From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marc Zyngier Subject: [PATCH v2 1/9] KVM: ARM: vgic: plug irq injection race Date: Thu, 19 Jun 2014 10:21:25 +0100 Message-ID: <1403169693-13982-2-git-send-email-marc.zyngier@arm.com> References: <1403169693-13982-1-git-send-email-marc.zyngier@arm.com> Cc: Christoffer Dall To: linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org Return-path: Received: from fw-tnat.austin.arm.com ([217.140.110.23]:43320 "EHLO collaborate-mta1.arm.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S932457AbaFSJVg (ORCPT ); Thu, 19 Jun 2014 05:21:36 -0400 In-Reply-To: <1403169693-13982-1-git-send-email-marc.zyngier@arm.com> Sender: kvm-owner@vger.kernel.org List-ID: As it stands, nothing prevents userspace from injecting an interrupt before the guest's GIC is actually initialized. This goes unnoticed so far (as everything is pretty much statically allocated), but ends up exploding in a spectacular way once we switch to a more dynamic allocation (the GIC data structure isn't there yet). The fix is to test for the "ready" flag in the VGIC distributor before trying to inject the interrupt. Note that in order to avoid breaking userspace, we have to ignore what is essentially an error. Signed-off-by: Marc Zyngier Acked-by: Christoffer Dall --- virt/kvm/arm/vgic.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c index 795ab48..c6da748 100644 --- a/virt/kvm/arm/vgic.c +++ b/virt/kvm/arm/vgic.c @@ -1446,7 +1446,8 @@ out: int kvm_vgic_inject_irq(struct kvm *kvm, int cpuid, unsigned int irq_num, bool level) { - if (vgic_update_irq_state(kvm, cpuid, irq_num, level)) + if (likely(vgic_initialized(kvm)) && + vgic_update_irq_state(kvm, cpuid, irq_num, level)) vgic_kick_vcpus(kvm); return 0; -- 1.8.3.4 From mboxrd@z Thu Jan 1 00:00:00 1970 From: marc.zyngier@arm.com (Marc Zyngier) Date: Thu, 19 Jun 2014 10:21:25 +0100 Subject: [PATCH v2 1/9] KVM: ARM: vgic: plug irq injection race In-Reply-To: <1403169693-13982-1-git-send-email-marc.zyngier@arm.com> References: <1403169693-13982-1-git-send-email-marc.zyngier@arm.com> Message-ID: <1403169693-13982-2-git-send-email-marc.zyngier@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org As it stands, nothing prevents userspace from injecting an interrupt before the guest's GIC is actually initialized. This goes unnoticed so far (as everything is pretty much statically allocated), but ends up exploding in a spectacular way once we switch to a more dynamic allocation (the GIC data structure isn't there yet). The fix is to test for the "ready" flag in the VGIC distributor before trying to inject the interrupt. Note that in order to avoid breaking userspace, we have to ignore what is essentially an error. Signed-off-by: Marc Zyngier Acked-by: Christoffer Dall --- virt/kvm/arm/vgic.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c index 795ab48..c6da748 100644 --- a/virt/kvm/arm/vgic.c +++ b/virt/kvm/arm/vgic.c @@ -1446,7 +1446,8 @@ out: int kvm_vgic_inject_irq(struct kvm *kvm, int cpuid, unsigned int irq_num, bool level) { - if (vgic_update_irq_state(kvm, cpuid, irq_num, level)) + if (likely(vgic_initialized(kvm)) && + vgic_update_irq_state(kvm, cpuid, irq_num, level)) vgic_kick_vcpus(kvm); return 0; -- 1.8.3.4