cxl_mem_mbox_send_cmd(cxlm, CXL_MBOX_OP_IDENTIFY, NULL, 0,
+				   (u8 *)&id, sizeof(id));
+	if (rc < 0)
+		return rc;
+
+	/*
+	 * TODO: enumerate DPA map, as 'ram' and 'pmem' do not alias.
+	 * For now, only the capacity is exported in sysfs
+	 */
+	cxlm->ram_range.start = 0;
+	cxlm->ram_range.end = le64_to_cpu(id.volatile_capacity) - 1;
+
+	cxlm->pmem_range.start = 0;
+	cxlm->pmem_range.end = le64_to_cpu(id.persistent_capacity) - 1;
+
+	memcpy(cxlm->firmware_version, id.fw_revision, sizeof(id.fw_revision));
+
+	return 0;
+}
+
 static int cxl_mem_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 {
 	struct device *dev = &pdev->dev;
-	int regloc;
+	struct cxl_mem *cxlm = NULL;
+	int rc, regloc, i;
+	u32 regloc_size;
+
+	rc = pcim_enable_device(pdev);
+	if (rc)
+		return rc;
 
 	regloc = cxl_mem_dvsec(pdev, PCI_DVSEC_ID_CXL_REGLOC_OFFSET);
 	if (!regloc) {
@@ -39,7 +544,40 @@ static int cxl_mem_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 		return -ENXIO;
 	}
 
-	return 0;
+	/* Get the size of the Register Locator DVSEC */
+	pci_read_config_dword(pdev, regloc + PCI_DVSEC_HEADER1, &regloc_size);
+	regloc_size = FIELD_GET(PCI_DVSEC_HEADER1_LENGTH_MASK, regloc_size);
+
+	regloc += PCI_DVSEC_ID_CXL_REGLOC_BLOCK1_OFFSET;
+
+	for (i = regloc; i < regloc + regloc_size; i += 8) {
+		u32 reg_lo, reg_hi;
+		u8 reg_type;
+
+		/* "register low and high" contain other bits */
+		pci_read_config_dword(pdev, i, &reg_lo);
+		pci_read_config_dword(pdev, i + 4, &reg_hi);
+
+		reg_type = FIELD_GET(CXL_REGLOC_RBI_MASK, reg_lo);
+
+		if (reg_type == CXL_REGLOC_RBI_MEMDEV) {
+			cxlm = cxl_mem_create(pdev, reg_lo, reg_hi);
+			break;
+		}
+	}
+
+	if (!cxlm)
+		return -ENODEV;
+
+	rc = cxl_mem_setup_regs(cxlm);
+	if (rc)
+		return rc;
+
+	rc = cxl_mem_setup_mailbox(cxlm);
+	if (rc)
+		return rc;
+
+	return cxl_mem_identify(cxlm);
 }
 
 static const struct pci_device_id cxl_mem_pci_tbl[] = {
diff --git a/drivers/cxl/pci.h b/drivers/cxl/pci.h
index e464bea3f4d3..af3ec078cf6c 100644
--- a/drivers/cxl/pci.h
+++ b/drivers/cxl/pci.h
@@ -9,9 +9,23 @@
  * See section 8.1 Configuration Space Registers in the CXL 2.0
  * Specification
  */
+#define PCI_DVSEC_HEADER1_LENGTH_MASK	GENMASK(31, 20)
 #define PCI_DVSEC_VENDOR_ID_CXL		0x1E98
 #define PCI_DVSEC_ID_CXL		0x0
 
 #define PCI_DVSEC_ID_CXL_REGLOC_OFFSET		0x8
+#define PCI_DVSEC_ID_CXL_REGLOC_BLOCK1_OFFSET	0xC
+
+/* BAR Indicator Register (BIR) */
+#define CXL_REGLOC_BIR_MASK GENMASK(2, 0)
+
+/* Register Block Identifier (RBI) */
+#define CXL_REGLOC_RBI_MASK GENMASK(15, 8)
+#define CXL_REGLOC_RBI_EMPTY 0
+#define CXL_REGLOC_RBI_COMPONENT 1
+#define CXL_REGLOC_RBI_VIRT 2
+#define CXL_REGLOC_RBI_MEMDEV 3
+
+#define CXL_REGLOC_ADDR_MASK GENMASK(31, 16)
 
 #endif /* __CXL_PCI_H__ */
-- 
2.30.0


^ permalink raw reply related	[flat|nested] 13+ messages in thread

* [PATCH v3 3/9] cxl/mem: Register CXL memX devices
  2021-02-12 22:25 [PATCH v3 0/9] CXL 2.0 Support Ben Widawsky
  2021-02-12 22:25 ` [PATCH v3 1/9] cxl/mem: Introduce a driver for CXL-2.0-Type-3 endpoints Ben Widawsky
  2021-02-12 22:25 ` [PATCH v3 2/9] cxl/mem: Find device capabilities Ben Widawsky
@ 2021-02-12 22:25 ` Ben Widawsky
  2021-02-15 16:30   ` Guenter Roeck
  2021-02-12 22:25 ` [PATCH v3 4/9] cxl/mem: Add basic IOCTL interface Ben Widawsky
                   ` (5 subsequent siblings)
  8 siblings, 1 reply; 13+ messages in thread
From: Ben Widawsky @ 2021-02-12 22:25 UTC (permalink / raw)
  To: linux-cxl
  Cc: Ben Widawsky, linux-acpi, linux-kernel, linux-nvdimm, linux-pci,
	Bjorn Helgaas, Chris Browy, Christoph Hellwig, Dan Williams,
	David Hildenbrand, David Rientjes, Ira Weiny, Jon Masters,
	Jonathan Cameron, Rafael Wysocki, Randy Dunlap, Vishal Verma,
	John Groves (jgroves),
	Kelley, Sean V, Jonathan Cameron

From: Dan Williams <dan.j.williams@intel.com>

Create the /sys/bus/cxl hierarchy to enumerate:

* Memory Devices (per-endpoint control devices)

* Memory Address Space Devices (platform address ranges with
  interleaving, performance, and persistence attributes)

* Memory Regions (active provisioned memory from an address space device
  that is in use as System RAM or delegated to libnvdimm as Persistent
  Memory regions).

For now, only the per-endpoint control devices are registered on the
'cxl' bus. However, going forward it will provide a mechanism to
coordinate cross-device interleave.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> (v2)
---
 Documentation/ABI/testing/sysfs-bus-cxl       |  26 ++
 .../driver-api/cxl/memory-devices.rst         |  17 +
 drivers/cxl/Makefile                          |   3 +
 drivers/cxl/bus.c                             |  29 ++
 drivers/cxl/cxl.h                             |   3 +
 drivers/cxl/mem.c                             | 301 +++++++++++++++++-
 6 files changed, 377 insertions(+), 2 deletions(-)
 create mode 100644 Documentation/ABI/testing/sysfs-bus-cxl
 create mode 100644 drivers/cxl/bus.c

diff --git a/Documentation/ABI/testing/sysfs-bus-cxl b/Documentation/ABI/testing/sysfs-bus-cxl
new file mode 100644
index 000000000000..2fe7490ad6a8
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-bus-cxl
@@ -0,0 +1,26 @@
+What:		/sys/bus/cxl/devices/memX/firmware_version
+Date:		December, 2020
+KernelVersion:	v5.12
+Contact:	linux-cxl@vger.kernel.org
+Description:
+		(RO) "FW Revision" string as reported by the Identify
+		Memory Device Output Payload in the CXL-2.0
+		specification.
+
+What:		/sys/bus/cxl/devices/memX/ram/size
+Date:		December, 2020
+KernelVersion:	v5.12
+Contact:	linux-cxl@vger.kernel.org
+Description:
+		(RO) "Volatile Only Capacity" as bytes. Represents the
+		identically named field in the Identify Memory Device Output
+		Payload in the CXL-2.0 specification.
+
+What:		/sys/bus/cxl/devices/memX/pmem/size
+Date:		December, 2020
+KernelVersion:	v5.12
+Contact:	linux-cxl@vger.kernel.org
+Description:
+		(RO) "Persistent Only Capacity" as bytes. Represents the
+		identically named field in the Identify Memory Device Output
+		Payload in the CXL-2.0 specification.
diff --git a/Documentation/driver-api/cxl/memory-devices.rst b/Documentation/driver-api/cxl/memory-devices.rst
index 43177e700d62..1bad466f9167 100644
--- a/Documentation/driver-api/cxl/memory-devices.rst
+++ b/Documentation/driver-api/cxl/memory-devices.rst
@@ -27,3 +27,20 @@ CXL Memory Device
 
 .. kernel-doc:: drivers/cxl/mem.c
    :internal:
+
+CXL Bus
+-------
+.. kernel-doc:: drivers/cxl/bus.c
+   :doc: cxl bus
+
+External Interfaces
+===================
+
+CXL IOCTL Interface
+-------------------
+
+.. kernel-doc:: include/uapi/linux/cxl_mem.h
+   :doc: UAPI
+
+.. kernel-doc:: include/uapi/linux/cxl_mem.h
+   :internal:
diff --git a/drivers/cxl/Makefile b/drivers/cxl/Makefile
index 4a30f7c3fc4a..a314a1891f4d 100644
--- a/drivers/cxl/Makefile
+++ b/drivers/cxl/Makefile
@@ -1,4 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_CXL_BUS) += cxl_bus.o
 obj-$(CONFIG_CXL_MEM) += cxl_mem.o
 
+ccflags-y += -DDEFAULT_SYMBOL_NAMESPACE=CXL
+cxl_bus-y := bus.o
 cxl_mem-y := mem.o
diff --git a/drivers/cxl/bus.c b/drivers/cxl/bus.c
new file mode 100644
index 000000000000..58f74796d525
--- /dev/null
+++ b/drivers/cxl/bus.c
@@ -0,0 +1,29 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright(c) 2020 Intel Corporation. All rights reserved. */
+#include <linux/device.h>
+#include <linux/module.h>
+
+/**
+ * DOC: cxl bus
+ *
+ * The CXL bus provides namespace for control devices and a rendezvous
+ * point for cross-device interleave coordination.
+ */
+struct bus_type cxl_bus_type = {
+	.name = "cxl",
+};
+EXPORT_SYMBOL_GPL(cxl_bus_type);
+
+static __init int cxl_bus_init(void)
+{
+	return bus_register(&cxl_bus_type);
+}
+
+static void cxl_bus_exit(void)
+{
+	bus_unregister(&cxl_bus_type);
+}
+
+module_init(cxl_bus_init);
+module_exit(cxl_bus_exit);
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
index 9cd9bc79fc48..63d7f7e01b83 100644
--- a/drivers/cxl/cxl.h
+++ b/drivers/cxl/cxl.h
@@ -55,6 +55,7 @@
 	(FIELD_GET(CXLMDEV_RESET_NEEDED_MASK, status) !=                       \
 	 CXLMDEV_RESET_NEEDED_NOT)
 
+struct cxl_memdev;
 /**
  * struct cxl_mem - A CXL memory device
  * @pdev: The PCI device associated with this CXL device.
@@ -72,6 +73,7 @@
 struct cxl_mem {
 	struct pci_dev *pdev;
 	void __iomem *regs;
+	struct cxl_memdev *cxlmd;
 
 	void __iomem *status_regs;
 	void __iomem *mbox_regs;
@@ -85,4 +87,5 @@ struct cxl_mem {
 	struct range ram_range;
 };
 
+extern struct bus_type cxl_bus_type;
 #endif /* __CXL_H__ */
diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c
index 2b289a311f27..f03482aa155d 100644
--- a/drivers/cxl/mem.c
+++ b/drivers/cxl/mem.c
@@ -1,11 +1,36 @@
 // SPDX-License-Identifier: GPL-2.0-only
 /* Copyright(c) 2020 Intel Corporation. All rights reserved. */
 #include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/cdev.h>
+#include <linux/idr.h>
 #include <linux/pci.h>
 #include <linux/io.h>
 #include "pci.h"
 #include "cxl.h"
 
+/**
+ * DOC: cxl mem
+ *
+ * This implements a CXL memory device ("type-3") as it is defined by the
+ * Compute Express Link specification.
+ *
+ * The driver has several responsibilities, mainly:
+ *  - Create the memX device and register on the CXL bus.
+ *  - Enumerate device's register interface and map them.
+ *  - Probe the device attributes to establish sysfs interface.
+ *  - Provide an IOCTL interface to userspace to communicate with the device for
+ *    things like firmware update.
+ *  - Support management of interleave sets.
+ *  - Handle and manage error conditions.
+ */
+
+/*
+ * An entire PCI topology full of devices should be enough for any
+ * config
+ */
+#define CXL_MEM_MAX_DEVS 65536
+
 #define cxl_doorbell_busy(cxlm)                                                \
 	(readl((cxlm)->mbox_regs + CXLDEV_MBOX_CTRL_OFFSET) &                  \
 	 CXLDEV_MBOX_CTRL_DOORBELL)
@@ -44,6 +69,27 @@ struct mbox_cmd {
 #define CXL_MBOX_SUCCESS 0
 };
 
+/**
+ * struct cxl_memdev - CXL bus object representing a Type-3 Memory Device
+ * @dev: driver core device object
+ * @cdev: char dev core object for ioctl operations
+ * @cxlm: pointer to the parent device driver data
+ * @ops_active: active user of @cxlm in ops handlers
+ * @ops_dead: completion when all @cxlm ops users have exited
+ * @id: id number of this memdev instance.
+ */
+struct cxl_memdev {
+	struct device dev;
+	struct cdev cdev;
+	struct cxl_mem *cxlm;
+	struct percpu_ref ops_active;
+	struct completion ops_dead;
+	int id;
+};
+
+static int cxl_mem_major;
+static DEFINE_IDA(cxl_memdev_ida);
+
 static int cxl_mem_wait_for_doorbell(struct cxl_mem *cxlm)
 {
 	const unsigned long start = jiffies;
@@ -265,6 +311,33 @@ static void cxl_mem_mbox_put(struct cxl_mem *cxlm)
 	mutex_unlock(&cxlm->mbox_mutex);
 }
 
+static long cxl_memdev_ioctl(struct file *file, unsigned int cmd,
+			     unsigned long arg)
+{
+	struct cxl_memdev *cxlmd;
+	struct inode *inode;
+	int rc = -ENOTTY;
+
+	inode = file_inode(file);
+	cxlmd = container_of(inode->i_cdev, typeof(*cxlmd), cdev);
+
+	if (!percpu_ref_tryget_live(&cxlmd->ops_active))
+		return -ENXIO;
+
+	/* TODO: ioctl body */
+
+	percpu_ref_put(&cxlmd->ops_active);
+
+	return rc;
+}
+
+static const struct file_operations cxl_memdev_fops = {
+	.owner = THIS_MODULE,
+	.unlocked_ioctl = cxl_memdev_ioctl,
+	.compat_ioctl = compat_ptr_ioctl,
+	.llseek = noop_llseek,
+};
+
 /**
  * cxl_mem_mbox_send_cmd() - Send a mailbox command to a memory device.
  * @cxlm: The CXL memory device to communicate with.
@@ -478,6 +551,197 @@ static int cxl_mem_dvsec(struct pci_dev *pdev, int dvsec)
 	return 0;
 }
 
