On Thu, Jun 29, 2023 at 02:12:27PM +0800, Binbin Wu wrote: >> > + /* >> > + * Check LAM_U48 in cr3_ctrl_bits to avoid guest_cpuid_has(). >> > + * If not set, vCPU doesn't supports LAM. >> > + */ >> > + if (!(vcpu->arch.cr3_ctrl_bits & X86_CR3_LAM_U48) || >> This is unnecessary, KVM should never allow the LAM bits in CR3 to be set if LAM >> isn't supported. A corner case is: If EPT is enabled, CR3 writes are not trapped. then guests can set the LAM bits in CR3 if hardware supports LAM regardless whether or not guest enumerates LAM.
