Re: [PATCH] x86: svm: make wbinvd faster

From: Bandan Das
Date: Sun Mar 01 2015 - 21:30:24 EST


Joel Schopp <joel.schopp@xxxxxxx> writes:

> From: David Kaplan <David.Kaplan@xxxxxxx>
> No need to re-decode WBINVD since we know what it is from the intercept.
>
> Signed-off-by: David Kaplan <David.Kaplan@xxxxxxx>
> [extracted from larger unlrelated patch, forward ported, tested]
> Signed-off-by: Joel Schopp <joel.schopp@xxxxxxx>
> ---
> arch/x86/kvm/svm.c | 10 +++++++++-
> 1 file changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
> index d319e0c..86ecd21 100644
> --- a/arch/x86/kvm/svm.c
> +++ b/arch/x86/kvm/svm.c
> @@ -2776,6 +2776,14 @@ static int skinit_interception(struct vcpu_svm *svm)
> return 1;
> }
>
> +static int wbinvd_interception(struct vcpu_svm *svm)
> +{
> + kvm_emulate_wbinvd(&svm->vcpu);
> + skip_emulated_instruction(&svm->vcpu);
> + return 1;
> +}
> +
> +
Can't we merge this to kvm_emulate_wbinvd, and just call that function
directly for both vmx and svm ?

> static int xsetbv_interception(struct vcpu_svm *svm)
> {
> u64 new_bv = kvm_read_edx_eax(&svm->vcpu);
> @@ -3376,7 +3384,7 @@ static int (*const svm_exit_handlers[])(struct vcpu_svm *svm) = {
> [SVM_EXIT_STGI] = stgi_interception,
> [SVM_EXIT_CLGI] = clgi_interception,
> [SVM_EXIT_SKINIT] = skinit_interception,
> - [SVM_EXIT_WBINVD] = emulate_on_interception,
So, this means x86_emulate_insn() in emulate.c has no callers left for the
wbinvd case ? vmx calls kvm_emulate_wbinvd directly too..

Bandan
> + [SVM_EXIT_WBINVD] = wbinvd_interception,
> [SVM_EXIT_MONITOR] = monitor_interception,
> [SVM_EXIT_MWAIT] = mwait_interception,
> [SVM_EXIT_XSETBV] = xsetbv_interception,
>
> --
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