[Qemu-devel] [PATCH 4/5] kvm: make hyperv vapic assist page migratable

[Paolo Bonzini <pbonzini@redhat.com>]

From: Vadim Rozenfeld <vrozenfe@redhat.com>

Signed-off-by: Vadim Rozenfeld <vrozenfe@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 target-i386/cpu.h     |  1 +
 target-i386/kvm.c     | 16 +++++++++++++---
 target-i386/machine.c | 22 ++++++++++++++++++++++
 3 files changed, 36 insertions(+), 3 deletions(-)

diff --git a/target-i386/cpu.h b/target-i386/cpu.h
index 3dba5ef..45bd554 100644
--- a/target-i386/cpu.h
+++ b/target-i386/cpu.h
@@ -864,6 +864,7 @@ typedef struct CPUX86State {
     uint64_t msr_gp_evtsel[MAX_GP_COUNTERS];
     uint64_t msr_hv_hypercall;
     uint64_t msr_hv_guest_os_id;
+    uint64_t msr_hv_vapic;
 
     /* exception/interrupt handling */
     int error_code;
diff --git a/target-i386/kvm.c b/target-i386/kvm.c
index 8f2854a..ddd437f 100644
--- a/target-i386/kvm.c
+++ b/target-i386/kvm.c
@@ -73,6 +73,7 @@ static bool has_msr_bndcfgs;
 static bool has_msr_kvm_steal_time;
 static int lm_capable_kernel;
 static bool has_msr_hv_hypercall;
+static bool has_msr_hv_vapic;
 
 static bool has_msr_architectural_pmu;
 static uint32_t num_architectural_pmu_counters;
@@ -496,6 +497,7 @@ int kvm_arch_init_vcpu(CPUState *cs)
         if (cpu->hyperv_vapic) {
             c->eax |= HV_X64_MSR_HYPERCALL_AVAILABLE;
             c->eax |= HV_X64_MSR_APIC_ACCESS_AVAILABLE;
+            has_msr_hv_vapic = true;
         }
 
         c = &cpuid_data.entries[cpuid_i++];
@@ -503,7 +505,7 @@ int kvm_arch_init_vcpu(CPUState *cs)
         if (cpu->hyperv_relaxed_timing) {
             c->eax |= HV_X64_RELAXED_TIMING_RECOMMENDED;
         }
-        if (cpu->hyperv_vapic) {
+        if (has_msr_hv_vapic) {
             c->eax |= HV_X64_APIC_ACCESS_RECOMMENDED;
         }
         c->ebx = cpu->hyperv_spinlock_attempts;
@@ -1233,8 +1235,9 @@ static int kvm_put_msrs(X86CPU *cpu, int level)
             kvm_msr_entry_set(&msrs[n++], HV_X64_MSR_HYPERCALL,
                               env->msr_hv_hypercall);
         }
-        if (cpu->hyperv_vapic) {
-            kvm_msr_entry_set(&msrs[n++], HV_X64_MSR_APIC_ASSIST_PAGE, 0);
+        if (has_msr_hv_vapic) {
+            kvm_msr_entry_set(&msrs[n++], HV_X64_MSR_APIC_ASSIST_PAGE,
+                              env->msr_hv_vapic);
         }
 
         /* Note: MSR_IA32_FEATURE_CONTROL is written separately, see
@@ -1524,6 +1527,10 @@ static int kvm_get_msrs(X86CPU *cpu)
         msrs[n++].index = HV_X64_MSR_HYPERCALL;
         msrs[n++].index = HV_X64_MSR_GUEST_OS_ID;
     }
+    if (has_msr_hv_vapic) {
+        msrs[n++].index = HV_X64_MSR_APIC_ASSIST_PAGE;
+    }
+
     msr_data.info.nmsrs = n;
     ret = kvm_vcpu_ioctl(CPU(cpu), KVM_GET_MSRS, &msr_data);
     if (ret < 0) {
@@ -1637,6 +1644,9 @@ static int kvm_get_msrs(X86CPU *cpu)
         case HV_X64_MSR_GUEST_OS_ID:
             env->msr_hv_guest_os_id = msrs[i].data;
             break;
+        case HV_X64_MSR_APIC_ASSIST_PAGE:
+            env->msr_hv_vapic = msrs[i].data;
+            break;
         }
     }
 
diff --git a/target-i386/machine.c b/target-i386/machine.c
index 96fd045..e72e270 100644
--- a/target-i386/machine.c
+++ b/target-i386/machine.c
@@ -574,6 +574,25 @@ static const VMStateDescription vmstate_msr_hypercall_hypercall = {
     }
 };
 
+static bool hyperv_vapic_enable_needed(void *opaque)
+{
+    X86CPU *cpu = opaque;
+    CPUX86State *env = &cpu->env;
+
+    return env->msr_hv_vapic != 0;
+}
+
+static const VMStateDescription vmstate_msr_hyperv_vapic = {
+    .name = "cpu/msr_hyperv_vapic",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .minimum_version_id_old = 1,
+    .fields      = (VMStateField []) {
+        VMSTATE_UINT64(env.msr_hv_vapic, X86CPU),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
 const VMStateDescription vmstate_x86_cpu = {
     .name = "cpu",
     .version_id = 12,
@@ -711,6 +730,9 @@ const VMStateDescription vmstate_x86_cpu = {
         }, {
             .vmsd = &vmstate_msr_hypercall_hypercall,
             .needed = hyperv_hypercall_enable_needed,
+        }, {
+            .vmsd = &vmstate_msr_hyperv_vapic,
+            .needed = hyperv_vapic_enable_needed,
         } , {
             /* empty */
         }
-- 
1.8.3.1