From: Ashish Kalra <ashish.kalra@xxxxxxx>
Add new KVM_FEATURE_SEV_LIVE_MIGRATION feature for guest to check
for host-side support for SEV live migration. Also add a new custom
MSR_KVM_SEV_LIVE_MIGRATION for guest to enable the SEV live migration
feature.
MSR is handled by userspace using MSR filters.
Signed-off-by: Ashish Kalra <ashish.kalra@xxxxxxx>
---
Documentation/virt/kvm/cpuid.rst | 5 +++++
Documentation/virt/kvm/msr.rst | 12 ++++++++++++
arch/x86/include/uapi/asm/kvm_para.h | 4 ++++
arch/x86/kvm/cpuid.c | 3 ++-
arch/x86/kvm/svm/svm.c | 22 ++++++++++++++++++++++
5 files changed, 45 insertions(+), 1 deletion(-)
diff --git a/Documentation/virt/kvm/cpuid.rst b/Documentation/virt/kvm/cpuid.rst
index cf62162d4be2..0bdb6cdb12d3 100644
--- a/Documentation/virt/kvm/cpuid.rst
+++ b/Documentation/virt/kvm/cpuid.rst
@@ -96,6 +96,11 @@ KVM_FEATURE_MSI_EXT_DEST_ID 15 guest checks this feature bit
before using extended destination
ID bits in MSI address bits 11-5.
+KVM_FEATURE_SEV_LIVE_MIGRATION 16 guest checks this feature bit before
+ using the page encryption state
+ hypercall to notify the page state
+ change
+
KVM_FEATURE_CLOCKSOURCE_STABLE_BIT 24 host will warn if no guest-side
per-cpu warps are expected in
kvmclock
diff --git a/Documentation/virt/kvm/msr.rst b/Documentation/virt/kvm/msr.rst
index e37a14c323d2..020245d16087 100644
--- a/Documentation/virt/kvm/msr.rst
+++ b/Documentation/virt/kvm/msr.rst
@@ -376,3 +376,15 @@ data:
write '1' to bit 0 of the MSR, this causes the host to re-scan its queue
and check if there are more notifications pending. The MSR is available
if KVM_FEATURE_ASYNC_PF_INT is present in CPUID.
+
+MSR_KVM_SEV_LIVE_MIGRATION:
+ 0x4b564d08
+
+ Control SEV Live Migration features.
+
+data:
+ Bit 0 enables (1) or disables (0) host-side SEV Live Migration feature,
+ in other words, this is guest->host communication that it's properly
+ handling the shared pages list.
+
+ All other bits are reserved.
diff --git a/arch/x86/include/uapi/asm/kvm_para.h b/arch/x86/include/uapi/asm/kvm_para.h
index 950afebfba88..f6bfa138874f 100644
--- a/arch/x86/include/uapi/asm/kvm_para.h
+++ b/arch/x86/include/uapi/asm/kvm_para.h
@@ -33,6 +33,7 @@
#define KVM_FEATURE_PV_SCHED_YIELD 13
#define KVM_FEATURE_ASYNC_PF_INT 14
#define KVM_FEATURE_MSI_EXT_DEST_ID 15
+#define KVM_FEATURE_SEV_LIVE_MIGRATION 16
#define KVM_HINTS_REALTIME 0
@@ -54,6 +55,7 @@
#define MSR_KVM_POLL_CONTROL 0x4b564d05
#define MSR_KVM_ASYNC_PF_INT 0x4b564d06
#define MSR_KVM_ASYNC_PF_ACK 0x4b564d07
+#define MSR_KVM_SEV_LIVE_MIGRATION 0x4b564d08
struct kvm_steal_time {
__u64 steal;
@@ -136,4 +138,6 @@ struct kvm_vcpu_pv_apf_data {
#define KVM_PV_EOI_ENABLED KVM_PV_EOI_MASK
#define KVM_PV_EOI_DISABLED 0x0
+#define KVM_SEV_LIVE_MIGRATION_ENABLED BIT_ULL(0)
+
#endif /* _UAPI_ASM_X86_KVM_PARA_H */
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 6bd2f8b830e4..4e2e69a692aa 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -812,7 +812,8 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
(1 << KVM_FEATURE_PV_SEND_IPI) |
(1 << KVM_FEATURE_POLL_CONTROL) |
(1 << KVM_FEATURE_PV_SCHED_YIELD) |
- (1 << KVM_FEATURE_ASYNC_PF_INT);
+ (1 << KVM_FEATURE_ASYNC_PF_INT) |
+ (1 << KVM_FEATURE_SEV_LIVE_MIGRATION);
if (sched_info_on())
entry->eax |= (1 << KVM_FEATURE_STEAL_TIME);
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 3cbf000beff1..1ac79e2f2a6c 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -2800,6 +2800,17 @@ static int svm_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
case MSR_F10H_DECFG:
msr_info->data = svm->msr_decfg;
break;
+ case MSR_KVM_SEV_LIVE_MIGRATION:
+ if (!sev_guest(vcpu->kvm))
+ return 1;
+
+ if (!guest_cpuid_has(vcpu, KVM_FEATURE_SEV_LIVE_MIGRATION))
+ return 1;
+
+ /*
+ * Let userspace handle the MSR using MSR filters.
+ */
+ return KVM_MSR_RET_FILTERED;
default:
return kvm_get_msr_common(vcpu, msr_info);
}
@@ -2996,6 +3007,17 @@ static int svm_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr)
svm->msr_decfg = data;
break;
}
+ case MSR_KVM_SEV_LIVE_MIGRATION:
+ if (!sev_guest(vcpu->kvm))
+ return 1;
+
+ if (!guest_cpuid_has(vcpu, KVM_FEATURE_SEV_LIVE_MIGRATION))
+ return 1;
+
+ /*
+ * Let userspace handle the MSR using MSR filters.
+ */
+ return KVM_MSR_RET_FILTERED;
case MSR_IA32_APICBASE:
if (kvm_vcpu_apicv_active(vcpu))
avic_update_vapic_bar(to_svm(vcpu), data);
--
2.17.1
