On Mon, Dec 14, 2009 at 08:37:44PM -0600, Anthony Liguori wrote:
Okay, I think I've figured out how this is supposed to work. With these
two patches to SeaBIOS and the patch to qemu, I can run:
I'm not sure why "Do not guard qemu shadow ram work around in
CONFIG_OPTIONROMS_DEPLOYED" patch is needed. The code today is:
if (CONFIG_OPTIONROMS_DEPLOYED) {
int reg = pci_config_readb(bdf, 0x5a + i);
if ((reg & 0x11) != 0x11) {
// Need to copy optionroms to work around qemu implementation
void *mem = (void*)(BUILD_ROM_START + i * 32*1024);
memcpy((void*)BUILD_BIOS_TMP_ADDR, mem, 32*1024);
pci_config_writeb(bdf, 0x5a + i, 0x33);
memcpy(mem, (void*)BUILD_BIOS_TMP_ADDR, 32*1024);
clear = 1;
} else {
pci_config_writeb(bdf, 0x5a + i, 0x33);
}
} else {
pci_config_writeb(bdf, 0x5a + i, 0x33);
}
So, in the non CONFIG_OPTIONROMS_DEPLOYED case, SeaBIOS will just do
the write enable call (pci_config_writeb(bdf, 0x5a + i, 0x33)). The
CONFIG_OPTIONROMS_DEPLOYED case should just be to copy the roms qemu
has deployed. If SeaBIOS is filling in the 0xc0000-0xf0000 space, it
shouldn't matter if the contents of that space is lost during the
write enable.