[Qemu-devel] Do I need update the microcode of virtual machine

[Li Qiang]

Hi Paolo, all,

I have a question about the intel microcode update for spectre variant#2.
>From my understanding, there is no need to update the microcode of VMs
because the kvm has expose the SPEC_CTL and PRED_CMD to the guest.
Also, if we need to update the micorcode in guest, who is the vendor for
this.
>From the hyper-v, I think I'm right.
-->
https://docs.microsoft.com/en-us/virtualization/hyper-v-on-windows/CVE-2017-5715-and-hyper-v-vms

But upon I update the centos guest, the host kvm/qemu has been updated.
The IBPB_ENABLED and IBRS_ENABLED are both zero if I don't update the
microcode in the guest.
If I update the guest micorcode, the are both 1.

So I want to know, if I should update the microcode in guest.
If the answer is Yes, then what about the Windows guest, how to update the
microcode?


Thanks,
Li Qiang