2 files changed, 9 insertions, 6 deletions

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 63e020be3da7..af36f89fe67a 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -448,7 +448,7 @@ struct kvm_vcpu_arch {
         u64 tsc_offset_adjustment;
         u64 this_tsc_nsec;
         u64 this_tsc_write;
-        u8  this_tsc_generation;
+        u64 this_tsc_generation;
         bool tsc_catchup;
         bool tsc_always_catchup;
         s8 virtual_tsc_shift;
@@ -591,7 +591,7 @@ struct kvm_arch {
         u64 cur_tsc_nsec;
         u64 cur_tsc_write;
         u64 cur_tsc_offset;
-        u8  cur_tsc_generation;
+        u64 cur_tsc_generation;
         int nr_vcpus_matched_tsc;
 
         spinlock_t pvclock_gtod_sync_lock;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 5a8691b0ed76..f056f855f8e6 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1215,6 +1215,7 @@ void kvm_write_tsc(struct kvm_vcpu *vcpu, struct msr_data *msr)
         unsigned long flags;
         s64 usdiff;
         bool matched;
+        bool already_matched;
         u64 data = msr->data;
 
         raw_spin_lock_irqsave(&kvm->arch.tsc_write_lock, flags);
@@ -1279,6 +1280,7 @@ void kvm_write_tsc(struct kvm_vcpu *vcpu, struct msr_data *msr)
                         pr_debug("kvm: adjusted tsc offset by %llu\n", delta);
                 }
                 matched = true;
+                already_matched = (vcpu->arch.this_tsc_generation == kvm->arch.cur_tsc_generation);
         } else {
                 /*
                  * We split periods of matched TSC writes into generations.
@@ -1294,7 +1296,7 @@ void kvm_write_tsc(struct kvm_vcpu *vcpu, struct msr_data *msr)
                 kvm->arch.cur_tsc_write = data;
                 kvm->arch.cur_tsc_offset = offset;
                 matched = false;
-                pr_debug("kvm: new tsc generation %u, clock %llu\n",
+                pr_debug("kvm: new tsc generation %llu, clock %llu\n",
                          kvm->arch.cur_tsc_generation, data);
         }
 
@@ -1319,10 +1321,11 @@ void kvm_write_tsc(struct kvm_vcpu *vcpu, struct msr_data *msr)
         raw_spin_unlock_irqrestore(&kvm->arch.tsc_write_lock, flags);
 
         spin_lock(&kvm->arch.pvclock_gtod_sync_lock);
-        if (matched)
-                kvm->arch.nr_vcpus_matched_tsc++;
-        else
+        if (!matched) {
                 kvm->arch.nr_vcpus_matched_tsc = 0;
+        } else if (!already_matched) {
+                kvm->arch.nr_vcpus_matched_tsc++;
+        }
 
         kvm_track_tsc_matching(vcpu);
         spin_unlock(&kvm->arch.pvclock_gtod_sync_lock);