@@ -96,6 +96,9 @@ 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_MIGRATION_CONTROL 16 guest checks this feature bit before
+ using MSR_KVM_MIGRATION_CONTROL
+
KVM_FEATURE_CLOCKSOURCE_STABLE_BIT 24 host will warn if no guest-side
per-cpu warps are expected in
kvmclock
@@ -376,3 +376,12 @@ 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_MIGRATION_CONTROL:
+ 0x4b564d08
+
+data:
+ This MSR is available if KVM_FEATURE_MIGRATION_CONTROL is present in
+ CPUID. Bit 0 represents whether live migration of the guest is allowed.
+ When a guest is started, bit 0 will be 1 if the guest has encrypted
+ memory and 0 if the guest does not have encrypted memory.
@@ -111,6 +111,7 @@ KVM_X86_OP(enable_smi_window)
KVM_X86_OP_NULL(mem_enc_op)
KVM_X86_OP_NULL(mem_enc_reg_region)
KVM_X86_OP_NULL(mem_enc_unreg_region)
+KVM_X86_OP(has_encrypted_memory)
KVM_X86_OP(get_msr_feature)
KVM_X86_OP(can_emulate_instruction)
KVM_X86_OP(apic_init_signal_blocked)
@@ -1364,6 +1364,7 @@ struct kvm_x86_ops {
int (*pre_leave_smm)(struct kvm_vcpu *vcpu, const char *smstate);
void (*enable_smi_window)(struct kvm_vcpu *vcpu);
+ bool (*has_encrypted_memory)(struct kvm *kvm);
int (*mem_enc_op)(struct kvm *kvm, void __user *argp);
int (*mem_enc_reg_region)(struct kvm *kvm, struct kvm_enc_region *argp);
int (*mem_enc_unreg_region)(struct kvm *kvm, struct kvm_enc_region *argp);
@@ -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_MIGRATION_CONTROL 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_MIGRATION_CONTROL 0x4b564d08
struct kvm_steal_time {
__u64 steal;
@@ -90,6 +92,8 @@ struct kvm_clock_pairing {
/* MSR_KVM_ASYNC_PF_INT */
#define KVM_ASYNC_PF_VEC_MASK GENMASK(7, 0)
+/* MSR_KVM_MIGRATION_CONTROL */
+#define KVM_MIGRATION_READY (1 << 0)
/* Operations for KVM_HC_MMU_OP */
#define KVM_MMU_OP_WRITE_PTE 1
@@ -892,7 +892,8 @@ 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_MIGRATION_CONTROL);
if (sched_info_on())
entry->eax |= (1 << KVM_FEATURE_STEAL_TIME);
@@ -4591,6 +4591,7 @@ static struct kvm_x86_ops svm_x86_ops __initdata = {
.pre_leave_smm = svm_pre_leave_smm,
.enable_smi_window = svm_enable_smi_window,
+ .has_encrypted_memory = sev_guest,
.mem_enc_op = svm_mem_enc_op,
.mem_enc_reg_region = svm_register_enc_region,
.mem_enc_unreg_region = svm_unregister_enc_region,
@@ -7670,6 +7670,11 @@ static bool vmx_check_apicv_inhibit_reasons(ulong bit)
return supported & BIT(bit);
}
+static bool vmx_has_encrypted_memory(struct kvm *kvm)
+{
+ return false;
+}
+
static struct kvm_x86_ops vmx_x86_ops __initdata = {
.hardware_unsetup = hardware_unsetup,
@@ -7800,6 +7805,8 @@ static struct kvm_x86_ops vmx_x86_ops __initdata = {
.complete_emulated_msr = kvm_complete_insn_gp,
.vcpu_deliver_sipi_vector = kvm_vcpu_deliver_sipi_vector,
+
+ .has_encrypted_memory = vmx_has_encrypted_memory,
};
static __init int hardware_setup(void)
@@ -3275,6 +3275,14 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
vcpu->arch.msr_kvm_poll_control = data;
break;
+ case MSR_KVM_MIGRATION_CONTROL:
+ if (!guest_pv_has(vcpu, KVM_FEATURE_MIGRATION_CONTROL))
+ return 1;
+
+ if (data != !static_call(kvm_x86_has_encrypted_memory)(vcpu->kvm))
+ return 1;
+ break;
+
case MSR_IA32_MCG_CTL:
case MSR_IA32_MCG_STATUS:
case MSR_IA32_MC0_CTL ... MSR_IA32_MCx_CTL(KVM_MAX_MCE_BANKS) - 1:
@@ -3568,6 +3576,12 @@ int kvm_get_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
msr_info->data = 0;
break;
+ case MSR_KVM_MIGRATION_CONTROL:
+ if (!guest_pv_has(vcpu, KVM_FEATURE_MIGRATION_CONTROL))
+ return 1;
+
+ msr_info->data = !static_call(kvm_x86_has_encrypted_memory)(vcpu->kvm);
+ break;
case MSR_KVM_STEAL_TIME:
if (!guest_pv_has(vcpu, KVM_FEATURE_STEAL_TIME))
return 1;
Add a new MSR that can be used to communicate whether the page encryption status bitmap is up to date and therefore whether live migration of an encrypted guest is possible. The MSR should be processed by userspace if it is going to live migrate the guest; the default implementation does nothing. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> --- Documentation/virt/kvm/cpuid.rst | 3 +++ Documentation/virt/kvm/msr.rst | 9 +++++++++ arch/x86/include/asm/kvm-x86-ops.h | 1 + arch/x86/include/asm/kvm_host.h | 1 + arch/x86/include/uapi/asm/kvm_para.h | 4 ++++ arch/x86/kvm/cpuid.c | 3 ++- arch/x86/kvm/svm/svm.c | 1 + arch/x86/kvm/vmx/vmx.c | 7 +++++++ arch/x86/kvm/x86.c | 14 ++++++++++++++ 9 files changed, 42 insertions(+), 1 deletion(-)