Re: ovmf / PCI passthrough impaired due to very limiting PCI64 aperture

[Eduardo Habkost]

On Wed, Jun 17, 2020 at 12:57:52PM -0300, Guilherme Piccoli wrote:
> Can't qemu reads the host physical bits and pass that as fw_cfg as
> "real_host_physbits" or something like that?
> OVMF could rely on that - if such property is available, we use it to
> extend the PCI64 aperture.

Giving a exact "real host physbits" value would be too limiting
if we still want to allow migration to smaller hosts.  But we can
provide extra information on CPUID or fw_cfg, yes.

I will try to write down a proposal to extend the KVM CPUID leaf
to provide extra information about MAXPHYADDR guarantees.

-- 
Eduardo