Re: [PATCH 2/2] [PATCH] disable kvm clock unless addr's LSB is set.

["Yang, Sheng" <sheng.yang@intel.com>]

On Thursday 06 March 2008 22:45:44 Glauber Costa wrote:
> Use LSB of the address passed through the msr to enable/disable
> the clock. Setting it to 1 enables it, setting it to 0 disables it.
>
> As the guest data structures are aligned anyway, this
> won't be a problem, as this bit is free.
>
> Guest is changed accordingly
>
> Signed-off-by: Glauber Costa <gcosta@redhat.com>
> ---
>  arch/x86/kernel/kvmclock.c |    2 +-
>  arch/x86/kvm/x86.c         |    9 ++++++++-
>  2 files changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c
> index 7c481a3..f654a12 100644
> --- a/arch/x86/kernel/kvmclock.c
> +++ b/arch/x86/kernel/kvmclock.c
> @@ -125,7 +125,7 @@ static int kvm_register_clock(void)
>  {
>  	int cpu = smp_processor_id();
>  	int low, high;
> -	low = (int)__pa(&per_cpu(hv_clock, cpu));
> +	low = (int)__pa(&per_cpu(hv_clock, cpu)) | 1;
>  	high = ((u64)__pa(&per_cpu(hv_clock, cpu)) >> 32);
>
>  	return native_write_msr_safe(MSR_KVM_SYSTEM_TIME, low, high);
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 6abd784..64beff6 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -591,8 +591,15 @@ int kvm_set_msr_common(struct kvm_vcpu *
>  		if (vcpu->arch.time_page)
>  			kvm_release_page_dirty(vcpu->arch.time_page);
>
> +		/* we verify if the enable bit is set... */
> +		if (!(data & 1)) {
> +			vcpu->arch.time = NULL;

This line made compiler complaining...

Thanks
Yang, Sheng

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