From patchwork Tue Jan 28 15:45:21 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alex Williamson X-Patchwork-Id: 314743 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 016462C009F for ; Wed, 29 Jan 2014 02:46:07 +1100 (EST) Received: from localhost ([::1]:37923 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1W8ArU-0004jf-TQ for incoming@patchwork.ozlabs.org; Tue, 28 Jan 2014 10:46:04 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:49271) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1W8Aqy-0004hY-Qd for qemu-devel@nongnu.org; Tue, 28 Jan 2014 10:45:38 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1W8Aqr-00057e-UM for qemu-devel@nongnu.org; Tue, 28 Jan 2014 10:45:32 -0500 Received: from mx1.redhat.com ([209.132.183.28]:49916) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1W8Aqr-00057V-Gp for qemu-devel@nongnu.org; Tue, 28 Jan 2014 10:45:25 -0500 Received: from int-mx01.intmail.prod.int.phx2.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id s0SFjLdI009893 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Tue, 28 Jan 2014 10:45:22 -0500 Received: from bling.home (ovpn-113-32.phx2.redhat.com [10.3.113.32]) by int-mx01.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id s0SFjL0g031517; Tue, 28 Jan 2014 10:45:21 -0500 From: Alex Williamson To: aliguori@amazon.com Date: Tue, 28 Jan 2014 08:45:21 -0700 Message-ID: <20140128154520.30053.99109.stgit@bling.home> In-Reply-To: <20140128153451.30053.92976.stgit@bling.home> References: <20140128153451.30053.92976.stgit@bling.home> User-Agent: StGit/0.17-dirty MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.67 on 10.5.11.11 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 209.132.183.28 Cc: Bandan Das , qemu-devel@nongnu.org, kvm@vger.kernel.org Subject: [Qemu-devel] [PULL v2 3/8] vfio: Do not reattempt a failed rom read X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org From: Bandan Das During lazy rom loading, if rom read fails, and the guest attempts a read again, vfio will again attempt it. Add a boolean to prevent this. There could be a case where a failed rom read might succeed the next time because of a device reset or such, but it's best to exclude unpredictable behavior Signed-off-by: Bandan Das Signed-off-by: Alex Williamson --- hw/misc/vfio.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/hw/misc/vfio.c b/hw/misc/vfio.c index ef615fc..30b1a78 100644 --- a/hw/misc/vfio.c +++ b/hw/misc/vfio.c @@ -191,6 +191,7 @@ typedef struct VFIODevice { bool has_flr; bool has_pm_reset; bool needs_reset; + bool rom_read_failed; } VFIODevice; typedef struct VFIOGroup { @@ -1125,6 +1126,7 @@ static void vfio_pci_load_rom(VFIODevice *vdev) vdev->rom_offset = reg_info.offset; if (!vdev->rom_size) { + vdev->rom_read_failed = true; error_report("vfio-pci: Cannot read device rom at " "%04x:%02x:%02x.%x\n", vdev->host.domain, vdev->host.bus, vdev->host.slot, @@ -1163,6 +1165,9 @@ static uint64_t vfio_rom_read(void *opaque, hwaddr addr, unsigned size) /* Load the ROM lazily when the guest tries to read it */ if (unlikely(!vdev->rom)) { vfio_pci_load_rom(vdev); + if (unlikely(!vdev->rom && !vdev->rom_read_failed)) { + vfio_pci_load_rom(vdev); + } } memcpy(&val, vdev->rom + addr, @@ -1230,6 +1235,7 @@ static void vfio_pci_size_rom(VFIODevice *vdev) PCI_BASE_ADDRESS_SPACE_MEMORY, &vdev->pdev.rom); vdev->pdev.has_rom = true; + vdev->rom_read_failed = false; } static void vfio_vga_write(void *opaque, hwaddr addr,