Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755536AbbG1Jqh (ORCPT ); Tue, 28 Jul 2015 05:46:37 -0400 Received: from mail-wi0-f179.google.com ([209.85.212.179]:37755 "EHLO mail-wi0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752315AbbG1Jp7 (ORCPT ); Tue, 28 Jul 2015 05:45:59 -0400 From: Jiri Slaby To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= , Paolo Bonzini , Jiri Slaby Subject: [PATCH 3.12 092/124] KVM: x86: make vapics_in_nmi_mode atomic Date: Tue, 28 Jul 2015 11:43:46 +0200 Message-Id: <8b5a084820646627b87a53cb47eec8db4fd14211.1438076484.git.jslaby@suse.cz> X-Mailer: git-send-email 2.4.6 In-Reply-To: <90d8a5681e4a9e320611b422f0ed012e148c2bca.1438076484.git.jslaby@suse.cz> References: <90d8a5681e4a9e320611b422f0ed012e148c2bca.1438076484.git.jslaby@suse.cz> In-Reply-To: References: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2693 Lines: 73 From: Radim Krčmář 3.12-stable review patch. If anyone has any objections, please let me know. =============== 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 [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 Signed-off-by: Jiri Slaby --- arch/x86/include/asm/kvm_host.h | 2 +- arch/x86/kvm/i8254.c | 2 +- arch/x86/kvm/lapic.c | 4 ++-- 3 files changed, 4 insertions(+), 4 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 7cb77dd749df..55f8ca8c20e4 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -562,7 +562,7 @@ struct kvm_arch { struct kvm_pic *vpic; struct kvm_ioapic *vioapic; struct kvm_pit *vpit; - int vapics_in_nmi_mode; + atomic_t vapics_in_nmi_mode; struct mutex apic_map_lock; struct kvm_apic_map *apic_map; diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c index 298781d4cfb4..1406ffde3e35 100644 --- a/arch/x86/kvm/i8254.c +++ b/arch/x86/kvm/i8254.c @@ -305,7 +305,7 @@ static void pit_do_work(struct kthread_work *work) * LVT0 to NMI delivery. Other PIC interrupts are just sent to * VCPU0, and only if its LVT0 is in EXTINT mode. */ - if (kvm->arch.vapics_in_nmi_mode > 0) + if (atomic_read(&kvm->arch.vapics_in_nmi_mode) > 0) kvm_for_each_vcpu(i, vcpu, kvm) kvm_apic_nmi_wd_deliver(vcpu); } diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index 92bbb397f59d..a4ce2b2f1418 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -1088,10 +1088,10 @@ 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) -- 2.4.6 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/