KVM: x86: fix pvclock guest stopped flag reporting

kvm_guest_time_update unconditionally clears hv_clock.flags field,
so the notification never reaches the guest.

Fix it by allowing PVCLOCK_GUEST_STOPPED to passthrough.

Reviewed-by: Eric B Munson <emunson@mgebm.net>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

1 files changed, 10 insertions, 3 deletions

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 91a595827deb..fb0d93788bfb 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1134,6 +1134,7 @@ static int kvm_guest_time_update(struct kvm_vcpu *v)
         unsigned long this_tsc_khz;
         s64 kernel_ns, max_kernel_ns;
         u64 tsc_timestamp;
+        u8 pvclock_flags;
 
         /* Keep irq disabled to prevent changes to the clock */
         local_irq_save(flags);
@@ -1215,7 +1216,14 @@ static int kvm_guest_time_update(struct kvm_vcpu *v)
         vcpu->hv_clock.system_time = kernel_ns + v->kvm->arch.kvmclock_offset;
         vcpu->last_kernel_ns = kernel_ns;
         vcpu->last_guest_tsc = tsc_timestamp;
-        vcpu->hv_clock.flags = 0;
+
+        pvclock_flags = 0;
+        if (vcpu->pvclock_set_guest_stopped_request) {
+                pvclock_flags |= PVCLOCK_GUEST_STOPPED;
+                vcpu->pvclock_set_guest_stopped_request = false;
+        }
+
+        vcpu->hv_clock.flags = pvclock_flags;
 
         /*
          * The interface expects us to write an even number signaling that the
@@ -2624,10 +2632,9 @@ static int kvm_vcpu_ioctl_x86_set_xcrs(struct kvm_vcpu *vcpu,
  */
 static int kvm_set_guest_paused(struct kvm_vcpu *vcpu)
 {
-        struct pvclock_vcpu_time_info *src = &vcpu->arch.hv_clock;
         if (!vcpu->arch.time_page)
                 return -EINVAL;
-        src->flags |= PVCLOCK_GUEST_STOPPED;
+        vcpu->arch.pvclock_set_guest_stopped_request = true;
         kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu);
         return 0;
 }