Re: [PATCH 1/6] KVM: SVM: Advance instruction pointer indr_intercept

From: Roedel, Joerg
Date: Tue Feb 22 2011 - 06:14:19 EST


On Wed, Feb 09, 2011 at 12:29:39PM -0500, Joerg Roedel wrote:
> In the dr_intercept function a new cpu-feature called
> decode-assists is implemented and used when available. This
> code-path does not advance the guest-rip causing the guest
> to dead-loop over mov-dr instructions. This is fixed by this
> patch.
>
> Signed-off-by: Joerg Roedel <joerg.roedel@xxxxxxx>
> ---
> arch/x86/kvm/svm.c | 2 ++
> 1 files changed, 2 insertions(+), 0 deletions(-)
>
> diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
> index 73a8f1d..bfb4948 100644
> --- a/arch/x86/kvm/svm.c
> +++ b/arch/x86/kvm/svm.c
> @@ -2777,6 +2777,8 @@ static int dr_interception(struct vcpu_svm *svm)
> kvm_register_write(&svm->vcpu, reg, val);
> }
>
> + skip_emulated_instruction(&svm->vcpu);
> +
> return 1;
> }

Btw. Can you meanwhile apply this patch? It fixes a bug which sends the
guest into an endless loop when decode assists is available on the host.

Joerg

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