Re: [PATCH] SVM: do not generate "external interrupt exit" if other exit is pending

[Joerg Roedel <joro@8bytes.org>]

On Sun, Sep 19, 2010 at 06:41:27PM +0200, Gleb Natapov wrote:
> Nested SVM checks for external interrupt after injecting nested exception.
> In case there is external interrupt pending the code generates "external
> interrupt exit" and overwrites previous exit info. If previously injected
> exception already generated exit it will be lost.

Right. Have you seen specific mismehavior due to this problem? I am just
curious how you found this :-)
And another question, can you put the reason for this "if(...) return"
into an comment before the statement? The whole svm-emulation thing is
complicated enough so that we should document it well in the code :-)

	Joerg

> 
> Signed-off-by: Gleb Natapov <gleb@redhat.com>
> diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
> index 43f5558..1a1f86b 100644
> --- a/arch/x86/kvm/svm.c
> +++ b/arch/x86/kvm/svm.c
> @@ -1707,6 +1707,9 @@ static inline bool nested_svm_intr(struct vcpu_svm *svm)
>  	if (!(svm->vcpu.arch.hflags & HF_HIF_MASK))
>  		return false;
>  
> +	if (svm->nested.exit_required)
> +		return false;
> +
>  	svm->vmcb->control.exit_code   = SVM_EXIT_INTR;
>  	svm->vmcb->control.exit_info_1 = 0;
>  	svm->vmcb->control.exit_info_2 = 0;
> --
> 			Gleb.