Traditional q35 memory layout is 2.75 GB of low memory, leaving room
for the pcie mmconfig at 0xb0000000 and the 32-bit pci mmio window at
0xc0000000. Because of that OVMF tags the memory range above
0xb0000000 as uncachable via mtrr.
A while ago qemu started to gigabyte-align memory by default (to make
huge pages more effective) and q35 uses only 2G of low memory in that
case. Which effectively makes the 32-bit pci mmio window start at
0x80000000.
This patch updates the mtrr setup code accordingly.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
2a0bd3bffc