[PATCH 1/2 V3] KVM: x86: reset RVI upon system reset

[Thadeu Lima de Souza Cascardo]

On Tue, Feb 14, 2017 at 06:50:49AM -0700, Tim Gardner wrote:
> From: Wei Wang <wei.w.wang at intel.com>
> 
> BugLink: http://bugs.launchpad.net/bugs/1660519
> 
> 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 at intel.com>
> Signed-off-by: Yang Zhang <yang.z.zhang at intel.com>
> Tested-by: Rongrong Liu <rongrongx.liu at intel.com>, Da Chun <ngugc at qq.com>
> Signed-off-by: Paolo Bonzini <pbonzini at redhat.com>
> (back ported from commit 4114c27d450bef228be9c7b0c40a888e18a3a636)
> Signed-off-by: Tim Gardner <tim.gardner at canonical.com>
> 

Why not cherry-pick 963fee1656603ce2e91ebb988cd5a92f2af41369, as
suggested by Stefan Bader? This would have made this both (963fee16 and
4114c27d) clean cherry picks.

Cascardo.

> Conflicts:
> 	arch/x86/kvm/vmx.c
> ---
> 
> v3 - no change from v2
> 
>  arch/x86/kvm/lapic.c |  3 +++
>  arch/x86/kvm/vmx.c   | 25 ++++++++++++++++++++++++-
>  2 files changed, 27 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
> index 701fd95..b805ae4 100644
> --- a/arch/x86/kvm/lapic.c
> +++ b/arch/x86/kvm/lapic.c
> @@ -1692,6 +1692,9 @@ 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));
>  	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 2b45251..6658c0b 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -6919,6 +6919,9 @@ static void vmx_set_rvi(int vector)
>  	u16 status;
>  	u8 old;
>  
> +	if (vector == -1)
> +		vector = 0;
> +
>  	status = vmcs_read16(GUEST_INTR_STATUS);
>  	old = (u8)status & 0xff;
>  	if ((u8)vector != old) {
> @@ -6930,10 +6933,30 @@ static void vmx_set_rvi(int vector)
>  
>  static void vmx_hwapic_irr_update(struct kvm_vcpu *vcpu, int max_irr)
>  {
> +	if (!is_guest_mode(vcpu)) {
> +		vmx_set_rvi(max_irr);
> +		return;
> +	}
> +
>  	if (max_irr == -1)
>  		return;
>  
> -	vmx_set_rvi(max_irr);
> +	/*
> +	 * In guest mode.  If a vmexit is needed, vmx_check_nested_events
> +	 * handles it.
> +	 */
> +	if (nested_exit_on_intr(vcpu))
> +		return;
> +
> +	/*
> +	 * Else, fall back to pre-APICv interrupt injection since L2
> +	 * is run without virtual interrupt delivery.
> +	 */
> +	if (!kvm_event_needs_reinjection(vcpu) &&
> +	    vmx_interrupt_allowed(vcpu)) {
> +		kvm_queue_interrupt(vcpu, max_irr, false);
> +		vmx_inject_irq(vcpu);
> +	}
>  }
>  
>  static void vmx_load_eoi_exitmap(struct kvm_vcpu *vcpu, u64 *eoi_exit_bitmap)
> -- 
> 2.7.4
> 
> 
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