pci: allow loading roms via fw_cfg.

This patch adds a pci bus property 'rombar' which specifies whenever
the pci rom should be loaded via pci rom bar (default) or via fw_cfg.
The later can be used for compatibility with older qemu versions where
no pci rom bar is present.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

hw/pci.c

diff --git a/hw/pci.c b/hw/pci.c
index 08e51f8..2bdf27e 100644
--- a/hw/pci.c
+++ b/hw/pci.c
@@ -64,6 +64,7 @@
     .props      = (Property[]) {
         DEFINE_PROP_PCI_DEVFN("addr", PCIDevice, devfn, -1),
         DEFINE_PROP_STRING("romfile", PCIDevice, romfile),
+        DEFINE_PROP_UINT32("rombar",  PCIDevice, rom_bar, 1),
         DEFINE_PROP_END_OF_LIST()
     }
 };
@@ -1501,6 +1502,20 @@
     if (strlen(pdev->romfile) == 0)
         return 0;
 
+    if (!pdev->rom_bar) {
+        /*
+         * Load rom via fw_cfg instead of creating a rom bar,
+         * for 0.11 compatibility.
+         */
+        int class = pci_get_word(pdev->config + PCI_CLASS_DEVICE);
+        if (class == 0x0300) {
+            rom_add_vga(pdev->romfile);
+        } else {
+            rom_add_option(pdev->romfile);
+        }
+        return 0;
+    }
+
     path = qemu_find_file(QEMU_FILE_TYPE_BIOS, pdev->romfile);
     if (path == NULL) {
         path = qemu_strdup(pdev->romfile);

hw/pci.h

diff --git a/hw/pci.h b/hw/pci.h
index 9b5ae97..ed048f5 100644
--- a/hw/pci.h
+++ b/hw/pci.h
@@ -177,6 +177,7 @@
     /* Location of option rom */
     char *romfile;
     ram_addr_t rom_offset;
+    uint32_t rom_bar;
 };
 
 PCIDevice *pci_register_device(PCIBus *bus, const char *name,