On 04/21/2010 07:03 PM, Marcelo Tosatti wrote:
diff --git a/virt/kvm/assigned-dev.c b/virt/kvm/assigned-dev.c
index 47ca447..7ac7bbe 100644
--- a/virt/kvm/assigned-dev.c
+++ b/virt/kvm/assigned-dev.c
@@ -64,24 +64,33 @@ static void kvm_assigned_dev_interrupt_work_handler(struct 
work_struct *work)
                                    interrupt_work);
        kvm = assigned_dev->kvm;

-       spin_lock_irq(&assigned_dev->assigned_dev_lock);
        if (assigned_dev->irq_requested_type&   KVM_DEV_IRQ_HOST_MSIX) {
                struct kvm_guest_msix_entry *guest_entries =
                        assigned_dev->guest_msix_entries;
+
+               spin_lock_irq(&assigned_dev->assigned_dev_lock);
                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;
+                       /*
+                        * If kvm_assigned_dev_intr sets pending for an
+                        * entry smaller than this work instance is
+                        * currently processing, a new work instance
+                        * will be queued.
+                        */
+                       spin_unlock_irq(&assigned_dev->assigned_dev_lock);
What happens if assigned_dev->entries_nr is changed here?
It does not. Interrupts and work instances are stopped before
irq_requested_type or entries_nr can change.

Interesting.  A comment please.

                        kvm_set_irq(assigned_dev->kvm,
                                    assigned_dev->irq_source_id,
                                    guest_entries[i].vector, 1);
+                       spin_lock_irq(&assigned_dev->assigned_dev_lock);
                }
+               spin_unlock_irq(&assigned_dev->assigned_dev_lock);
        } else
                kvm_set_irq(assigned_dev->kvm, assigned_dev->irq_source_id,
                            assigned_dev->guest_irq, 1);

-       spin_unlock_irq(&assigned_dev->assigned_dev_lock);
  }
A less dangerous fix is to copy all vectors to be triggered into a
local array, drop the lock, and replay the array into kvm_set_irq().
The else branch could do this as well.
Its a bit large, 256 max vectors.

Yeah.

--
error compiling committee.c: too many arguments to function

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