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| author | Michael S. Tsirkin <mst@redhat.com> | 2010-01-13 18:58:09 +0200 |
|---|---|---|
| committer | Marcelo Tosatti <mtosatti@redhat.com> | 2010-01-25 12:26:37 -0200 |
| commit | f1d1c309f35e9b0fb961cffd70fbd04f450ec47c (patch) | |
| tree | b616c8bcd1d453c8dc4fcc5b927cc4a4f8a7e207 /virt | |
| parent | 82b7005f0e72d8d1a8226e4c192cbb0850d10b3f (diff) | |
| download | linux-f1d1c309f35e9b0fb961cffd70fbd04f450ec47c.tar.gz linux-f1d1c309f35e9b0fb961cffd70fbd04f450ec47c.tar.bz2 linux-f1d1c309f35e9b0fb961cffd70fbd04f450ec47c.zip | |
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>
Diffstat (limited to 'virt')
| -rw-r--r-- | virt/kvm/eventfd.c | 15 |
1 files changed, 13 insertions, 2 deletions
diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c index 30f70fd511c4..62e4cd947a90 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); |