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charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 4/11/24 18:31, Sean Christopherson wrote: > Force set a synthetic feature, GUEST_PCID, if PCID can be safely used in > virtual machines, even if the kernel itself disables PCID support, and > advertise PCID support in KVM if GUEST_PCID is set. > > When running on a CPU that is affected by Intel's "Global INVLPG" erratum, > which does NOT affect VMX non-root mode, it is safe to virtualize PCID for > KVM guests, even though it is not safe for the kernel itself to enable PCID. > Ditto for if the kernel disables PCID because CR4.PGE isn't supported. But the guest would not use it if the f/m/s matches, right? If the advantage is basically not splitting the migration pool, is that a concern for the affected Alder Lake/Gracemont/Raptor Lake processors? Paolo