Re: [PATCH 01/12] KVM: x86: host-initiated EFER.LME write affects the MMU

On Wed, Feb 09, 2022, Paolo Bonzini wrote:

While the guest runs, EFER.LME cannot change unless CR0.PG is clear, and therefore EFER.NX is the only bit that can affect the MMU role. However, set_efer accepts a host-initiated change to EFER.LME even with CR0.PG=1. In that case, the MMU has to be reset.

Fixes: 11988499e62b ("KVM: x86: Skip EFER vs. guest CPUID checks for host-initiated writes") Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini pbonzini@redhat.com

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Ugh, but KVM_SET_SREGS handles this... It's basically KVM's equivalent of VMX putting EFER in the VMCS, but then also allowing EFER in the load/store lists.

Reviewed-by: Sean Christopherson seanjc@google.com