Messages in this thread | | | Subject | Re: [PART1 RFC 5/9] svm: Add VMEXIT handlers for AVIC | From | Suravee Suthikulpanit <> | Date | Fri, 19 Feb 2016 18:39:52 +0700 |
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Hi,
On 2/19/16 00:18, Paolo Bonzini wrote: > > > On 18/02/2016 17:27, Radim Krčmář wrote: >> 2016-02-18 16:53+0100, Paolo Bonzini: >>> Patch 9 is okay, but it is also necessary to clear IsRunning in >>> kvm_arch_vcpu_blocking and set it in kvm_arch_vcpu_unblocking. In >>> addition, vcpu_put/vcpu_load should not modify IsRunning between >>> kvm_arch_vcpu_blocking and kvm_arch_vcpu_unblocking. Do you agree? >> >> Yes. >> >> I think we don't need to clear IsRunning on preemption, which would >> simplify the protection. (I haven't thought much about userspace exit, >> so maybe we could skip that one as well, but we don't need to now.) >> >> The reason for that is that KVM knows that the VCPU was scheduled out, >> so it couldn't do much in the AVIC VMEXIT. >> (KVM could force scheduler to pritioritize the VCPU, but our kick >> doesn't do that now and it seems like a bad idea.) >> >> Does it seem reasonable? > > Yes, and in fact it wouldn't need to clear and set IsRunning on > vcpu_put/vcpu_load; only on vcpu_blocking/vcpu_unblocking. > > The IsRunning flag is more of a IsNotHalted flag, in the end. > > Paolo >
Good point. I have made the change by introducing new function pointer, kvm_x86_ops.vcpu_blocking() and kvm_x86_ops.vcpu_unblocking(). Then provides the hook to set/unset the IsRunningBit here. Also, I no longer set the bit in the vcpu_load/vcpu_put.
If this is okay. I'll send out V2 soon.
Thanks, Suravee
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