From 0e3dfda91d9fe8e2c4d0b5d21434b173a241eeaf Mon Sep 17 00:00:00 2001 From: Christoffer Dall Date: Tue, 24 Nov 2015 16:23:05 +0100 Subject: KVM: arm/arm64: arch_timer: Preserve physical dist. active state on LR.active We were incorrectly removing the active state from the physical distributor on the timer interrupt when the timer output level was deasserted. We shouldn't be doing this without considering the virtual interrupt's active state, because the architecture requires that when an LR has the HW bit set and the pending or active bits set, then the physical interrupt must also have the corresponding bits set. This addresses an issue where we have been observing an inconsistency between the LR state and the physical distributor state where the LR state was active and the physical distributor was not active, which shouldn't happen. Reviewed-by: Marc Zyngier Signed-off-by: Christoffer Dall --- virt/kvm/arm/vgic.c | 34 ++++++++++++++++++++++------------ 1 file changed, 22 insertions(+), 12 deletions(-) (limited to 'virt/kvm/arm/vgic.c') diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c index 533538385d5d..97e2c088e1e9 100644 --- a/virt/kvm/arm/vgic.c +++ b/virt/kvm/arm/vgic.c @@ -1096,6 +1096,27 @@ static void vgic_retire_lr(int lr_nr, struct kvm_vcpu *vcpu) vgic_set_lr(vcpu, lr_nr, vlr); } +static bool dist_active_irq(struct kvm_vcpu *vcpu) +{ + struct vgic_dist *dist = &vcpu->kvm->arch.vgic; + + return test_bit(vcpu->vcpu_id, dist->irq_active_on_cpu); +} + +bool kvm_vgic_map_is_active(struct kvm_vcpu *vcpu, struct irq_phys_map *map) +{ + int i; + + for (i = 0; i < vcpu->arch.vgic_cpu.nr_lr; i++) { + struct vgic_lr vlr = vgic_get_lr(vcpu, i); + + if (vlr.irq == map->virt_irq && vlr.state & LR_STATE_ACTIVE) + return true; + } + + return dist_active_irq(vcpu); +} + /* * An interrupt may have been disabled after being made pending on the * CPU interface (the classic case is a timer running while we're @@ -1248,7 +1269,7 @@ static void __kvm_vgic_flush_hwstate(struct kvm_vcpu *vcpu) * may have been serviced from another vcpu. In all cases, * move along. */ - if (!kvm_vgic_vcpu_pending_irq(vcpu) && !kvm_vgic_vcpu_active_irq(vcpu)) + if (!kvm_vgic_vcpu_pending_irq(vcpu) && !dist_active_irq(vcpu)) goto epilog; /* SGIs */ @@ -1479,17 +1500,6 @@ int kvm_vgic_vcpu_pending_irq(struct kvm_vcpu *vcpu) return test_bit(vcpu->vcpu_id, dist->irq_pending_on_cpu); } -int kvm_vgic_vcpu_active_irq(struct kvm_vcpu *vcpu) -{ - struct vgic_dist *dist = &vcpu->kvm->arch.vgic; - - if (!irqchip_in_kernel(vcpu->kvm)) - return 0; - - return test_bit(vcpu->vcpu_id, dist->irq_active_on_cpu); -} - - void vgic_kick_vcpus(struct kvm *kvm) { struct kvm_vcpu *vcpu; -- cgit v1.2.1 From 9f958c11b780af74fc311b96d6124740aa21cc68 Mon Sep 17 00:00:00 2001 From: Christoffer Dall Date: Tue, 24 Nov 2015 16:34:31 +0100 Subject: KVM: arm/arm64: vgic: Trust the LR state for HW IRQs We were probing the physial distributor state for the active state of a HW virtual IRQ, because we had seen evidence that the LR state was not cleared when the guest deactivated a virtual interrupted. However, this issue turned out to be a software bug in the GIC, which was solved by: 84aab5e68c2a5e1e18d81ae8308c3ce25d501b29 (KVM: arm/arm64: arch_timer: Preserve physical dist. active state on LR.active, 2015-11-24) Therefore, get rid of the complexities and just look at the LR. Reviewed-by: Marc Zyngier Signed-off-by: Christoffer Dall --- virt/kvm/arm/vgic.c | 16 ++-------------- 1 file changed, 2 insertions(+), 14 deletions(-) (limited to 'virt/kvm/arm/vgic.c') diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c index 97e2c088e1e9..65461f821a75 100644 --- a/virt/kvm/arm/vgic.c +++ b/virt/kvm/arm/vgic.c @@ -1417,25 +1417,13 @@ static bool vgic_process_maintenance(struct kvm_vcpu *vcpu) static bool vgic_sync_hwirq(struct kvm_vcpu *vcpu, int lr, struct vgic_lr vlr) { struct vgic_dist *dist = &vcpu->kvm->arch.vgic; - struct irq_phys_map *map; - bool phys_active; bool level_pending; - int ret; if (!(vlr.state & LR_HW)) return false; - map = vgic_irq_map_search(vcpu, vlr.irq); - BUG_ON(!map); - - ret = irq_get_irqchip_state(map->irq, - IRQCHIP_STATE_ACTIVE, - &phys_active); - - WARN_ON(ret); - - if (phys_active) - return 0; + if (vlr.state & LR_STATE_ACTIVE) + return false; spin_lock(&dist->lock); level_pending = process_queued_irq(vcpu, lr, vlr); -- cgit v1.2.1 From fdec12c12ed4333afb49c9948c29fbd5fb52da97 Mon Sep 17 00:00:00 2001 From: Christoffer Dall Date: Thu, 10 Dec 2015 22:46:50 +0100 Subject: KVM: arm/arm64: vgic: Fix kvm_vgic_map_is_active's dist check External inputs to the vgic from time to time need to poke into the state of a virtual interrupt, the prime example is the architected timer code. Since the IRQ's active state can be represented in two places; the LR or the distributor, we first loop over the LRs but if not active in the LRs we just return if *any* IRQ is active on the VCPU in question. This is of course bogus, as we should check if the specific IRQ in quesiton is active on the distributor instead. Reported-by: Eric Auger Acked-by: Marc Zyngier Signed-off-by: Christoffer Dall Signed-off-by: Marc Zyngier --- virt/kvm/arm/vgic.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'virt/kvm/arm/vgic.c') diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c index 65461f821a75..7a2f449bd85d 100644 --- a/virt/kvm/arm/vgic.c +++ b/virt/kvm/arm/vgic.c @@ -1114,7 +1114,7 @@ bool kvm_vgic_map_is_active(struct kvm_vcpu *vcpu, struct irq_phys_map *map) return true; } - return dist_active_irq(vcpu); + return vgic_irq_is_active(vcpu, map->virt_irq); } /* -- cgit v1.2.1