KVM: Fix guest shared interrupt with in-kernel irqchip
Every call of kvm_set_irq() should offer an irq_source_id, which is
allocated by kvm_request_irq_source_id(). Based on irq_source_id, we
identify the irq source and implement logical OR for shared level
interrupts.
The allocated irq_source_id can be freed by kvm_free_irq_source_id().
Currently, we support at most sizeof(unsigned long) different irq sources.
[Amit: - rebase to kvm.git HEAD
- move definition of KVM_USERSPACE_IRQ_SOURCE_ID to common file
- move kvm_request_irq_source_id to the update_irq ioctl]
[Xiantao: - Add kvm/ia64 stuff and make it work for kvm/ia64 guests]
Signed-off-by: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Xiantao Zhang <xiantao.zhang@intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/virt/kvm/irq_comm.c b/virt/kvm/irq_comm.c
index d0169f5..55ad76e 100644
--- a/virt/kvm/irq_comm.c
+++ b/virt/kvm/irq_comm.c
@@ -25,15 +25,23 @@
#include "ioapic.h"
/* This should be called with the kvm->lock mutex held */
-void kvm_set_irq(struct kvm *kvm, int irq, int level)
+void kvm_set_irq(struct kvm *kvm, int irq_source_id, int irq, int level)
{
+ unsigned long *irq_state = (unsigned long *)&kvm->arch.irq_states[irq];
+
+ /* Logical OR for level trig interrupt */
+ if (level)
+ set_bit(irq_source_id, irq_state);
+ else
+ clear_bit(irq_source_id, irq_state);
+
/* Not possible to detect if the guest uses the PIC or the
* IOAPIC. So set the bit in both. The guest will ignore
* writes to the unused one.
*/
- kvm_ioapic_set_irq(kvm->arch.vioapic, irq, level);
+ kvm_ioapic_set_irq(kvm->arch.vioapic, irq, !!(*irq_state));
#ifdef CONFIG_X86
- kvm_pic_set_irq(pic_irqchip(kvm), irq, level);
+ kvm_pic_set_irq(pic_irqchip(kvm), irq, !!(*irq_state));
#endif
}
@@ -58,3 +66,31 @@
{
hlist_del(&kian->link);
}
+
+/* The caller must hold kvm->lock mutex */
+int kvm_request_irq_source_id(struct kvm *kvm)
+{
+ unsigned long *bitmap = &kvm->arch.irq_sources_bitmap;
+ int irq_source_id = find_first_zero_bit(bitmap,
+ sizeof(kvm->arch.irq_sources_bitmap));
+ if (irq_source_id >= sizeof(kvm->arch.irq_sources_bitmap)) {
+ printk(KERN_WARNING "kvm: exhaust allocatable IRQ sources!\n");
+ irq_source_id = -EFAULT;
+ } else
+ set_bit(irq_source_id, bitmap);
+ return irq_source_id;
+}
+
+void kvm_free_irq_source_id(struct kvm *kvm, int irq_source_id)
+{
+ int i;
+
+ if (irq_source_id <= 0 ||
+ irq_source_id >= sizeof(kvm->arch.irq_sources_bitmap)) {
+ printk(KERN_ERR "kvm: IRQ source ID out of range!\n");
+ return;
+ }
+ for (i = 0; i < KVM_IOAPIC_NUM_PINS; i++)
+ clear_bit(irq_source_id, &kvm->arch.irq_states[i]);
+ clear_bit(irq_source_id, &kvm->arch.irq_sources_bitmap);
+}
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index cf0ab8e..a87f45e 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -105,14 +105,12 @@
*/
mutex_lock(&assigned_dev->kvm->lock);
kvm_set_irq(assigned_dev->kvm,
+ assigned_dev->irq_source_id,
assigned_dev->guest_irq, 1);
mutex_unlock(&assigned_dev->kvm->lock);
kvm_put_kvm(assigned_dev->kvm);
}
-/* FIXME: Implement the OR logic needed to make shared interrupts on
- * this line behave properly
- */
static irqreturn_t kvm_assigned_dev_intr(int irq, void *dev_id)
{
struct kvm_assigned_dev_kernel *assigned_dev =
@@ -134,7 +132,7 @@
dev = container_of(kian, struct kvm_assigned_dev_kernel,
ack_notifier);
- kvm_set_irq(dev->kvm, dev->guest_irq, 0);
+ kvm_set_irq(dev->kvm, dev->irq_source_id, dev->guest_irq, 0);
enable_irq(dev->host_irq);
}
@@ -146,6 +144,7 @@
free_irq(assigned_dev->host_irq, (void *)assigned_dev);
kvm_unregister_irq_ack_notifier(kvm, &assigned_dev->ack_notifier);
+ kvm_free_irq_source_id(kvm, assigned_dev->irq_source_id);
if (cancel_work_sync(&assigned_dev->interrupt_work))
/* We had pending work. That means we will have to take
@@ -215,6 +214,11 @@
match->ack_notifier.gsi = assigned_irq->guest_irq;
match->ack_notifier.irq_acked = kvm_assigned_dev_ack_irq;
kvm_register_irq_ack_notifier(kvm, &match->ack_notifier);
+ r = kvm_request_irq_source_id(kvm);
+ if (r < 0)
+ goto out_release;
+ else
+ match->irq_source_id = r;
/* Even though this is PCI, we don't want to use shared
* interrupts. Sharing host devices with guest-assigned devices