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Message-Id: <1447944843-17731-11-git-send-email-eric.auger@linaro.org>
Date: Thu, 19 Nov 2015 14:54:00 +0000
From: Eric Auger <eric.auger@...aro.org>
To: eric.auger@...com, eric.auger@...aro.org,
alex.williamson@...hat.com, b.reynal@...tualopensystems.com,
christoffer.dall@...aro.org, marc.zyngier@....com,
linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.cs.columbia.edu,
kvm@...r.kernel.org
Cc: andre.przywara@....com, linux-kernel@...r.kernel.org,
patches@...aro.org
Subject: [PATCH v4 10/13] KVM: arm/arm64: vgic: forwarding control
Implements kvm_vgic_[set|unset]_forward.
Handle low-level VGIC programming: physical IRQ/guest IRQ mapping,
list register cleanup, VGIC state machine. Also interacts with
the irqchip.
Signed-off-by: Eric Auger <eric.auger@...aro.org>
---
v3 -> v4:
- use the target vCPU in set/unset_forward
- rebase after removal of vgic_irq_lr_map
- clarify set/unset_forward comments,
- host_irq renamed into irq and virt_irq (SPI ID) now used in
place of SPI index (former guest_irq)
- replaced BUG_ON by WARN_ON
- simplify unset_forward implementation by using vgic_unqueue_irqs
- handle edge mapped unshared IRQs
v2 -> v3:
- on unforward, we do not compute & output the active state anymore.
This means if the unforward happens while the physical IRQ is
active, we will not VFIO mask the IRQ while deactiving it. If a
new physical IRQ hits, the corresponding virtual IRQ might not
be injected (hence lost) due to VGIC state machine.
bypass rfc v2:
- use irq_set_vcpu_affinity API
- use irq_set_irqchip_state instead of chip->irq_eoi
bypass rfc:
- rename kvm_arch_{set|unset}_forward into
kvm_vgic_{set|unset}_forward. Remove __KVM_HAVE_ARCH_HALT_GUEST.
The function is bound to be called by ARM code only.
v4 -> v5:
- fix arm64 compilation issues, ie. also defines
__KVM_HAVE_ARCH_HALT_GUEST for arm64
v3 -> v4:
- code originally located in kvm_vfio_arm.c
- kvm_arch_vfio_{set|unset}_forward renamed into
kvm_arch_{set|unset}_forward
- split into 2 functions (set/unset) since unset does not fail anymore
- unset can be invoked at whatever time. Extra care is taken to handle
transition in VGIC state machine, LR cleanup, ...
v2 -> v3:
- renaming of kvm_arch_set_fwd_state into kvm_arch_vfio_set_forward
- takes a bool arg instead of kvm_fwd_irq_action enum
- removal of KVM_VFIO_IRQ_CLEANUP
- platform device check now happens here
- more precise errors returned
- irq_eoi handled externally to this patch (VGIC)
- correct enable_irq bug done twice
- reword the commit message
- correct check of platform_bus_type
- use raw_spin_lock_irqsave and check the validity of the handler
---
include/kvm/arm_vgic.h | 5 +++
virt/kvm/arm/vgic.c | 118 +++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 123 insertions(+)
diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
index 9bf6a30..8090ab4 100644
--- a/include/kvm/arm_vgic.h
+++ b/include/kvm/arm_vgic.h
@@ -368,4 +368,9 @@ static inline int vgic_v3_probe(struct device_node *vgic_node,
}
#endif
+int kvm_vgic_set_forward(struct kvm *kvm, unsigned int irq,
+ unsigned int virt_irq);
+void kvm_vgic_unset_forward(struct kvm *kvm, unsigned int irq,
+ unsigned int virt_irq);
+
#endif
diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c
index e96f79e..bd500b4 100644
--- a/virt/kvm/arm/vgic.c
+++ b/virt/kvm/arm/vgic.c
@@ -2500,3 +2500,121 @@ int kvm_set_msi(struct kvm_kernel_irq_routing_entry *e,
{
return 0;
}
+
+/**
+ * kvm_vgic_set_forward - Set IRQ forwarding
+ *
+ * @kvm: handle to the VM
+ * @irq: the host linux IRQ
+ * @virt_irq: the guest SPI ID
+ *
+ * This function is supposed to be called only if the IRQ
+ * is not in progress: ie. not active at GIC level and not
+ * currently under injection in the guest. The physical IRQ must
+ * also be disabled and all vCPUs must have been exited and
+ * prevented from being re-entered.
