On Mon, 2014-11-24 at 13:28 +0100, Gerd Hoffmann wrote:
> On Mo, 2014-11-24 at 11:47 +0200, Marcel Apfelbaum wrote:
> > Removed the assumption that the system has only one primary root bus.
> > When mapping memory and IO regions go over all buses, skipping
> > secondary and absent buses.
>
Hi Gerd,
Thanks for the review.
> I guess there are qemu patches adding support for multiple pci busses
> somewhere?
Yes, an RFC will be released soon on QEMU mailing list,
is a work in progress and I am currently trying to decide
if I wait for a fully functional series or release is sooner
for comments.
>
> > + for (i = 0; i <= MaxPCIBus; i++) {
> > + struct pci_region *r_io = &bus[i].r[PCI_REGION_TYPE_IO];
> > + u64 sum = pci_region_sum(r_io);
> > + if (bus[i].bus_dev || !sum)
> > + continue;
> > +
> > + sum_pci = ALIGN(sum_pci, sum);
> > + sum_free = ALIGN(sum_free, sum);
> > + if (sum + sum_pci < 0x4000) {
> > + /* traditional region is big enough, use it */
> > + r_io->base = 0xc000 + sum_pci;
> > + sum_pci += sum;
> > + } else if (sum < pci_io_low_end - 0x1000 - sum_free) {
> > + /* use the larger region at 0x1000 */
> > + r_io->base = 0x1000 + sum_free;
> > + sum_free += sum;
> > + } else {
> > + /* not enough io address space -> error out */
> > + return -1;
> > + }
>
> Hmm, that assigns the io regions in bus order. I think it would be
> better to integrate this with the packing logic we already have:
> regions are sorted by size for best packing. Regions behind pci bridges
> are grouped together. I think we could group regions belonging to a pci
> bus in a simliar way.
You are right, but only partial. Let me explain (as I understand it).
The devices IO regions behind the bus are *already* packed (sorted by size).
The buses themselves are indeed not sorted by their total IO space.
The same is happening in pci_bios_init_root_regions_mem with the MMIO regions.
It seems that what I have to do is simply replace the current bus enumeration:
for (i = 0; i <= MaxPCIBus; i++) {
with one that goes over the sorted list of buses in decreasing order of their
total mem/IO consumed.
Do you agree?
Also, it seems cleaner to add a patch on top of this (and re-sending the series
again)
since while not optimal, it is still correct.
Thanks,
Marcel
>
> cheers,
> Gerd
>
>
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