Re: [PATCH 3/8] KVM: Activate fpu on clts

Avi Kivity
2010-02-04T13:05:21Z

On 02/02/2010 10:16 AM, Paolo Bonzini wrote:
> On 01/21/2010 02:31 PM, Avi Kivity wrote:
>> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
>> index feca59f..09207ba 100644
>> --- a/arch/x86/kvm/x86.c
>> +++ b/arch/x86/kvm/x86.c
>> @@ -3266,6 +3266,7 @@ int emulate_invlpg(struct kvm_vcpu *vcpu, gva_t
>> address)
>> int emulate_clts(struct kvm_vcpu *vcpu)
>> {
>> kvm_x86_ops->set_cr0(vcpu, kvm_read_cr0_bits(vcpu, ~X86_CR0_TS));
>> + kvm_x86_ops->fpu_activate(vcpu);
>> return X86EMUL_CONTINUE;
>> }
>
> Can this code be reached if CLTS is executed in real mode? That would
> cause a NULL-pointer access on VMX.

How would this cause a null pointer access?

--
Do not meddle in the internals of kernels, for they are subtle and quick to panic.