Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756115Ab0AMRBS (ORCPT ); Wed, 13 Jan 2010 12:01:18 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756117Ab0AMRBQ (ORCPT ); Wed, 13 Jan 2010 12:01:16 -0500 Received: from mx1.redhat.com ([209.132.183.28]:41334 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756115Ab0AMRBM (ORCPT ); Wed, 13 Jan 2010 12:01:12 -0500 Date: Wed, 13 Jan 2010 18:58:09 +0200 From: "Michael S. Tsirkin" To: Avi Kivity , Marcelo Tosatti , "Michael S. Tsirkin" , Gregory Haskins , Gleb Natapov , Julia Lawall , kvm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] kvm: only allow one gsi per fd Message-ID: <20100113165809.GA13334@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.19 (2009-01-05) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1877 Lines: 57 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 srorm 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 --- This patch is IMO a good candidate for 2.6.33 and 2.6.32.x. 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 30f70fd..62e4cd9 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); -- 1.6.6.144.g5c3af -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/