Re: [PATCH] x86: vdso: fix pvclock races with task migration

From: Paolo Bonzini
Date: Tue Apr 07 2015 - 07:11:53 EST




On 02/04/2015 20:44, Radim KrÄmÃÅ wrote:
> If we were migrated right after __getcpu, but before reading the
> migration_count, we wouldn't notice that we read TSC of a different
> VCPU, nor that KVM's bug made pvti invalid, as only migration_count
> on source VCPU is increased.
>
> Change vdso instead of updating migration_count on destination.
>
> Fixes: 0a4e6be9ca17 ("x86: kvm: Revert "remove sched notifier for cross-cpu migrations"")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Radim KrÄmÃÅ <rkrcmar@xxxxxxxxxx>

Applying this, but removing the "Fixes" tag because a guest patch cannot
fix a host patch (it can work around it or complement it).

Paolo
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