RE: [PATCH] KVM: x86: reset RVI upon system reset

Wang, Wei W
2014-11-05T07:42:07Z

On 05/11/2014 2:14, Tiejun Chen wrote:
> > A bug was reported as follows: when running Windows 7 32-bit guests on
> > qemu-kvm, sometimes the guests run into blue screen during reboot. The
> > problem was that a guest's RVI was not cleared when it rebooted. This
> patch has fixed the problem.
> >
> > Signed-off-by: Wei Wang <wei.w.wang@intel.com>
> > Signed-off-by: Yang Zhang <yang.z.zhang@intel.com>
> > Tested-by: Rongrong Liu <rongrongx.liu@intel.com>, Da Chun
> > <ngugc@qq.com>
> > ---
> > arch/x86/kvm/lapic.c | 3 +++
> > arch/x86/kvm/vmx.c | 12 ++++++------
> > 2 files changed, 9 insertions(+), 6 deletions(-)
> >
> > diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index
> > 66dd173..6942742 100644
> > --- a/arch/x86/kvm/lapic.c
> > +++ b/arch/x86/kvm/lapic.c
> > @@ -1712,6 +1712,9 @@ void kvm_apic_post_state_restore(struct
> kvm_vcpu *vcpu,
> > apic->isr_count = kvm_apic_vid_enabled(vcpu->kvm) ?
> > 1 : count_vectors(apic->regs + APIC_ISR);
> > apic->highest_isr_cache = -1;
> > + if (kvm_x86_ops->hwapic_irr_update)
> > + kvm_x86_ops->hwapic_irr_update(vcpu,
> > + apic_find_highest_irr(apic));
>
> Could we pass 0 directly? Because looks we just need to clear RVI.
>
> kvm_x86_ops->hwapic_irr_update(vcpu, 0);
>
> I think this already makes sense based on your description.
>
> Thanks
> Tiejun

No. This is a restore function, and we cannot assume that the callers always need to reset to the initial state.

Wei
>
> > kvm_x86_ops->hwapic_isr_update(vcpu->kvm,
> apic_find_highest_isr(apic));
> > kvm_make_request(KVM_REQ_EVENT, vcpu);
> > kvm_rtc_eoi_tracking_restore_one(vcpu);
> > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index
> > fe4d2f4..d632548 100644
> > --- a/arch/x86/kvm/vmx.c
> > +++ b/arch/x86/kvm/vmx.c
> > @@ -7292,19 +7292,19 @@ static void vmx_set_rvi(int vector)
> > static void vmx_hwapic_irr_update(struct kvm_vcpu *vcpu, int max_irr)
> > {
> > if (max_irr == -1)
> > + max_irr = 0;
> > +
> > + if (!is_guest_mode(vcpu)) {
> > + vmx_set_rvi(max_irr);
> > return;
> > + }
> >
> > /*
> > * If a vmexit is needed, vmx_check_nested_events handles it.
> > */
> > - if (is_guest_mode(vcpu) && nested_exit_on_intr(vcpu))
> > + if ((is_guest_mode(vcpu) && nested_exit_on_intr(vcpu)) || max_irr
> ==
> > +0)
> > return;
> >
> > - if (!is_guest_mode(vcpu)) {
> > - vmx_set_rvi(max_irr);
> > - return;
> > - }
> > -
> > /*
> > * Fall back to pre-APICv interrupt injection since L2
> > * is run without virtual interrupt delivery.
> >