On Mon, Aug 14, 2017 at 05:45:02PM +0100, Anthony PERARD wrote: > On Mon, Aug 14, 2017 at 06:53:14PM +0300, Michael S. Tsirkin wrote: > > On Mon, Aug 14, 2017 at 03:55:50PM +0100, Anthony PERARD wrote: > > > On Fri, Aug 11, 2017 at 08:18:28PM +0300, Michael S. Tsirkin wrote: > > > > On Fri, Aug 11, 2017 at 04:11:37PM +0100, Anthony PERARD wrote: > > > > > To do PCI passthrough with Xen, the property acpi-pcihp-bsel needs to > > > > > be > > > > > set, but this was done only when ACPI tables are built which is not > > > > > needed for a Xen guest. The need for the property starts with commit > > > > > "pc: pcihp: avoid adding ACPI_PCIHP_PROP_BSEL twice" > > > > > (f0c9d64a68b776374ec4732424a3e27753ce37b6). > > > > > > > > > > Set pci info before checking for the needs to build ACPI tables. > > > > > > > > > > Reported-by: Sander Eikelenboom <li...@eikelenboom.it> > > > > > Tested-by: Sander Eikelenboom <li...@eikelenboom.it> > > > > > Signed-off-by: Anthony PERARD <anthony.per...@citrix.com> > > > > > > > > I am worried that Xen will come to depend on specific > > > > assignment of bsel which isn't guaranteed. Thoughts on > > > > how to avoid that? > > > > > > Is it possible to have a different BSEL than 0 with PIIX ? > > > > With PCI to PCI bridges, yes. > > > > > Also, I don't known if having more than on PCI bus is going to work on > > > Xen, there is nothing in our ACPI tables beyond _SB.PCI0, and nothing to > > > use a different BSEL. > > > > My worry is someone might decide to implement hotplug for pci to pci > > bridges on Xen. If doing that, it's important to use the qemu supplied > > acpi tables. > > I can always add assert((xen_enable() && !bsel) || !xen_enable()) in > acpi_set_bsel(), so if someone was going to make any change, he would > find out about bsel quicker. But I don't see Xen using QEMU supplied > ACPI tables anytime soon.
In that case I'd prefer assigning bsel 0 just for the root bus on xen. -- MST _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org https://lists.xen.org/xen-devel