The comment in kvm_get_shadow_phys_bits refers to MKTME, but the same is actually true of SME and SEV. Just use CPUID[0x8000_0008].EAX[7:0] unconditionally, it is simplest and works even if memory is not encrypted.
Cc: stable@vger.kernel.org Reported-by: Tom Lendacky thomas.lendacky@amd.com Signed-off-by: Paolo Bonzini pbonzini@redhat.com --- arch/x86/kvm/mmu/mmu.c | 12 ++++-------- 1 file changed, 4 insertions(+), 8 deletions(-)
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 6f92b40d798c..8b8edfbdbaef 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -538,15 +538,11 @@ void kvm_mmu_set_mask_ptes(u64 user_mask, u64 accessed_mask, static u8 kvm_get_shadow_phys_bits(void) { /* - * boot_cpu_data.x86_phys_bits is reduced when MKTME is detected - * in CPU detection code, but MKTME treats those reduced bits as - * 'keyID' thus they are not reserved bits. Therefore for MKTME - * we should still return physical address bits reported by CPUID. + * boot_cpu_data.x86_phys_bits is reduced when MKTME or SME are detected + * in CPU detection code, but the processor treats those reduced bits as + * 'keyID' thus they are not reserved bits. Therefore KVM needs to look at + * the physical address bits reported by CPUID. */ - if (!boot_cpu_has(X86_FEATURE_TME) || - WARN_ON_ONCE(boot_cpu_data.extended_cpuid_level < 0x80000008)) - return boot_cpu_data.x86_phys_bits; - return cpuid_eax(0x80000008) & 0xff; }