From: Raghavendra Rao Ananta <rananta@google.com>
To: Marc Zyngier <maz@kernel.org>, Andrew Jones <drjones@redhat.com>,
James Morse <james.morse@arm.com>,
Alexandru Elisei <alexandru.elisei@arm.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>, Peter Shier <pshier@google.com>,
Ricardo Koller <ricarkol@google.com>,
Oliver Upton <oupton@google.com>,
Reiji Watanabe <reijiw@google.com>,
Jing Zhang <jingzhangos@google.com>,
Raghavendra Rao Anata <rananta@google.com>,
linux-arm-kernel@lists.infradead.org,
kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org,
kvm@vger.kernel.org
Subject: [RFC PATCH v3 03/11] KVM: Introduce KVM_CAP_ARM_HVC_FW_REG_BMAP
Date: Tue, 4 Jan 2022 19:49:10 +0000 [thread overview]
Message-ID: <20220104194918.373612-4-rananta@google.com> (raw)
In-Reply-To: <20220104194918.373612-1-rananta@google.com>
Introduce the KVM ARM64 capability, KVM_CAP_ARM_HVC_FW_REG_BMAP,
to indicate the support for psuedo-firmware bitmap extension.
Each of these registers holds a feature-set exposed to the guest
in the form of a bitmap. If supported, a simple 'read' of the
capability should return the number of psuedo-firmware registers
supported. User-space can utilize this to discover the registers.
It can further explore or modify the features using the classical
GET/SET_ONE_REG interface.
Signed-off-by: Raghavendra Rao Ananta <rananta@google.com>
---
Documentation/virt/kvm/api.rst | 21 +++++++++++++++++++++
include/uapi/linux/kvm.h | 1 +
2 files changed, 22 insertions(+)
diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
index aeeb071c7688..646176537f2c 100644
--- a/Documentation/virt/kvm/api.rst
+++ b/Documentation/virt/kvm/api.rst
@@ -6925,6 +6925,27 @@ indicated by the fd to the VM this is called on.
This is intended to support intra-host migration of VMs between userspace VMMs,
upgrading the VMM process without interrupting the guest.
+7.30 KVM_CAP_ARM_HVC_FW_REG_BMAP
+--------------------------------
+
+:Architectures: arm64
+:Parameters: None
+:Returns: Number of psuedo-firmware registers supported
+
+This capability indicates that KVM for arm64 supports the psuedo-firmware
+register bitmap extension. Each of these registers represent the features
+supported by a particular type in the form of a bitmap. By default, these
+registers are set with the upper limit of the features that are supported.
+
+The registers can be accessed via the standard SET_ONE_REG and KVM_GET_ONE_REG
+interfaces. The user-space is expected to read the number of these registers
+available by reading KVM_CAP_ARM_HVC_FW_REG_BMAP, read the current bitmap
+configuration via GET_ONE_REG for each register, and then write back the
+desired bitmap of features that it wishes the guest to see via SET_ONE_REG.
+
+Note that KVM doesn't allow the user-space to modify these registers after
+the VM (any of the vCPUs) has started running.