+static struct cxl_memdev *to_cxl_memdev(struct device *dev)
+{
+	return container_of(dev, struct cxl_memdev, dev);
+}
+
+static void cxl_memdev_release(struct device *dev)
+{
+	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
+
+	percpu_ref_exit(&cxlmd->ops_active);
+	ida_free(&cxl_memdev_ida, cxlmd->id);
+	kfree(cxlmd);
+}
+
+static char *cxl_memdev_devnode(struct device *dev, umode_t *mode, kuid_t *uid,
+				kgid_t *gid)
+{
+	return kasprintf(GFP_KERNEL, "cxl/%s", dev_name(dev));
+}
+
+static ssize_t firmware_version_show(struct device *dev,
+				     struct device_attribute *attr, char *buf)
+{
+	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
+	struct cxl_mem *cxlm = cxlmd->cxlm;
+
+	return sprintf(buf, "%.16s\n", cxlm->firmware_version);
+}
+static DEVICE_ATTR_RO(firmware_version);
+
+static ssize_t payload_max_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
+	struct cxl_mem *cxlm = cxlmd->cxlm;
+
+	return sprintf(buf, "%zu\n", cxlm->payload_size);
+}
+static DEVICE_ATTR_RO(payload_max);
+
+static ssize_t ram_size_show(struct device *dev, struct device_attribute *attr,
+			     char *buf)
+{
+	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
+	struct cxl_mem *cxlm = cxlmd->cxlm;
+	unsigned long long len = range_len(&cxlm->ram_range);
+
+	return sprintf(buf, "%#llx\n", len);
+}
+
+static struct device_attribute dev_attr_ram_size =
+	__ATTR(size, 0444, ram_size_show, NULL);
+
+static ssize_t pmem_size_show(struct device *dev, struct device_attribute *attr,
+			      char *buf)
+{
+	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
+	struct cxl_mem *cxlm = cxlmd->cxlm;
+	unsigned long long len = range_len(&cxlm->pmem_range);
+
+	return sprintf(buf, "%#llx\n", len);
+}
+
+static struct device_attribute dev_attr_pmem_size =
+	__ATTR(size, 0444, pmem_size_show, NULL);
+
+static struct attribute *cxl_memdev_attributes[] = {
+	&dev_attr_firmware_version.attr,
+	&dev_attr_payload_max.attr,
+	NULL,
+};
+
+static struct attribute *cxl_memdev_pmem_attributes[] = {
+	&dev_attr_pmem_size.attr,
+	NULL,
+};
+
+static struct attribute *cxl_memdev_ram_attributes[] = {
+	&dev_attr_ram_size.attr,
+	NULL,
+};
+
+static struct attribute_group cxl_memdev_attribute_group = {
+	.attrs = cxl_memdev_attributes,
+};
+
+static struct attribute_group cxl_memdev_ram_attribute_group = {
+	.name = "ram",
+	.attrs = cxl_memdev_ram_attributes,
+};
+
+static struct attribute_group cxl_memdev_pmem_attribute_group = {
+	.name = "pmem",
+	.attrs = cxl_memdev_pmem_attributes,
+};
+
+static const struct attribute_group *cxl_memdev_attribute_groups[] = {
+	&cxl_memdev_attribute_group,
+	&cxl_memdev_ram_attribute_group,
+	&cxl_memdev_pmem_attribute_group,
+	NULL,
+};
+
+static const struct device_type cxl_memdev_type = {
+	.name = "cxl_memdev",
+	.release = cxl_memdev_release,
+	.devnode = cxl_memdev_devnode,
+	.groups = cxl_memdev_attribute_groups,
+};
+
+static void cxlmdev_unregister(void *_cxlmd)
+{
+	struct cxl_memdev *cxlmd = _cxlmd;
+	struct device *dev = &cxlmd->dev;
+
+	percpu_ref_kill(&cxlmd->ops_active);
+	cdev_device_del(&cxlmd->cdev, dev);
+	wait_for_completion(&cxlmd->ops_dead);
+	cxlmd->cxlm = NULL;
+	put_device(dev);
+}
+
+static void cxlmdev_ops_active_release(struct percpu_ref *ref)
+{
+	struct cxl_memdev *cxlmd =
+		container_of(ref, typeof(*cxlmd), ops_active);
+
+	complete(&cxlmd->ops_dead);
+}
+
+static int cxl_mem_add_memdev(struct cxl_mem *cxlm)
+{
+	struct pci_dev *pdev = cxlm->pdev;
+	struct cxl_memdev *cxlmd;
+	struct device *dev;
+	struct cdev *cdev;
+	int rc;
+
+	cxlmd = kzalloc(sizeof(*cxlmd), GFP_KERNEL);
+	if (!cxlmd)
+		return -ENOMEM;
+	init_completion(&cxlmd->ops_dead);
+
+	/*
+	 * @cxlm is deallocated when the driver unbinds so operations
+	 * that are using it need to hold a live reference.
+	 */
+	cxlmd->cxlm = cxlm;
+	rc = percpu_ref_init(&cxlmd->ops_active, cxlmdev_ops_active_release, 0,
+			     GFP_KERNEL);
+	if (rc)
+		goto err_ref;
+
+	rc = ida_alloc_range(&cxl_memdev_ida, 0, CXL_MEM_MAX_DEVS, GFP_KERNEL);
+	if (rc < 0)
+		goto err_id;
+	cxlmd->id = rc;
+
+	dev = &cxlmd->dev;
+	device_initialize(dev);
+	dev->parent = &pdev->dev;
+	dev->bus = &cxl_bus_type;
+	dev->devt = MKDEV(cxl_mem_major, cxlmd->id);
+	dev->type = &cxl_memdev_type;
+	dev_set_name(dev, "mem%d", cxlmd->id);
+
+	cdev = &cxlmd->cdev;
+	cdev_init(cdev, &cxl_memdev_fops);
+
+	rc = cdev_device_add(cdev, dev);
+	if (rc)
+		goto err_add;
+
+	return devm_add_action_or_reset(dev->parent, cxlmdev_unregister, cxlmd);
+
+err_add:
+	ida_free(&cxl_memdev_ida, cxlmd->id);
+err_id:
+	/*
+	 * Theoretically userspace could have already entered the fops,
+	 * so flush ops_active.
+	 */
+	percpu_ref_kill(&cxlmd->ops_active);
+	wait_for_completion(&cxlmd->ops_dead);
+	percpu_ref_exit(&cxlmd->ops_active);
+err_ref:
+	kfree(cxlmd);
+
+	return rc;
+}
+
 /**
  * cxl_mem_identify() - Send the IDENTIFY command to the device.
  * @cxlm: The device to identify.
@@ -577,7 +841,11 @@ static int cxl_mem_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 	if (rc)
 		return rc;
 
-	return cxl_mem_identify(cxlm);
+	rc = cxl_mem_identify(cxlm);
+	if (rc)
+		return rc;
+
+	return cxl_mem_add_memdev(cxlm);
 }
 
 static const struct pci_device_id cxl_mem_pci_tbl[] = {
@@ -596,5 +864,34 @@ static struct pci_driver cxl_mem_driver = {
 	},
 };
 
+static __init int cxl_mem_init(void)
+{
+	dev_t devt;
+	int rc;
+
+	rc = alloc_chrdev_region(&devt, 0, CXL_MEM_MAX_DEVS, "cxl");
+	if (rc)
+		return rc;
+
+	cxl_mem_major = MAJOR(devt);
+
+	rc = pci_register_driver(&cxl_mem_driver);
+	if (rc) {
+		unregister_chrdev_region(MKDEV(cxl_mem_major, 0),
+					 CXL_MEM_MAX_DEVS);
+		return rc;
+	}
+
+	return 0;
+}
+
+static __exit void cxl_mem_exit(void)
+{
+	pci_unregister_driver(&cxl_mem_driver);
+	unregister_chrdev_region(MKDEV(cxl_mem_major, 0), CXL_MEM_MAX_DEVS);
+}
+
 MODULE_LICENSE("GPL v2");
-module_pci_driver(cxl_mem_driver);
+module_init(cxl_mem_init);
+module_exit(cxl_mem_exit);
+MODULE_IMPORT_NS(CXL);
-- 
2.30.0


^ permalink raw reply related	[flat|nested] 13+ messages in thread

* [PATCH v3 4/9] cxl/mem: Add basic IOCTL interface
  2021-02-12 22:25 [PATCH v3 0/9] CXL 2.0 Support Ben Widawsky
                   ` (2 preceding siblings ...)
  2021-02-12 22:25 ` [PATCH v3 3/9] cxl/mem: Register CXL memX devices Ben Widawsky
@ 2021-02-12 22:25 ` Ben Widawsky
  2021-02-12 22:25 ` [PATCH v3 5/9] cxl/mem: Add a "RAW" send command Ben Widawsky
                   ` (4 subsequent siblings)
  8 siblings, 0 replies; 13+ messages in thread
From: Ben Widawsky @ 2021-02-12 22:25 UTC (permalink / raw)
  To: linux-cxl
  Cc: Ben Widawsky, linux-acpi, linux-kernel, linux-nvdimm, linux-pci,
	Bjorn Helgaas, Chris Browy, Christoph Hellwig, Dan Williams,
	David Hildenbrand, David Rientjes, Ira Weiny, Jon Masters,
	Jonathan Cameron, Rafael Wysocki, Randy Dunlap, Vishal Verma,
	John Groves (jgroves),
	Kelley, Sean V, kernel test robot

Add a straightforward IOCTL that provides a mechanism for userspace to
query the supported memory device commands. CXL commands as they appear
to userspace are described as part of the UAPI kerneldoc. The command
list returned via this IOCTL will contain the full set of commands that
the driver supports, however, some of those commands may not be
available for use by userspace.

Memory device commands first appear in the CXL 2.0 specification. They
are submitted through a mailbox mechanism specified in the CXL 2.0
specification.

The send command allows userspace to issue mailbox commands directly to
the hardware. The list of available commands to send are the output of
the query command. The driver verifies basic properties of the command
and possibly inspect the input (or output) payload to determine whether
or not the command is allowed (or might taint the kernel).

Reported-by: kernel test robot <lkp@intel.com> # bug in earlier revision
Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com> (v2)
---
 .clang-format                                 |   1 +
 .../userspace-api/ioctl/ioctl-number.rst      |   1 +
 drivers/cxl/mem.c                             | 280 +++++++++++++++++-
 include/uapi/linux/cxl_mem.h                  | 154 ++++++++++
 4 files changed, 435 insertions(+), 1 deletion(-)
 create mode 100644 include/uapi/linux/cxl_mem.h

diff --git a/.clang-format b/.clang-format
index 10dc5a9a61b3..3f11c8901b43 100644
--- a/.clang-format
+++ b/.clang-format
@@ -109,6 +109,7 @@ ForEachMacros:
   - 'css_for_each_child'
   - 'css_for_each_descendant_post'
   - 'css_for_each_descendant_pre'
+  - 'cxl_for_each_cmd'
   - 'device_for_each_child_node'
   - 'dma_fence_chain_for_each'
   - 'do_for_each_ftrace_op'
diff --git a/Documentation/userspace-api/ioctl/ioctl-number.rst b/Documentation/userspace-api/ioctl/ioctl-number.rst
index a4c75a28c839..6eb8e634664d 100644
--- a/Documentation/userspace-api/ioctl/ioctl-number.rst
+++ b/Documentation/userspace-api/ioctl/ioctl-number.rst
@@ -352,6 +352,7 @@ Code  Seq#    Include File                                           Comments
                                                                      <mailto:michael.klein@puffin.lb.shuttle.de>
 0xCC  00-0F  drivers/misc/ibmvmc.h                                   pseries VMC driver
 0xCD  01     linux/reiserfs_fs.h
+0xCE  01-02  uapi/linux/cxl_mem.h                                    Compute Express Link Memory Devices
 0xCF  02     fs/cifs/ioctl.c
 0xDB  00-0F  drivers/char/mwave/mwavepub.h
 0xDD  00-3F                                                          ZFCP device driver see drivers/s390/scsi/
diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c
index f03482aa155d..d764a35afea9 100644
--- a/drivers/cxl/mem.c
+++ b/drivers/cxl/mem.c
@@ -1,5 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0-only
 /* Copyright(c) 2020 Intel Corporation. All rights reserved. */
+#include <uapi/linux/cxl_mem.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/cdev.h>
@@ -39,6 +40,7 @@
 #define CXL_MAILBOX_TIMEOUT_MS (2 * HZ)
 
 enum opcode {
+	CXL_MBOX_OP_INVALID		= 0x0000,
 	CXL_MBOX_OP_IDENTIFY		= 0x4000,
 	CXL_MBOX_OP_MAX			= 0x10000
 };
@@ -90,6 +92,49 @@ struct cxl_memdev {
 static int cxl_mem_major;
 static DEFINE_IDA(cxl_memdev_ida);
 
+/**
+ * struct cxl_mem_command - Driver representation of a memory device command
+ * @info: Command information as it exists for the UAPI
+ * @opcode: The actual bits used for the mailbox protocol
+ *
+ * The cxl_mem_command is the driver's internal representation of commands that
+ * are supported by the driver. Some of these commands may not be supported by
+ * the hardware. The driver will use @info to validate the fields passed in by
+ * the user then submit the @opcode to the hardware.
+ *
+ * See struct cxl_command_info.
+ */
+struct cxl_mem_command {
+	struct cxl_command_info info;
+	enum opcode opcode;
+};
+
+#define CXL_CMD(_id, sin, sout)                                                \
+	[CXL_MEM_COMMAND_ID_##_id] = {                                         \
+	.info =	{                                                              \
+			.id = CXL_MEM_COMMAND_ID_##_id,                        \
+			.size_in = sin,                                        \
+			.size_out = sout,                                      \
+		},                                                             \
+	.opcode = CXL_MBOX_OP_##_id,                                           \
+	}
+
+/*
+ * This table defines the supported mailbox commands for the driver. This table
+ * is made up of a UAPI structure. Non-negative values as parameters in the
+ * table will be validated against the user's input. For example, if size_in is
+ * 0, and the user passed in 1, it is an error.
+ */
+static struct cxl_mem_command mem_commands[] = {
+	CXL_CMD(IDENTIFY, 0, 0x43),
+};
+
+#define cxl_for_each_cmd(cmd)                                                  \
+	for ((cmd) = &mem_commands[0];                                         \
+	     ((cmd) - mem_commands) < ARRAY_SIZE(mem_commands); (cmd)++)
+
+#define cxl_cmd_count ARRAY_SIZE(mem_commands)
+
 static int cxl_mem_wait_for_doorbell(struct cxl_mem *cxlm)
 {
 	const unsigned long start = jiffies;
@@ -311,6 +356,239 @@ static void cxl_mem_mbox_put(struct cxl_mem *cxlm)
 	mutex_unlock(&cxlm->mbox_mutex);
 }
 
