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

Jan Kiszka
2011-01-03T16:46:08Z

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Am 03.01.2011 17:40, Glauber Costa wrote:
> 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...

Ah, true, those three are part of the section that is zeroed. Will drop
that hunk on repost.

Guess we should rather move some other variables in that region too and
avoid clearing them manually like above...

Jan

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