KVM: x86: release kvmclock page on reset

When a vcpu is reset, kvmclock page keeps being written to this days.
This is wrong and inconsistent: a cpu reset should take it to its
initial state.

Signed-off-by: Glauber Costa <glommer@redhat.com>
CC: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 7faf262..712af90 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1453,6 +1453,14 @@ static int kvm_pv_enable_async_pf(struct kvm_vcpu *vcpu, u64 data)
        return 0;
 }
 
+static void kvmclock_reset(struct kvm_vcpu *vcpu)
+{
+       if (vcpu->arch.time_page) {
+               kvm_release_page_dirty(vcpu->arch.time_page);
+               vcpu->arch.time_page = NULL;
+       }
+}
+
 int kvm_set_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 data)
 {
        switch (msr) {
@@ -1510,10 +1518,7 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 data)
                break;
        case MSR_KVM_SYSTEM_TIME_NEW:
        case MSR_KVM_SYSTEM_TIME: {
-               if (vcpu->arch.time_page) {
-                       kvm_release_page_dirty(vcpu->arch.time_page);
-                       vcpu->arch.time_page = NULL;
-               }
+               kvmclock_reset(vcpu);
 
                vcpu->arch.time = data;
                kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu);
@@ -5837,10 +5842,7 @@ void kvm_put_guest_fpu(struct kvm_vcpu *vcpu)
 
 void kvm_arch_vcpu_free(struct kvm_vcpu *vcpu)
 {
-       if (vcpu->arch.time_page) {
-               kvm_release_page_dirty(vcpu->arch.time_page);
-               vcpu->arch.time_page = NULL;
-       }
+       kvmclock_reset(vcpu);
 
        free_cpumask_var(vcpu->arch.wbinvd_dirty_mask);
        fx_free(vcpu);
@@ -5901,6 +5903,8 @@ int kvm_arch_vcpu_reset(struct kvm_vcpu *vcpu)
        kvm_make_request(KVM_REQ_EVENT, vcpu);
        vcpu->arch.apf.msr_val = 0;
 
+       kvmclock_reset(vcpu);
+
        kvm_clear_async_pf_completion_queue(vcpu);
        kvm_async_pf_hash_reset(vcpu);
        vcpu->arch.apf.halted = false;