From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alex Williamson Subject: [RFC PATCH v2 8/9] vfio/pci: Fixup PCI option ROMs Date: Fri, 12 Feb 2016 17:17:18 -0700 Message-ID: <20160213001718.17724.39810.stgit@gimli.home> References: <20160213000436.17724.35780.stgit@gimli.home> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Cc: alex.williamson@redhat.com, allen.m.kay@intel.com, kvm@vger.kernel.org To: qemu-devel@nongnu.org Return-path: Received: from mx1.redhat.com ([209.132.183.28]:54301 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752123AbcBMART (ORCPT ); Fri, 12 Feb 2016 19:17:19 -0500 In-Reply-To: <20160213000436.17724.35780.stgit@gimli.home> Sender: kvm-owner@vger.kernel.org List-ID: Devices like Intel graphics are known to not only have bad checksums, but also the wrong device ID. This is not so surprising given that the video BIOS is typically part of the system firmware image rather that embedded into the device and needs to support any IGD device installed into the system. Signed-off-by: Alex Williamson --- hw/vfio/pci.c | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c index 4c376a8..07af5ca 100644 --- a/hw/vfio/pci.c +++ b/hw/vfio/pci.c @@ -832,6 +832,36 @@ static void vfio_pci_load_rom(VFIOPCIDevice *vdev) break; } } + + /* + * Test the ROM signature against our device, if the vendor is correct + * but the device ID doesn't match, store the correct device ID and + * recompute the checksum. Intel IGD devices need this and are known + * to have bogus checksums so we can't simply adjust the checksum. + */ + if (pci_get_word(vdev->rom) == 0xaa55 && + pci_get_word(vdev->rom + 0x18) + 8 < vdev->rom_size && + !memcmp(vdev->rom + pci_get_word(vdev->rom + 0x18), "PCIR", 4)) { + uint16_t vid, did; + + vid = pci_get_word(vdev->rom + pci_get_word(vdev->rom + 0x18) + 4); + did = pci_get_word(vdev->rom + pci_get_word(vdev->rom + 0x18) + 6); + + if (vid == vdev->vendor_id && did != vdev->device_id) { + int i; + uint8_t csum, *data = vdev->rom; + + pci_set_word(vdev->rom + pci_get_word(vdev->rom + 0x18) + 6, + vdev->device_id); + data[6] = 0; + + for (csum = 0, i = 0; i < vdev->rom_size; i++) { + csum += data[i]; + } + + data[6] = -csum; + } + } } static uint64_t vfio_rom_read(void *opaque, hwaddr addr, unsigned size)