kvm: skip tsc synchronization on shutdown

[PATCH] kvm: skip tsc synchronization on shutdown

Vladimir Sementsov-Ogievskiy posted 1 patch 1 week, 5 days ago

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git fetch https://github.com/patchew-project/qemu tags/patchew/20260127201831.179237-1-vsementsov@yandex-team.ru

Maintainers: "Michael S. Tsirkin" <mst@redhat.com>, Marcel Apfelbaum <marcel.apfelbaum@gmail.com>, Paolo Bonzini <pbonzini@redhat.com>, Richard Henderson <richard.henderson@linaro.org>, Eduardo Habkost <eduardo@habkost.net>

hw/i386/kvm/clock.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

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[PATCH] kvm: skip tsc synchronization on shutdown

Posted by Vladimir Sementsov-Ogievskiy 1 week, 5 days ago

That doesn't make real sense, but may take much time when
there are a lot of vCPUs. Let's just skip it.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
---
 hw/i386/kvm/clock.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/hw/i386/kvm/clock.c b/hw/i386/kvm/clock.c
index aba6842a22..46efdbed14 100644
--- a/hw/i386/kvm/clock.c
+++ b/hw/i386/kvm/clock.c
@@ -207,7 +207,9 @@ static void kvmclock_vm_state_change(void *opaque, bool running,
 
         s->runstate_paused = runstate_check(RUN_STATE_PAUSED);
 
-        kvm_synchronize_all_tsc();
+        if (!runstate_check(RUN_STATE_SHUTDOWN)) {
+            kvm_synchronize_all_tsc();
+        }
 
         kvm_update_clock(s);
         /*
-- 
2.52.0

Re: [PATCH] kvm: skip tsc synchronization on shutdown

Posted by Philippe Mathieu-Daudé 1 week, 4 days ago

On 27/1/26 21:18, Vladimir Sementsov-Ogievskiy wrote:
> That doesn't make real sense, but may take much time when
> there are a lot of vCPUs. Let's just skip it.
> 
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
> ---
>   hw/i386/kvm/clock.c | 4 +++-
>   1 file changed, 3 insertions(+), 1 deletion(-)

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>