target/i386: Fix VM migration when interrupt based APF is enabled

Commit Message

Vitaly Kuznetsov Sept. 17, 2020, 10:23 a.m. UTC

VM with  interrupt based APF enabled fails to migrate:
qemu-system-x86_64: error: failed to set MSR 0x4b564d02 to 0xf3

We have two issues:
1) There is a typo in kvm_put_msrs() and we write async_pf_int_msr
to MSR_KVM_ASYNC_PF_EN (instead of MSR_KVM_ASYNC_PF_INT)

2) We restore MSR_KVM_ASYNC_PF_EN before MSR_KVM_ASYNC_PF_INT is set
and this violates the check in KVM.

Re-order MSR_KVM_ASYNC_PF_EN/MSR_KVM_ASYNC_PF_INT setting (and
kvm_get_msrs() for consistency) and fix the typo.

Signed-off-by: Vitaly Kuznetsov <[e-mail]>
---
This fixes queued but not yet pushed to git commit
"target/i386: support KVM_FEATURE_ASYNC_PF_INT"
---
 target/i386/kvm.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

Patch

diff --git a/target/i386/kvm.c b/target/i386/kvm.c
index b26370662075..4a8b3a41c1bc 100644
--- a/target/i386/kvm.c
+++ b/target/i386/kvm.c
@@ -2818,12 +2818,12 @@  static int kvm_put_msrs(X86CPU *cpu, int level)
         kvm_msr_entry_add(cpu, MSR_IA32_TSC, env->tsc);
         kvm_msr_entry_add(cpu, MSR_KVM_SYSTEM_TIME, env->system_time_msr);
         kvm_msr_entry_add(cpu, MSR_KVM_WALL_CLOCK, env->wall_clock_msr);
+        if (env->features[FEAT_KVM] & (1 << KVM_FEATURE_ASYNC_PF_INT)) {
+            kvm_msr_entry_add(cpu, MSR_KVM_ASYNC_PF_INT, env->async_pf_int_msr);
+        }
         if (env->features[FEAT_KVM] & (1 << KVM_FEATURE_ASYNC_PF)) {
             kvm_msr_entry_add(cpu, MSR_KVM_ASYNC_PF_EN, env->async_pf_en_msr);
         }
-        if (env->features[FEAT_KVM] & (1 << KVM_FEATURE_ASYNC_PF_INT)) {
-            kvm_msr_entry_add(cpu, MSR_KVM_ASYNC_PF_EN, env->async_pf_int_msr);
-        }
         if (env->features[FEAT_KVM] & (1 << KVM_FEATURE_PV_EOI)) {
             kvm_msr_entry_add(cpu, MSR_KVM_PV_EOI_EN, env->pv_eoi_en_msr);
         }
@@ -3206,12 +3206,12 @@  static int kvm_get_msrs(X86CPU *cpu)
 #endif
     kvm_msr_entry_add(cpu, MSR_KVM_SYSTEM_TIME, 0);
     kvm_msr_entry_add(cpu, MSR_KVM_WALL_CLOCK, 0);
-    if (env->features[FEAT_KVM] & (1 << KVM_FEATURE_ASYNC_PF)) {
-        kvm_msr_entry_add(cpu, MSR_KVM_ASYNC_PF_EN, 0);
-    }
     if (env->features[FEAT_KVM] & (1 << KVM_FEATURE_ASYNC_PF_INT)) {
         kvm_msr_entry_add(cpu, MSR_KVM_ASYNC_PF_INT, 0);
     }
+    if (env->features[FEAT_KVM] & (1 << KVM_FEATURE_ASYNC_PF)) {
+        kvm_msr_entry_add(cpu, MSR_KVM_ASYNC_PF_EN, 0);
+    }
     if (env->features[FEAT_KVM] & (1 << KVM_FEATURE_PV_EOI)) {
         kvm_msr_entry_add(cpu, MSR_KVM_PV_EOI_EN, 0);
     }