On Mon, Aug 12, 2013 at 08:37:00AM +0200, Gerd Hoffmann wrote:
Hi,
If we make it a rule that PCI is`setup before ACPI tables are read, then QEMU can do the patching itself when it detects BIOS reading the tables.
Approach makes sense to me. The ordering constrain shouldn't be a big burden, hardware detection+bringup (including pci setup) is the first thing done by the firmware, loading/generating acpi tables is one of the last things. And it avoids the need to communicate the addresses (or patch locations) between qemu+firmware.
What do you want to use this for? pmbase and xbar are simple, they are just a single register read. pci io windows needs a root bus scan, but should be doable too.
Right. We'll need to migrate the offsets for patching since they are tied to specific AML and this can change.
Gerd, Laszlo,others, does this rule work for alternative firmwares?
It surely works for coreboot, and I would be very surprised if this causes trouble for ovmf.
cheers, Gerd