[PATCH v7 06/17] KVM: arm/arm64: VGIC: add refcounting for IRQs
Andre Przywara
andre.przywara at arm.com
Tue Jun 28 05:32:19 PDT 2016
In the moment our struct vgic_irq's are statically allocated at guest
creation time. So getting a pointer to an IRQ structure is trivial and
safe. LPIs are more dynamic, they can be mapped and unmapped at any time
during the guest's _runtime_.
In preparation for supporting LPIs we introduce reference counting for
those structures using the kernel's kref infrastructure.
Since private IRQs and SPIs are statically allocated, the reqcount never
drops to 0 at the moment, but we increase it when an IRQ gets onto a VCPU
list and decrease it when it gets removed.
This introduces vgic_put_irq(), which wraps kref_put and hides the
release function from the callers.
Signed-off-by: Andre Przywara <andre.przywara at arm.com>
---
include/kvm/vgic/vgic.h | 1 +
virt/kvm/arm/vgic/vgic-init.c | 2 ++
virt/kvm/arm/vgic/vgic-mmio-v2.c | 8 ++++++++
virt/kvm/arm/vgic/vgic-mmio-v3.c | 10 +++++++---
virt/kvm/arm/vgic/vgic-mmio.c | 22 +++++++++++++++++++++
virt/kvm/arm/vgic/vgic-v2.c | 1 +
virt/kvm/arm/vgic/vgic-v3.c | 1 +
virt/kvm/arm/vgic/vgic.c | 41 +++++++++++++++++++++++++++++++++-------
virt/kvm/arm/vgic/vgic.h | 1 +
9 files changed, 77 insertions(+), 10 deletions(-)
diff --git a/include/kvm/vgic/vgic.h b/include/kvm/vgic/vgic.h
index 2f26f37..a296d94 100644
--- a/include/kvm/vgic/vgic.h
+++ b/include/kvm/vgic/vgic.h
@@ -96,6 +96,7 @@ struct vgic_irq {
bool active; /* not used for LPIs */
bool enabled;
bool hw; /* Tied to HW IRQ */
+ struct kref refcount; /* Used for LPIs */
u32 hwintid; /* HW INTID number */
union {
u8 targets; /* GICv2 target VCPUs mask */
diff --git a/virt/kvm/arm/vgic/vgic-init.c b/virt/kvm/arm/vgic/vgic-init.c
index 90cae48..ac3c1a5 100644
--- a/virt/kvm/arm/vgic/vgic-init.c
+++ b/virt/kvm/arm/vgic/vgic-init.c
@@ -177,6 +177,7 @@ static int kvm_vgic_dist_init(struct kvm *kvm, unsigned int nr_spis)
spin_lock_init(&irq->irq_lock);
irq->vcpu = NULL;
irq->target_vcpu = vcpu0;
+ kref_init(&irq->refcount);
if (dist->vgic_model == KVM_DEV_TYPE_ARM_VGIC_V2)
irq->targets = 0;
else
@@ -211,6 +212,7 @@ static void kvm_vgic_vcpu_init(struct kvm_vcpu *vcpu)
irq->vcpu = NULL;
irq->target_vcpu = vcpu;
irq->targets = 1U << vcpu->vcpu_id;
+ kref_init(&irq->refcount);
if (vgic_irq_is_sgi(i)) {
/* SGIs */
irq->enabled = 1;
diff --git a/virt/kvm/arm/vgic/vgic-mmio-v2.c b/virt/kvm/arm/vgic/vgic-mmio-v2.c
index a213936..4152348 100644
--- a/virt/kvm/arm/vgic/vgic-mmio-v2.c
+++ b/virt/kvm/arm/vgic/vgic-mmio-v2.c
@@ -102,6 +102,7 @@ static void vgic_mmio_write_sgir(struct kvm_vcpu *source_vcpu,
irq->source |= 1U << source_vcpu->vcpu_id;
vgic_queue_irq_unlock(source_vcpu->kvm, irq);
+ vgic_put_irq(source_vcpu->kvm, irq);
}
}
@@ -116,6 +117,8 @@ static unsigned long vgic_mmio_read_target(struct kvm_vcpu *vcpu,
struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, intid + i);
val |= (u64)irq->targets << (i * 8);
+
+ vgic_put_irq(vcpu->kvm, irq);
}
return val;
@@ -143,6 +146,7 @@ static void vgic_mmio_write_target(struct kvm_vcpu *vcpu,
irq->target_vcpu = kvm_get_vcpu(vcpu->kvm, target);
spin_unlock(&irq->irq_lock);
+ vgic_put_irq(vcpu->kvm, irq);
}
}
