Hi,
> > Not sure whenever qemu adds some extra space for hotplug to the 64bit
> > hole and if so how it calculates the size then. But the guest os should
> > stick to those ranges when configuring hotplugged devices.
> currently firmware would assign 64-bit BARs after reserved-memory-end
> (not sure about ovmf though)
Ah, right, reserved-memory-end is checked too if present. Both seabios
and ovmf should do that.
> but QEMU on ACPI side will add 64-bit _CRS only
> for firmware mapped devices (i.e. no space reserved for hotplug).
Yes. Tested meanwhile, looks like this (seabios):
100000000-17fffffff : System RAM
180000000-1c1ffffff : PCI Bus 0000:00
180000000-1bfffffff : 0000:00:0f.0
1c0000000-1c07fffff : PCI Bus 0000:04
1c0000000-1c07fffff : 0000:04:00.0
1c0000000-1c07fffff : virtio-pci
1c0800000-1c0ffffff : PCI Bus 0000:03
1c0800000-1c0ffffff : 0000:03:00.0
1c0800000-1c0ffffff : virtio-pci
1c1000000-1c17fffff : PCI Bus 0000:02
1c1000000-1c17fffff : 0000:02:00.0
1c1000000-1c17fffff : virtio-pci
1c1800000-1c19fffff : PCI Bus 0000:08
1c1a00000-1c1bfffff : PCI Bus 0000:07
1c1c00000-1c1dfffff : PCI Bus 0000:06
1c1e00000-1c1ffffff : PCI Bus 0000:05
seabios assigns a 2M memory window to pci bridges (which support
hotplug) even in case no device is connected, so there is some space for
hotplug because of that.
/me should try the same with ovmf ...
cheers,
Gerd
