Nicolas Saenz Julienne nsaenz@amazon.com writes:
Don't apply the stimer's counter side effects when modifying its value from user-space, as this may trigger spurious interrupts.
For example:
- The stimer is configured in auto-enable mode.
- The stimer's count is set and the timer enabled.
- The stimer expires, an interrupt is injected.
- The VM is live migrated.
- The stimer config and count are deserialized, auto-enable is ON, the stimer is re-enabled.
- The stimer expires right away, and injects an unwarranted interrupt.
Cc: stable@vger.kernel.org Fixes: 1f4b34f825e8 ("kvm/x86: Hyper-V SynIC timers") Signed-off-by: Nicolas Saenz Julienne nsaenz@amazon.com
Changes since v2:
- reword commit message/subject.
Changes since v1:
- Cover all 'stimer->config.enable' updates.
arch/x86/kvm/hyperv.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c index 7c2dac6824e2..238afd7335e4 100644 --- a/arch/x86/kvm/hyperv.c +++ b/arch/x86/kvm/hyperv.c @@ -727,10 +727,12 @@ static int stimer_set_count(struct kvm_vcpu_hv_stimer *stimer, u64 count, stimer_cleanup(stimer); stimer->count = count;
- if (stimer->count == 0)
stimer->config.enable = 0;- else if (stimer->config.auto_enable)
stimer->config.enable = 1;
- if (!host) {
if (stimer->count == 0)stimer->config.enable = 0;else if (stimer->config.auto_enable)stimer->config.enable = 1;- }
if (stimer->config.enable) stimer_mark_pending(stimer, false);
LGTM, thanks!
Reviewed-by: Vitaly Kuznetsov vkuznets@redhat.com