RE: [PATCH 1/2] KVM: nVMX: Fix nested vmexit ack intr before load vmcs01

[Liu, RongrongX]

> -----Original Message-----
> From: kvm-owner@xxxxxxxxxxxxxxx [mailto:kvm-owner@xxxxxxxxxxxxxxx]
> On Behalf Of Wanpeng Li
> Sent: Friday, August 01, 2014 4:12 PM
> To: Paolo Bonzini; Jan Kiszka
> Cc: Marcelo Tosatti; Gleb Natapov; Bandan Das; Zhang, Yang Z;
> kvm@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Wanpeng Li
> Subject: [PATCH 1/2] KVM: nVMX: Fix nested vmexit ack intr before load
> vmcs01
> 
> External interrupt will cause L1 vmexit w/ reason external interrupt when L2
> is running. Then L1 will pick up the interrupt through vmcs12 if L1 set the ack
> interrupt bit. Commit 77b0f5d (KVM: nVMX: Ack and write vector info to
> intr_info if L1 asks us to) get intr that belongs to L1 before load vmcs01 which
> is wrong, especially this lead to the obvious L1 ack APICv behavior weired
> since APICv is for L1 instead of L2. This patch fix it by ack intr after load
> vmcs01.
> 
> Signed-off-by: Wanpeng Li <wanpeng.li@xxxxxxxxxxxxxxx>

Tested-by:  Liu, RongrongX <rongrongx.liu@xxxxxxxxx>

> ---
>  arch/x86/kvm/vmx.c | 16 ++++++++--------
>  1 file changed, 8 insertions(+), 8 deletions(-)
> 
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index
> e618f34..b8122b3 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -8754,14 +8754,6 @@ static void nested_vmx_vmexit(struct kvm_vcpu
> *vcpu, u32 exit_reason,
>  	prepare_vmcs12(vcpu, vmcs12, exit_reason, exit_intr_info,
>  		       exit_qualification);
> 
> -	if ((exit_reason == EXIT_REASON_EXTERNAL_INTERRUPT)
> -	    && nested_exit_intr_ack_set(vcpu)) {
> -		int irq = kvm_cpu_get_interrupt(vcpu);
> -		WARN_ON(irq < 0);
> -		vmcs12->vm_exit_intr_info = irq |
> -			INTR_INFO_VALID_MASK | INTR_TYPE_EXT_INTR;
> -	}
> -
>  	trace_kvm_nested_vmexit_inject(vmcs12->vm_exit_reason,
>  				       vmcs12->exit_qualification,
>  				       vmcs12->idt_vectoring_info_field, @@ -
> 8771,6 +8763,14 @@ static void nested_vmx_vmexit(struct kvm_vcpu *vcpu,
> u32 exit_reason,
> 
>  	vmx_load_vmcs01(vcpu);
> 
> +	if ((exit_reason == EXIT_REASON_EXTERNAL_INTERRUPT)
> +	    && nested_exit_intr_ack_set(vcpu)) {
> +		int irq = kvm_cpu_get_interrupt(vcpu);
> +		WARN_ON(irq < 0);
> +		vmcs12->vm_exit_intr_info = irq |
> +			INTR_INFO_VALID_MASK | INTR_TYPE_EXT_INTR;
> +	}
> +
>  	vm_entry_controls_init(vmx, vmcs_read32(VM_ENTRY_CONTROLS));
>  	vm_exit_controls_init(vmx, vmcs_read32(VM_EXIT_CONTROLS));
>  	vmx_segment_cache_clear(vmx);
> --
> 1.9.1
> 
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