On 06/17/20 18:33, Eduardo Habkost wrote: > 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.
Thank you -- if this can be detected in the guest via CPUID, then I prefer that to fw_cfg. We need to keep an eye on x-file-slots for fw_cfg. Thanks Laszlo