@@ -157,6 +161,8 @@ static unsigned long vgic_mmio_read_sgipend(struct kvm_vcpu *vcpu,
struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, intid + i);
val |= (u64)irq->source << (i * 8);
+
+ vgic_put_irq(vcpu->kvm, irq);
}
return val;
}
@@ -178,6 +184,7 @@ static void vgic_mmio_write_sgipendc(struct kvm_vcpu *vcpu,
irq->pending = false;
spin_unlock(&irq->irq_lock);
+ vgic_put_irq(vcpu->kvm, irq);
}
}
@@ -201,6 +208,7 @@ static void vgic_mmio_write_sgipends(struct kvm_vcpu *vcpu,
} else {
spin_unlock(&irq->irq_lock);
}
+ vgic_put_irq(vcpu->kvm, irq);
}
}
diff --git a/virt/kvm/arm/vgic/vgic-mmio-v3.c b/virt/kvm/arm/vgic/vgic-mmio-v3.c
index fc7b6c9..829909e 100644
--- a/virt/kvm/arm/vgic/vgic-mmio-v3.c
+++ b/virt/kvm/arm/vgic/vgic-mmio-v3.c
@@ -80,15 +80,17 @@ static unsigned long vgic_mmio_read_irouter(struct kvm_vcpu *vcpu,
{
int intid = VGIC_ADDR_TO_INTID(addr, 64);
struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, NULL, intid);
+ unsigned long ret = 0;
if (!irq)
return 0;
/* The upper word is RAZ for us. */
- if (addr & 4)
- return 0;
+ if (!(addr & 4))
+ ret = extract_bytes(READ_ONCE(irq->mpidr), addr & 7, len);
- return extract_bytes(READ_ONCE(irq->mpidr), addr & 7, len);
+ vgic_put_irq(vcpu->kvm, irq);
+ return ret;
}
static void vgic_mmio_write_irouter(struct kvm_vcpu *vcpu,
@@ -112,6 +114,7 @@ static void vgic_mmio_write_irouter(struct kvm_vcpu *vcpu,
irq->target_vcpu = kvm_mpidr_to_vcpu(vcpu->kvm, irq->mpidr);
spin_unlock(&irq->irq_lock);
+ vgic_put_irq(vcpu->kvm, irq);
}
static unsigned long vgic_mmio_read_v3r_typer(struct kvm_vcpu *vcpu,
@@ -445,5 +448,6 @@ void vgic_v3_dispatch_sgi(struct kvm_vcpu *vcpu, u64 reg)
irq->pending = true;
vgic_queue_irq_unlock(vcpu->kvm, irq);
+ vgic_put_irq(vcpu->kvm, irq);
}
}
diff --git a/virt/kvm/arm/vgic/vgic-mmio.c b/virt/kvm/arm/vgic/vgic-mmio.c
index 9f6fab7..630d1c3 100644
--- a/virt/kvm/arm/vgic/vgic-mmio.c
+++ b/virt/kvm/arm/vgic/vgic-mmio.c
@@ -56,6 +56,8 @@ unsigned long vgic_mmio_read_enable(struct kvm_vcpu *vcpu,
if (irq->enabled)
value |= (1U << i);
+
+ vgic_put_irq(vcpu->kvm, irq);
}
return value;
@@ -74,6 +76,8 @@ void vgic_mmio_write_senable(struct kvm_vcpu *vcpu,
spin_lock(&irq->irq_lock);
irq->enabled = true;
vgic_queue_irq_unlock(vcpu->kvm, irq);
+
+ vgic_put_irq(vcpu->kvm, irq);
}
}
@@ -92,6 +96,7 @@ void vgic_mmio_write_cenable(struct kvm_vcpu *vcpu,
irq->enabled = false;
spin_unlock(&irq->irq_lock);
+ vgic_put_irq(vcpu->kvm, irq);
}
}
@@ -108,6 +113,8 @@ unsigned long vgic_mmio_read_pending(struct kvm_vcpu *vcpu,
if (irq->pending)
value |= (1U << i);
+
+ vgic_put_irq(vcpu->kvm, irq);
}
return value;
@@ -129,6 +136,7 @@ void vgic_mmio_write_spending(struct kvm_vcpu *vcpu,
irq->soft_pending = true;
vgic_queue_irq_unlock(vcpu->kvm, irq);
+ vgic_put_irq(vcpu->kvm, irq);
}
}
@@ -152,6 +160,7 @@ void vgic_mmio_write_cpending(struct kvm_vcpu *vcpu,
}
spin_unlock(&irq->irq_lock);
+ vgic_put_irq(vcpu->kvm, irq);
}
}
@@ -168,6 +177,8 @@ unsigned long vgic_mmio_read_active(struct kvm_vcpu *vcpu,
if (irq->active)
value |= (1U << i);
+
+ vgic_put_irq(vcpu->kvm, irq);
}
return value;
@@ -190,6 +201,7 @@ static void vgic_mmio_change_active(struct kvm_vcpu *vcpu, struct vgic_irq *irq,
* IRQ, so we release and re-acquire the spin_lock to let the
* other thread sync back the IRQ.
