Cc Eduardo, 2018-02-26 20:41 GMT+08:00 Paolo Bonzini <pbonzini@xxxxxxxxxx>: > On 26/02/2018 13:22, Borislav Petkov wrote: >> On Mon, Feb 26, 2018 at 01:18:07PM +0100, Paolo Bonzini wrote: >>>> In this context, "host-initiated" write means written by KVM userspace >>>> with ioctl(KVM_SET_MSR). It generally happens only on VM startup, reset >>>> or live migration. >>> >>> To be clear, the target of the write is still the vCPU's emulated MSR. >> >> So how am I to imagine this as a user: >> >> qemu-system-x86_64 --microcode-revision=0xdeadbeef... > > More like "-cpu foo,ucode_rev=0xdeadbeef". But in practice what would > happen is one of the following: > > 1) "-cpu host" sets ucode_rev to the same value of the host, everyone > else leaves it to zero as is now. Hi Paolo, Do you mean the host admin to get the ucode_rev from the host and set to -cpu host, ucode_rev=xxxxxx or qemu get the ucode_rev directly by rdmsr? Regards, Wanpeng Li
