[Qemu-devel] [PULL 17/25] target/i386: kvm: Block migration for vCPUs exposed with nested virtualization

[Paolo Bonzini]

From: Liran Alon <address@hidden>

Commit d98f26073beb ("target/i386: kvm: add VMX migration blocker")
added a migration blocker for vCPU exposed with Intel VMX.
However, migration should also be blocked for vCPU exposed with
AMD SVM.

Both cases should be blocked because QEMU should extract additional
vCPU state from KVM that should be migrated as part of vCPU VMState.
E.g. Whether vCPU is running in guest-mode or host-mode.

Fixes: d98f26073beb ("target/i386: kvm: add VMX migration blocker")
Reviewed-by: Maran Wilson <address@hidden>
Signed-off-by: Liran Alon <address@hidden>
Message-Id: <address@hidden>
Signed-off-by: Paolo Bonzini <address@hidden>
---
 target/i386/cpu.c |  6 ------
 target/i386/cpu.h | 22 ++++++++++++++++++++++
 target/i386/kvm.c | 14 +++++++-------
 3 files changed, 29 insertions(+), 13 deletions(-)

diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index c330fd9..61e44cb 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -5215,12 +5215,6 @@ static int x86_cpu_filter_features(X86CPU *cpu)
     return rv;
 }
 
-#define IS_INTEL_CPU(env) ((env)->cpuid_vendor1 == CPUID_VENDOR_INTEL_1 && \
-                           (env)->cpuid_vendor2 == CPUID_VENDOR_INTEL_2 && \
-                           (env)->cpuid_vendor3 == CPUID_VENDOR_INTEL_3)
-#define IS_AMD_CPU(env) ((env)->cpuid_vendor1 == CPUID_VENDOR_AMD_1 && \
-                         (env)->cpuid_vendor2 == CPUID_VENDOR_AMD_2 && \
-                         (env)->cpuid_vendor3 == CPUID_VENDOR_AMD_3)
 static void x86_cpu_realizefn(DeviceState *dev, Error **errp)
 {
     CPUState *cs = CPU(dev);
diff --git a/target/i386/cpu.h b/target/i386/cpu.h
index 7f48136..4ae4145 100644
--- a/target/i386/cpu.h
+++ b/target/i386/cpu.h
@@ -722,6 +722,13 @@ typedef uint32_t FeatureWordArray[FEATURE_WORDS];
 
 #define CPUID_VENDOR_HYGON    "HygonGenuine"
 
+#define IS_INTEL_CPU(env) ((env)->cpuid_vendor1 == CPUID_VENDOR_INTEL_1 && \
+                           (env)->cpuid_vendor2 == CPUID_VENDOR_INTEL_2 && \
+                           (env)->cpuid_vendor3 == CPUID_VENDOR_INTEL_3)
+#define IS_AMD_CPU(env) ((env)->cpuid_vendor1 == CPUID_VENDOR_AMD_1 && \
+                         (env)->cpuid_vendor2 == CPUID_VENDOR_AMD_2 && \
+                         (env)->cpuid_vendor3 == CPUID_VENDOR_AMD_3)
+
 #define CPUID_MWAIT_IBE     (1U << 1) /* Interrupts can exit capability */
 #define CPUID_MWAIT_EMX     (1U << 0) /* enumeration supported */
 
@@ -1848,6 +1855,21 @@ static inline int32_t x86_get_a20_mask(CPUX86State *env)
     }
 }
 
+static inline bool cpu_has_vmx(CPUX86State *env)
+{
+    return (env->features[FEAT_1_ECX] & CPUID_EXT_VMX);
+}
+
+static inline bool cpu_has_svm(CPUX86State *env)
+{
+    return (env->features[FEAT_8000_0001_ECX] & CPUID_EXT3_SVM);
+}
+
+static inline bool cpu_has_nested_virt(CPUX86State *env)
+{
+    return (cpu_has_vmx(env) || cpu_has_svm(env));
+}
+
 /* fpu_helper.c */
 void update_fp_status(CPUX86State *env);
 void update_mxcsr_status(CPUX86State *env);
diff --git a/target/i386/kvm.c b/target/i386/kvm.c
index 9864aa0..f9872f1 100644
--- a/target/i386/kvm.c
+++ b/target/i386/kvm.c
@@ -1299,7 +1299,7 @@ static int hyperv_init_vcpu(X86CPU *cpu)
 }
 
 static Error *invtsc_mig_blocker;
-static Error *vmx_mig_blocker;
+static Error *nested_virt_mig_blocker;
 
 #define KVM_MAX_CPUID_ENTRIES  100
 
@@ -1597,13 +1597,13 @@ int kvm_arch_init_vcpu(CPUState *cs)
                                   !!(c->ecx & CPUID_EXT_SMX);
     }
 
-    if ((env->features[FEAT_1_ECX] & CPUID_EXT_VMX) && !vmx_mig_blocker) {
-        error_setg(&vmx_mig_blocker,
-                   "Nested VMX virtualization does not support live migration 
yet");
-        r = migrate_add_blocker(vmx_mig_blocker, &local_err);
+    if (cpu_has_nested_virt(env) && !nested_virt_mig_blocker) {
+        error_setg(&nested_virt_mig_blocker,
+                   "Nested virtualization does not support live migration 
yet");
+        r = migrate_add_blocker(nested_virt_mig_blocker, &local_err);
         if (local_err) {
             error_report_err(local_err);
-            error_free(vmx_mig_blocker);
+            error_free(nested_virt_mig_blocker);
             return r;
         }
     }
@@ -1674,7 +1674,7 @@ int kvm_arch_init_vcpu(CPUState *cs)
  fail:
     migrate_del_blocker(invtsc_mig_blocker);
  fail2:
-    migrate_del_blocker(vmx_mig_blocker);
+    migrate_del_blocker(nested_virt_mig_blocker);
 
     return r;
 }
-- 
1.8.3.1