+/**
+ * handle_mailbox_cmd_from_user() - Dispatch a mailbox command.
+ * @cxlmd: The CXL memory device to communicate with.
+ * @cmd: The validated command.
+ * @in_payload: Pointer to userspace's input payload.
+ * @out_payload: Pointer to userspace's output payload.
+ * @s: The command submitted by userspace. Has output fields.
+ *
+ * Return:
+ *  * %0	- Mailbox transaction succeeded.
+ *  * %-EFAULT	- Something happened with copy_to/from_user.
+ *  * %-ENOMEM  - Couldn't allocate a bounce buffer.
+ *  * %-EINTR	- Mailbox acquisition interrupted.
+ *  * %-E2BIG   - Output payload would overrun user's buffer.
+ *
+ * Creates the appropriate mailbox command on behalf of a userspace request.
+ * Return value, size, and output payload are all copied out to @u. The
+ * parameters for the command must be validated before calling this function.
+ *
+ * A 0 return code indicates the command executed successfully, not that it was
+ * itself successful. IOW, the cmd->retval should always be checked if wanting
+ * to determine the actual result.
+ */
+static int handle_mailbox_cmd_from_user(struct cxl_memdev *cxlmd,
+					const struct cxl_mem_command *cmd,
+					u64 in_payload, u64 out_payload,
+					struct cxl_send_command __user *s)
+{
+	struct cxl_mem *cxlm = cxlmd->cxlm;
+	struct device *dev = &cxlmd->dev;
+	struct mbox_cmd mbox_cmd = {
+		.opcode = cmd->opcode,
+		.size_in = cmd->info.size_in,
+	};
+	s32 user_size_out;
+	int rc;
+
+	if (get_user(user_size_out, &s->out.size))
+		return -EFAULT;
+
+	if (cmd->info.size_out > 0) /* fixed size command */
+		mbox_cmd.payload_out = kvzalloc(cmd->info.size_out, GFP_KERNEL);
+	else if (cmd->info.size_out < 0) /* variable */
+		mbox_cmd.payload_out = kvzalloc(cxlm->payload_size, GFP_KERNEL);
+
+	if (cmd->info.size_in) {
+		mbox_cmd.payload_in = kvzalloc(cmd->info.size_in, GFP_KERNEL);
+		if (!mbox_cmd.payload_in) {
+			rc = -ENOMEM;
+			goto out;
+		}
+
+		if (copy_from_user(mbox_cmd.payload_in,
+				   u64_to_user_ptr(in_payload),
+				   cmd->info.size_in)) {
+			rc = -EFAULT;
+			goto out;
+		}
+	}
+
+	rc = cxl_mem_mbox_get(cxlm);
+	if (rc)
+		goto out;
+
+	dev_dbg(dev,
+		"Submitting %s command for user\n"
+		"\topcode: %x\n"
+		"\tsize: %ub\n",
+		cxl_command_names[cmd->info.id].name, mbox_cmd.opcode,
+		cmd->info.size_in);
+
+	rc = __cxl_mem_mbox_send_cmd(cxlm, &mbox_cmd);
+	cxl_mem_mbox_put(cxlm);
+	if (rc)
+		goto out;
+
+	rc = put_user(mbox_cmd.return_code, &s->retval);
+	if (rc)
+		goto out;
+
+	if (user_size_out < mbox_cmd.size_out) {
+		rc = -E2BIG;
+		goto out;
+	}
+
+	if (mbox_cmd.size_out) {
+		if (copy_to_user(u64_to_user_ptr(out_payload),
+				 mbox_cmd.payload_out, mbox_cmd.size_out)) {
+			rc = -EFAULT;
+			goto out;
+		}
+	}
+
+	rc = put_user(mbox_cmd.size_out, &s->out.size);
+
+out:
+	kvfree(mbox_cmd.payload_in);
+	kvfree(mbox_cmd.payload_out);
+	return rc;
+}
+
+/**
+ * cxl_validate_cmd_from_user() - Check fields for CXL_MEM_SEND_COMMAND.
+ * @cxlm: &struct cxl_mem device whose mailbox will be used.
+ * @send_cmd: &struct cxl_send_command copied in from userspace.
+ * @out_cmd: Sanitized and populated &struct cxl_mem_command.
+ *
+ * Return:
+ *  * %0	- @out_cmd is ready to send.
+ *  * %-ENOTTY	- Invalid command specified.
+ *  * %-EINVAL	- Reserved fields or invalid values were used.
+ *  * %-ENOMEM	- Input or output buffer wasn't sized properly.
+ *
+ * The result of this command is a fully validated command in @out_cmd that is
+ * safe to send to the hardware.
+ *
+ * See handle_mailbox_cmd_from_user()
+ */
+static int cxl_validate_cmd_from_user(struct cxl_mem *cxlm,
+				      const struct cxl_send_command *send_cmd,
+				      struct cxl_mem_command *out_cmd)
+{
+	const struct cxl_command_info *info;
+	struct cxl_mem_command *c;
+
+	if (send_cmd->id == 0 || send_cmd->id >= CXL_MEM_COMMAND_ID_MAX)
+		return -ENOTTY;
+
+	/*
+	 * The user can never specify an input payload larger than
+	 * hardware supports, but output can be arbitrarily large,
+	 * simply write out as much data as the hardware provides.
+	 */
+	if (send_cmd->in.size > cxlm->payload_size)
+		return -EINVAL;
+
+	if (send_cmd->flags & ~CXL_MEM_COMMAND_FLAG_MASK)
+		return -EINVAL;
+
+	if (send_cmd->rsvd)
+		return -EINVAL;
+
+	if (send_cmd->in.rsvd || send_cmd->out.rsvd)
+		return -EINVAL;
+
+	/* Convert user's command into the internal representation */
+	c = &mem_commands[send_cmd->id];
+	info = &c->info;
+
+	/* Check the input buffer is the expected size */
+	if (info->size_in >= 0 && info->size_in != send_cmd->in.size)
+		return -ENOMEM;
+
+	/* Check the output buffer is at least large enough */
+	if (info->size_out >= 0 && send_cmd->out.size < info->size_out)
+		return -ENOMEM;
+
+	/* Setting a few const fields here... */
+	memcpy(out_cmd, c, sizeof(*c));
+	out_cmd->info.size_in = send_cmd->in.size;
+	out_cmd->info.size_out = send_cmd->out.size;
+
+	return 0;
+}
+
+static int cxl_query_cmd(struct cxl_memdev *cxlmd,
+			 struct cxl_mem_query_commands __user *q)
+{
+	struct device *dev = &cxlmd->dev;
+	struct cxl_mem_command *cmd;
+	u32 n_commands;
+	int j = 0;
+
+	dev_dbg(dev, "Query IOCTL\n");
+
+	if (get_user(n_commands, &q->n_commands))
+		return -EFAULT;
+
+	/* returns the total number if 0 elements are requested. */
+	if (n_commands == 0)
+		return put_user(cxl_cmd_count, &q->n_commands);
+
+	/*
+	 * otherwise, return max(n_commands, total commands) cxl_command_info
+	 * structures.
+	 */
+	cxl_for_each_cmd(cmd) {
+		const struct cxl_command_info *info = &cmd->info;
+
+		if (copy_to_user(&q->commands[j++], info, sizeof(*info)))
+			return -EFAULT;
+
+		if (j == n_commands)
+			break;
+	}
+
+	return 0;
+}
+
+static int cxl_send_cmd(struct cxl_memdev *cxlmd,
+			struct cxl_send_command __user *s)
+{
+	struct device *dev = &cxlmd->dev;
+	struct cxl_send_command send;
+	struct cxl_mem_command c;
+	int rc;
+
+	dev_dbg(dev, "Send IOCTL\n");
+
+	if (copy_from_user(&send, s, sizeof(send)))
+		return -EFAULT;
+
+	rc = cxl_validate_cmd_from_user(cxlmd->cxlm, &send, &c);
+	if (rc)
+		return rc;
+
+	return handle_mailbox_cmd_from_user(cxlmd, &c, send.in.payload,
+					    send.out.payload, s);
+}
+
+static long __cxl_memdev_ioctl(struct cxl_memdev *cxlmd, unsigned int cmd,
+			       unsigned long arg)
+{
+	switch (cmd) {
+	case CXL_MEM_QUERY_COMMANDS:
+		return cxl_query_cmd(cxlmd, (void __user *)arg);
+	case CXL_MEM_SEND_COMMAND:
+		return cxl_send_cmd(cxlmd, (void __user *)arg);
+	default:
+		return -ENOTTY;
+	}
+}
+
 static long cxl_memdev_ioctl(struct file *file, unsigned int cmd,
 			     unsigned long arg)
 {
@@ -324,7 +602,7 @@ static long cxl_memdev_ioctl(struct file *file, unsigned int cmd,
 	if (!percpu_ref_tryget_live(&cxlmd->ops_active))
 		return -ENXIO;
 
-	/* TODO: ioctl body */
+	rc = __cxl_memdev_ioctl(cxlmd, cmd, arg);
 
 	percpu_ref_put(&cxlmd->ops_active);
 
diff --git a/include/uapi/linux/cxl_mem.h b/include/uapi/linux/cxl_mem.h
new file mode 100644
index 000000000000..18cea908ad0b
--- /dev/null
+++ b/include/uapi/linux/cxl_mem.h
@@ -0,0 +1,154 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+/*
+ * CXL IOCTLs for Memory Devices
+ */
+
+#ifndef _UAPI_CXL_MEM_H_
+#define _UAPI_CXL_MEM_H_
+
+#include <linux/types.h>
+
+/**
+ * DOC: UAPI
+ *
+ * Not all of all commands that the driver supports are always available for use
+ * by userspace. Userspace must check the results from the QUERY command in
+ * order to determine the live set of commands.
+ */
+
+#define CXL_MEM_QUERY_COMMANDS _IOR(0xCE, 1, struct cxl_mem_query_commands)
+#define CXL_MEM_SEND_COMMAND _IOWR(0xCE, 2, struct cxl_send_command)
+
+#define CXL_CMDS                                                          \
+	___C(INVALID, "Invalid Command"),                                 \
+	___C(IDENTIFY, "Identify Command"),                               \
+	___C(MAX, "invalid / last command")
+
+#define ___C(a, b) CXL_MEM_COMMAND_ID_##a
+enum { CXL_CMDS };
+
+#undef ___C
+#define ___C(a, b) { b }
+static const struct {
+	const char *name;
+} cxl_command_names[] = { CXL_CMDS };
+
+/*
+ * Here's how this actually breaks out:
+ * cxl_command_names[] = {
+ *	[CXL_MEM_COMMAND_ID_INVALID] = { "Invalid Command" },
+ *	[CXL_MEM_COMMAND_ID_IDENTIFY] = { "Identify Command" },
+ *	...
+ *	[CXL_MEM_COMMAND_ID_MAX] = { "invalid / last command" },
+ * };
+ */
+
+#undef ___C
+
+/**
+ * struct cxl_command_info - Command information returned from a query.
+ * @id: ID number for the command.
+ * @flags: Flags that specify command behavior.
+ * @size_in: Expected input size, or -1 if variable length.
+ * @size_out: Expected output size, or -1 if variable length.
+ *
+ * Represents a single command that is supported by both the driver and the
+ * hardware. This is returned as part of an array from the query ioctl. The
+ * following would be a command that takes a variable length input and returns 0
+ * bytes of output.
+ *
+ *  - @id = 10
+ *  - @flags = 0
+ *  - @size_in = -1
+ *  - @size_out = 0
+ *
+ * See struct cxl_mem_query_commands.
+ */
+struct cxl_command_info {
+	__u32 id;
+
+	__u32 flags;
+#define CXL_MEM_COMMAND_FLAG_MASK GENMASK(0, 0)
+
+	__s32 size_in;
+	__s32 size_out;
+};
+
+/**
+ * struct cxl_mem_query_commands - Query supported commands.
+ * @n_commands: In/out parameter. When @n_commands is > 0, the driver will
+ *		return min(num_support_commands, n_commands). When @n_commands
+ *		is 0, driver will return the number of total supported commands.
+ * @rsvd: Reserved for future use.
+ * @commands: Output array of supported commands. This array must be allocated
+ *            by userspace to be at least min(num_support_commands, @n_commands)
+ *
+ * Allow userspace to query the available commands supported by both the driver,
+ * and the hardware. Commands that aren't supported by either the driver, or the
+ * hardware are not returned in the query.
+ *
+ * Examples:
+ *
+ *  - { .n_commands = 0 } // Get number of supported commands
+ *  - { .n_commands = 15, .commands = buf } // Return first 15 (or less)
+ *    supported commands
+ *
+ *  See struct cxl_command_info.
+ */
+struct cxl_mem_query_commands {
+	/*
+	 * Input: Number of commands to return (space allocated by user)
+	 * Output: Number of commands supported by the driver/hardware
+	 *
+	 * If n_commands is 0, kernel will only return number of commands and
+	 * not try to populate commands[], thus allowing userspace to know how
+	 * much space to allocate
+	 */
+	__u32 n_commands;
+	__u32 rsvd;
+
+	struct cxl_command_info __user commands[]; /* out: supported commands */
+};
+
+/**
+ * struct cxl_send_command - Send a command to a memory device.
+ * @id: The command to send to the memory device. This must be one of the
+ *	commands returned by the query command.
+ * @flags: Flags for the command (input).
+ * @rsvd: Must be zero.
+ * @retval: Return value from the memory device (output).
+ * @in.size: Size of the payload to provide to the device (input).
+ * @in.rsvd: Must be zero.
+ * @in.payload: Pointer to memory for payload input, payload is little endian.
+ * @out.size: Size of the payload received from the device (input/output). This
+ *	      field is filled in by userspace to let the driver know how much
+ *	      space was allocated for output. It is populated by the driver to
+ *	      let userspace know how large the output payload actually was.
+ * @out.rsvd: Must be zero.
+ * @out.payload: Pointer to memory for payload output, payload is little endian.
+ *
+ * Mechanism for userspace to send a command to the hardware for processing. The
+ * driver will do basic validation on the command sizes. In some cases even the
+ * payload may be introspected. Userspace is required to allocate large enough
+ * buffers for size_out which can be variable length in certain situations.
+ */
+struct cxl_send_command {
+	__u32 id;
+	__u32 flags;
+	__u32 rsvd;
+	__u32 retval;
+
+	struct {
+		__s32 size;
+		__u32 rsvd;
+		__u64 payload;
+	} in;
+
+	struct {
+		__s32 size;
+		__u32 rsvd;
+		__u64 payload;
+	} out;
+};
+
+#endif
-- 
2.30.0


^ permalink raw reply related	[flat|nested] 13+ messages in thread

* [PATCH v3 5/9] cxl/mem: Add a "RAW" send command
  2021-02-12 22:25 [PATCH v3 0/9] CXL 2.0 Support Ben Widawsky
                   ` (3 preceding siblings ...)
  2021-02-12 22:25 ` [PATCH v3 4/9] cxl/mem: Add basic IOCTL interface Ben Widawsky
@ 2021-02-12 22:25 ` Ben Widawsky
  2021-02-12 22:25 ` [PATCH v3 6/9] cxl/mem: Enable commands via CEL Ben Widawsky
                   ` (3 subsequent siblings)
  8 siblings, 0 replies; 13+ messages in thread
From: Ben Widawsky @ 2021-02-12 22:25 UTC (permalink / raw)
  To: linux-cxl
  Cc: Ben Widawsky, linux-acpi, linux-kernel, linux-nvdimm, linux-pci,
	Bjorn Helgaas, Chris Browy, Christoph Hellwig, Dan Williams,
	David Hildenbrand, David Rientjes, Ira Weiny, Jon Masters,
	Jonathan Cameron, Rafael Wysocki, Randy Dunlap, Vishal Verma,
	John Groves (jgroves),
	Kelley, Sean V, Ariel Sibley

The CXL memory device send interface will have a number of supported
commands. The raw command is not such a command. Raw commands allow
userspace to send a specified opcode to the underlying hardware and
bypass all driver checks on the command. The primary use for this
command is to [begrudgingly] allow undocumented vendor specific hardware
commands.

