Re: [PATCH 0/7] KVM: x86: APX reg prep work

[Chang S. Bae]

On 4/3/2026 9:03 AM, Paolo Bonzini wrote:
> But until the kernel starts using APX, I would do the save/restore near 
> kvm_load_xfeatures(), because __vmx_vcpu_run()/__svm_vcpu_run() would 
> have to check whether xcr0.apx is set or not. 
Right, I'd much prefer this. Then, it requires to audit whether any 
fast-path handler could access EGPRs.

But there are cases with the new {RD|WR}MSR (MSR_IMM) instructions that 
appear to access GPRs. Because of this, the EGPR saving/restoring needs 
to happen earlier.