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authorRadim Krčmář <rkrcmar@redhat.com>2015-07-01 16:31:49 +0300
committerPaolo Bonzini <pbonzini@redhat.com>2015-07-03 19:55:17 +0300
commit42720138b06301cc8a7ee8a495a6d021c4b6a9bc (patch)
treefbffa8a4feceef419b8d1f56cd521148095a8ba5 /arch/x86/kvm/lapic.c
parent2ecd9d29abb171d6e97a4f3eb29d7456a11401b7 (diff)
downloadlinux-42720138b06301cc8a7ee8a495a6d021c4b6a9bc.tar.xz
KVM: x86: make vapics_in_nmi_mode atomic
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] Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/lapic.c')
-rw-r--r--arch/x86/kvm/lapic.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 36e9de1b4127..607a56b35327 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -1263,10 +1263,10 @@ 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)