While not the main motivation, it also allows prototyping new hardware
commands without a driver patch and rebuild.

While this all sounds very powerful it comes with a couple of caveats:
1. Bug reports using raw commands will not get the same level of
   attention as bug reports using supported commands (via taint).
2. Supported commands will be rejected by the RAW command.

With this comes new debugfs knob to allow full access to your toes with
your weapon of choice.

Cc: Ariel Sibley <Ariel.Sibley@microchip.com>
Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com> (v2)
---
 drivers/cxl/Kconfig          |  18 ++++++
 drivers/cxl/mem.c            | 121 +++++++++++++++++++++++++++++++++++
 include/uapi/linux/cxl_mem.h |  12 +++-
 3 files changed, 150 insertions(+), 1 deletion(-)

diff --git a/drivers/cxl/Kconfig b/drivers/cxl/Kconfig
index 9e80b311e928..97dc4d751651 100644
--- a/drivers/cxl/Kconfig
+++ b/drivers/cxl/Kconfig
@@ -32,4 +32,22 @@ config CXL_MEM
 	  Chapter 2.3 Type 3 CXL Device in the CXL 2.0 specification.
 
 	  If unsure say 'm'.
+
+config CXL_MEM_RAW_COMMANDS
+	bool "RAW Command Interface for Memory Devices"
+	depends on CXL_MEM
+	help
+	  Enable CXL RAW command interface.
+
+	  The CXL driver ioctl interface may assign a kernel ioctl command
+	  number for each specification defined opcode. At any given point in
+	  time the number of opcodes that the specification defines and a device
+	  may implement may exceed the kernel's set of associated ioctl function
+	  numbers. The mismatch is either by omission, specification is too new,
+	  or by design. When prototyping new hardware, or developing / debugging
+	  the driver it is useful to be able to submit any possible command to
+	  the hardware, even commands that may crash the kernel due to their
+	  potential impact to memory currently in use by the kernel.
+
+	  If developing CXL hardware or the driver say Y, otherwise say N.
 endif
diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c
index d764a35afea9..a819f090ffe2 100644
--- a/drivers/cxl/mem.c
+++ b/drivers/cxl/mem.c
@@ -1,6 +1,8 @@
 // SPDX-License-Identifier: GPL-2.0-only
 /* Copyright(c) 2020 Intel Corporation. All rights reserved. */
 #include <uapi/linux/cxl_mem.h>
+#include <linux/security.h>
+#include <linux/debugfs.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/cdev.h>
@@ -41,7 +43,14 @@
 
 enum opcode {
 	CXL_MBOX_OP_INVALID		= 0x0000,
+	CXL_MBOX_OP_RAW			= CXL_MBOX_OP_INVALID,
+	CXL_MBOX_OP_ACTIVATE_FW		= 0x0202,
 	CXL_MBOX_OP_IDENTIFY		= 0x4000,
+	CXL_MBOX_OP_SET_PARTITION_INFO	= 0x4101,
+	CXL_MBOX_OP_SET_LSA		= 0x4103,
+	CXL_MBOX_OP_SET_SHUTDOWN_STATE	= 0x4204,
+	CXL_MBOX_OP_SCAN_MEDIA		= 0x4304,
+	CXL_MBOX_OP_GET_SCAN_MEDIA	= 0x4305,
 	CXL_MBOX_OP_MAX			= 0x10000
 };
 
@@ -91,6 +100,8 @@ struct cxl_memdev {
 
 static int cxl_mem_major;
 static DEFINE_IDA(cxl_memdev_ida);
+static struct dentry *cxl_debugfs;
+static bool cxl_raw_allow_all;
 
 /**
  * struct cxl_mem_command - Driver representation of a memory device command
@@ -127,6 +138,49 @@ struct cxl_mem_command {
  */
 static struct cxl_mem_command mem_commands[] = {
 	CXL_CMD(IDENTIFY, 0, 0x43),
+#ifdef CONFIG_CXL_MEM_RAW_COMMANDS
+	CXL_CMD(RAW, ~0, ~0),
+#endif
+};
+
+/*
+ * Commands that RAW doesn't permit. The rationale for each:
+ *
+ * CXL_MBOX_OP_ACTIVATE_FW: Firmware activation requires adjustment /
+ * coordination of transaction timeout values at the root bridge level.
+ *
+ * CXL_MBOX_OP_SET_PARTITION_INFO: The device memory map may change live
+ * and needs to be coordinated with HDM updates.
+ *
+ * CXL_MBOX_OP_SET_LSA: The label storage area may be cached by the
+ * driver and any writes from userspace invalidates those contents.
+ *
+ * CXL_MBOX_OP_SET_SHUTDOWN_STATE: Set shutdown state assumes no writes
+ * to the device after it is marked clean, userspace can not make that
+ * assertion.
+ *
+ * CXL_MBOX_OP_[GET_]SCAN_MEDIA: The kernel provides a native error list that
+ * is kept up to date with patrol notifications and error management.
+ */
+static u16 cxl_disabled_raw_commands[] = {
+	CXL_MBOX_OP_ACTIVATE_FW,
+	CXL_MBOX_OP_SET_PARTITION_INFO,
+	CXL_MBOX_OP_SET_LSA,
+	CXL_MBOX_OP_SET_SHUTDOWN_STATE,
+	CXL_MBOX_OP_SCAN_MEDIA,
+	CXL_MBOX_OP_GET_SCAN_MEDIA,
+};
+
+/*
+ * Command sets that RAW doesn't permit. All opcodes in this set are
+ * disabled because they pass plain text security payloads over the
+ * user/kernel boundary. This functionality is intended to be wrapped
+ * behind the keys ABI which allows for encrypted payloads in the UAPI
+ */
+static u8 security_command_sets[] = {
+	0x44, /* Sanitize */
+	0x45, /* Persistent Memory Data-at-rest Security */
+	0x46, /* Security Passthrough */
 };
 
 #define cxl_for_each_cmd(cmd)                                                  \
@@ -157,6 +211,16 @@ static int cxl_mem_wait_for_doorbell(struct cxl_mem *cxlm)
 	return 0;
 }
 
+static bool cxl_is_security_command(u16 opcode)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(security_command_sets); i++)
+		if (security_command_sets[i] == (opcode >> 8))
+			return true;
+	return false;
+}
+
 static void cxl_mem_mbox_timeout(struct cxl_mem *cxlm,
 				 struct mbox_cmd *mbox_cmd)
 {
@@ -427,6 +491,9 @@ static int handle_mailbox_cmd_from_user(struct cxl_memdev *cxlmd,
 		cxl_command_names[cmd->info.id].name, mbox_cmd.opcode,
 		cmd->info.size_in);
 
+	dev_WARN_ONCE(dev, cmd->info.id == CXL_MEM_COMMAND_ID_RAW,
+		      "raw command path used\n");
+
 	rc = __cxl_mem_mbox_send_cmd(cxlm, &mbox_cmd);
 	cxl_mem_mbox_put(cxlm);
 	if (rc)
@@ -457,6 +524,29 @@ static int handle_mailbox_cmd_from_user(struct cxl_memdev *cxlmd,
 	return rc;
 }
 
+static bool cxl_mem_raw_command_allowed(u16 opcode)
+{
+	int i;
+
+	if (!IS_ENABLED(CONFIG_CXL_MEM_RAW_COMMANDS))
+		return false;
+
+	if (security_locked_down(LOCKDOWN_NONE))
+		return false;
+
+	if (cxl_raw_allow_all)
+		return true;
+
+	if (cxl_is_security_command(opcode))
+		return false;
+
+	for (i = 0; i < ARRAY_SIZE(cxl_disabled_raw_commands); i++)
+		if (cxl_disabled_raw_commands[i] == opcode)
+			return false;
+
+	return true;
+}
+
 /**
  * cxl_validate_cmd_from_user() - Check fields for CXL_MEM_SEND_COMMAND.
  * @cxlm: &struct cxl_mem device whose mailbox will be used.
@@ -468,6 +558,7 @@ static int handle_mailbox_cmd_from_user(struct cxl_memdev *cxlmd,
  *  * %-ENOTTY	- Invalid command specified.
  *  * %-EINVAL	- Reserved fields or invalid values were used.
  *  * %-ENOMEM	- Input or output buffer wasn't sized properly.
+ *  * %-EPERM	- Attempted to use a protected command.
  *
  * The result of this command is a fully validated command in @out_cmd that is
  * safe to send to the hardware.
@@ -492,6 +583,29 @@ static int cxl_validate_cmd_from_user(struct cxl_mem *cxlm,
 	if (send_cmd->in.size > cxlm->payload_size)
 		return -EINVAL;
 
+	/* Checks are bypassed for raw commands but along comes the taint! */
+	if (send_cmd->id == CXL_MEM_COMMAND_ID_RAW) {
+		const struct cxl_mem_command temp = {
+			.info = {
+				.id = CXL_MEM_COMMAND_ID_RAW,
+				.flags = 0,
+				.size_in = send_cmd->in.size,
+				.size_out = send_cmd->out.size,
+			},
+			.opcode = send_cmd->raw.opcode
+		};
+
+		if (send_cmd->raw.rsvd)
+			return -EINVAL;
+
+		if (!cxl_mem_raw_command_allowed(send_cmd->raw.opcode))
+			return -EPERM;
+
+		memcpy(out_cmd, &temp, sizeof(temp));
+
+		return 0;
+	}
+
 	if (send_cmd->flags & ~CXL_MEM_COMMAND_FLAG_MASK)
 		return -EINVAL;
 
@@ -1144,6 +1258,7 @@ static struct pci_driver cxl_mem_driver = {
 
 static __init int cxl_mem_init(void)
 {
+	struct dentry *mbox_debugfs;
 	dev_t devt;
 	int rc;
 
@@ -1160,11 +1275,17 @@ static __init int cxl_mem_init(void)
 		return rc;
 	}
 
+	cxl_debugfs = debugfs_create_dir("cxl", NULL);
+	mbox_debugfs = debugfs_create_dir("mbox", cxl_debugfs);
+	debugfs_create_bool("cxl_raw_allow_all", 0600, mbox_debugfs,
+			    &cxl_raw_allow_all);
+
 	return 0;
 }
 
 static __exit void cxl_mem_exit(void)
 {
+	debugfs_remove_recursive(cxl_debugfs);
 	pci_unregister_driver(&cxl_mem_driver);
 	unregister_chrdev_region(MKDEV(cxl_mem_major, 0), CXL_MEM_MAX_DEVS);
 }
diff --git a/include/uapi/linux/cxl_mem.h b/include/uapi/linux/cxl_mem.h
index 18cea908ad0b..8eb669150ecb 100644
--- a/include/uapi/linux/cxl_mem.h
+++ b/include/uapi/linux/cxl_mem.h
@@ -22,6 +22,7 @@
 #define CXL_CMDS                                                          \
 	___C(INVALID, "Invalid Command"),                                 \
 	___C(IDENTIFY, "Identify Command"),                               \
+	___C(RAW, "Raw device command"),                                  \
 	___C(MAX, "invalid / last command")
 
 #define ___C(a, b) CXL_MEM_COMMAND_ID_##a
@@ -115,6 +116,9 @@ struct cxl_mem_query_commands {
  * @id: The command to send to the memory device. This must be one of the
  *	commands returned by the query command.
  * @flags: Flags for the command (input).
+ * @raw: Special fields for raw commands
+ * @raw.opcode: Opcode passed to hardware when using the RAW command.
+ * @raw.rsvd: Must be zero.
  * @rsvd: Must be zero.
  * @retval: Return value from the memory device (output).
  * @in.size: Size of the payload to provide to the device (input).
@@ -135,7 +139,13 @@ struct cxl_mem_query_commands {
 struct cxl_send_command {
 	__u32 id;
 	__u32 flags;
-	__u32 rsvd;
+	union {
+		struct {
+			__u16 opcode;
+			__u16 rsvd;
+		} raw;
+		__u32 rsvd;
+	};
 	__u32 retval;
 
 	struct {
-- 
2.30.0


^ permalink raw reply related	[flat|nested] 13+ messages in thread

* [PATCH v3 6/9] cxl/mem: Enable commands via CEL
  2021-02-12 22:25 [PATCH v3 0/9] CXL 2.0 Support Ben Widawsky
                   ` (4 preceding siblings ...)
  2021-02-12 22:25 ` [PATCH v3 5/9] cxl/mem: Add a "RAW" send command Ben Widawsky
@ 2021-02-12 22:25 ` Ben Widawsky
  2021-02-14  5:46   ` [PATCH v4 06/09] " Ben Widawsky
  2021-02-12 22:25 ` [PATCH v3 7/9] cxl/mem: Add set of informational commands Ben Widawsky
                   ` (2 subsequent siblings)
  8 siblings, 1 reply; 13+ messages in thread
From: Ben Widawsky @ 2021-02-12 22:25 UTC (permalink / raw)
  To: linux-cxl
  Cc: Ben Widawsky, linux-acpi, linux-kernel, linux-nvdimm, linux-pci,
	Bjorn Helgaas, Chris Browy, Christoph Hellwig, Dan Williams,
	David Hildenbrand, David Rientjes, Ira Weiny, Jon Masters,
	Jonathan Cameron, Rafael Wysocki, Randy Dunlap, Vishal Verma,
	John Groves (jgroves),
	Kelley, Sean V

CXL devices identified by the memory-device class code must implement
the Device Command Interface (described in 8.2.9 of the CXL 2.0 spec).
While the driver already maintains a list of commands it supports, there
is still a need to be able to distinguish between commands that the
driver knows about from commands that are optionally supported by the
hardware.

The Command Effects Log (CEL) is specified in the CXL 2.0 specification.
The CEL is one of two types of logs, the other being vendor specific.
They are distinguished in hardware/spec via UUID. The CEL is useful for
2 things:
1. Determine which optional commands are supported by the CXL device.
2. Enumerate any vendor specific commands

The CEL is used by the driver to determine which commands are available
in the hardware and therefore which commands userspace is allowed to
execute. The set of enabled commands might be a subset of commands which
are advertised in UAPI via CXL_MEM_SEND_COMMAND IOCTL.

With the CEL enabling comes a internal flag to indicate a base set of
commands that are enabled regardless of CEL. Such commands are required
for basic interaction with the hardware and thus can be useful in debug
cases, for example if the CEL is corrupted.

