Re: [PATCH v2 11/17] kvm: x86: Reset paravirtual MSRs

Glauber Costa
2011-01-03T16:40:19Z

On Mon, 2011-01-03 at 09:33 +0100, Jan Kiszka wrote:
> From: Jan Kiszka <jan.kiszka@siemens.com>
>
> Make sure to clear MSR_KVM_SYSTEM_TIME, MSR_KVM_WALL_CLOCK, and
> MSR_KVM_ASYNC_PF_EN so that a freshly booted guest cannot be disturbed
> by old values.
>
> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
> CC: Glauber Costa <glommer@redhat.com>
> ---
> target-i386/kvm.c | 10 ++++++++++
> 1 files changed, 10 insertions(+), 0 deletions(-)
>
> diff --git a/target-i386/kvm.c b/target-i386/kvm.c
> index d8f26bf..664a4a0 100644
> --- a/target-i386/kvm.c
> +++ b/target-i386/kvm.c
> @@ -453,6 +453,9 @@ void kvm_arch_reset_vcpu(CPUState *env)
> env->nmi_injected = 0;
> env->nmi_pending = 0;
> env->xcr0 = 1;
> + env->system_time_msr = 0;
> + env->wall_clock_msr = 0;
> + env->async_pf_en_msr = 0;

Have you seen this happening? I'd expect CPUState to be zeroed out over
init. And if it is not, I guess we should...