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Subject[PATCH 09/43] KVM: Add MSI-X interrupt injection logic
Date
From: Sheng Yang <sheng@linux.intel.com>

We have to handle more than one interrupt with one handler for MSI-X. Avi
suggested to use a flag to indicate the pending. So here is it.

Signed-off-by: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
---
include/linux/kvm_host.h | 1 +
virt/kvm/kvm_main.c | 66 +++++++++++++++++++++++++++++++++++++++++-----
2 files changed, 60 insertions(+), 7 deletions(-)
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 432edc2..3832243 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -319,6 +319,7 @@ struct kvm_irq_ack_notifier {
void (*irq_acked)(struct kvm_irq_ack_notifier *kian);
};

+#define KVM_ASSIGNED_MSIX_PENDING 0x1
struct kvm_guest_msix_entry {
u32 vector;
u16 entry;
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index fd33def..7c20e06 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -95,25 +95,69 @@ static struct kvm_assigned_dev_kernel *kvm_find_assigned_dev(struct list_head *h
return NULL;
}

+static int find_index_from_host_irq(struct kvm_assigned_dev_kernel
+ *assigned_dev, int irq)
+{
+ int i, index;
+ struct msix_entry *host_msix_entries;
+
+ host_msix_entries = assigned_dev->host_msix_entries;
+
+ index = -1;
+ for (i = 0; i < assigned_dev->entries_nr; i++)
+ if (irq == host_msix_entries[i].vector) {
+ index = i;
+ break;
+ }
+ if (index < 0) {
+ printk(KERN_WARNING "Fail to find correlated MSI-X entry!\n");
+ return 0;
+ }
+
+ return index;
+}
+
static void kvm_assigned_dev_interrupt_work_handler(struct work_struct *work)
{
struct kvm_assigned_dev_kernel *assigned_dev;
+ struct kvm *kvm;
+ int irq, i;

assigned_dev = container_of(work, struct kvm_assigned_dev_kernel,
interrupt_work);
+ kvm = assigned_dev->kvm;

/* This is taken to safely inject irq inside the guest. When
* the interrupt injection (or the ioapic code) uses a
* finer-grained lock, update this
*/
- mutex_lock(&assigned_dev->kvm->lock);
- kvm_set_irq(assigned_dev->kvm, assigned_dev->irq_source_id,
- assigned_dev->guest_irq, 1);
-
- if (assigned_dev->irq_requested_type & KVM_ASSIGNED_DEV_GUEST_MSI) {
- enable_irq(assigned_dev->host_irq);
- assigned_dev->host_irq_disabled = false;
+ mutex_lock(&kvm->lock);
+ if (assigned_dev->irq_requested_type & KVM_ASSIGNED_DEV_MSIX) {
+ struct kvm_guest_msix_entry *guest_entries =
+ assigned_dev->guest_msix_entries;
+ for (i = 0; i < assigned_dev->entries_nr; i++) {
+ if (!(guest_entries[i].flags &
+ KVM_ASSIGNED_MSIX_PENDING))
+ continue;
+ guest_entries[i].flags &= ~KVM_ASSIGNED_MSIX_PENDING;
+ kvm_set_irq(assigned_dev->kvm,
+ assigned_dev->irq_source_id,
+ guest_entries[i].vector, 1);
+ irq = assigned_dev->host_msix_entries[i].vector;
+ if (irq != 0)
+ enable_irq(irq);
+ assigned_dev->host_irq_disabled = false;
+ }
+ } else {
+ kvm_set_irq(assigned_dev->kvm, assigned_dev->irq_source_id,
+ assigned_dev->guest_irq, 1);
+ if (assigned_dev->irq_requested_type &
+ KVM_ASSIGNED_DEV_GUEST_MSI) {
+ enable_irq(assigned_dev->host_irq);
+ assigned_dev->host_irq_disabled = false;
+ }
}
+
mutex_unlock(&assigned_dev->kvm->lock);
}

@@ -122,6 +166,14 @@ static irqreturn_t kvm_assigned_dev_intr(int irq, void *dev_id)
struct kvm_assigned_dev_kernel *assigned_dev =
(struct kvm_assigned_dev_kernel *) dev_id;

+ if (assigned_dev->irq_requested_type == KVM_ASSIGNED_DEV_MSIX) {
+ int index = find_index_from_host_irq(assigned_dev, irq);
+ if (index < 0)
+ return IRQ_HANDLED;
+ assigned_dev->guest_msix_entries[index].flags |=
+ KVM_ASSIGNED_MSIX_PENDING;
+ }
+
schedule_work(&assigned_dev->interrupt_work);

disable_irq_nosync(irq);
--
1.6.0.6


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