The implementation leaves the statically defined table of commands and
supplements it with a bitmap to determine commands that are enabled.
This organization was chosen for the following reasons:
- Smaller memory footprint. Doesn't need a table per device.
- Reduce memory allocation complexity.
- Fixed command IDs to opcode mapping for all devices makes development
  and debugging easier.
- Certain helpers are easily achievable, like cxl_for_each_cmd().

Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
---
 drivers/cxl/cxl.h            |   2 +
 drivers/cxl/mem.c            | 224 ++++++++++++++++++++++++++++++++++-
 include/uapi/linux/cxl_mem.h |   1 +
 3 files changed, 224 insertions(+), 3 deletions(-)

diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
index 63d7f7e01b83..a1aa9f787a2a 100644
--- a/drivers/cxl/cxl.h
+++ b/drivers/cxl/cxl.h
@@ -67,6 +67,7 @@ struct cxl_memdev;
  *                (CXL 2.0 8.2.8.4.3 Mailbox Capabilities Register)
  * @mbox_mutex: Mutex to synchronize mailbox access.
  * @firmware_version: Firmware version for the memory device.
+ * @enabled_commands: Hardware commands found enabled in CEL.
  * @pmem: Persistent memory capacity information.
  * @ram: Volatile memory capacity information.
  */
@@ -82,6 +83,7 @@ struct cxl_mem {
 	size_t payload_size;
 	struct mutex mbox_mutex; /* Protects device mailbox and firmware */
 	char firmware_version[0x10];
+	unsigned long *enabled_cmds;
 
 	struct range pmem_range;
 	struct range ram_range;
diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c
index a819f090ffe2..b026c1167bda 100644
--- a/drivers/cxl/mem.c
+++ b/drivers/cxl/mem.c
@@ -45,6 +45,8 @@ enum opcode {
 	CXL_MBOX_OP_INVALID		= 0x0000,
 	CXL_MBOX_OP_RAW			= CXL_MBOX_OP_INVALID,
 	CXL_MBOX_OP_ACTIVATE_FW		= 0x0202,
+	CXL_MBOX_OP_GET_SUPPORTED_LOGS	= 0x0400,
+	CXL_MBOX_OP_GET_LOG		= 0x0401,
 	CXL_MBOX_OP_IDENTIFY		= 0x4000,
 	CXL_MBOX_OP_SET_PARTITION_INFO	= 0x4101,
 	CXL_MBOX_OP_SET_LSA		= 0x4103,
@@ -103,10 +105,28 @@ static DEFINE_IDA(cxl_memdev_ida);
 static struct dentry *cxl_debugfs;
 static bool cxl_raw_allow_all;
 
+enum {
+	CEL_UUID,
+	VENDOR_DEBUG_UUID,
+};
+
+/* See CXL 2.0 Table 170. Get Log Input Payload */
+static const uuid_t log_uuid[] = {
+	[CEL_UUID] = UUID_INIT(0xda9c0b5, 0xbf41, 0x4b78, 0x8f, 0x79, 0x96,
+			       0xb1, 0x62, 0x3b, 0x3f, 0x17),
+	[VENDOR_DEBUG_UUID] = UUID_INIT(0xe1819d9, 0x11a9, 0x400c, 0x81, 0x1f,
+					0xd6, 0x07, 0x19, 0x40, 0x3d, 0x86),
+};
+
 /**
  * struct cxl_mem_command - Driver representation of a memory device command
  * @info: Command information as it exists for the UAPI
  * @opcode: The actual bits used for the mailbox protocol
+ * @flags: Set of flags effecting driver behavior.
+ *
+ *  * %CXL_CMD_FLAG_FORCE_ENABLE: In cases of error, commands with this flag
+ *    will be enabled by the driver regardless of what hardware may have
+ *    advertised.
  *
  * The cxl_mem_command is the driver's internal representation of commands that
  * are supported by the driver. Some of these commands may not be supported by
@@ -118,9 +138,12 @@ static bool cxl_raw_allow_all;
 struct cxl_mem_command {
 	struct cxl_command_info info;
 	enum opcode opcode;
+	u32 flags;
+#define CXL_CMD_FLAG_NONE 0
+#define CXL_CMD_FLAG_FORCE_ENABLE BIT(0)
 };
 
-#define CXL_CMD(_id, sin, sout)                                                \
+#define CXL_CMD(_id, sin, sout, _flags)                                        \
 	[CXL_MEM_COMMAND_ID_##_id] = {                                         \
 	.info =	{                                                              \
 			.id = CXL_MEM_COMMAND_ID_##_id,                        \
@@ -128,6 +151,7 @@ struct cxl_mem_command {
 			.size_out = sout,                                      \
 		},                                                             \
 	.opcode = CXL_MBOX_OP_##_id,                                           \
+	.flags = _flags,                                                       \
 	}
 
 /*
@@ -137,10 +161,11 @@ struct cxl_mem_command {
  * 0, and the user passed in 1, it is an error.
  */
 static struct cxl_mem_command mem_commands[] = {
-	CXL_CMD(IDENTIFY, 0, 0x43),
+	CXL_CMD(IDENTIFY, 0, 0x43, CXL_CMD_FLAG_FORCE_ENABLE),
 #ifdef CONFIG_CXL_MEM_RAW_COMMANDS
-	CXL_CMD(RAW, ~0, ~0),
+	CXL_CMD(RAW, ~0, ~0, 0),
 #endif
+	CXL_CMD(GET_SUPPORTED_LOGS, 0, ~0, CXL_CMD_FLAG_FORCE_ENABLE),
 };
 
 /*
@@ -619,6 +644,10 @@ static int cxl_validate_cmd_from_user(struct cxl_mem *cxlm,
 	c = &mem_commands[send_cmd->id];
 	info = &c->info;
 
+	/* Check that the command is enabled for hardware */
+	if (!test_bit(info->id, cxlm->enabled_cmds))
+		return -ENOTTY;
+
 	/* Check the input buffer is the expected size */
 	if (info->size_in >= 0 && info->size_in != send_cmd->in.size)
 		return -ENOMEM;
@@ -915,6 +944,14 @@ static struct cxl_mem *cxl_mem_create(struct pci_dev *pdev, u32 reg_lo,
 	mutex_init(&cxlm->mbox_mutex);
 	cxlm->pdev = pdev;
 	cxlm->regs = regs + offset;
+	cxlm->enabled_cmds =
+		devm_kmalloc_array(dev, BITS_TO_LONGS(cxl_cmd_count),
+				   sizeof(unsigned long),
+				   GFP_KERNEL | __GFP_ZERO);
+	if (!cxlm->enabled_cmds) {
+		dev_err(dev, "No memory available for bitmap\n");
+		return NULL;
+	}
 
 	dev_dbg(dev, "Mapped CXL Memory Device resource\n");
 	return cxlm;
@@ -1134,6 +1171,183 @@ static int cxl_mem_add_memdev(struct cxl_mem *cxlm)
 	return rc;
 }
 
+static int cxl_xfer_log(struct cxl_mem *cxlm, uuid_t *uuid, u32 size, u8 *out)
+{
+	u32 remaining = size;
+	u32 offset = 0;
+
+	while (remaining) {
+		u32 xfer_size = min_t(u32, remaining, cxlm->payload_size);
+		struct cxl_mbox_get_log {
+			uuid_t uuid;
+			__le32 offset;
+			__le32 length;
+		} __packed log = {
+			.uuid = *uuid,
+			.offset = cpu_to_le32(offset),
+			.length = cpu_to_le32(xfer_size)
+		};
+		int rc;
+
+		rc = cxl_mem_mbox_send_cmd(cxlm, CXL_MBOX_OP_GET_LOG,
+					   (u8 *)&log, sizeof(log), out,
+					   xfer_size);
+		if (rc < 0)
+			return rc;
+
+		out += xfer_size;
+		remaining -= xfer_size;
+		offset += xfer_size;
+	}
+
+	return 0;
+}
+
+static inline struct cxl_mem_command *cxl_mem_find_command(u16 opcode)
+{
+	struct cxl_mem_command *c;
+
+	cxl_for_each_cmd(c)
+		if (c->opcode == opcode)
+			return c;
+
+	return NULL;
+}
+
+/**
+ * cxl_walk_cel() - Walk through the Command Effects Log.
+ * @cxlm: Device.
+ * @size: Length of the Command Effects Log.
+ * @cel: CEL
+ *
+ * Iterate over each entry in the CEL and determine if the driver supports the
+ * command. If so, the command is enabled for the device and can be used later.
+ */
+static void cxl_walk_cel(struct cxl_mem *cxlm, size_t size, u8 *cel)
+{
+	struct cel_entry {
+		__le16 opcode;
+		__le16 effect;
+	} __packed * cel_entry;
+	const int cel_entries = size / sizeof(*cel_entry);
+	int i;
+
+	cel_entry = (struct cel_entry *)cel;
+
+	for (i = 0; i < cel_entries; i++) {
+		u16 opcode = le16_to_cpu(cel_entry[i].opcode);
+		struct cxl_mem_command *cmd = cxl_mem_find_command(opcode);
+
+		if (!cmd) {
+			dev_dbg(&cxlm->pdev->dev,
+				"Opcode 0x%04x unsupported by driver", opcode);
+			continue;
+		}
+
+		set_bit(cmd->info.id, cxlm->enabled_cmds);
+	}
+}
+
+struct cxl_mbox_get_supported_logs {
+	__le16 entries;
+	u8 rsvd[6];
+	struct gsl_entry {
+		uuid_t uuid;
+		__le32 size;
+	} __packed entry[];
+} __packed;
+
+static struct cxl_mbox_get_supported_logs *cxl_get_gsl(struct cxl_mem *cxlm)
+{
+	struct cxl_mbox_get_supported_logs temp, *ret;
+	struct device *dev = &cxlm->pdev->dev;
+	int rc;
+
+	rc = cxl_mem_mbox_send_cmd(cxlm, CXL_MBOX_OP_GET_SUPPORTED_LOGS, NULL,
+				   0, (u8 *)&temp, sizeof(temp));
+	if (rc < 0)
+		return ERR_PTR(rc);
+
+	if (rc < sizeof(temp) + (le16_to_cpu(temp.entries) * sizeof(struct gsl_entry))) {
+		dev_err(dev, "Incongruent log size\n");
+		return ERR_PTR(-ENXIO);
+	}
+
+	ret = kvmalloc(rc, GFP_KERNEL);
+	if (!ret)
+		return ERR_PTR(-ENOMEM);
+
+	rc = cxl_mem_mbox_send_cmd(cxlm, CXL_MBOX_OP_GET_SUPPORTED_LOGS, NULL,
+				   0, (u8 *)ret, rc);
+	if (rc < 0) {
+		kvfree(ret);
+		return ERR_PTR(rc);
+	}
+
+	return ret;
+}
+
+/**
+ * cxl_mem_enumerate_cmds() - Enumerate commands for a device.
+ * @cxlm: The device.
+ *
+ * Returns 0 if enumerate completed successfully.
+ *
+ * CXL devices have optional support for certain commands. This function will
+ * determine the set of supported commands for the hardware and update the
+ * enabled_cmds bitmap in the @cxlm.
+ */
+static int cxl_mem_enumerate_cmds(struct cxl_mem *cxlm)
+{
+	struct cxl_mbox_get_supported_logs *gsl;
+	struct device *dev = &cxlm->pdev->dev;
+	struct cxl_mem_command *cmd;
+	int i, rc;
+
+	gsl = cxl_get_gsl(cxlm);
+	if (IS_ERR(gsl))
+		return PTR_ERR(gsl);
+
+	rc = -ENOENT;
+	for (i = 0; i < le16_to_cpu(gsl->entries); i++) {
+		u32 size = le32_to_cpu(gsl->entry[i].size);
+		uuid_t uuid = gsl->entry[i].uuid;
+		u8 *log;
+
+		dev_dbg(dev, "Found LOG type %pU of size %d", &uuid, size);
+
+		if (!uuid_equal(&uuid, &log_uuid[CEL_UUID]))
+			continue;
+
+		log = kvmalloc(size, GFP_KERNEL);
+		if (!log) {
+			rc = -ENOMEM;
+			goto out;
+		}
+
+		rc = cxl_xfer_log(cxlm, &uuid, size, log);
+		if (rc) {
+			kvfree(log);
+			goto out;
+		}
+
+		cxl_walk_cel(cxlm, size, log);
+		kvfree(log);
+
+		/* In case CEL was bogus, enable some default commands. */
+		cxl_for_each_cmd(cmd)
+			if (cmd->flags & CXL_CMD_FLAG_FORCE_ENABLE)
+				set_bit(cmd->info.id, cxlm->enabled_cmds);
+
+		/* Found the required CEL */
+		rc = 0;
+	}
+
+out:
+	kvfree(gsl);
+	return rc;
+}
+
 /**
  * cxl_mem_identify() - Send the IDENTIFY command to the device.
  * @cxlm: The device to identify.
@@ -1233,6 +1447,10 @@ static int cxl_mem_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 	if (rc)
 		return rc;
 
+	rc = cxl_mem_enumerate_cmds(cxlm);
+	if (rc)
+		return rc;
+
 	rc = cxl_mem_identify(cxlm);
 	if (rc)
 		return rc;
diff --git a/include/uapi/linux/cxl_mem.h b/include/uapi/linux/cxl_mem.h
index 8eb669150ecb..3b5bf4b58fb4 100644
--- a/include/uapi/linux/cxl_mem.h
+++ b/include/uapi/linux/cxl_mem.h
@@ -23,6 +23,7 @@
 	___C(INVALID, "Invalid Command"),                                 \
 	___C(IDENTIFY, "Identify Command"),                               \
 	___C(RAW, "Raw device command"),                                  \
+	___C(GET_SUPPORTED_LOGS, "Get Supported Logs"),                   \
 	___C(MAX, "invalid / last command")
 
 #define ___C(a, b) CXL_MEM_COMMAND_ID_##a
-- 
2.30.0


^ permalink raw reply related	[flat|nested] 13+ messages in thread

* [PATCH v3 7/9] cxl/mem: Add set of informational commands
  2021-02-12 22:25 [PATCH v3 0/9] CXL 2.0 Support Ben Widawsky
                   ` (5 preceding siblings ...)
  2021-02-12 22:25 ` [PATCH v3 6/9] cxl/mem: Enable commands via CEL Ben Widawsky
@ 2021-02-12 22:25 ` Ben Widawsky
  2021-02-12 22:25 ` [PATCH v3 8/9] MAINTAINERS: Add maintainers of the CXL driver Ben Widawsky
  2021-02-12 22:25 ` [RFC PATCH 9/9] cxl/mem: Add payload dumping for debug Ben Widawsky
  8 siblings, 0 replies; 13+ messages in thread
From: Ben Widawsky @ 2021-02-12 22:25 UTC (permalink / raw)
  To: linux-cxl
  Cc: Ben Widawsky, linux-acpi, linux-kernel, linux-nvdimm, linux-pci,
	Bjorn Helgaas, Chris Browy, Christoph Hellwig, Dan Williams,
	David Hildenbrand, David Rientjes, Ira Weiny, Jon Masters,
	Jonathan Cameron, Rafael Wysocki, Randy Dunlap, Vishal Verma,
	John Groves (jgroves),
	Kelley, Sean V, Jonathan Cameron

Add initial set of formal commands beyond basic identify and command
enumeration.

Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> (v2)
---
 drivers/cxl/mem.c            | 9 +++++++++
 include/uapi/linux/cxl_mem.h | 5 +++++
 2 files changed, 14 insertions(+)

diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c
index b026c1167bda..3bca8451348a 100644
--- a/drivers/cxl/mem.c
+++ b/drivers/cxl/mem.c
@@ -44,12 +44,16 @@
 enum opcode {
 	CXL_MBOX_OP_INVALID		= 0x0000,
 	CXL_MBOX_OP_RAW			= CXL_MBOX_OP_INVALID,
+	CXL_MBOX_OP_GET_FW_INFO		= 0x0200,
 	CXL_MBOX_OP_ACTIVATE_FW		= 0x0202,
 	CXL_MBOX_OP_GET_SUPPORTED_LOGS	= 0x0400,
 	CXL_MBOX_OP_GET_LOG		= 0x0401,
 	CXL_MBOX_OP_IDENTIFY		= 0x4000,
+	CXL_MBOX_OP_GET_PARTITION_INFO	= 0x4100,
 	CXL_MBOX_OP_SET_PARTITION_INFO	= 0x4101,
+	CXL_MBOX_OP_GET_LSA		= 0x4102,
 	CXL_MBOX_OP_SET_LSA		= 0x4103,
+	CXL_MBOX_OP_GET_HEALTH_INFO	= 0x4200,
 	CXL_MBOX_OP_SET_SHUTDOWN_STATE	= 0x4204,
 	CXL_MBOX_OP_SCAN_MEDIA		= 0x4304,
 	CXL_MBOX_OP_GET_SCAN_MEDIA	= 0x4305,
@@ -166,6 +170,11 @@ static struct cxl_mem_command mem_commands[] = {
 	CXL_CMD(RAW, ~0, ~0, 0),
 #endif
 	CXL_CMD(GET_SUPPORTED_LOGS, 0, ~0, CXL_CMD_FLAG_FORCE_ENABLE),
+	CXL_CMD(GET_FW_INFO, 0, 0x50, 0),
+	CXL_CMD(GET_PARTITION_INFO, 0, 0x20, 0),
+	CXL_CMD(GET_LSA, 0x8, ~0, 0),
+	CXL_CMD(GET_HEALTH_INFO, 0, 0x12, 0),
+	CXL_CMD(GET_LOG, 0x18, ~0, CXL_CMD_FLAG_FORCE_ENABLE),
 };
 
 /*
diff --git a/include/uapi/linux/cxl_mem.h b/include/uapi/linux/cxl_mem.h
index 3b5bf4b58fb4..7670fe0e605a 100644
--- a/include/uapi/linux/cxl_mem.h
+++ b/include/uapi/linux/cxl_mem.h
@@ -24,6 +24,11 @@
 	___C(IDENTIFY, "Identify Command"),                               \
 	___C(RAW, "Raw device command"),                                  \
 	___C(GET_SUPPORTED_LOGS, "Get Supported Logs"),                   \
+	___C(GET_FW_INFO, "Get FW Info"),                                 \
+	___C(GET_PARTITION_INFO, "Get Partition Information"),            \
+	___C(GET_LSA, "Get Label Storage Area"),                          \
+	___C(GET_HEALTH_INFO, "Get Health Info"),                         \
+	___C(GET_LOG, "Get Log"),                                         \
 	___C(MAX, "invalid / last command")
 
 #define ___C(a, b) CXL_MEM_COMMAND_ID_##a
-- 
2.30.0


^ permalink raw reply related	[flat|nested] 13+ messages in thread

* [PATCH v3 8/9] MAINTAINERS: Add maintainers of the CXL driver
  2021-02-12 22:25 [PATCH v3 0/9] CXL 2.0 Support Ben Widawsky
                   ` (6 preceding siblings ...)
  2021-02-12 22:25 ` [PATCH v3 7/9] cxl/mem: Add set of informational commands Ben Widawsky
@ 2021-02-12 22:25 ` Ben Widawsky
  2021-02-12 22:25 ` [RFC PATCH 9/9] cxl/mem: Add payload dumping for debug Ben Widawsky
  8 siblings, 0 replies; 13+ messages in thread
From: Ben Widawsky @ 2021-02-12 22:25 UTC (permalink / raw)
  To: linux-cxl
  Cc: Ben Widawsky, linux-acpi, linux-kernel, linux-nvdimm, linux-pci,
	Bjorn Helgaas, Chris Browy, Christoph Hellwig, Dan Williams,
	David Hildenbrand, David Rientjes, Ira Weiny, Jon Masters,
	Jonathan Cameron, Rafael Wysocki, Randy Dunlap, Vishal Verma,
	John Groves (jgroves),
	Kelley, Sean V, Alison Schofield

Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Alison Schofield <alison.schofield@intel.com>
Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
---
 MAINTAINERS | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index 6eff4f720c72..93c8694a8f04 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -4444,6 +4444,17 @@ M:	Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
 S:	Maintained
 F:	include/linux/compiler_attributes.h
 
+COMPUTE EXPRESS LINK (CXL)
+M:	Alison Schofield <alison.schofield@intel.com>
+M:	Vishal Verma <vishal.l.verma@intel.com>
+M:	Ira Weiny <ira.weiny@intel.com>
+M:	Ben Widawsky <ben.widawsky@intel.com>
+M:	Dan Williams <dan.j.williams@intel.com>
+L:	linux-cxl@vger.kernel.org
+S:	Maintained
+F:	drivers/cxl/
+F:	include/uapi/linux/cxl_mem.h
+
 CONEXANT ACCESSRUNNER USB DRIVER
 L:	accessrunner-general@lists.sourceforge.net
 S:	Orphan
-- 
2.30.0


^ permalink raw reply related	[flat|nested] 13+ messages in thread

* [RFC PATCH 9/9] cxl/mem: Add payload dumping for debug
  2021-02-12 22:25 [PATCH v3 0/9] CXL 2.0 Support Ben Widawsky
                   ` (7 preceding siblings ...)
  2021-02-12 22:25 ` [PATCH v3 8/9] MAINTAINERS: Add maintainers of the CXL driver Ben Widawsky
@ 2021-02-12 22:25 ` Ben Widawsky
  8 siblings, 0 replies; 13+ messages in thread
From: Ben Widawsky @ 2021-02-12 22:25 UTC (permalink / raw)
  To: linux-cxl
  Cc: Ben Widawsky, linux-acpi, linux-kernel, linux-nvdimm, linux-pci,
	Bjorn Helgaas, Chris Browy, Christoph Hellwig, Dan Williams,
	David Hildenbrand, David Rientjes, Ira Weiny, Jon Masters,
	Jonathan Cameron, Rafael Wysocki, Randy Dunlap, Vishal Verma,
	John Groves (jgroves),
	Kelley, Sean V

It's often useful in debug scenarios to see what the hardware has dumped
out. As it stands today, any device error will result in the payload not
being copied out, so there is no way to triage commands which weren't
expected to fail (and sometimes the payload may have that information).

The functionality is protected by normal kernel security mechanisms as
well as a CONFIG option in the CXL driver.

This was extracted from the original version of the CXL enabling patch
series.

Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
---
 drivers/cxl/Kconfig | 13 +++++++++++++
 drivers/cxl/mem.c   |  8 ++++++++
 2 files changed, 21 insertions(+)

diff --git a/drivers/cxl/Kconfig b/drivers/cxl/Kconfig
index 97dc4d751651..3eec9276e586 100644
--- a/drivers/cxl/Kconfig
+++ b/drivers/cxl/Kconfig
@@ -50,4 +50,17 @@ config CXL_MEM_RAW_COMMANDS
 	  potential impact to memory currently in use by the kernel.
 
 	  If developing CXL hardware or the driver say Y, otherwise say N.
+
+config CXL_MEM_INSECURE_DEBUG
+	bool "CXL.mem debugging"
+	depends on CXL_MEM
+	help
+	  Enable debug of all CXL command payloads.
+
+	  Some CXL devices and controllers support encryption and other
+	  security features. The payloads for the commands that enable
+	  those features may contain sensitive clear-text security
+	  material. Disable debug of those command payloads by default.
+	  If you are a kernel developer actively working on CXL
+	  security enabling say Y, otherwise say N.
 endif
diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c
index 3bca8451348a..09c11935b824 100644
--- a/drivers/cxl/mem.c
+++ b/drivers/cxl/mem.c
@@ -341,6 +341,14 @@ static int __cxl_mem_mbox_send_cmd(struct cxl_mem *cxlm,
 
 	/* #5 */
 	rc = cxl_mem_wait_for_doorbell(cxlm);
+
+	if (!cxl_is_security_command(mbox_cmd->opcode) ||
+	    IS_ENABLED(CONFIG_CXL_MEM_INSECURE_DEBUG)) {
+		print_hex_dump_debug("Payload ", DUMP_PREFIX_OFFSET, 16, 1,
+				     mbox_cmd->payload_in, mbox_cmd->size_in,
+				     true);
+	}
+
 	if (rc == -ETIMEDOUT) {
 		cxl_mem_mbox_timeout(cxlm, mbox_cmd);
 		return rc;
-- 
2.30.0


^ permalink raw reply related	[flat|nested] 13+ messages in thread

* [PATCH v4 06/09] cxl/mem: Enable commands via CEL
  2021-02-12 22:25 ` [PATCH v3 6/9] cxl/mem: Enable commands via CEL Ben Widawsky
@ 2021-02-14  5:46   ` Ben Widawsky
  2021-02-14 16:10     ` Ben Widawsky
  0 siblings, 1 reply; 13+ messages in thread
From: Ben Widawsky @ 2021-02-14  5:46 UTC (permalink / raw)
  To: Dan Williams
  Cc: Ben Widawsky, linux-acpi, linux-kernel, linux-nvdimm, linux-pci,
	Bjorn Helgaas, Chris Browy, Christoph Hellwig, David Hildenbrand,
	David Rientjes, Ira Weiny, Jon Masters, Jonathan Cameron,
	Rafael Wysocki, Randy Dunlap, Vishal Verma, John Groves (jgroves),
	Kelley, Sean V

CXL devices identified by the memory-device class code must implement
the Device Command Interface (described in 8.2.9 of the CXL 2.0 spec).
While the driver already maintains a list of commands it supports, there
is still a need to be able to distinguish between commands that the
driver knows about from commands that are optionally supported by the
hardware.

The Command Effects Log (CEL) is specified in the CXL 2.0 specification.
The CEL is one of two types of logs, the other being vendor specific.
They are distinguished in hardware/spec via UUID. The CEL is useful for
2 things:
1. Determine which optional commands are supported by the CXL device.
2. Enumerate any vendor specific commands

The CEL is used by the driver to determine which commands are available
in the hardware and therefore which commands userspace is allowed to
execute. The set of enabled commands might be a subset of commands which
are advertised in UAPI via CXL_MEM_SEND_COMMAND IOCTL.

With the CEL enabling comes a internal flag to indicate a base set of
commands that are enabled regardless of CEL. Such commands are required
for basic interaction with the hardware and thus can be useful in debug
cases, for example if the CEL is corrupted.

The implementation leaves the statically defined table of commands and
supplements it with a bitmap to determine commands that are enabled.
This organization was chosen for the following reasons:
- Smaller memory footprint. Doesn't need a table per device.
- Reduce memory allocation complexity.
- Fixed command IDs to opcode mapping for all devices makes development
  and debugging easier.
- Certain helpers are easily achievable, like cxl_for_each_cmd().

Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
---
 drivers/cxl/cxl.h            |   2 +
 drivers/cxl/mem.c            | 213 ++++++++++++++++++++++++++++++++++-
 include/uapi/linux/cxl_mem.h |   1 +
 3 files changed, 213 insertions(+), 3 deletions(-)

diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
index 63d7f7e01b83..a1aa9f787a2a 100644
--- a/drivers/cxl/cxl.h
+++ b/drivers/cxl/cxl.h
@@ -67,6 +67,7 @@ struct cxl_memdev;
  *                (CXL 2.0 8.2.8.4.3 Mailbox Capabilities Register)
  * @mbox_mutex: Mutex to synchronize mailbox access.
  * @firmware_version: Firmware version for the memory device.
+ * @enabled_commands: Hardware commands found enabled in CEL.
  * @pmem: Persistent memory capacity information.
  * @ram: Volatile memory capacity information.
  */
@@ -82,6 +83,7 @@ struct cxl_mem {
 	size_t payload_size;
 	struct mutex mbox_mutex; /* Protects device mailbox and firmware */
 	char firmware_version[0x10];
+	unsigned long *enabled_cmds;
 
 	struct range pmem_range;
 	struct range ram_range;
diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c
index a819f090ffe2..712a8ccc496a 100644
--- a/drivers/cxl/mem.c
+++ b/drivers/cxl/mem.c
@@ -45,6 +45,8 @@ enum opcode {
 	CXL_MBOX_OP_INVALID		= 0x0000,
 	CXL_MBOX_OP_RAW			= CXL_MBOX_OP_INVALID,
 	CXL_MBOX_OP_ACTIVATE_FW		= 0x0202,
+	CXL_MBOX_OP_GET_SUPPORTED_LOGS	= 0x0400,
+	CXL_MBOX_OP_GET_LOG		= 0x0401,
 	CXL_MBOX_OP_IDENTIFY		= 0x4000,
 	CXL_MBOX_OP_SET_PARTITION_INFO	= 0x4101,
 	CXL_MBOX_OP_SET_LSA		= 0x4103,
@@ -103,10 +105,28 @@ static DEFINE_IDA(cxl_memdev_ida);
 static struct dentry *cxl_debugfs;
 static bool cxl_raw_allow_all;
 
+enum {
+	CEL_UUID,
+	VENDOR_DEBUG_UUID,
+};
+
+/* See CXL 2.0 Table 170. Get Log Input Payload */
+static const uuid_t log_uuid[] = {
+	[CEL_UUID] = UUID_INIT(0xda9c0b5, 0xbf41, 0x4b78, 0x8f, 0x79, 0x96,
+			       0xb1, 0x62, 0x3b, 0x3f, 0x17),
+	[VENDOR_DEBUG_UUID] = UUID_INIT(0xe1819d9, 0x11a9, 0x400c, 0x81, 0x1f,
+					0xd6, 0x07, 0x19, 0x40, 0x3d, 0x86),
+};
+
 /**
  * struct cxl_mem_command - Driver representation of a memory device command
  * @info: Command information as it exists for the UAPI
  * @opcode: The actual bits used for the mailbox protocol
+ * @flags: Set of flags effecting driver behavior.
+ *
+ *  * %CXL_CMD_FLAG_FORCE_ENABLE: In cases of error, commands with this flag
+ *    will be enabled by the driver regardless of what hardware may have
+ *    advertised.
  *
  * The cxl_mem_command is the driver's internal representation of commands that
  * are supported by the driver. Some of these commands may not be supported by
@@ -118,9 +138,12 @@ static bool cxl_raw_allow_all;
 struct cxl_mem_command {
 	struct cxl_command_info info;
 	enum opcode opcode;
+	u32 flags;
+#define CXL_CMD_FLAG_NONE 0
+#define CXL_CMD_FLAG_FORCE_ENABLE BIT(0)
 };
 