*/
+
while (irq->vcpu && /* IRQ may have state in an LR somewhere */
irq->vcpu->cpu != -1) /* VCPU thread is running */
cond_resched_lock(&irq->irq_lock);
@@ -242,6 +254,7 @@ void vgic_mmio_write_cactive(struct kvm_vcpu *vcpu,
for_each_set_bit(i, &val, len * 8) {
struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, intid + i);
vgic_mmio_change_active(vcpu, irq, false);
+ vgic_put_irq(vcpu->kvm, irq);
}
vgic_change_active_finish(vcpu, intid);
}
@@ -257,6 +270,7 @@ void vgic_mmio_write_sactive(struct kvm_vcpu *vcpu,
for_each_set_bit(i, &val, len * 8) {
struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, intid + i);
vgic_mmio_change_active(vcpu, irq, true);
+ vgic_put_irq(vcpu->kvm, irq);
}
vgic_change_active_finish(vcpu, intid);
}
@@ -272,6 +286,8 @@ unsigned long vgic_mmio_read_priority(struct kvm_vcpu *vcpu,
struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, intid + i);
val |= (u64)irq->priority << (i * 8);
+
+ vgic_put_irq(vcpu->kvm, irq);
}
return val;
@@ -298,6 +314,8 @@ void vgic_mmio_write_priority(struct kvm_vcpu *vcpu,
/* Narrow the priority range to what we actually support */
irq->priority = (val >> (i * 8)) & GENMASK(7, 8 - VGIC_PRI_BITS);
spin_unlock(&irq->irq_lock);
+
+ vgic_put_irq(vcpu->kvm, irq);
}
}
@@ -313,6 +331,8 @@ unsigned long vgic_mmio_read_config(struct kvm_vcpu *vcpu,
if (irq->config == VGIC_CONFIG_EDGE)
value |= (2U << (i * 2));
+
+ vgic_put_irq(vcpu->kvm, irq);
}
return value;
@@ -345,6 +365,8 @@ void vgic_mmio_write_config(struct kvm_vcpu *vcpu,
irq->pending = irq->line_level | irq->soft_pending;
}
spin_unlock(&irq->irq_lock);
+
+ vgic_put_irq(vcpu->kvm, irq);
}
}
diff --git a/virt/kvm/arm/vgic/vgic-v2.c b/virt/kvm/arm/vgic/vgic-v2.c
index 80313de..cedde7d 100644
--- a/virt/kvm/arm/vgic/vgic-v2.c
+++ b/virt/kvm/arm/vgic/vgic-v2.c
@@ -124,6 +124,7 @@ void vgic_v2_fold_lr_state(struct kvm_vcpu *vcpu)
}
spin_unlock(&irq->irq_lock);
+ vgic_put_irq(vcpu->kvm, irq);
}
}
diff --git a/virt/kvm/arm/vgic/vgic-v3.c b/virt/kvm/arm/vgic/vgic-v3.c
index e48a22e..f0ac064 100644
--- a/virt/kvm/arm/vgic/vgic-v3.c
+++ b/virt/kvm/arm/vgic/vgic-v3.c
@@ -113,6 +113,7 @@ void vgic_v3_fold_lr_state(struct kvm_vcpu *vcpu)
}
spin_unlock(&irq->irq_lock);
+ vgic_put_irq(vcpu->kvm, irq);
}
}
diff --git a/virt/kvm/arm/vgic/vgic.c b/virt/kvm/arm/vgic/vgic.c
index 69b61ab..b90705c 100644
--- a/virt/kvm/arm/vgic/vgic.c
+++ b/virt/kvm/arm/vgic/vgic.c
@@ -48,13 +48,20 @@ struct vgic_global __section(.hyp.text) kvm_vgic_global_state;
struct vgic_irq *vgic_get_irq(struct kvm *kvm, struct kvm_vcpu *vcpu,
u32 intid)
{
- /* SGIs and PPIs */
- if (intid <= VGIC_MAX_PRIVATE)
- return &vcpu->arch.vgic_cpu.private_irqs[intid];
+ struct vgic_dist *dist = &kvm->arch.vgic;
+ struct vgic_irq *irq;
+
+ if (intid <= VGIC_MAX_PRIVATE) { /* SGIs and PPIs */
