Re: [RFC 29/33] KVM: VMX: Save instruction length on EPT violation

[Sean Christopherson]

On Wed, Nov 08, 2023, Alexander Graf wrote:
> 
> On 08.11.23 12:18, Nicolas Saenz Julienne wrote:
> > Save the length of the instruction that triggered an EPT violation in
> > struct kvm_vcpu_arch. This will be used to populate Hyper-V VSM memory
> > intercept messages.
> > 
> > Signed-off-by: Nicolas Saenz Julienne <nsaenz@xxxxxxxxxx>
> 
> 
> In v1, please do this for SVM as well :)

Why?  KVM caches values on VMX because VMREAD is measurable slower than memory
accesses, especially when running nested.  SVM has no such problems.  I wouldn't
be surprised if adding a "cache" is actually less performant due to increased
pressure and misses on the hardware cache.