On 10/15/2010 03:51 PM, Stefan Weil wrote:
PCI device with different device ids sometimes share
the same rom code. Only the device id and the checksum
differ in a boot rom for such devices.
BTW, SeaBIOS doesn't reject ROMs when they're loaded via rombar, only
when they're loaded via romfile.
Maybe it's better to use fw_cfg to explicitly tell SeaBIOS to ignore the
PCI device id in the rom header for a certain device?
Regards,
Anthony Liguori
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 the device id (and the checksum)
in qemu, all emulated family members can share the same
boot rom.
Cc: Markus Armbruster<arm...@redhat.com>
Cc: Michael S. Tsirkin<m...@redhat.com>
Signed-off-by: Stefan Weil<w...@mail.berlios.de>
---
hw/pci.c | 53 +++++++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 53 insertions(+), 0 deletions(-)
diff --git a/hw/pci.c b/hw/pci.c
index 1280d4d..c1f8218 100644
--- a/hw/pci.c
+++ b/hw/pci.c
@@ -1797,6 +1797,57 @@ 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 device id 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_device_id(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;
+
+ /* 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);
+
+ /* Don't patch a rom with wrong vendor id (might be changed if needed). */
+ if (vendor_id != rom_vendor_id) {
+ return;
+ }
+
+ PCI_DPRINTF("ROM id %04x%04x / PCI id %04x%04x\n",
+ vendor_id, device_id, rom_vendor_id, rom_device_id);
+
+ if (device_id != rom_device_id) {
+ /* Patch device id and checksum (at offset 6 for etherboot roms). */
+ uint8_t checksum;
+ checksum = ptr[6];
+ 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)
{
@@ -1849,6 +1900,8 @@ static int pci_add_option_rom(PCIDevice *pdev)
load_image(path, ptr);
qemu_free(path);
+ pci_patch_device_id(pdev, ptr, size);
+
pci_register_bar(pdev, PCI_ROM_SLOT, size,
0, pci_map_option_rom);