+ */
+int kvm_vgic_set_forward(struct kvm *kvm, unsigned int irq,
+ unsigned int virt_irq)
+{
+ struct vgic_dist *dist = &kvm->arch.vgic;
+ struct kvm_vcpu *vcpu;
+ struct irq_phys_map *map;
+ int cpu_id;
+
+ kvm_debug("%s irq=%d virt_irq=%d\n", __func__, irq, virt_irq);
+
+ cpu_id = dist->irq_spi_cpu[virt_irq - VGIC_NR_PRIVATE_IRQS];
+ vcpu = kvm_get_vcpu(kvm, cpu_id);
+ if (!vcpu)
+ return 0;
+ /*
+ * let's tell the irqchip driver that after this function
+ * returns, a new occurrence of that physical irq will be handled
+ * as a forwarded IRQ, ie. the host will only perform priority
+ * drop but will not deactivate the physical IRQ: guest will
+ */
+ irq_set_vcpu_affinity(irq, vcpu);
+
+ /*
+ * let's program the vgic so that after this function returns
+ * any subsequent virt_irq injection will be considered as
+ * forwarded and LR will be programmed with HWbit set
+ */
+ map = kvm_vgic_map_phys_irq(vcpu, virt_irq, irq, false);
+
+ return !map;
+}
+
+/**
+ * kvm_vgic_unset_forward - Unset IRQ forwarding
+ *
+ * @kvm: handle to the VM
+ * @irq: host Linux IRQ number
+ * @virt_irq: virtual SPI ID
+ *
+ * This function must be called when the host irq is disabled
+ * and all vCPUs have been exited and prevented from being re-entered.
+ */
+void kvm_vgic_unset_forward(struct kvm *kvm,
+ unsigned int irq,
+ unsigned int virt_irq)
+{
+ struct vgic_dist *dist = &kvm->arch.vgic;
+ struct kvm_vcpu *vcpu;
+ int cpu_id;
+ bool active, is_level;
+ struct irq_phys_map *map;
+
+ kvm_debug("%s irq=%d virt_irq=%d\n", __func__, irq, virt_irq);
+
+ spin_lock(&dist->lock);
+
+ cpu_id = dist->irq_spi_cpu[virt_irq - VGIC_NR_PRIVATE_IRQS];
+ vcpu = kvm_get_vcpu(kvm, cpu_id);
+ is_level = !vgic_irq_is_edge(vcpu, virt_irq);
+
+ irq_get_irqchip_state(irq, IRQCHIP_STATE_ACTIVE, &active);
+
+ if (!vcpu)
+ goto out;
+
+ map = vgic_irq_map_search(vcpu, virt_irq);
+ if (!map || map->shared || kvm_vgic_unmap_phys_irq(vcpu, map)) {
+ WARN_ON(1);
+ goto out;
+ }
+
+ if (!active) {
+ /*
+ * The physical IRQ is not active so no virtual IRQ
+ * is under injection, reset the level state which was
+ * not modelled.
+ */
+ vgic_dist_irq_clear_level(vcpu, virt_irq);
+ goto out;
+ }
+
+ vgic_unqueue_irqs(vcpu);
+
+ if (vgic_dist_irq_is_pending(vcpu, virt_irq) ||
+ vgic_irq_is_active(vcpu, virt_irq)) {
+ /*
+ * on next flush, LR for virt_irq will be programmed
+ * with maintenance IRQ. For level sensitive IRQ,
+ * let's set the level which was not modelled up to now
+ */
+ if (is_level)
+ vgic_dist_irq_set_level(vcpu, virt_irq);
+ } else {
+ vgic_dist_irq_clear_level(vcpu, virt_irq);
+ }
+
+out:
+ /* Let's deactivate and unmap the physical IRQ from the vCPU */
+ irq_set_irqchip_state(irq, IRQCHIP_STATE_ACTIVE, false);
+ irq_set_vcpu_affinity(irq, NULL);
+
+ spin_unlock(&dist->lock);
+}
+
--
1.9.1
--
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