From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoffer Dall Subject: Re: [PATCH v2 6/9] KVM: arm/arm64: use a vcpu request on irq injection Date: Tue, 4 Apr 2017 19:42:08 +0200 Message-ID: <20170404174208.GB31208@cbox> References: <20170331160658.4331-1-drjones@redhat.com> <20170331160658.4331-7-drjones@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: marc.zyngier@arm.com, pbonzini@redhat.com, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org To: Andrew Jones Return-path: Content-Disposition: inline In-Reply-To: <20170331160658.4331-7-drjones@redhat.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu List-Id: kvm.vger.kernel.org On Fri, Mar 31, 2017 at 06:06:55PM +0200, Andrew Jones wrote: > Don't use request-less VCPU kicks when injecting IRQs, as a VCPU > kick meant to trigger the interrupt injection could be sent while > the VCPU is outside guest mode, which means no IPI is sent, and > after it has called kvm_vgic_flush_hwstate(), meaning it won't see > the updated GIC state until its next exit some time later for some > other reason. > > Signed-off-by: Andrew Jones > --- > arch/arm/include/asm/kvm_host.h | 1 + > arch/arm/kvm/arm.c | 1 + > arch/arm64/include/asm/kvm_host.h | 1 + > virt/kvm/arm/arch_timer.c | 1 + > virt/kvm/arm/vgic/vgic.c | 12 ++++++++++-- > 5 files changed, 14 insertions(+), 2 deletions(-) > > diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h > index afed5d44634d..0b8a6d6b3cb3 100644 > --- a/arch/arm/include/asm/kvm_host.h > +++ b/arch/arm/include/asm/kvm_host.h > @@ -47,6 +47,7 @@ > > #define KVM_REQ_PAUSE 8 > #define KVM_REQ_POWER_OFF 9 > +#define KVM_REQ_IRQ_PENDING 10 > > u32 *kvm_vcpu_reg(struct kvm_vcpu *vcpu, u8 reg_num, u32 mode); > int __attribute_const__ kvm_target_cpu(void); > diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c > index 7ed39060b1cf..a106feccf314 100644 > --- a/arch/arm/kvm/arm.c > +++ b/arch/arm/kvm/arm.c > @@ -768,6 +768,7 @@ static int vcpu_interrupt_line(struct kvm_vcpu *vcpu, int number, bool level) > * trigger a world-switch round on the running physical CPU to set the > * virtual IRQ/FIQ fields in the HCR appropriately. > */ > + kvm_make_request(KVM_REQ_IRQ_PENDING, vcpu); > kvm_vcpu_kick(vcpu); > > return 0; > diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h > index e78895f675d0..7057512b3474 100644 > --- a/arch/arm64/include/asm/kvm_host.h > +++ b/arch/arm64/include/asm/kvm_host.h > @@ -44,6 +44,7 @@ > > #define KVM_REQ_PAUSE 8 > #define KVM_REQ_POWER_OFF 9 > +#define KVM_REQ_IRQ_PENDING 10 > > int __attribute_const__ kvm_target_cpu(void); > int kvm_reset_vcpu(struct kvm_vcpu *vcpu); > diff --git a/virt/kvm/arm/arch_timer.c b/virt/kvm/arm/arch_timer.c > index 35d7100e0815..3c48abbf951b 100644 > --- a/virt/kvm/arm/arch_timer.c > +++ b/virt/kvm/arm/arch_timer.c > @@ -95,6 +95,7 @@ static void kvm_timer_inject_irq_work(struct work_struct *work) > * If the vcpu is blocked we want to wake it up so that it will see > * the timer has expired when entering the guest. > */ > + kvm_make_request(KVM_REQ_IRQ_PENDING, vcpu); > kvm_vcpu_kick(vcpu); > } > > diff --git a/virt/kvm/arm/vgic/vgic.c b/virt/kvm/arm/vgic/vgic.c > index 654dfd40e449..31fb89057f0c 100644 > --- a/virt/kvm/arm/vgic/vgic.c > +++ b/virt/kvm/arm/vgic/vgic.c > @@ -283,8 +283,10 @@ bool vgic_queue_irq_unlock(struct kvm *kvm, struct vgic_irq *irq) > * won't see this one until it exits for some other > * reason. > */ > - if (vcpu) > + if (vcpu) { > + kvm_make_request(KVM_REQ_IRQ_PENDING, vcpu); > kvm_vcpu_kick(vcpu); > + } > return false; > } > > @@ -330,6 +332,7 @@ bool vgic_queue_irq_unlock(struct kvm *kvm, struct vgic_irq *irq) > spin_unlock(&irq->irq_lock); > spin_unlock(&vcpu->arch.vgic_cpu.ap_list_lock); > > + kvm_make_request(KVM_REQ_IRQ_PENDING, vcpu); > kvm_vcpu_kick(vcpu); > > return true; > @@ -654,6 +657,9 @@ void kvm_vgic_flush_hwstate(struct kvm_vcpu *vcpu) > spin_lock(&vcpu->arch.vgic_cpu.ap_list_lock); > vgic_flush_lr_state(vcpu); > spin_unlock(&vcpu->arch.vgic_cpu.ap_list_lock); > + > + /* The GIC is now ready to deliver the IRQ. */ > + clear_bit(KVM_REQ_IRQ_PENDING, &vcpu->requests); this is not going to be called when we don't have the vgic, which means that if vcpu_interrupt_line() is used as you modify it above, the request will never get cleared. > } > > int kvm_vgic_vcpu_pending_irq(struct kvm_vcpu *vcpu) > @@ -691,8 +697,10 @@ void vgic_kick_vcpus(struct kvm *kvm) > * a good kick... > */ > kvm_for_each_vcpu(c, vcpu, kvm) { > - if (kvm_vgic_vcpu_pending_irq(vcpu)) > + if (kvm_vgic_vcpu_pending_irq(vcpu)) { > + kvm_make_request(KVM_REQ_IRQ_PENDING, vcpu); > kvm_vcpu_kick(vcpu); > + } > } > } > > -- > 2.9.3 > Thanks, -Christoffer