Messages in this thread | | | Subject | Re: [PATCH] KVM: X86: Allow userspace to define the microcode version | From | Paolo Bonzini <> | Date | Mon, 26 Feb 2018 13:41:38 +0100 |
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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.
2) Only Amazon uses this feature and we ignore it. :)
Paolo
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