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authorMichael S. Tsirkin <mst@redhat.com>2010-01-13 18:58:09 +0200
committerMarcelo Tosatti <mtosatti@redhat.com>2010-01-25 12:26:37 -0200
commitf1d1c309f35e9b0fb961cffd70fbd04f450ec47c (patch)
treeb616c8bcd1d453c8dc4fcc5b927cc4a4f8a7e207
parent82b7005f0e72d8d1a8226e4c192cbb0850d10b3f (diff)
downloadlinaro-lsk-f1d1c309f35e9b0fb961cffd70fbd04f450ec47c.tar.gz
KVM: only allow one gsi per fd
Looks like repeatedly binding same fd to multiple gsi's with irqfd can use up a ton of kernel memory for irqfd structures. A simple fix is to allow each fd to only trigger one gsi: triggering a storm of interrupts in guest is likely useless anyway, and we can do it by binding a single gsi to many interrupts if we really want to. Cc: stable@kernel.org Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Acked-by: Acked-by: Gregory Haskins <ghaskins@novell.com> Signed-off-by: Avi Kivity <avi@redhat.com>
-rw-r--r--virt/kvm/eventfd.c15
1 files changed, 13 insertions, 2 deletions
diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
index 30f70fd511c..62e4cd947a9 100644
--- a/virt/kvm/eventfd.c
+++ b/virt/kvm/eventfd.c
@@ -166,7 +166,7 @@ irqfd_ptable_queue_proc(struct file *file, wait_queue_head_t *wqh,
static int
kvm_irqfd_assign(struct kvm *kvm, int fd, int gsi)
{
- struct _irqfd *irqfd;
+ struct _irqfd *irqfd, *tmp;
struct file *file = NULL;
struct eventfd_ctx *eventfd = NULL;
int ret;
@@ -203,9 +203,20 @@ kvm_irqfd_assign(struct kvm *kvm, int fd, int gsi)
init_waitqueue_func_entry(&irqfd->wait, irqfd_wakeup);
init_poll_funcptr(&irqfd->pt, irqfd_ptable_queue_proc);
+ spin_lock_irq(&kvm->irqfds.lock);
+
+ ret = 0;
+ list_for_each_entry(tmp, &kvm->irqfds.items, list) {
+ if (irqfd->eventfd != tmp->eventfd)
+ continue;
+ /* This fd is used for another irq already. */
+ ret = -EBUSY;
+ spin_unlock_irq(&kvm->irqfds.lock);
+ goto fail;
+ }
+
events = file->f_op->poll(file, &irqfd->pt);
- spin_lock_irq(&kvm->irqfds.lock);
list_add_tail(&irqfd->list, &kvm->irqfds.items);
spin_unlock_irq(&kvm->irqfds.lock);