Doug / smarc-fsl-linux-kernel

Download as
Browse Code ยป

Commit f1d1c309f35e9b0fb961cffd70fbd04f450ec47c

Authored by Michael S. Tsirkin
Committed by Marcelo Tosatti
1 parent 82b7005f0e
Exists in master and in 7 other branches imx_3.0.35_4.1.0, imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga, smarc-l5.0.0_1.0.0-ga

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>

Showing 1 changed file with 13 additions and 2 deletions Side-by-side Diff

... ... @@ -166,7 +166,7 @@
166 166 static int
167 167 kvm_irqfd_assign(struct kvm *kvm, int fd, int gsi)
168 168 {
169   - struct _irqfd *irqfd;
  169 + struct _irqfd *irqfd, *tmp;
170 170 struct file *file = NULL;
171 171 struct eventfd_ctx *eventfd = NULL;
172 172 int ret;
173 173  
... ... @@ -203,9 +203,20 @@
203 203 init_waitqueue_func_entry(&irqfd->wait, irqfd_wakeup);
204 204 init_poll_funcptr(&irqfd->pt, irqfd_ptable_queue_proc);
205 205  
  206 + spin_lock_irq(&kvm->irqfds.lock);
  207 +
  208 + ret = 0;
  209 + list_for_each_entry(tmp, &kvm->irqfds.items, list) {
  210 + if (irqfd->eventfd != tmp->eventfd)
  211 + continue;
  212 + /* This fd is used for another irq already. */
  213 + ret = -EBUSY;
  214 + spin_unlock_irq(&kvm->irqfds.lock);
  215 + goto fail;
  216 + }
  217 +
206 218 events = file->f_op->poll(file, &irqfd->pt);
207 219  
208   - spin_lock_irq(&kvm->irqfds.lock);
209 220 list_add_tail(&irqfd->list, &kvm->irqfds.items);
210 221 spin_unlock_irq(&kvm->irqfds.lock);
211 222