From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:48722) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1W3NPu-0000I6-Dx for qemu-devel@nongnu.org; Wed, 15 Jan 2014 05:09:52 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1W3NPo-0004lJ-ES for qemu-devel@nongnu.org; Wed, 15 Jan 2014 05:09:46 -0500 Received: from mx1.redhat.com ([209.132.183.28]:46586) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1W3NPo-0004lC-5A for qemu-devel@nongnu.org; Wed, 15 Jan 2014 05:09:40 -0500 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id s0FA9c6a020727 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Wed, 15 Jan 2014 05:09:39 -0500 From: Bandan Das Date: Wed, 15 Jan 2014 15:38:06 +0530 Message-Id: <1389780486-10826-3-git-send-email-bsd@redhat.com> In-Reply-To: <1389780486-10826-1-git-send-email-bsd@redhat.com> References: <1389780486-10826-1-git-send-email-bsd@redhat.com> Subject: [Qemu-devel] [PATCH v2 2/2] vfio: Do not reattempt a failed rom read List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: alex.williamson@redhat.com 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 --- v2: Check for vdev->rom first followed by the rom_read_failed flag hw/misc/vfio.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/hw/misc/vfio.c b/hw/misc/vfio.c index d2e68e2..5ed9cbe 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, -- 1.8.3.1