Hi Bjorn, Thanks for the feedback. Much of the issues you mentioned look pretty straight forward to resolve, and will fix of for the next revision. I have some immediate follow up comments to two issues you brought up: On Tue, 6 Oct 2015, Bjorn Helgaas wrote:
+static int vmd_find_free_domain(void) +{ + int domain = -1; + struct pci_bus *bus = NULL; + + while ((bus = pci_find_next_bus(bus)) != NULL) + domain = max_t(int, domain, pci_domain_nr(bus)); + if (domain < 0) + return -ENODEV; + return domain + 1; +}The PCI core should own domain number allocation. We have a little bit of generic domain support, e.g., pci_get_new_domain_nr(). On x86, I think that is compiled-in, but currently not used -- currently x86 only uses _SEG from ACPI. How would you handle collisions between a domain number assigned here (or via pci_get_new_domain_nr()) and a hot-added host bridge where _SEG uses the same domain?
Thank you for bringing this up as I hadn't thought much about it and may have misunderstood the meaning of _SEG. AIUI, it is used to identify a logical grouping. The OS does not need to use the same identifier for the domain, so we there's no need to collide if we can assign the domain of a a new _SEG to the next available domain_nr. On pci_get_new_domain_nr(), can we make this use something like an ida instead of an atomic? I think we'd like to put domains back into the available pool if someone unbinds it. I imagine someone will test unbinding/rebinding these devices in a loop for a while, and will file a bug after the atomic increments to 64k. :)
+ resource_list_for_each_entry(entry, &resources) { + struct resource *source, *resource = entry->res; + + if (!i) { + resource->start = 0; + resource->end = (resource_size( + &vmd->dev->resource[0]) >> 20) - 1; + resource->flags = IORESOURCE_BUS | IORESOURCE_PCI_FIXED;I thought BAR0 was CFGBAR. I missed the connection to a bus number aperture.
Right, BAR0 is the CFGBAR and is the device's aperture to access its domain's config space. Based on your comment, I assume that's not a bus resource, though it seems to work with the posted code. :) -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
