From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alex Williamson Subject: [PULL 3/7] vfio: Do not reattempt a failed rom read Date: Fri, 17 Jan 2014 12:25:26 -0700 Message-ID: <20140117192526.10456.40427.stgit@bling.home> References: <20140117192252.10456.96113.stgit@bling.home> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Cc: Bandan Das , qemu-devel@nongnu.org, kvm@vger.kernel.org To: aliguori@amazon.com Return-path: Received: from mx1.redhat.com ([209.132.183.28]:7882 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752915AbaAQTZa (ORCPT ); Fri, 17 Jan 2014 14:25:30 -0500 In-Reply-To: <20140117192252.10456.96113.stgit@bling.home> Sender: kvm-owner@vger.kernel.org List-ID: 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,