[Qemu-devel] [PATCH v1] kvm/x86: Remove Hyper-V SynIC timer stopping

[Andrey Smetanin]

It's possible that guest send us Hyper-V EOM at the middle
of Hyper-V SynIC timer running, so we start processing of Hyper-V
SynIC timers in vcpu context and stop the Hyper-V SynIC timer
uncoditionally and lose time expiration which Windows 2012R2 guest
expects.

The patch fixes such situation by not stopping Hyper-V SynIC timer
at all, because it's safe to restart it without stop in vcpu context
and timer callback always returns HRTIMER_NORESTART.

Signed-off-by: Andrey Smetanin <address@hidden>
CC: Gleb Natapov <address@hidden>
CC: Paolo Bonzini <address@hidden>
CC: Roman Kagan <address@hidden>
CC: Denis V. Lunev <address@hidden>
CC: address@hidden

---
 arch/x86/kvm/hyperv.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index 8ff8829..f34f666 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -598,7 +598,6 @@ void kvm_hv_process_stimers(struct kvm_vcpu *vcpu)
        for (i = 0; i < ARRAY_SIZE(hv_vcpu->stimer); i++)
                if (test_and_clear_bit(i, hv_vcpu->stimer_pending_bitmap)) {
                        stimer = &hv_vcpu->stimer[i];
-                       stimer_stop(stimer);
                        if (stimer->config & HV_STIMER_ENABLE) {
                                time_now = get_time_ref_counter(vcpu->kvm);
                                if (time_now >= stimer->exp_time)
-- 
2.4.3