linux-kernel - [RFC PATCH v4 14/39] KVM: arm64: Add SPE capability and VCPU feature

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Message-Id: <20210825161815.266051-15-alexandru.elisei@arm.com>
Date:   Wed, 25 Aug 2021 17:17:50 +0100
From:   Alexandru Elisei <alexandru.elisei@....com>
To:     maz@...nel.org, james.morse@....com, suzuki.poulose@....com,
        linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.cs.columbia.edu,
        will@...nel.org, linux-kernel@...r.kernel.org
Subject: [RFC PATCH v4 14/39] KVM: arm64: Add SPE capability and VCPU feature

Add the KVM_CAP_ARM_SPE capability which allows userspace to discover if
SPE emulation is available. Add the KVM_ARM_VCPU_SPE feature which
enables the emulation for a VCPU.

Both are disabled for now.

Signed-off-by: Alexandru Elisei <alexandru.elisei@....com>
---
 Documentation/virt/kvm/api.rst    | 9 +++++++++
 arch/arm64/include/uapi/asm/kvm.h | 1 +
 arch/arm64/kvm/arm.c              | 3 +++
 include/uapi/linux/kvm.h          | 1 +
 4 files changed, 14 insertions(+)

diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
index 994faa24690a..68fada258b80 100644
--- a/Documentation/virt/kvm/api.rst
+++ b/Documentation/virt/kvm/api.rst
@@ -7315,3 +7315,12 @@ The argument to KVM_ENABLE_CAP is also a bitmask, and must be a subset
 of the result of KVM_CHECK_EXTENSION.  KVM will forward to userspace
 the hypercalls whose corresponding bit is in the argument, and return
 ENOSYS for the others.
+
+8.35 KVM_CAP_ARM_SPE
+--------------------
+
+:Architectures: arm64
+
+This capability indicates that Statistical Profiling Extension (SPE) emulation
+is available in KVM. SPE emulation is enabled for each VCPU which has the
+feature bit KVM_ARM_VCPU_SPE set.
diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
index b3edde68bc3e..9f0a8ea50ea9 100644
--- a/arch/arm64/include/uapi/asm/kvm.h
+++ b/arch/arm64/include/uapi/asm/kvm.h
@@ -106,6 +106,7 @@ struct kvm_regs {
 #define KVM_ARM_VCPU_SVE		4 /* enable SVE for this CPU */
 #define KVM_ARM_VCPU_PTRAUTH_ADDRESS	5 /* VCPU uses address authentication */
 #define KVM_ARM_VCPU_PTRAUTH_GENERIC	6 /* VCPU uses generic authentication */
+#define KVM_ARM_VCPU_SPE		7 /* enable SPE for this CPU */
 
 struct kvm_vcpu_init {
 	__u32 target;
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index e8a7c0c3a086..22544eb367f3 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -304,6 +304,9 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 	case KVM_CAP_ARM_VCPU_SUPPORTED_CPUS:
 		r = 1;
 		break;
+	case KVM_CAP_ARM_SPE:
+		r = 0;
+		break;
 	default:
 		r = 0;
 	}
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index e5acc925c528..930ef91f7916 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -1114,6 +1114,7 @@ struct kvm_ppc_resize_hpt {
 #define KVM_CAP_ARM_MTE 205
 #define KVM_CAP_ARM_LOCK_USER_MEMORY_REGION 206
 #define KVM_CAP_ARM_VCPU_SUPPORTED_CPUS 207
+#define KVM_CAP_ARM_SPE 208
 
 #ifdef KVM_CAP_IRQ_ROUTING
 
-- 
2.33.0