diff options
| author | Michael S. Tsirkin <mst@redhat.com> | 2010-01-13 18:58:09 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2010-01-28 15:02:43 -0800 |
| commit | f0d13b89d4b12f331a0dd1d646a69060e49b1951 (patch) | |
| tree | 858ee93856e55fe6dd30f83f013cdb0933003934 /virt | |
| parent | 70be4d76c0e5d426067601a79be0b33ea673f3ff (diff) | |
KVM: only allow one gsi per fd
commit f1d1c309f35e9b0fb961cffd70fbd04f450ec47c upstream.
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.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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 bb4ebd89b9ff..251282c43ac8 100644 --- a/virt/kvm/eventfd.c +++ b/virt/kvm/eventfd.c @@ -168,7 +168,7 @@ 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; @@ -205,9 +205,20 @@ 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); |