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| author | Radim Krčmář <rkrcmar@redhat.com> | 2015-07-01 15:31:49 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-07-10 10:37:59 -0700 |
| commit | 18358e27d477847f49a509ed50f4b70bab8e8f8b (patch) | |
| tree | 47db2bbfd6842d7bd634f84bb089a16f29358688 /arch/x86/kvm/lapic.c | |
| parent | 11ac9ad9ab48551a5bb17748d7e9d8676b28c692 (diff) | |
| download | lwn-18358e27d477847f49a509ed50f4b70bab8e8f8b.tar.gz lwn-18358e27d477847f49a509ed50f4b70bab8e8f8b.zip | |
KVM: x86: make vapics_in_nmi_mode atomic
commit 42720138b06301cc8a7ee8a495a6d021c4b6a9bc upstream.
Writes were a bit racy, but hard to turn into a bug at the same time.
(Particularly because modern Linux doesn't use this feature anymore.)
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
[Actually the next patch makes it much, much easier to trigger the race
so I'm including this one for stable@ as well. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/x86/kvm/lapic.c')
| -rw-r--r-- | arch/x86/kvm/lapic.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index 453e5fbbb7ae..6456734a4ca6 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -1109,10 +1109,10 @@ static void apic_manage_nmi_watchdog(struct kvm_lapic *apic, u32 lvt0_val) if (!nmi_wd_enabled) { apic_debug("Receive NMI setting on APIC_LVT0 " "for cpu %d\n", apic->vcpu->vcpu_id); - apic->vcpu->kvm->arch.vapics_in_nmi_mode++; + atomic_inc(&apic->vcpu->kvm->arch.vapics_in_nmi_mode); } } else if (nmi_wd_enabled) - apic->vcpu->kvm->arch.vapics_in_nmi_mode--; + atomic_dec(&apic->vcpu->kvm->arch.vapics_in_nmi_mode); } static int apic_reg_write(struct kvm_lapic *apic, u32 reg, u32 val) |