Re: [PATCH V3 2/5] KVM: SVM: Inject #UD for STGI if EFER.SVME=0 and SVM Lock and DEV are not available

[Sean Christopherson]

On Thu, Jan 22, 2026, Kevin Cheng wrote:
> The AMD APM states that STGI causes a #UD if SVM is not enabled and
> neither SVM Lock nor the device exclusion vector (DEV) are supported.
> Support for DEV is part of the SKINIT architecture. Fix the STGI exit
> handler by injecting #UD when these conditions are met.

This is entirely pointless.  SVML and SKINIT can never bet set in guest caps.
There are many things that are documented in the SDM/APM that don't have "correct"
handling in KVM, because they're completely unsupported.

_If_ this is causing someone enough heartburn to want to "fix", just add a comment
in nested_svm_check_permissions() stating that KVM doesn't support SVML or SKINIT.