On Wed, 31 Mar 2021 at 01:02, Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote: > > There is no need to include changes to vcpu->requests into > the pvclock_gtod_sync_lock critical section. The changes to > the shared data structures (in pvclock_update_vm_gtod_copy) > already occur under the lock. > > Cc: David Woodhouse <dwmw@xxxxxxxxxxxx> > Cc: Marcelo Tosatti <mtosatti@xxxxxxxxxx> > Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx> Reviewed-by: Wanpeng Li <wanpengli@xxxxxxxxxxx> > --- > arch/x86/kvm/x86.c | 10 ++++------ > 1 file changed, 4 insertions(+), 6 deletions(-) > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index fe806e894212..0a83eff40b43 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -2562,10 +2562,12 @@ static void kvm_gen_update_masterclock(struct kvm *kvm) > > kvm_hv_invalidate_tsc_page(kvm); > > - spin_lock(&ka->pvclock_gtod_sync_lock); > kvm_make_mclock_inprogress_request(kvm); > + > /* no guest entries from this point */ > + spin_lock(&ka->pvclock_gtod_sync_lock); > pvclock_update_vm_gtod_copy(kvm); > + spin_unlock(&ka->pvclock_gtod_sync_lock); > > kvm_for_each_vcpu(i, vcpu, kvm) > kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu); > @@ -2573,8 +2575,6 @@ static void kvm_gen_update_masterclock(struct kvm *kvm) > /* guest entries allowed */ > kvm_for_each_vcpu(i, vcpu, kvm) > kvm_clear_request(KVM_REQ_MCLOCK_INPROGRESS, vcpu); > - > - spin_unlock(&ka->pvclock_gtod_sync_lock); > #endif > } > > @@ -7740,16 +7740,14 @@ static void kvm_hyperv_tsc_notifier(void) > struct kvm_arch *ka = &kvm->arch; > > spin_lock(&ka->pvclock_gtod_sync_lock); > - > pvclock_update_vm_gtod_copy(kvm); > + spin_unlock(&ka->pvclock_gtod_sync_lock); > > kvm_for_each_vcpu(cpu, vcpu, kvm) > kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu); > > kvm_for_each_vcpu(cpu, vcpu, kvm) > kvm_clear_request(KVM_REQ_MCLOCK_INPROGRESS, vcpu); > - > - spin_unlock(&ka->pvclock_gtod_sync_lock); > } > mutex_unlock(&kvm_lock); > } > -- > 2.26.2 > >
