The active register handlers are shared between the v2 and v3
emulation, so their implementation goes into vgic-mmio.c, to be
easily referenced from the v3 emulation as well later.
Since activation/deactivation of an interrupt may happen entirely
in the guest without it ever exiting, we need some extra logic to
properly track the active state.
Putting it on an ap_list on activation is similar to the normal case
handled by vgic_queue_irq_unlock(), but differs in some details that
make a separate implementation worthwhile.
Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx>
---
Changelog RFC..v1:
- handling queueing in write handler
- remove IRQ lock from read handler
Changelog v1 .. v2:
- adapt to new MMIO framework
Changelog v3 .. v4:
- specify accessor width
- use IRQ number accessor macro
- drop elaborate write_sactive handler and use new vgic_queue_irq_unlock()
- properly emulate clear active by halting the guest (Christoffer)
- replace extract_bytes() with simple return
virt/kvm/arm/vgic/vgic-mmio-v2.c | 4 +-
virt/kvm/arm/vgic/vgic-mmio.c | 82 ++++++++++++++++++++++++++++++++++++++++
virt/kvm/arm/vgic/vgic-mmio.h | 10 +++++
3 files changed, 94 insertions(+), 2 deletions(-)
diff --git a/virt/kvm/arm/vgic/vgic-mmio-v2.c b/virt/kvm/arm/vgic/vgic-mmio-v2.c
index c13a708..12e101b 100644
--- a/virt/kvm/arm/vgic/vgic-mmio-v2.c
+++ b/virt/kvm/arm/vgic/vgic-mmio-v2.c
@@ -84,10 +84,10 @@ static const struct vgic_register_region vgic_v2_dist_registers[] = {
vgic_mmio_read_pending, vgic_mmio_write_cpending, 1,
VGIC_ACCESS_32bit),
REGISTER_DESC_WITH_BITS_PER_IRQ(GIC_DIST_ACTIVE_SET,
- vgic_mmio_read_raz, vgic_mmio_write_wi, 1,
+ vgic_mmio_read_active, vgic_mmio_write_sactive, 1,
VGIC_ACCESS_32bit),
REGISTER_DESC_WITH_BITS_PER_IRQ(GIC_DIST_ACTIVE_CLEAR,
- vgic_mmio_read_raz, vgic_mmio_write_wi, 1,
+ vgic_mmio_read_active, vgic_mmio_write_cactive, 1,
VGIC_ACCESS_32bit),
REGISTER_DESC_WITH_BITS_PER_IRQ(GIC_DIST_PRI,
vgic_mmio_read_raz, vgic_mmio_write_wi, 8,
diff --git a/virt/kvm/arm/vgic/vgic-mmio.c b/virt/kvm/arm/vgic/vgic-mmio.c
index d8dc8f6..74d140e 100644
--- a/virt/kvm/arm/vgic/vgic-mmio.c
+++ b/virt/kvm/arm/vgic/vgic-mmio.c
@@ -155,6 +155,88 @@ void vgic_mmio_write_cpending(struct kvm_vcpu *vcpu,
}
}
+unsigned long vgic_mmio_read_active(struct kvm_vcpu *vcpu,
+ gpa_t addr, unsigned int len)
+{
+ u32 intid = VGIC_ADDR_TO_INTID(addr, 1);
+ u32 value = 0;
+ int i;
+
+ /* Loop over all IRQs affected by this read */
+ for (i = 0; i < len * 8; i++) {
+ struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, intid + i);
+
+ if (irq->active)
+ value |= (1U << i);
+ }
+
+ return value;
+}
+
+void vgic_mmio_write_cactive(struct kvm_vcpu *vcpu,
+ gpa_t addr, unsigned int len,
+ unsigned long val)
+{
+ u32 intid = VGIC_ADDR_TO_INTID(addr, 1);
+ int i;
+
+ kvm_arm_halt_guest(vcpu->kvm);
+ for_each_set_bit(i, &val, len * 8) {
+ struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, intid + i);
+
+ spin_lock(&irq->irq_lock);
+ /*
+ * If this virtual IRQ was written into a list register, we
+ * have to make sure the CPU that runs the VCPU thread has
+ * synced back LR state to the struct vgic_irq. We can only
+ * know this for sure, when either this irq is not assigned to
+ * anyone's AP list anymore, or the VCPU thread is not
+ * running on any CPUs.
+ *
+ * In the opposite case, we know the VCPU thread may be on its
+ * way back from the guest and still has to sync back this
+ * 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);
+
+ irq->active = false;
+ spin_unlock(&irq->irq_lock);
+ }
+ kvm_arm_resume_guest(vcpu->kvm);
+}
+
+void vgic_mmio_write_sactive(struct kvm_vcpu *vcpu,
+ gpa_t addr, unsigned int len,
+ unsigned long val)
+{
+ u32 intid = VGIC_ADDR_TO_INTID(addr, 1);
+ int i;
+
+ for_each_set_bit(i, &val, len * 8) {
+ struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, intid + i);
+
+ spin_lock(&irq->irq_lock);
+
+ /*
+ * If the IRQ was already active or it was on a VCPU before
+ * or there is no target VCPU assigned at the moment, then
+ * just proceed.
+ */
+ if (irq->active || irq->vcpu || !irq->target_vcpu) {
+ irq->active = true;
+
+ spin_unlock(&irq->irq_lock);
+ continue;
+ }
+
+ irq->active = true;
+ vgic_queue_irq_unlock(vcpu->kvm, irq);
+ }
+}
+
static int match_region(const void *key, const void *elt)
{
const unsigned int offset = (unsigned long)key;
diff --git a/virt/kvm/arm/vgic/vgic-mmio.h b/virt/kvm/arm/vgic/vgic-mmio.h
index 01db98a..dd96a71 100644
--- a/virt/kvm/arm/vgic/vgic-mmio.h
+++ b/virt/kvm/arm/vgic/vgic-mmio.h
@@ -106,6 +106,16 @@ void vgic_mmio_write_cpending(struct kvm_vcpu *vcpu,
gpa_t addr, unsigned int len,
unsigned long val);
+unsigned long vgic_mmio_read_active(struct kvm_vcpu *vcpu,
+ gpa_t addr, unsigned int len);
+
+void vgic_mmio_write_cactive(struct kvm_vcpu *vcpu,
+ gpa_t addr, unsigned int len,
+ unsigned long val);
+
+void vgic_mmio_write_sactive(struct kvm_vcpu *vcpu,
+ gpa_t addr, unsigned int len,
+ unsigned long val);
unsigned int vgic_v2_init_dist_iodev(struct vgic_io_device *dev);
--
2.8.2
--
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