From patchwork Mon Oct 10 10:46:22 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Gerd Hoffmann X-Patchwork-Id: 9369337 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 56D7B60487 for ; Mon, 10 Oct 2016 10:47:07 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 48E95294BE for ; Mon, 10 Oct 2016 10:47:07 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 3CD0629521; Mon, 10 Oct 2016 10:47:07 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id D4D35294BE for ; Mon, 10 Oct 2016 10:47:06 +0000 (UTC) Received: from localhost ([::1]:48792 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1btY6r-000875-TI for patchwork-qemu-devel@patchwork.kernel.org; Mon, 10 Oct 2016 06:47:05 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:47652) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1btY6K-00084f-ND for qemu-devel@nongnu.org; Mon, 10 Oct 2016 06:46:33 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1btY6G-0008Gh-Pf for qemu-devel@nongnu.org; Mon, 10 Oct 2016 06:46:32 -0400 Received: from mx1.redhat.com ([209.132.183.28]:54100) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1btY6G-0008GT-JX for qemu-devel@nongnu.org; Mon, 10 Oct 2016 06:46:28 -0400 Received: from int-mx10.intmail.prod.int.phx2.redhat.com (int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 1C0928553C for ; Mon, 10 Oct 2016 10:46:28 +0000 (UTC) Received: from nilsson.home.kraxel.org (ovpn-116-18.ams2.redhat.com [10.36.116.18]) by int-mx10.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id u9AAkRr2025554; Mon, 10 Oct 2016 06:46:27 -0400 Received: by nilsson.home.kraxel.org (Postfix, from userid 500) id BAE9F808FB; Mon, 10 Oct 2016 12:46:26 +0200 (CEST) From: Gerd Hoffmann To: qemu-devel@nongnu.org Date: Mon, 10 Oct 2016 12:46:22 +0200 Message-Id: <1476096382-7981-1-git-send-email-kraxel@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.28]); Mon, 10 Oct 2016 10:46:28 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH] xhci: limit the number of link trbs we are willing to process X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Gerd Hoffmann Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP Needed to avoid we run in circles forever in case the guest builds an endless loop with link trbs. Reported-by: Li Qiang Tested-by: P J P Signed-off-by: Gerd Hoffmann --- hw/usb/hcd-xhci.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/hw/usb/hcd-xhci.c b/hw/usb/hcd-xhci.c index 726435c..ee4fa48 100644 --- a/hw/usb/hcd-xhci.c +++ b/hw/usb/hcd-xhci.c @@ -54,6 +54,8 @@ * to the specs when it gets them */ #define ER_FULL_HACK +#define TRB_LINK_LIMIT 4 + #define LEN_CAP 0x40 #define LEN_OPER (0x400 + 0x10 * MAXPORTS) #define LEN_RUNTIME ((MAXINTRS + 1) * 0x20) @@ -1000,6 +1002,7 @@ static TRBType xhci_ring_fetch(XHCIState *xhci, XHCIRing *ring, XHCITRB *trb, dma_addr_t *addr) { PCIDevice *pci_dev = PCI_DEVICE(xhci); + uint32_t link_cnt = 0; while (1) { TRBType type; @@ -1026,6 +1029,9 @@ static TRBType xhci_ring_fetch(XHCIState *xhci, XHCIRing *ring, XHCITRB *trb, ring->dequeue += TRB_SIZE; return type; } else { + if (++link_cnt > TRB_LINK_LIMIT) { + return 0; + } ring->dequeue = xhci_mask64(trb->parameter); if (trb->control & TRB_LK_TC) { ring->ccs = !ring->ccs; @@ -1043,6 +1049,7 @@ static int xhci_ring_chain_length(XHCIState *xhci, const XHCIRing *ring) bool ccs = ring->ccs; /* hack to bundle together the two/three TDs that make a setup transfer */ bool control_td_set = 0; + uint32_t link_cnt = 0; while (1) { TRBType type; @@ -1058,6 +1065,9 @@ static int xhci_ring_chain_length(XHCIState *xhci, const XHCIRing *ring) type = TRB_TYPE(trb); if (type == TR_LINK) { + if (++link_cnt > TRB_LINK_LIMIT) { + return -length; + } dequeue = xhci_mask64(trb.parameter); if (trb.control & TRB_LK_TC) { ccs = !ccs;