Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934757AbbHJK0c (ORCPT ); Mon, 10 Aug 2015 06:26:32 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:44220 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934275AbbHJKSB (ORCPT ); Mon, 10 Aug 2015 06:18:01 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "=?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?=" , "Paolo Bonzini" Date: Mon, 10 Aug 2015 12:12:31 +0200 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 064/110] KVM: x86: make vapics_in_nmi_mode atomic In-Reply-To: X-SA-Exim-Connect-IP: 2.173.94.72 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2370 Lines: 66 3.2.71-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Radim Krčmář 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 [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings --- 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(-) --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -472,7 +472,7 @@ 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; unsigned int tss_addr; struct page *apic_access_page; --- a/arch/x86/kvm/i8254.c +++ b/arch/x86/kvm/i8254.c @@ -318,7 +318,7 @@ static void pit_do_work(struct work_stru * 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); } --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -757,10 +757,10 @@ static void apic_manage_nmi_watchdog(str 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) -- 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/