On 31/03/2017 18:06, 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 <drjones@xxxxxxxxxx>
> ---
> 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);
> }
>
> 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);
> + }
> }
> }
>
>
Reviewed-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