+
8. Other capabilities.
======================
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 1daa45268de2..209b43dbbc3c 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -1131,6 +1131,7 @@ struct kvm_ppc_resize_hpt {
#define KVM_CAP_EXIT_ON_EMULATION_FAILURE 204
#define KVM_CAP_ARM_MTE 205
#define KVM_CAP_VM_MOVE_ENC_CONTEXT_FROM 206
+#define KVM_CAP_ARM_HVC_FW_REG_BMAP 207
#ifdef KVM_CAP_IRQ_ROUTING
--
2.34.1.448.ga2b2bfdf31-goog
next prev parent reply other threads:[~2022-01-04 19:49 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-04 19:49 [RFC PATCH v3 00/11] KVM: arm64: Add support for hypercall services selection Raghavendra Rao Ananta
2022-01-04 19:49 ` [RFC PATCH v3 01/11] KVM: Capture VM start Raghavendra Rao Ananta
2022-01-07 6:06 ` Reiji Watanabe
2022-01-07 23:43 ` Raghavendra Rao Ananta
2022-01-08 0:04 ` Jim Mattson
2022-01-10 23:07 ` Raghavendra Rao Ananta
2022-01-10 23:57 ` Jim Mattson
2022-01-11 18:52 ` Raghavendra Rao Ananta
2022-01-11 19:16 ` Jim Mattson
2022-01-12 18:29 ` Raghavendra Rao Ananta
2022-01-13 17:21 ` Sean Christopherson
2022-01-14 0:42 ` Raghavendra Rao Ananta
2022-01-14 1:10 ` Sean Christopherson
2022-01-14 21:51 ` Reiji Watanabe
2022-01-18 22:54 ` Raghavendra Rao Ananta
2022-01-19 0:07 ` Sean Christopherson
2022-01-19 7:47 ` Reiji Watanabe
2022-01-20 0:27 ` Sean Christopherson
2022-01-20 19:16 ` Raghavendra Rao Ananta
2022-01-25 15:15 ` Marc Zyngier
2022-01-25 15:10 ` Marc Zyngier
2022-01-11 0:03 ` Reiji Watanabe
2022-01-11 18:54 ` Raghavendra Rao Ananta
2022-01-08 1:06 ` Sean Christopherson
2022-01-10 23:23 ` Raghavendra Rao Ananta
2022-01-11 17:36 ` Sean Christopherson
2022-01-11 18:46 ` Raghavendra Rao Ananta
2022-01-11 19:04 ` Sean Christopherson
2022-01-12 18:08 ` Raghavendra Rao Ananta
2022-01-12 18:24 ` Sean Christopherson
2022-01-12 18:31 ` Sean Christopherson
2022-01-04 19:49 ` [RFC PATCH v3 02/11] KVM: arm64: Factor out firmware register handling from psci.c Raghavendra Rao Ananta
2022-01-04 19:49 ` Raghavendra Rao Ananta [this message]
2022-01-08 5:40 ` [RFC PATCH v3 03/11] KVM: Introduce KVM_CAP_ARM_HVC_FW_REG_BMAP Reiji Watanabe
2022-01-10 23:40 ` Raghavendra Rao Ananta
2022-01-11 4:33 ` Reiji Watanabe
2022-01-04 19:49 ` [RFC PATCH v3 04/11] KVM: arm64: Setup a framework for hypercall bitmap firmware registers Raghavendra Rao Ananta
2022-01-10 6:28 ` Reiji Watanabe
2022-01-11 0:50 ` Raghavendra Rao Ananta
2022-01-12 5:11 ` Reiji Watanabe
2022-01-12 18:02 ` Raghavendra Rao Ananta
2022-01-14 6:23 ` Reiji Watanabe
2022-01-19 6:42 ` Jason Wang
2022-01-19 10:21 ` Marc Zyngier
2022-01-04 19:49 ` [RFC PATCH v3 05/11] KVM: arm64: Add standard hypervisor firmware register Raghavendra Rao Ananta
2022-01-04 19:49 ` [RFC PATCH v3 06/11] KVM: arm64: Add vendor " Raghavendra Rao Ananta
2022-01-04 19:49 ` [RFC PATCH v3 07/11] Docs: KVM: Add doc for the bitmap firmware registers Raghavendra Rao Ananta
2022-01-04 19:49 ` [RFC PATCH v3 08/11] Docs: KVM: Rename psci.rst to hypercalls.rst Raghavendra Rao Ananta
2022-01-04 19:49 ` [RFC PATCH v3 09/11] tools: Import ARM SMCCC definitions Raghavendra Rao Ananta
2022-01-04 19:49 ` [RFC PATCH v3 10/11] selftests: KVM: aarch64: Introduce hypercall ABI test Raghavendra Rao Ananta
2022-01-04 19:49 ` [RFC PATCH v3 11/11] selftests: KVM: aarch64: Add the bitmap firmware registers to get-reg-list Raghavendra Rao Ananta
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