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From:   "Wang, Wei W" <wei.w.wang@intel.com>
To:     "Christopherson,, Sean" <seanjc@google.com>
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Subject: RE: [PATCH v1 05/18] KVM: selftests/hardware_disable_test: code
 consolidation and cleanup
Thread-Topic: [PATCH v1 05/18] KVM: selftests/hardware_disable_test: code
 consolidation and cleanup
Thread-Index: AQHY55yuIXKRns508k+BGhcyAkdsga4hY2oAgADNh4CAAFyPAIAAfM3w
Date:   Fri, 28 Oct 2022 02:16:55 +0000
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On Friday, October 28, 2022 2:03 AM, Sean Christopherson wrote:
> But why does it matter what pCPU a vCPU is running on?  Wouldn't the
> probability of triggering a race between kvm_on_user_return() and
> hardware_disable() be _higher_ if there are more pCPUs returning to users=
pace?

I think the point there is that the vcpus and those syscall threads need to=
 be on the
same pCPUs. Linux by default has its own load balancing for threads to run =
on. If the
vcpus and syscall threads are scattered on different pCPUs, kvm_on_user_ret=
urn
would less likely to be triggered when the syscall threads return to usersp=
ace.