KVM: x86: Identify vCPU0 by its vcpu_idx instead of its vCPUs array entry

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>
Reviewed-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20210910183220.2397812-3-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 42c5c7a195aee9fb4e0dc0dbe37523b2fd29a3d9..11017c94f0aa69773ab6b7d7634cb634e393fddd 100644 (file)
--- 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;
 }