Hi, On 24/07/2020 00:38, Stefano Stabellini wrote:
+ bridge->dt_node = dev; + bridge->sysdata = cfg; + bridge->ops = &ops->pci_ops; + + if( !dt_property_read_u32(dev, "linux,pci-domain", &segment) ) + { + printk(XENLOG_ERR "\"linux,pci-domain\" property in not available in DT\n"); + return -ENODEV; + } + + bridge->segment = (u16)segment;My understanding is that a Linux pci-domain doesn't correspond exactly to a PCI segment. See for instance: https://lists.gnu.org/archive/html/qemu-devel/2018-04/msg03885.html Do we need to care about the difference? If we mean pci-domain here, should we just call them as such instead of calling them "segments" in Xen (if they are not segments)?
So we definitely need a segment number in hand because this is what the admin will use to assign a PCI device to a guest.
The segment number is just a value defined by the software. So as long as Linux and Xen agrees with the number, then we should be ok.
Looking at the code, I think Linux is using 'segment' as 'domain'. So they should be interchangeably. I am not sure what other OS does though.
Cheers, -- Julien Grall
