From nobody Mon Feb 9 02:28:29 2026 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zoho.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1487362387414463.544812199008; Fri, 17 Feb 2017 12:13:07 -0800 (PST) Received: from localhost ([::1]:55632 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ceotu-0003Ou-4Q for importer@patchew.org; Fri, 17 Feb 2017 15:13:06 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:44008) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ceobS-0003i8-AF for qemu-devel@nongnu.org; Fri, 17 Feb 2017 14:54:03 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ceobN-0005AK-I0 for qemu-devel@nongnu.org; Fri, 17 Feb 2017 14:54:02 -0500 Received: from mail.kernel.org ([198.145.29.136]:34142) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1ceobN-00059H-Bi for qemu-devel@nongnu.org; Fri, 17 Feb 2017 14:53:57 -0500 Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 7B79D201BB; Fri, 17 Feb 2017 19:53:55 +0000 (UTC) Received: from redhat.com (pool-96-237-235-121.bstnma.fios.verizon.net [96.237.235.121]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 181D620108; Fri, 17 Feb 2017 19:53:54 +0000 (UTC) Date: Fri, 17 Feb 2017 21:53:53 +0200 From: "Michael S. Tsirkin" To: qemu-devel@nongnu.org Message-ID: <1487361200-29966-2-git-send-email-mst@redhat.com> References: <1487361200-29966-1-git-send-email-mst@redhat.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <1487361200-29966-1-git-send-email-mst@redhat.com> X-Mailer: git-send-email 2.8.0.287.g0deeb61 X-Mutt-Fcc: =sent X-Virus-Scanned: ClamAV using ClamSMTP X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x [fuzzy] X-Received-From: 198.145.29.136 Subject: [Qemu-devel] [PULL 01/23] pci/pcie: don't assume cap id 0 is reserved 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: Marcel Apfelbaum , Peter Maydell , Alex Williamson , Peter Xu Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" VFIO actually wants to create a capability with ID =3D=3D 0. This is done to make guest drivers skip the given capability. pcie_add_capability then trips up on this capability when looking for end of capability list. To support this use-case, it's easy enough to switch to e.g. 0xffffffff for these comparisons - we can be sure it will never match a 16-bit capability ID. Signed-off-by: Michael S. Tsirkin Reviewed-by: Peter Xu Reviewed-by: Alex Williamson --- hw/pci/pcie.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/hw/pci/pcie.c b/hw/pci/pcie.c index cbd4bb4..f4dd177 100644 --- a/hw/pci/pcie.c +++ b/hw/pci/pcie.c @@ -610,7 +610,8 @@ bool pcie_cap_is_arifwd_enabled(const PCIDevice *dev) * uint16_t ext_cap_size */ =20 -static uint16_t pcie_find_capability_list(PCIDevice *dev, uint16_t cap_id, +/* Passing a cap_id value > 0xffff will return 0 and put end of list in pr= ev */ +static uint16_t pcie_find_capability_list(PCIDevice *dev, uint32_t cap_id, uint16_t *prev_p) { uint16_t prev =3D 0; @@ -679,9 +680,11 @@ void pcie_add_capability(PCIDevice *dev, } else { uint16_t prev; =20 - /* 0 is reserved cap id. use internally to find the last capability - in the linked list */ - next =3D pcie_find_capability_list(dev, 0, &prev); + /* + * 0xffffffff is not a valid cap id (it's a 16 bit field). use + * internally to find the last capability in the linked list. + */ + next =3D pcie_find_capability_list(dev, 0xffffffff, &prev); =20 assert(prev >=3D PCI_CONFIG_SPACE_SIZE); assert(next =3D=3D 0); --=20 MST