Re: [PATCH v2] KVM: nVMX/nSVM: Don't intercept #UD when running L2

Radim Krčmář
2017-11-10T21:37:44Z

2017-11-06 16:15+0200, Liran Alon:
> When running L2, #UD should be intercepted by L1 or just forwarded
> directly to L2. It should not reach L0 x86 emulator.
> Therefore, set intercept for #UD only based on L1 exception-bitmap.
>
> Also add WARN_ON_ONCE() on L0 #UD intercept handlers to make sure
> it is never reached while running L2.
>
> This improves commit ae1f57670703 ("KVM: nVMX: Do not emulate #UD while
> in guest mode") by removing an unnecessary exit from L2 to L0 on #UD
> when L1 doesn't intercept it.
>
> In addition, SVM L0 #UD intercept handler doesn't handle correctly the
> case it is raised from L2. In this case, it should forward the #UD to
> guest instead of x86 emulator. As done in VMX #UD intercept handler.
> This commit fixes this issue as-well.
>
> Signed-off-by: Liran Alon <liran.alon@oracle.com>
> Reviewed-by: Nikita Leshenko <nikita.leshchenko@oracle.com>
> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> ---

Applied, thanks.