On Wed, May 20, 2020 at 07:23:32PM +0200, Paolo Bonzini wrote:
On 20/05/20 19:13, Stefan Hajnoczi wrote:
Hi, libvirt refuses to set KVM_HINTS_DEDICATED when the CPU model is not host-passthrough.
Is there a reason for this limitation?
My understanding is that KVM_HINTS_DEDICATED means the vCPU is pinned to a host CPU that is not shared with other tasks. Any KVM vCPU should be able to support this feature, regardless of whether host-passthrough is used or not.
Perhaps it's because KVM_HINTS_DEDICATED enables mwait passthrough, and the details of mwait vary per CPU model?
KVM_HINTS_DEDICATED (now known as KVM_HINTS_REALTIME) is also used by cpuidle-haltpoll. In that case we don't care about mwait. CPU passthrough can prevent live migration, so I think we should relax this check, if possible. Wim: Can you let us know what the original intention of checking for cpu-passthrough was? Thanks, Stefan