Re: [Qemu-devel] [PATCH 2/5] i386: Add CPUID bit and feature words for IA32_ARCH_CAPABILITIES MSR

[Paolo Bonzini]

On 28/06/2018 20:30, Eduardo Habkost wrote:
>> For migration to work, you need to add new "features" corresponding to
>> the bits in the MSR, and include them in the Icelake-Server and
>> Icelake-Client models.  Unfortunately there is no code for this in QEMU
>> yet, though the API is there in KVM.
> Will all Icelake VCPUs of a given model have the same value on
> MSR_IA32_ARCH_CAPABILITIES?
> 
> If not, we can't choose a value that will work on all cases, and
> it will require management software to be smarter and explicitly
> configure some of the MSR bits on the command-line.

We can expect that it will change as more vulnerabilities are found and
more microcode updates are issued.  We should get it right from the
beginning.

Paolo