+ irq = &vcpu->arch.vgic_cpu.private_irqs[intid];
+ kref_get(&irq->refcount);
+ return irq;
+ }
- /* SPIs */
- if (intid <= VGIC_MAX_SPI)
- return &kvm->arch.vgic.spis[intid - VGIC_NR_PRIVATE_IRQS];
+ if (intid <= VGIC_MAX_SPI) { /* SPIs */
+ irq = &dist->spis[intid - VGIC_NR_PRIVATE_IRQS];
+ kref_get(&irq->refcount);
+ return irq;
+ }
/* LPIs are not yet covered */
if (intid >= VGIC_MIN_LPI)
@@ -64,6 +71,17 @@ struct vgic_irq *vgic_get_irq(struct kvm *kvm, struct kvm_vcpu *vcpu,
return NULL;
}
+/* The refcount should never drop to 0 at the moment. */
+static void vgic_irq_release(struct kref *ref)
+{
+ WARN_ON(1);
+}
+
+void vgic_put_irq(struct kvm *kvm, struct vgic_irq *irq)
+{
+ kref_put(&irq->refcount, vgic_irq_release);
+}
+
/**
* kvm_vgic_target_oracle - compute the target vcpu for an irq
*
@@ -236,6 +254,7 @@ retry:
goto retry;
}
+ kref_get(&irq->refcount);
list_add_tail(&irq->ap_list, &vcpu->arch.vgic_cpu.ap_list_head);
irq->vcpu = vcpu;
@@ -269,14 +288,17 @@ static int vgic_update_irq_pending(struct kvm *kvm, int cpuid,
if (!irq)
return -EINVAL;
- if (irq->hw != mapped_irq)
+ if (irq->hw != mapped_irq) {
+ vgic_put_irq(kvm, irq);
return -EINVAL;
+ }
spin_lock(&irq->irq_lock);
if (!vgic_validate_injection(irq, level)) {
/* Nothing to see here, move along... */
spin_unlock(&irq->irq_lock);
+ vgic_put_irq(kvm, irq);
return 0;
}
@@ -288,6 +310,7 @@ static int vgic_update_irq_pending(struct kvm *kvm, int cpuid,
}
vgic_queue_irq_unlock(kvm, irq);
+ vgic_put_irq(kvm, irq);
return 0;
}
@@ -330,6 +353,7 @@ int kvm_vgic_map_phys_irq(struct kvm_vcpu *vcpu, u32 virt_irq, u32 phys_irq)
irq->hwintid = phys_irq;
spin_unlock(&irq->irq_lock);
+ vgic_put_irq(vcpu->kvm, irq);
return 0;
}
@@ -349,6 +373,7 @@ int kvm_vgic_unmap_phys_irq(struct kvm_vcpu *vcpu, unsigned int virt_irq)
irq->hwintid = 0;
spin_unlock(&irq->irq_lock);
+ vgic_put_irq(vcpu->kvm, irq);
return 0;
}
@@ -386,6 +411,7 @@ retry:
list_del(&irq->ap_list);
irq->vcpu = NULL;
spin_unlock(&irq->irq_lock);
+ vgic_put_irq(vcpu->kvm, irq);
continue;
}
@@ -614,6 +640,7 @@ bool kvm_vgic_map_is_active(struct kvm_vcpu *vcpu, unsigned int virt_irq)
spin_lock(&irq->irq_lock);
map_is_active = irq->hw && irq->active;
spin_unlock(&irq->irq_lock);
+ vgic_put_irq(vcpu->kvm, irq);
return map_is_active;
}
diff --git a/virt/kvm/arm/vgic/vgic.h b/virt/kvm/arm/vgic/vgic.h
index c752152..5b79c34 100644
--- a/virt/kvm/arm/vgic/vgic.h
+++ b/virt/kvm/arm/vgic/vgic.h
@@ -38,6 +38,7 @@ struct vgic_vmcr {
struct vgic_irq *vgic_get_irq(struct kvm *kvm, struct kvm_vcpu *vcpu,
u32 intid);
+void vgic_put_irq(struct kvm *kvm, struct vgic_irq *irq);
bool vgic_queue_irq_unlock(struct kvm *kvm, struct vgic_irq *irq);
void vgic_kick_vcpus(struct kvm *kvm);
--
2.9.0
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