Re: [PATCH] KVM: nVMX: Fix injection of PENDING_INTERRUPT and NMI_WINDOW exits to L1

[Jan Kiszka <jan.kiszka@web.de>]

[-- Attachment #1: Type: text/plain, Size: 1517 bytes --]

On 2013-02-16 12:51, Jan Kiszka wrote:
> From: Jan Kiszka <jan.kiszka@siemens.com>
> 
> The comment was wrong: enable_irq_window might be called after
> prepare_vmcs02 when we left L2 to prepare IRQ injecting for L1. Same for
> NMIs.
> 
> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
> ---
>  arch/x86/kvm/vmx.c |   10 +++-------
>  1 files changed, 3 insertions(+), 7 deletions(-)
> 
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index 81a25de..68a045ae 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -6113,14 +6113,10 @@ static bool nested_vmx_exit_handled(struct kvm_vcpu *vcpu)
>  	case EXIT_REASON_TRIPLE_FAULT:
>  		return 1;
>  	case EXIT_REASON_PENDING_INTERRUPT:
> +		return nested_cpu_has(vmcs12, CPU_BASED_VIRTUAL_INTR_PENDING);
>  	case EXIT_REASON_NMI_WINDOW:
> -		/*
> -		 * prepare_vmcs02() set the CPU_BASED_VIRTUAL_INTR_PENDING bit
> -		 * (aka Interrupt Window Exiting) only when L1 turned it on,
> -		 * so if we got a PENDING_INTERRUPT exit, this must be for L1.
> -		 * Same for NMI Window Exiting.
> -		 */
> -		return 1;
> +		return vmcs12->pin_based_vm_exec_control &
> +			PIN_BASED_NMI_EXITING;
>  	case EXIT_REASON_TASK_SWITCH:
>  		return 1;
>  	case EXIT_REASON_CPUID:
> 

No, this is wrong. I first wrote a patch that ignored enable_irq_window
when the guest is not interested in external IRQs. But then I thought
that wasn't correct. I tend to believe now my first idea was better.

Need to rethink.

Jan


[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 263 bytes --]