From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751893AbbD3MOm (ORCPT ); Thu, 30 Apr 2015 08:14:42 -0400 Received: from ip4-83-240-67-251.cust.nbox.cz ([83.240.67.251]:53689 "EHLO ip4-83-240-18-248.cust.nbox.cz" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751476AbbD3MMf (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 , Shannon Zhao , Jiri Slaby Subject: [PATCH 3.12 59/63] arm/arm64: KVM: Require in-kernel vgic for the arch timers Date: Thu, 30 Apr 2015 14:12:28 +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: 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 05971120fca43e0357789a14b3386bb56eef2201 upstream. It is curently possible to run a VM with architected timers support without creating an in-kernel VGIC, which will result in interrupts from the virtual timer going nowhere. To address this issue, move the architected timers initialization to the time when we run a VCPU for the first time, and then only initialize (and enable) the architected timers if we have a properly created and initialized in-kernel VGIC. When injecting interrupts from the virtual timer to the vgic, the current setup should ensure that this never calls an on-demand init of the VGIC, which is the only call path that could return an error from kvm_vgic_inject_irq(), so capture the return value and raise a warning if there's an error there. We also change the kvm_timer_init() function from returning an int to be a void function, since the function always succeeds. Reviewed-by: Marc Zyngier Signed-off-by: Christoffer Dall Signed-off-by: Shannon Zhao Signed-off-by: Jiri Slaby --- arch/arm/kvm/arm.c | 9 +++++++++ include/kvm/arm_arch_timer.h | 10 ++++------ virt/kvm/arm/arch_timer.c | 30 ++++++++++++++++++++++-------- 3 files changed, 35 insertions(+), 14 deletions(-) diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c index 86dee11838ab..28b60461936e 100644 --- a/arch/arm/kvm/arm.c +++ b/arch/arm/kvm/arm.c @@ -439,6 +439,7 @@ static void update_vttbr(struct kvm *kvm) static int kvm_vcpu_first_run_init(struct kvm_vcpu *vcpu) { + struct kvm *kvm = vcpu->kvm; int ret; if (likely(vcpu->arch.has_run_once)) @@ -456,6 +457,14 @@ static int kvm_vcpu_first_run_init(struct kvm_vcpu *vcpu) return ret; } + /* + * Enable the arch timers only if we have an in-kernel VGIC + * and it has been properly initialized, since we cannot handle + * interrupts from the virtual timer with a userspace gic. + */ + if (irqchip_in_kernel(kvm) && vgic_initialized(kvm)) + kvm_timer_enable(kvm); + return 0; } diff --git a/include/kvm/arm_arch_timer.h b/include/kvm/arm_arch_timer.h index 6d9aeddc09bf..327b155e7cc9 100644 --- a/include/kvm/arm_arch_timer.h +++ b/include/kvm/arm_arch_timer.h @@ -60,7 +60,8 @@ struct arch_timer_cpu { #ifdef CONFIG_KVM_ARM_TIMER int kvm_timer_hyp_init(void); -int kvm_timer_init(struct kvm *kvm); +void kvm_timer_enable(struct kvm *kvm); +void kvm_timer_init(struct kvm *kvm); void kvm_timer_vcpu_reset(struct kvm_vcpu *vcpu, const struct kvm_irq_level *irq); void kvm_timer_vcpu_init(struct kvm_vcpu *vcpu); @@ -73,11 +74,8 @@ static inline int kvm_timer_hyp_init(void) return 0; }; -static inline int kvm_timer_init(struct kvm *kvm) -{ - return 0; -} - +static inline void kvm_timer_enable(struct kvm *kvm) {} +static inline void kvm_timer_init(struct kvm *kvm) {} static inline void kvm_timer_vcpu_reset(struct kvm_vcpu *vcpu, const struct kvm_irq_level *irq) {} static inline void kvm_timer_vcpu_init(struct kvm_vcpu *vcpu) {} diff --git a/virt/kvm/arm/arch_timer.c b/virt/kvm/arm/arch_timer.c index c2e1ef4604e8..52b4225da32d 100644 --- a/virt/kvm/arm/arch_timer.c +++ b/virt/kvm/arm/arch_timer.c @@ -61,12 +61,14 @@ static void timer_disarm(struct arch_timer_cpu *timer) static void kvm_timer_inject_irq(struct kvm_vcpu *vcpu) { + int ret; struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu; timer->cntv_ctl |= ARCH_TIMER_CTRL_IT_MASK; - kvm_vgic_inject_irq(vcpu->kvm, vcpu->vcpu_id, - timer->irq->irq, - timer->irq->level); + ret = kvm_vgic_inject_irq(vcpu->kvm, vcpu->vcpu_id, + timer->irq->irq, + timer->irq->level); + WARN_ON(ret); } static irqreturn_t kvm_arch_timer_handler(int irq, void *dev_id) @@ -273,12 +275,24 @@ void kvm_timer_vcpu_terminate(struct kvm_vcpu *vcpu) timer_disarm(timer); } -int kvm_timer_init(struct kvm *kvm) +void kvm_timer_enable(struct kvm *kvm) { - if (timecounter && wqueue) { - kvm->arch.timer.cntvoff = kvm_phys_timer_read(); + if (kvm->arch.timer.enabled) + return; + + /* + * There is a potential race here between VCPUs starting for the first + * time, which may be enabling the timer multiple times. That doesn't + * hurt though, because we're just setting a variable to the same + * variable that it already was. The important thing is that all + * VCPUs have the enabled variable set, before entering the guest, if + * the arch timers are enabled. + */ + if (timecounter && wqueue) kvm->arch.timer.enabled = 1; - } +} - return 0; +void kvm_timer_init(struct kvm *kvm) +{ + kvm->arch.timer.cntvoff = kvm_phys_timer_read(); } -- 2.3.5