Re: [PATCH] KVM: x86: pvclock: Handle first-time write to pvclock-page contains random junk

["Radim Krčmář" <rkrcmar@redhat.com>]

2017-11-05 16:11+0200, Liran Alon:
> When guest passes KVM it's pvclock-page GPA via WRMSR to
> MSR_KVM_SYSTEM_TIME / MSR_KVM_SYSTEM_TIME_NEW, KVM don't initialize
> pvclock-page to some start-values. It just requests a clock-update which
> will happen before entering to guest.
> 
> The clock-update logic will call kvm_setup_pvclock_page() to update the
> pvclock-page with info. However, kvm_setup_pvclock_page() *wrongly*
> assumes that the version-field is initialized to an even number. This is
> wrong because at first-time write, field could be any-value.
> 
> Fix simply makes sure that if first-time version-field is odd, increment
> it once more to make it even and only then start standard logic.
> This follows same logic as done in other pvclock shared-pages (See
> kvm_write_wall_clock() and record_steal_time()).
> 
> Signed-off-by: Liran Alon <liran.alon@oracle.com>
> Reviewed-by: Nikita Leshenko <nikita.leshchenko@oracle.com>
> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> ---

Applied, thanks.