Re: [PATCH 2/2] KVM: SVM: Emulate next_rip svm feature

[Avi Kivity <avi@redhat.com>]

  On 07/27/2010 07:14 PM, Joerg Roedel wrote:
> This patch implements the emulations of the svm next_rip
> feature in the nested svm implementation in kvm.
>
> Signed-off-by: Joerg Roedel<joerg.roedel@amd.com>
> ---
>   arch/x86/kvm/svm.c |    8 +++++++-
>   1 files changed, 7 insertions(+), 1 deletions(-)
>
> diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
> index 7d10f2c..b44c9cc 100644
> --- a/arch/x86/kvm/svm.c
> +++ b/arch/x86/kvm/svm.c
> @@ -1919,6 +1919,7 @@ static int nested_svm_vmexit(struct vcpu_svm *svm)
>   	nested_vmcb->control.exit_info_2       = vmcb->control.exit_info_2;
>   	nested_vmcb->control.exit_int_info     = vmcb->control.exit_int_info;
>   	nested_vmcb->control.exit_int_info_err = vmcb->control.exit_int_info_err;
> +	nested_vmcb->control.next_rip          = vmcb->control.next_rip;
>

Can it be really this simple?  Suppose we emulate a nested guest 
instruction just before vmexit, doesn't that invalidate 
vmcb->control.next_rip?  Can that happen?

-- 
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.