-#define CXL_CMD(_id, sin, sout)                                                \
+#define CXL_CMD(_id, sin, sout, _flags)                                        \
 	[CXL_MEM_COMMAND_ID_##_id] = {                                         \
 	.info =	{                                                              \
 			.id = CXL_MEM_COMMAND_ID_##_id,                        \
@@ -128,6 +151,7 @@ struct cxl_mem_command {
 			.size_out = sout,                                      \
 		},                                                             \
 	.opcode = CXL_MBOX_OP_##_id,                                           \
+	.flags = _flags,                                                       \
 	}
 
 /*
@@ -137,10 +161,11 @@ struct cxl_mem_command {
  * 0, and the user passed in 1, it is an error.
  */
 static struct cxl_mem_command mem_commands[] = {
-	CXL_CMD(IDENTIFY, 0, 0x43),
+	CXL_CMD(IDENTIFY, 0, 0x43, CXL_CMD_FLAG_FORCE_ENABLE),
 #ifdef CONFIG_CXL_MEM_RAW_COMMANDS
-	CXL_CMD(RAW, ~0, ~0),
+	CXL_CMD(RAW, ~0, ~0, 0),
 #endif
+	CXL_CMD(GET_SUPPORTED_LOGS, 0, ~0, CXL_CMD_FLAG_FORCE_ENABLE),
 };
 
 /*
@@ -619,6 +644,10 @@ static int cxl_validate_cmd_from_user(struct cxl_mem *cxlm,
 	c = &mem_commands[send_cmd->id];
 	info = &c->info;
 
+	/* Check that the command is enabled for hardware */
+	if (!test_bit(info->id, cxlm->enabled_cmds))
+		return -ENOTTY;
+
 	/* Check the input buffer is the expected size */
 	if (info->size_in >= 0 && info->size_in != send_cmd->in.size)
 		return -ENOMEM;
@@ -915,6 +944,14 @@ static struct cxl_mem *cxl_mem_create(struct pci_dev *pdev, u32 reg_lo,
 	mutex_init(&cxlm->mbox_mutex);
 	cxlm->pdev = pdev;
 	cxlm->regs = regs + offset;
+	cxlm->enabled_cmds =
+		devm_kmalloc_array(dev, BITS_TO_LONGS(cxl_cmd_count),
+				   sizeof(unsigned long),
+				   GFP_KERNEL | __GFP_ZERO);
+	if (!cxlm->enabled_cmds) {
+		dev_err(dev, "No memory available for bitmap\n");
+		return NULL;
+	}
 
 	dev_dbg(dev, "Mapped CXL Memory Device resource\n");
 	return cxlm;
@@ -1134,6 +1171,172 @@ static int cxl_mem_add_memdev(struct cxl_mem *cxlm)
 	return rc;
 }
 
+static int cxl_xfer_log(struct cxl_mem *cxlm, uuid_t *uuid, u32 size, u8 *out)
+{
+	u32 remaining = size;
+	u32 offset = 0;
+
+	while (remaining) {
+		u32 xfer_size = min_t(u32, remaining, cxlm->payload_size);
+		struct cxl_mbox_get_log {
+			uuid_t uuid;
+			__le32 offset;
+			__le32 length;
+		} __packed log = {
+			.uuid = *uuid,
+			.offset = cpu_to_le32(offset),
+			.length = cpu_to_le32(xfer_size)
+		};
+		int rc;
+
+		rc = cxl_mem_mbox_send_cmd(cxlm, CXL_MBOX_OP_GET_LOG,
+					   (u8 *)&log, sizeof(log), out,
+					   xfer_size);
+		if (rc < 0)
+			return rc;
+
+		out += xfer_size;
+		remaining -= xfer_size;
+		offset += xfer_size;
+	}
+
+	return 0;
+}
+
+static inline struct cxl_mem_command *cxl_mem_find_command(u16 opcode)
+{
+	struct cxl_mem_command *c;
+
+	cxl_for_each_cmd(c)
+		if (c->opcode == opcode)
+			return c;
+
+	return NULL;
+}
+
+/**
+ * cxl_walk_cel() - Walk through the Command Effects Log.
+ * @cxlm: Device.
+ * @size: Length of the Command Effects Log.
+ * @cel: CEL
+ *
+ * Iterate over each entry in the CEL and determine if the driver supports the
+ * command. If so, the command is enabled for the device and can be used later.
+ */
+static void cxl_walk_cel(struct cxl_mem *cxlm, size_t size, u8 *cel)
+{
+	struct cel_entry {
+		__le16 opcode;
+		__le16 effect;
+	} __packed * cel_entry;
+	const int cel_entries = size / sizeof(*cel_entry);
+	int i;
+
+	cel_entry = (struct cel_entry *)cel;
+
+	for (i = 0; i < cel_entries; i++) {
+		u16 opcode = le16_to_cpu(cel_entry[i].opcode);
+		struct cxl_mem_command *cmd = cxl_mem_find_command(opcode);
+
+		if (!cmd) {
+			dev_dbg(&cxlm->pdev->dev,
+				"Opcode 0x%04x unsupported by driver", opcode);
+			continue;
+		}
+
+		set_bit(cmd->info.id, cxlm->enabled_cmds);
+	}
+}
+
+struct cxl_mbox_get_supported_logs {
+	__le16 entries;
+	u8 rsvd[6];
+	struct gsl_entry {
+		uuid_t uuid;
+		__le32 size;
+	} __packed entry[];
+} __packed;
+
+static struct cxl_mbox_get_supported_logs *cxl_get_gsl(struct cxl_mem *cxlm)
+{
+	struct cxl_mbox_get_supported_logs *ret;
+	int rc;
+
+	ret = kvmalloc(cxlm->payload_size, GFP_KERNEL);
+	if (!ret)
+		return ERR_PTR(-ENOMEM);
+
+	rc = cxl_mem_mbox_send_cmd(cxlm, CXL_MBOX_OP_GET_SUPPORTED_LOGS, NULL,
+				   0, (u8 *)ret, sizeof(*ret));
+	if (rc < 0) {
+		kvfree(ret);
+		return ERR_PTR(rc);
+	}
+
+	return ret;
+}
+
+/**
+ * cxl_mem_enumerate_cmds() - Enumerate commands for a device.
+ * @cxlm: The device.
+ *
+ * Returns 0 if enumerate completed successfully.
+ *
+ * CXL devices have optional support for certain commands. This function will
+ * determine the set of supported commands for the hardware and update the
+ * enabled_cmds bitmap in the @cxlm.
+ */
+static int cxl_mem_enumerate_cmds(struct cxl_mem *cxlm)
+{
+	struct cxl_mbox_get_supported_logs *gsl;
+	struct device *dev = &cxlm->pdev->dev;
+	struct cxl_mem_command *cmd;
+	int i, rc;
+
+	gsl = cxl_get_gsl(cxlm);
+	if (IS_ERR(gsl))
+		return PTR_ERR(gsl);
+
+	rc = -ENOENT;
+	for (i = 0; i < le16_to_cpu(gsl->entries); i++) {
+		u32 size = le32_to_cpu(gsl->entry[i].size);
+		uuid_t uuid = gsl->entry[i].uuid;
+		u8 *log;
+
+		dev_dbg(dev, "Found LOG type %pU of size %d", &uuid, size);
+
+		if (!uuid_equal(&uuid, &log_uuid[CEL_UUID]))
+			continue;
+
+		log = kvmalloc(size, GFP_KERNEL);
+		if (!log) {
+			rc = -ENOMEM;
+			goto out;
+		}
+
+		rc = cxl_xfer_log(cxlm, &uuid, size, log);
+		if (rc) {
+			kvfree(log);
+			goto out;
+		}
+
+		cxl_walk_cel(cxlm, size, log);
+		kvfree(log);
+
+		/* In case CEL was bogus, enable some default commands. */
+		cxl_for_each_cmd(cmd)
+			if (cmd->flags & CXL_CMD_FLAG_FORCE_ENABLE)
+				set_bit(cmd->info.id, cxlm->enabled_cmds);
+
+		/* Found the required CEL */
+		rc = 0;
+	}
+
+out:
+	kvfree(gsl);
+	return rc;
+}
+
 /**
  * cxl_mem_identify() - Send the IDENTIFY command to the device.
  * @cxlm: The device to identify.
@@ -1233,6 +1436,10 @@ static int cxl_mem_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 	if (rc)
 		return rc;
 
+	rc = cxl_mem_enumerate_cmds(cxlm);
+	if (rc)
+		return rc;
+
 	rc = cxl_mem_identify(cxlm);
 	if (rc)
 		return rc;
diff --git a/include/uapi/linux/cxl_mem.h b/include/uapi/linux/cxl_mem.h
index 8eb669150ecb..3b5bf4b58fb4 100644
--- a/include/uapi/linux/cxl_mem.h
+++ b/include/uapi/linux/cxl_mem.h
@@ -23,6 +23,7 @@
 	___C(INVALID, "Invalid Command"),                                 \
 	___C(IDENTIFY, "Identify Command"),                               \
 	___C(RAW, "Raw device command"),                                  \
+	___C(GET_SUPPORTED_LOGS, "Get Supported Logs"),                   \
 	___C(MAX, "invalid / last command")
 
 #define ___C(a, b) CXL_MEM_COMMAND_ID_##a
-- 
2.30.1


^ permalink raw reply related	[flat|nested] 13+ messages in thread

* Re: [PATCH v4 06/09] cxl/mem: Enable commands via CEL
  2021-02-14  5:46   ` [PATCH v4 06/09] " Ben Widawsky
@ 2021-02-14 16:10     ` Ben Widawsky
  0 siblings, 0 replies; 13+ messages in thread
From: Ben Widawsky @ 2021-02-14 16:10 UTC (permalink / raw)
  To: Dan Williams
  Cc: linux-acpi, linux-kernel, linux-nvdimm, linux-pci, Bjorn Helgaas,
	Chris Browy, Christoph Hellwig, David Hildenbrand,
	David Rientjes, Ira Weiny, Jon Masters, Jonathan Cameron,
	Rafael Wysocki, Randy Dunlap, Vishal Verma, John Groves (jgroves),
	Kelley, Sean V

On 21-02-13 21:46:33, Ben Widawsky wrote:
> CXL devices identified by the memory-device class code must implement
> the Device Command Interface (described in 8.2.9 of the CXL 2.0 spec).
> While the driver already maintains a list of commands it supports, there
> is still a need to be able to distinguish between commands that the
> driver knows about from commands that are optionally supported by the
> hardware.
> 
> The Command Effects Log (CEL) is specified in the CXL 2.0 specification.
> The CEL is one of two types of logs, the other being vendor specific.
> They are distinguished in hardware/spec via UUID. The CEL is useful for
> 2 things:
> 1. Determine which optional commands are supported by the CXL device.
> 2. Enumerate any vendor specific commands
> 
> The CEL is used by the driver to determine which commands are available
> in the hardware and therefore which commands userspace is allowed to
> execute. The set of enabled commands might be a subset of commands which
> are advertised in UAPI via CXL_MEM_SEND_COMMAND IOCTL.
> 
> With the CEL enabling comes a internal flag to indicate a base set of
> commands that are enabled regardless of CEL. Such commands are required
> for basic interaction with the hardware and thus can be useful in debug
> cases, for example if the CEL is corrupted.
> 
> The implementation leaves the statically defined table of commands and
> supplements it with a bitmap to determine commands that are enabled.
> This organization was chosen for the following reasons:
> - Smaller memory footprint. Doesn't need a table per device.
> - Reduce memory allocation complexity.
> - Fixed command IDs to opcode mapping for all devices makes development
>   and debugging easier.
> - Certain helpers are easily achievable, like cxl_for_each_cmd().
> 
> Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
> Reviewed-by: Dan Williams <dan.j.williams@intel.com>

See below for explanation on why the v4...

