Messages in this thread | | | Subject | Re: [PATCH 2/2] KVM: x86: Identify vCPU0 by its vcpu_idx instead of walking vCPUs array | From | Paolo Bonzini <> | Date | Wed, 22 Sep 2021 09:41:12 +0200 |
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On 20/09/21 16:57, Sean Christopherson wrote: > On Mon, Sep 13, 2021, Vitaly Kuznetsov wrote: >> Sean Christopherson <seanjc@google.com> writes: >> >>> Use vcpu_idx to identify vCPU0 when updating HyperV's TSC page, which is >>> shared by all vCPUs and "owned" by vCPU0 (because vCPU0 is the only vCPU >>> that's guaranteed to exist). Using kvm_get_vcpu() to find vCPU works, >>> but it's a rather odd and suboptimal method to check the index of a given >>> vCPU. >>> >>> No functional change intended. >>> >>> Signed-off-by: Sean Christopherson <seanjc@google.com> >>> --- >>> arch/x86/kvm/x86.c | 2 +- >>> 1 file changed, 1 insertion(+), 1 deletion(-) >>> >>> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c >>> index 86539c1686fa..6ab851df08d1 100644 >>> --- a/arch/x86/kvm/x86.c >>> +++ b/arch/x86/kvm/x86.c >>> @@ -2969,7 +2969,7 @@ static int kvm_guest_time_update(struct kvm_vcpu *v) >>> offsetof(struct compat_vcpu_info, time)); >>> if (vcpu->xen.vcpu_time_info_set) >>> kvm_setup_pvclock_page(v, &vcpu->xen.vcpu_time_info_cache, 0); >>> - if (v == kvm_get_vcpu(v->kvm, 0)) >>> + if (!v->vcpu_idx) >>> kvm_hv_setup_tsc_page(v->kvm, &vcpu->hv_clock); >>> return 0; >>> } >> >> " ... instead of walking vCPUs array" in the Subject line is a bit >> confusing because kvm_get_vcpu() doesn't actually walk anything, it just >> returns 'kvm->vcpus[i]' after checking that we actually have that many >> vCPUs. The patch itself is OK, so > > Argh, yes, I have a feeling I wrote the changelog after digging into the history > of kvm_get_vcpu(). > > Paolo, can you tweak the shortlog to: > > KVM: x86: Identify vCPU0 by its vcpu_idx instead of its vCPUs array entry >
Done and queued. Patch 1 required some further s390 changes.
Paolo
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