Re: [PATCH v1 3/6] KVM: VMX: Add new ops in kvm_x86_ops for LASS violation check

[Zeng Guang]

On 6/5/2023 11:47 AM, Gao, Chao wrote:
> On Thu, Jun 01, 2023 at 10:23:06PM +0800, Zeng Guang wrote:
> > diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
> > index 92d8e65fe88c..98666d1e7727 100644
> > --- a/arch/x86/include/asm/kvm_host.h
> > +++ b/arch/x86/include/asm/kvm_host.h
> > @@ -1731,6 +1731,8 @@ struct kvm_x86_ops {
> > 	 * Returns vCPU specific APICv inhibit reasons
> > 	 */
> > 	unsigned long (*vcpu_get_apicv_inhibit_reasons)(struct kvm_vcpu *vcpu);
> > +
> > +	bool (*check_lass)(struct kvm_vcpu *vcpu, u64 access, u64 la, u32 flags);
> It is better to declare the @la as gva_t since the address is a virtual address.
>
> Both @access and @flags provide additional informaiton about a memory access. I
> think we can drop one of them e.g. adding a new bit X86EMUL_F_IMPLICIT_ACCESS.
>
> Or maybe in the first place, we can just extend PFERR_? for SKIP_LASS/LAM
> behavior instead of adding another set of flags (X86EMUL_F_?). The benefit of
> adding new flags is they won't collide with future hardware extensions. I am not
> sure.
Make sense. Prefer to adding a new bit of X86EMUL flags.
PFERR_ is used for page fault case and actually not proper to be taken for
LASS/LAM usage.