On Wed, Apr 18, 2018 at 12:36:37PM +0200, Paolo Bonzini wrote: > On 18/04/2018 11:03, Eduardo Habkost wrote: > >>> QEMU setting ucode_rev automatically using the host value when > >>> using "-cpu host" (with no need for explicit ucode_rev option) > >>> makes sense to me. > >> QEMU can't get the host value by rdmsr MSR_IA32_UCODE_REV directly > >> since rdmsr will #GP when ring !=0, any idea? > > By looking at kvm_get_msr_feature(), it looks like > > ioctl(system_fd, KVM_GET_MSRS) would return the host MSR value > > for us. > > Yes, that's exactly what it was introduced for (together with other MSRs > including VMX capabilities). Can't qemu do: grep microcode /proc/cpuinfo | awk '{ print $3 }' | head -n 1 ? :) -- Regards/Gruss, Boris. Good mailing practices for 400: avoid top-posting and trim the reply.