From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750802AbbD3MOt (ORCPT ); Thu, 30 Apr 2015 08:14:49 -0400 Received: from ip4-83-240-67-251.cust.nbox.cz ([83.240.67.251]:53700 "EHLO ip4-83-240-18-248.cust.nbox.cz" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751477AbbD3MMf (ORCPT ); Thu, 30 Apr 2015 08:12:35 -0400 From: Jiri Slaby To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Christoffer Dall , Marc Zyngier , =?UTF-8?q?Alex=20Benn=C3=A9e?= , Shannon Zhao , Jiri Slaby Subject: [PATCH 3.12 63/63] arm/arm64: KVM: Keep elrsr/aisr in sync with software model Date: Thu, 30 Apr 2015 14:12:32 +0200 Message-Id: X-Mailer: git-send-email 2.3.5 In-Reply-To: <45aaf85687dd6ac119c55c5ec0dbe0bef0e62235.1430387326.git.jslaby@suse.cz> References: <45aaf85687dd6ac119c55c5ec0dbe0bef0e62235.1430387326.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 From: Christoffer Dall 3.12-stable review patch. If anyone has any objections, please let me know. =============== commit ae705930fca6322600690df9dc1c7d0516145a93 upstream. There is an interesting bug in the vgic code, which manifests itself when the KVM run loop has a signal pending or needs a vmid generation rollover after having disabled interrupts but before actually switching to the guest. In this case, we flush the vgic as usual, but we sync back the vgic state and exit to userspace before entering the guest. The consequence is that we will be syncing the list registers back to the software model using the GICH_ELRSR and GICH_EISR from the last execution of the guest, potentially overwriting a list register containing an interrupt. This showed up during migration testing where we would capture a state where the VM has masked the arch timer but there were no interrupts, resulting in a hung test. Cc: Marc Zyngier Reported-by: Alex Bennee Signed-off-by: Christoffer Dall Signed-off-by: Alex Bennée Acked-by: Marc Zyngier Signed-off-by: Shannon Zhao Signed-off-by: Jiri Slaby --- virt/kvm/arm/vgic.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c index 865a89178c82..ecea20153b42 100644 --- a/virt/kvm/arm/vgic.c +++ b/virt/kvm/arm/vgic.c @@ -881,6 +881,7 @@ static bool vgic_queue_irq(struct kvm_vcpu *vcpu, u8 sgi_source_id, int irq) lr, irq, vgic_cpu->vgic_lr[lr]); BUG_ON(!test_bit(lr, vgic_cpu->lr_used)); vgic_cpu->vgic_lr[lr] |= GICH_LR_PENDING_BIT; + __clear_bit(lr, (unsigned long *)vgic_cpu->vgic_elrsr); return true; } @@ -894,6 +895,7 @@ static bool vgic_queue_irq(struct kvm_vcpu *vcpu, u8 sgi_source_id, int irq) vgic_cpu->vgic_lr[lr] = MK_LR_PEND(sgi_source_id, irq); vgic_cpu->vgic_irq_lr_map[irq] = lr; set_bit(lr, vgic_cpu->lr_used); + __clear_bit(lr, (unsigned long *)vgic_cpu->vgic_elrsr); if (!vgic_irq_is_edge(vcpu, irq)) vgic_cpu->vgic_lr[lr] |= GICH_LR_EOI; @@ -1048,6 +1050,14 @@ static bool vgic_process_maintenance(struct kvm_vcpu *vcpu) if (vgic_cpu->vgic_misr & GICH_MISR_U) vgic_cpu->vgic_hcr &= ~GICH_HCR_UIE; + /* + * In the next iterations of the vcpu loop, if we sync the vgic state + * after flushing it, but before entering the guest (this happens for + * pending signals and vmid rollovers), then make sure we don't pick + * up any old maintenance interrupts here. + */ + memset(vgic_cpu->vgic_eisr, 0, sizeof(vgic_cpu->vgic_eisr[0]) * 2); + return level_pending; } -- 2.3.5