On Fri, Aug 03, 2012 at 11:25:44AM +0530, Nikunj A Dadhania wrote:
> On Thu, 2 Aug 2012 16:56:28 -0300, Marcelo Tosatti <mtosatti@xxxxxxxxxx> wrote:
> > >
> > > + case MSR_KVM_VCPU_STATE:
> > > + vcpu->arch.v_state.vs_page = gfn_to_page(vcpu->kvm, data >> PAGE_SHIFT);
> > > + vcpu->arch.v_state.vs_offset = data & ~(PAGE_MASK | KVM_MSR_ENABLED);
> >
> > Assign vs_offset after success.
> >
> > > +
> > > + if (is_error_page(vcpu->arch.v_state.vs_page)) {
> > > + kvm_release_page_clean(vcpu->arch.time_page);
> > > + vcpu->arch.v_state.vs_page = NULL;
> > > + pr_info("KVM: VCPU_STATE - Unable to pin the page\n");
> >
> > Missing break or return;
> >
> > > + }
> > > + vcpu->arch.v_state.msr_val = data;
> > > + break;
> > > +
> > > case MSR_IA32_MCG_CTL:
> >
> > Please verify this code carefully again.
> >
> > Also leaking the page reference.
> >
> > > vcpu->arch.apf.msr_val = 0;
> > > vcpu->arch.st.msr_val = 0;
> > > + vcpu->arch.v_state.msr_val = 0;
> >
> > Add a newline and comment (or even better a new helper).
> > >
> > > kvmclock_reset(vcpu);
> >
>
> How about something like the below. I have tried to look at time_page
> for reference:
>
>
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 580abcf..c82cc12 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -1604,6 +1604,16 @@ static void kvm_clear_vcpu_state(struct kvm_vcpu *vcpu)
> kunmap_atomic(kaddr);
> }
>
> +static void kvm_vcpu_state_reset(struct kvm_vcpu *vcpu)
> +{
> + vcpu->arch.v_state.msr_val = 0;
> + vcpu->arch.v_state.vs_offset = 0;
> + if (vcpu->arch.v_state.vs_page) {
> + kvm_release_page_dirty(vcpu->arch.v_state.vs_page);
> + vcpu->arch.v_state.vs_page = NULL;
> + }
> +}
> +
> int kvm_set_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 data)
> {
> bool pr = false;
> @@ -1724,14 +1734,17 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 data)
> break;
>
> case MSR_KVM_VCPU_STATE:
> + kvm_vcpu_state_reset(vcpu);
> +
> vcpu->arch.v_state.vs_page = gfn_to_page(vcpu->kvm, data >> PAGE_SHIFT);
> - vcpu->arch.v_state.vs_offset = data & ~(PAGE_MASK | KVM_MSR_ENABLED);
Should also fail if its not enabled (KVM_MSR_ENABLED bit).
What is the point of having non-NULL vs_page pointer if KVM_MSR_ENABLED
bit is not set?
The rest is fine, thanks.
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