> ---
>  drivers/cxl/cxl.h            |   2 +
>  drivers/cxl/mem.c            | 213 ++++++++++++++++++++++++++++++++++-
>  include/uapi/linux/cxl_mem.h |   1 +
>  3 files changed, 213 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
> index 63d7f7e01b83..a1aa9f787a2a 100644
> --- a/drivers/cxl/cxl.h
> +++ b/drivers/cxl/cxl.h
> @@ -67,6 +67,7 @@ struct cxl_memdev;
>   *                (CXL 2.0 8.2.8.4.3 Mailbox Capabilities Register)
>   * @mbox_mutex: Mutex to synchronize mailbox access.
>   * @firmware_version: Firmware version for the memory device.
> + * @enabled_commands: Hardware commands found enabled in CEL.
>   * @pmem: Persistent memory capacity information.
>   * @ram: Volatile memory capacity information.
>   */
> @@ -82,6 +83,7 @@ struct cxl_mem {
>  	size_t payload_size;
>  	struct mutex mbox_mutex; /* Protects device mailbox and firmware */
>  	char firmware_version[0x10];
> +	unsigned long *enabled_cmds;
>  
>  	struct range pmem_range;
>  	struct range ram_range;
> diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c
> index a819f090ffe2..712a8ccc496a 100644
> --- a/drivers/cxl/mem.c
> +++ b/drivers/cxl/mem.c
> @@ -45,6 +45,8 @@ enum opcode {
>  	CXL_MBOX_OP_INVALID		= 0x0000,
>  	CXL_MBOX_OP_RAW			= CXL_MBOX_OP_INVALID,
>  	CXL_MBOX_OP_ACTIVATE_FW		= 0x0202,
> +	CXL_MBOX_OP_GET_SUPPORTED_LOGS	= 0x0400,
> +	CXL_MBOX_OP_GET_LOG		= 0x0401,
>  	CXL_MBOX_OP_IDENTIFY		= 0x4000,
>  	CXL_MBOX_OP_SET_PARTITION_INFO	= 0x4101,
>  	CXL_MBOX_OP_SET_LSA		= 0x4103,
> @@ -103,10 +105,28 @@ static DEFINE_IDA(cxl_memdev_ida);
>  static struct dentry *cxl_debugfs;
>  static bool cxl_raw_allow_all;
>  
> +enum {
> +	CEL_UUID,
> +	VENDOR_DEBUG_UUID,
> +};
> +
> +/* See CXL 2.0 Table 170. Get Log Input Payload */
> +static const uuid_t log_uuid[] = {
> +	[CEL_UUID] = UUID_INIT(0xda9c0b5, 0xbf41, 0x4b78, 0x8f, 0x79, 0x96,
> +			       0xb1, 0x62, 0x3b, 0x3f, 0x17),
> +	[VENDOR_DEBUG_UUID] = UUID_INIT(0xe1819d9, 0x11a9, 0x400c, 0x81, 0x1f,
> +					0xd6, 0x07, 0x19, 0x40, 0x3d, 0x86),
> +};
> +
>  /**
>   * struct cxl_mem_command - Driver representation of a memory device command
>   * @info: Command information as it exists for the UAPI
>   * @opcode: The actual bits used for the mailbox protocol
> + * @flags: Set of flags effecting driver behavior.
> + *
> + *  * %CXL_CMD_FLAG_FORCE_ENABLE: In cases of error, commands with this flag
> + *    will be enabled by the driver regardless of what hardware may have
> + *    advertised.
>   *
>   * The cxl_mem_command is the driver's internal representation of commands that
>   * are supported by the driver. Some of these commands may not be supported by
> @@ -118,9 +138,12 @@ static bool cxl_raw_allow_all;
>  struct cxl_mem_command {
>  	struct cxl_command_info info;
>  	enum opcode opcode;
> +	u32 flags;
> +#define CXL_CMD_FLAG_NONE 0
> +#define CXL_CMD_FLAG_FORCE_ENABLE BIT(0)
>  };
>  
> -#define CXL_CMD(_id, sin, sout)                                                \
> +#define CXL_CMD(_id, sin, sout, _flags)                                        \
>  	[CXL_MEM_COMMAND_ID_##_id] = {                                         \
>  	.info =	{                                                              \
>  			.id = CXL_MEM_COMMAND_ID_##_id,                        \
> @@ -128,6 +151,7 @@ struct cxl_mem_command {
>  			.size_out = sout,                                      \
>  		},                                                             \
>  	.opcode = CXL_MBOX_OP_##_id,                                           \
> +	.flags = _flags,                                                       \
>  	}
>  
>  /*
> @@ -137,10 +161,11 @@ struct cxl_mem_command {
>   * 0, and the user passed in 1, it is an error.
>   */
>  static struct cxl_mem_command mem_commands[] = {
> -	CXL_CMD(IDENTIFY, 0, 0x43),
> +	CXL_CMD(IDENTIFY, 0, 0x43, CXL_CMD_FLAG_FORCE_ENABLE),
>  #ifdef CONFIG_CXL_MEM_RAW_COMMANDS
> -	CXL_CMD(RAW, ~0, ~0),
> +	CXL_CMD(RAW, ~0, ~0, 0),
>  #endif
> +	CXL_CMD(GET_SUPPORTED_LOGS, 0, ~0, CXL_CMD_FLAG_FORCE_ENABLE),
>  };
>  
>  /*
> @@ -619,6 +644,10 @@ static int cxl_validate_cmd_from_user(struct cxl_mem *cxlm,
>  	c = &mem_commands[send_cmd->id];
>  	info = &c->info;
>  
> +	/* Check that the command is enabled for hardware */
> +	if (!test_bit(info->id, cxlm->enabled_cmds))
> +		return -ENOTTY;
> +
>  	/* Check the input buffer is the expected size */
>  	if (info->size_in >= 0 && info->size_in != send_cmd->in.size)
>  		return -ENOMEM;
> @@ -915,6 +944,14 @@ static struct cxl_mem *cxl_mem_create(struct pci_dev *pdev, u32 reg_lo,
>  	mutex_init(&cxlm->mbox_mutex);
>  	cxlm->pdev = pdev;
>  	cxlm->regs = regs + offset;
> +	cxlm->enabled_cmds =
> +		devm_kmalloc_array(dev, BITS_TO_LONGS(cxl_cmd_count),
> +				   sizeof(unsigned long),
> +				   GFP_KERNEL | __GFP_ZERO);
> +	if (!cxlm->enabled_cmds) {
> +		dev_err(dev, "No memory available for bitmap\n");
> +		return NULL;
> +	}
>  
>  	dev_dbg(dev, "Mapped CXL Memory Device resource\n");
>  	return cxlm;
> @@ -1134,6 +1171,172 @@ static int cxl_mem_add_memdev(struct cxl_mem *cxlm)
>  	return rc;
>  }
>  
> +static int cxl_xfer_log(struct cxl_mem *cxlm, uuid_t *uuid, u32 size, u8 *out)
> +{
> +	u32 remaining = size;
> +	u32 offset = 0;
> +
> +	while (remaining) {
> +		u32 xfer_size = min_t(u32, remaining, cxlm->payload_size);
> +		struct cxl_mbox_get_log {
> +			uuid_t uuid;
> +			__le32 offset;
> +			__le32 length;
> +		} __packed log = {
> +			.uuid = *uuid,
> +			.offset = cpu_to_le32(offset),
> +			.length = cpu_to_le32(xfer_size)
> +		};
> +		int rc;
> +
> +		rc = cxl_mem_mbox_send_cmd(cxlm, CXL_MBOX_OP_GET_LOG,
> +					   (u8 *)&log, sizeof(log), out,
> +					   xfer_size);
> +		if (rc < 0)
> +			return rc;
> +
> +		out += xfer_size;
> +		remaining -= xfer_size;
> +		offset += xfer_size;
> +	}
> +
> +	return 0;
> +}
> +
> +static inline struct cxl_mem_command *cxl_mem_find_command(u16 opcode)
> +{
> +	struct cxl_mem_command *c;
> +
> +	cxl_for_each_cmd(c)
> +		if (c->opcode == opcode)
> +			return c;
> +
> +	return NULL;
> +}
> +
> +/**
> + * cxl_walk_cel() - Walk through the Command Effects Log.
> + * @cxlm: Device.
> + * @size: Length of the Command Effects Log.
> + * @cel: CEL
> + *
> + * Iterate over each entry in the CEL and determine if the driver supports the
> + * command. If so, the command is enabled for the device and can be used later.
> + */
> +static void cxl_walk_cel(struct cxl_mem *cxlm, size_t size, u8 *cel)
> +{
> +	struct cel_entry {
> +		__le16 opcode;
> +		__le16 effect;
> +	} __packed * cel_entry;
> +	const int cel_entries = size / sizeof(*cel_entry);
> +	int i;
> +
> +	cel_entry = (struct cel_entry *)cel;
> +
> +	for (i = 0; i < cel_entries; i++) {
> +		u16 opcode = le16_to_cpu(cel_entry[i].opcode);
> +		struct cxl_mem_command *cmd = cxl_mem_find_command(opcode);
> +
> +		if (!cmd) {
> +			dev_dbg(&cxlm->pdev->dev,
> +				"Opcode 0x%04x unsupported by driver", opcode);
> +			continue;
> +		}
> +
> +		set_bit(cmd->info.id, cxlm->enabled_cmds);
> +	}
> +}
> +
> +struct cxl_mbox_get_supported_logs {
> +	__le16 entries;
> +	u8 rsvd[6];
> +	struct gsl_entry {
> +		uuid_t uuid;
> +		__le32 size;
> +	} __packed entry[];
> +} __packed;
> +
> +static struct cxl_mbox_get_supported_logs *cxl_get_gsl(struct cxl_mem *cxlm)
> +{
> +	struct cxl_mbox_get_supported_logs *ret;
> +	int rc;
> +
> +	ret = kvmalloc(cxlm->payload_size, GFP_KERNEL);
> +	if (!ret)
> +		return ERR_PTR(-ENOMEM);
> +
> +	rc = cxl_mem_mbox_send_cmd(cxlm, CXL_MBOX_OP_GET_SUPPORTED_LOGS, NULL,
> +				   0, (u8 *)ret, sizeof(*ret));
> +	if (rc < 0) {
> +		kvfree(ret);
> +		return ERR_PTR(rc);
> +	}
> +
> +	return ret;
> +}

In v3 the logic here got reworked and it attempted to get the actual size of the
get_supported_logs payload. The way I wrote it, if there was even 1 supported
log (CEL is required, so there would be), it would overrun the stack variable
'temp'. This was trying to be too miserly and this version simply allocates the
full payload amount.

Userspace commands were already guarded against this issue both logically, and
they never use stack variables.

You might be wondering, how do you know the max payload size is enough to hold
all the supported logs? You do not. I'd call this a spec bug and I'll work that
separately. Unlike other commands, there is no way to provide an offset into the
output here. While unlikely this will happen in practice, the spec should
address it.

> +
> +/**
> + * cxl_mem_enumerate_cmds() - Enumerate commands for a device.
> + * @cxlm: The device.
> + *
> + * Returns 0 if enumerate completed successfully.
> + *
> + * CXL devices have optional support for certain commands. This function will
> + * determine the set of supported commands for the hardware and update the
> + * enabled_cmds bitmap in the @cxlm.
> + */
> +static int cxl_mem_enumerate_cmds(struct cxl_mem *cxlm)
> +{
> +	struct cxl_mbox_get_supported_logs *gsl;
> +	struct device *dev = &cxlm->pdev->dev;
> +	struct cxl_mem_command *cmd;
> +	int i, rc;
> +
> +	gsl = cxl_get_gsl(cxlm);
> +	if (IS_ERR(gsl))
> +		return PTR_ERR(gsl);
> +
> +	rc = -ENOENT;
> +	for (i = 0; i < le16_to_cpu(gsl->entries); i++) {
> +		u32 size = le32_to_cpu(gsl->entry[i].size);
> +		uuid_t uuid = gsl->entry[i].uuid;
> +		u8 *log;
> +
> +		dev_dbg(dev, "Found LOG type %pU of size %d", &uuid, size);
> +
> +		if (!uuid_equal(&uuid, &log_uuid[CEL_UUID]))
> +			continue;
> +
> +		log = kvmalloc(size, GFP_KERNEL);
> +		if (!log) {
> +			rc = -ENOMEM;
> +			goto out;
> +		}
> +
> +		rc = cxl_xfer_log(cxlm, &uuid, size, log);
> +		if (rc) {
> +			kvfree(log);
> +			goto out;
> +		}
> +
> +		cxl_walk_cel(cxlm, size, log);
> +		kvfree(log);
> +
> +		/* In case CEL was bogus, enable some default commands. */
> +		cxl_for_each_cmd(cmd)
> +			if (cmd->flags & CXL_CMD_FLAG_FORCE_ENABLE)
> +				set_bit(cmd->info.id, cxlm->enabled_cmds);
> +
> +		/* Found the required CEL */
> +		rc = 0;
> +	}
> +
> +out:
> +	kvfree(gsl);
> +	return rc;
> +}
> +
>  /**
>   * cxl_mem_identify() - Send the IDENTIFY command to the device.
>   * @cxlm: The device to identify.
> @@ -1233,6 +1436,10 @@ static int cxl_mem_probe(struct pci_dev *pdev, const struct pci_device_id *id)
>  	if (rc)
>  		return rc;
>  
> +	rc = cxl_mem_enumerate_cmds(cxlm);
> +	if (rc)
> +		return rc;
> +
>  	rc = cxl_mem_identify(cxlm);
>  	if (rc)
>  		return rc;
> diff --git a/include/uapi/linux/cxl_mem.h b/include/uapi/linux/cxl_mem.h
> index 8eb669150ecb..3b5bf4b58fb4 100644
> --- a/include/uapi/linux/cxl_mem.h
> +++ b/include/uapi/linux/cxl_mem.h
> @@ -23,6 +23,7 @@
>  	___C(INVALID, "Invalid Command"),                                 \
>  	___C(IDENTIFY, "Identify Command"),                               \
>  	___C(RAW, "Raw device command"),                                  \
> +	___C(GET_SUPPORTED_LOGS, "Get Supported Logs"),                   \
>  	___C(MAX, "invalid / last command")
>  
>  #define ___C(a, b) CXL_MEM_COMMAND_ID_##a
> -- 
> 2.30.1
> 

^ permalink raw reply	[flat|nested] 13+ messages in thread

* Re: [PATCH v3 3/9] cxl/mem: Register CXL memX devices
  2021-02-12 22:25 ` [PATCH v3 3/9] cxl/mem: Register CXL memX devices Ben Widawsky
@ 2021-02-15 16:30   ` Guenter Roeck
  0 siblings, 0 replies; 13+ messages in thread
From: Guenter Roeck @ 2021-02-15 16:30 UTC (permalink / raw)
  To: Ben Widawsky
  Cc: linux-cxl, linux-acpi, linux-kernel, linux-nvdimm, linux-pci,
	Bjorn Helgaas, Chris Browy, Christoph Hellwig, Dan Williams,
	David Hildenbrand, David Rientjes, Ira Weiny, Jon Masters,
	Jonathan Cameron, Rafael Wysocki, Randy Dunlap, Vishal Verma,
	John Groves (jgroves),
	Kelley, Sean V

On Fri, Feb 12, 2021 at 02:25:35PM -0800, Ben Widawsky wrote:
> From: Dan Williams <dan.j.williams@intel.com>
> 
> Create the /sys/bus/cxl hierarchy to enumerate:
> 
> * Memory Devices (per-endpoint control devices)
> 
> * Memory Address Space Devices (platform address ranges with
>   interleaving, performance, and persistence attributes)
> 
> * Memory Regions (active provisioned memory from an address space device
>   that is in use as System RAM or delegated to libnvdimm as Persistent
>   Memory regions).
> 
> For now, only the per-endpoint control devices are registered on the
> 'cxl' bus. However, going forward it will provide a mechanism to
> coordinate cross-device interleave.
> 
> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
> Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> (v2)

arm:allmodconfig, i386:allyesconfig, mips:allmodconfig:

drivers/cxl/mem.c:335:2: error: implicit declaration of function 'writeq'; did you mean 'writel'? [-Werror=implicit-function-declaration]
  335 |  writeq(cmd_reg, cxlm->mbox_regs + CXLDEV_MBOX_CMD_OFFSET);

In file included from <command-line>:
drivers/cxl/mem.c: In function '__cxl_mem_mbox_send_cmd':
include/linux/compiler_types.h:320:38: error: call to '__compiletime_assert_266' declared with attribute error: FIELD_GET: mask is zero

and many similar errors.

Guenter

^ permalink raw reply	[flat|nested] 13+ messages in thread

end of thread, other threads:[~2021-02-15 16:32 UTC | newest]

Thread overview: 13+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-02-12 22:25 [PATCH v3 0/9] CXL 2.0 Support Ben Widawsky
2021-02-12 22:25 ` [PATCH v3 1/9] cxl/mem: Introduce a driver for CXL-2.0-Type-3 endpoints Ben Widawsky
2021-02-12 22:25 ` [PATCH v3 2/9] cxl/mem: Find device capabilities Ben Widawsky
2021-02-12 22:25 ` [PATCH v3 3/9] cxl/mem: Register CXL memX devices Ben Widawsky
2021-02-15 16:30   ` Guenter Roeck
2021-02-12 22:25 ` [PATCH v3 4/9] cxl/mem: Add basic IOCTL interface Ben Widawsky
2021-02-12 22:25 ` [PATCH v3 5/9] cxl/mem: Add a "RAW" send command Ben Widawsky
2021-02-12 22:25 ` [PATCH v3 6/9] cxl/mem: Enable commands via CEL Ben Widawsky
2021-02-14  5:46   ` [PATCH v4 06/09] " Ben Widawsky
2021-02-14 16:10     ` Ben Widawsky
2021-02-12 22:25 ` [PATCH v3 7/9] cxl/mem: Add set of informational commands Ben Widawsky
2021-02-12 22:25 ` [PATCH v3 8/9] MAINTAINERS: Add maintainers of the CXL driver Ben Widawsky
2021-02-12 22:25 ` [RFC PATCH 9/9] cxl/mem: Add payload dumping for debug Ben Widawsky

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