On Thu, Jan 06, 2022, Wanpeng Li wrote: > From: Wanpeng Li <wanpengli@xxxxxxxxxxx> > > As commit 0c5f81dad46 (KVM: LAPIC: Inject timer interrupt via posted interrupt) > mentioned that the host admin should well tune the guest setup, so that vCPUs > are placed on isolated pCPUs, and with several pCPUs surplus for *busy* housekeeping. > It is better to disable mwait/hlt/pause vmexits to keep the vCPUs in non-root > mode. However, we may isolate pCPUs for other purpose like DPDK or we can make > some guests isolated and others not, we may lose vmx preemption timer/timer fastpath > due to not well tuned setup, and the checking in kvm_can_post_timer_interrupt() > is not enough. Let's guarantee mwait/hlt is advertised before enabling posted-interrupt > interrupt. vmx preemption timer/timer fastpath can continue to work if both of them > are not advertised. > > Reported-by: Aili Yao <yaoaili@xxxxxxxxxxxx> > Cc: Aili Yao <yaoaili@xxxxxxxxxxxx> > Cc: Sean Christopherson <seanjc@xxxxxxxxxx> > Signed-off-by: Wanpeng Li <wanpengli@xxxxxxxxxxx> > --- Reviewed-by: Sean Christopherson <seanjc@xxxxxxxxxx>
