On Sun, Mar 08, 2015 at 12:13:40PM -0400, Kevin O'Connor wrote:
> On Sun, Mar 08, 2015 at 01:16:15PM +0200, Marcel Apfelbaum wrote:
> > If multiple root busses are used, root bus 0 cannot use all the
> > pci holes ranges. Remove the IO/mem ranges used by the other
> > primary busses.
> [...]
> > - aml_append(crs,
> > - aml_word_io(aml_min_fixed, aml_max_fixed,
> > - aml_pos_decode, aml_entire_range,
> > - 0x0000, 0x0D00, 0xFFFF, 0x0000, 0xF300));
> > +
> > + /* prepare PCI IO ranges */
> > + range.base = 0x0D00;
> > + range.limit = 0xFFFF;
> > + if (QLIST_EMPTY(&io_ranges)) {
> > + aml_append(crs,
> > + aml_word_io(aml_min_fixed, aml_max_fixed,
> > + aml_pos_decode, aml_entire_range,
> > + 0x0000, range.base, range.limit,
> > + 0x0000, range.limit - range.base + 1));
> > + } else {
> > + QLIST_FOREACH(entry, &io_ranges, entry) {
> > + if (range.base < entry->base) {
> > + aml_append(crs,
> > + aml_word_io(aml_min_fixed, aml_max_fixed,
> > + aml_pos_decode, aml_entire_range,
> > + 0x0000, range.base, entry->base - 1,
> > + 0x0000, entry->base - range.base));
> > + }
> > + range.base = entry->limit + 1;
> > + if (!QLIST_NEXT(entry, entry)) {
> > + aml_append(crs,
> > + aml_word_io(aml_min_fixed, aml_max_fixed,
> > + aml_pos_decode, aml_entire_range,
> > + 0x0000, range.base, range.limit,
> > + 0x0000, range.limit - range.base + 1));
> > + }
> > + }
> > + }
>
> If I read this correctly, it looks like a machine with two root buses
> and 20 devices, each with one memory range and one io range, would end
> up with 40 CRS ranges (ie, a CRS range for every resource).
I think that's only if you stick multiple devices directly behind the
bridge. Looks like with a single pci bridge behind root, there will
only be 2 ranges.
Maybe try to enforce this sane topology?
> It also
> looks like this furthers the requirement that the guest firmware
> assign the PCI resources prior to QEMU being able to generate the ACPI
> tables.
That seems unavoidable unless we want to assign ranges from
hardware/management.
Which I think would be a mistake: management doesn't really know,
or care.
>
> -Kevin
