On Tue, Oct 19, 2010 at 11:08:21PM +0200, Stefan Weil wrote:
> PCI devices with different vendor or device ids sometimes share
> the same rom code. Only the ids and the checksum
> differs in a boot rom for such devices.
>
> The i825xx ethernet controller family is a typical example
> which is implemented in hw/eepro100.c. It uses at least
> 3 different device ids, so normally 3 boot roms would be needed.
>
> By automatically patching vendor id and device id (and the checksum)
> in qemu, all emulated family members can share the same boot rom.
>
> VGA bios roms are another example with different vendor and device ids.
>
> Only qemu's built-in default rom files will be patched.
>
> v2:
> * Patch also the vendor id (and remove the sanity check for vendor id).
>
> v3:
> * Don't patch a rom file when its name was set by the user.
> Thus we avoid modifications of unknown rom data.
>
> Cc: Gerd Hoffmann <kra...@redhat.com>
> Cc: Markus Armbruster <arm...@redhat.com>
> Cc: Michael S. Tsirkin <m...@redhat.com>
> Signed-off-by: Stefan Weil <w...@mail.berlios.de>
Looks safe enough for me.
Applied.
> ---
> hw/pci.c | 73 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++---
> 1 files changed, 69 insertions(+), 4 deletions(-)
>
> diff --git a/hw/pci.c b/hw/pci.c
> index 1280d4d..74cbea5 100644
> --- a/hw/pci.c
> +++ b/hw/pci.c
> @@ -78,7 +78,7 @@ static struct BusInfo pci_bus_info = {
>
> static void pci_update_mappings(PCIDevice *d);
> static void pci_set_irq(void *opaque, int irq_num, int level);
> -static int pci_add_option_rom(PCIDevice *pdev);
> +static int pci_add_option_rom(PCIDevice *pdev, bool is_default_rom);
> static void pci_del_option_rom(PCIDevice *pdev);
>
> static uint16_t pci_default_sub_vendor_id = PCI_SUBVENDOR_ID_REDHAT_QUMRANET;
> @@ -1672,6 +1672,7 @@ static int pci_qdev_init(DeviceState *qdev, DeviceInfo
> *base)
> PCIDeviceInfo *info = container_of(base, PCIDeviceInfo, qdev);
> PCIBus *bus;
> int devfn, rc;
> + bool is_default_rom;
>
> /* initialize cap_present for pci_is_express() and pci_config_size() */
> if (info->is_express) {
> @@ -1692,9 +1693,12 @@ static int pci_qdev_init(DeviceState *qdev, DeviceInfo
> *base)
> }
>
> /* rom loading */
> - if (pci_dev->romfile == NULL && info->romfile != NULL)
> + is_default_rom = false;
> + if (pci_dev->romfile == NULL && info->romfile != NULL) {
> pci_dev->romfile = qemu_strdup(info->romfile);
> - pci_add_option_rom(pci_dev);
> + is_default_rom = true;
> + }
> + pci_add_option_rom(pci_dev, is_default_rom);
>
> if (qdev->hotplugged) {
> rc = bus->hotplug(bus->hotplug_qdev, pci_dev, 1);
> @@ -1797,8 +1801,64 @@ static void pci_map_option_rom(PCIDevice *pdev, int
> region_num, pcibus_t addr, p
> cpu_register_physical_memory(addr, size, pdev->rom_offset);
> }
>
> +/* Patch the PCI vendor and device ids in a PCI rom image if necessary.
> + This is needed for an option rom which is used for more than one device.
> */
> +static void pci_patch_ids(PCIDevice *pdev, uint8_t *ptr, int size)
> +{
> + uint16_t vendor_id;
> + uint16_t device_id;
> + uint16_t rom_vendor_id;
> + uint16_t rom_device_id;
> + uint16_t rom_magic;
> + uint16_t pcir_offset;
> + uint8_t checksum;
> +
> + /* Words in rom data are little endian (like in PCI configuration),
> + so they can be read / written with pci_get_word / pci_set_word. */
> +
> + /* Only a valid rom will be patched. */
> + rom_magic = pci_get_word(ptr);
> + if (rom_magic != 0xaa55) {
> + PCI_DPRINTF("Bad ROM magic %04x\n", rom_magic);
> + return;
> + }
> + pcir_offset = pci_get_word(ptr + 0x18);
> + if (pcir_offset + 8 >= size || memcmp(ptr + pcir_offset, "PCIR", 4)) {
> + PCI_DPRINTF("Bad PCIR offset 0x%x or signature\n", pcir_offset);
> + return;
> + }
> +
> + vendor_id = pci_get_word(pdev->config + PCI_VENDOR_ID);
> + device_id = pci_get_word(pdev->config + PCI_DEVICE_ID);
> + rom_vendor_id = pci_get_word(ptr + pcir_offset + 4);
> + rom_device_id = pci_get_word(ptr + pcir_offset + 6);
> +
> + PCI_DPRINTF("%s: ROM id %04x%04x / PCI id %04x%04x\n", pdev->romfile,
> + vendor_id, device_id, rom_vendor_id, rom_device_id);
> +
> + checksum = ptr[6];
> +
> + if (vendor_id != rom_vendor_id) {
> + /* Patch vendor id and checksum (at offset 6 for etherboot roms). */
> + checksum += (uint8_t)rom_vendor_id + (uint8_t)(rom_vendor_id >> 8);
> + checksum -= (uint8_t)vendor_id + (uint8_t)(vendor_id >> 8);
> + PCI_DPRINTF("ROM checksum %02x / %02x\n", ptr[6], checksum);
> + ptr[6] = checksum;
> + pci_set_word(ptr + pcir_offset + 4, vendor_id);
> + }
> +
> + if (device_id != rom_device_id) {
> + /* Patch device id and checksum (at offset 6 for etherboot roms). */
> + checksum += (uint8_t)rom_device_id + (uint8_t)(rom_device_id >> 8);
> + checksum -= (uint8_t)device_id + (uint8_t)(device_id >> 8);
> + PCI_DPRINTF("ROM checksum %02x / %02x\n", ptr[6], checksum);
> + ptr[6] = checksum;
> + pci_set_word(ptr + pcir_offset + 6, device_id);
> + }
> +}
> +
> /* Add an option rom for the device */
> -static int pci_add_option_rom(PCIDevice *pdev)
> +static int pci_add_option_rom(PCIDevice *pdev, bool is_default_rom)
> {
> int size;
> char *path;
> @@ -1849,6 +1909,11 @@ static int pci_add_option_rom(PCIDevice *pdev)
> load_image(path, ptr);
> qemu_free(path);
>
> + if (is_default_rom) {
> + /* Only the default rom images will be patched (if needed). */
> + pci_patch_ids(pdev, ptr, size);
> + }
> +
> pci_register_bar(pdev, PCI_ROM_SLOT, size,
> 0, pci_map_option_rom);
>
> --
> 1.7.1
