Re: [RFC PATCH v1 03/28] kvm: svm: Use the hardware provided GPA instead of page walk

[Borislav Petkov]

On Mon, Aug 22, 2016 at 07:24:07PM -0400, Brijesh Singh wrote:
> From: Tom Lendacky <thomas.lendacky@xxxxxxx>
> 
> When a guest causes a NPF which requires emulation, KVM sometimes walks
> the guest page tables to translate the GVA to a GPA. This is unnecessary
> most of the time on AMD hardware since the hardware provides the GPA in
> EXITINFO2.
> 
> The only exception cases involve string operations involving rep or
> operations that use two memory locations. With rep, the GPA will only be
> the value of the initial NPF and with dual memory locations we won't know
> which memory address was translated into EXITINFO2.
> 
> Signed-off-by: Tom Lendacky <thomas.lendacky@xxxxxxx>
> ---
>  arch/x86/include/asm/kvm_emulate.h |    3 +++
>  arch/x86/include/asm/kvm_host.h    |    3 +++
>  arch/x86/kvm/svm.c                 |    2 ++
>  arch/x86/kvm/x86.c                 |   17 ++++++++++++++++-
>  4 files changed, 24 insertions(+), 1 deletion(-)

FWIW, LGTM. (Gotta love replying in acronyms :-))

Reviewed-by: Borislav Petkov <bp@xxxxxxx>

-- 
Regards/Gruss,
    Boris.

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