Messages in this thread | | | Subject | Re: [PART1 RFC 5/9] svm: Add VMEXIT handlers for AVIC | From | Suravee Suthikulpanit <> | Date | Thu, 3 Mar 2016 17:42:22 +0700 |
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Hi
On 02/19/2016 12:18 AM, 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 >
In facts, instead of setting up the vAPIC backing page address when calling kvm_arch_vcpu_load(), we should be able to do it when calling kvm_arch_vcpu_sched_in(). This seems more appropriate since the kvm_arch_vcpu_load() is also called in many unnecessary occasions via vcpu_load() (in the arch/x86/kvm/x86.c). The same goes for the kvm_arch_vcpu_put().
However, there is no kvm_arch_vcpu_sched_out(). But that can be added easily.
What do you think?
Suravee
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