When using ACPI PCI hotplug, hotplugging a device with large BARs may fail if bridge windows programmed by firmware are not large enough.
Reproducer: $ qemu-kvm -monitor stdio -M q35 -m 4G \ -global ICH9-LPC.acpi-pci-hotplug-with-bridge-support=on \ -device id=rp1,pcie-root-port,bus=pcie.0,chassis=4 \ disk_image
wait till linux guest boots, then hotplug device: (qemu) device_add qxl,bus=rp1
hotplug on guest side fails with: pci 0000:01:00.0: [1b36:0100] type 00 class 0x038000 pci 0000:01:00.0: reg 0x10: [mem 0x00000000-0x03ffffff] pci 0000:01:00.0: reg 0x14: [mem 0x00000000-0x03ffffff] pci 0000:01:00.0: reg 0x18: [mem 0x00000000-0x00001fff] pci 0000:01:00.0: reg 0x1c: [io 0x0000-0x001f] pci 0000:01:00.0: BAR 0: no space for [mem size 0x04000000] pci 0000:01:00.0: BAR 0: failed to assign [mem size 0x04000000] pci 0000:01:00.0: BAR 1: no space for [mem size 0x04000000] pci 0000:01:00.0: BAR 1: failed to assign [mem size 0x04000000] pci 0000:01:00.0: BAR 2: assigned [mem 0xfe800000-0xfe801fff] pci 0000:01:00.0: BAR 3: assigned [io 0x1000-0x101f] qxl 0000:01:00.0: enabling device (0000 -> 0003) Unable to create vram_mapping qxl: probe of 0000:01:00.0 failed with error -12
However when using native PCIe hotplug '-global ICH9-LPC.acpi-pci-hotplug-with-bridge-support=off' it works fine, since kernel attempts to reassign unused resources.
Use the same machinery as native PCIe hotplug to (re)assign resources.
Link: https://lore.kernel.org/r/20230424191557.2464760-1-imammedo@redhat.com Signed-off-by: Igor Mammedov imammedo@redhat.com Signed-off-by: Bjorn Helgaas bhelgaas@google.com Acked-by: Michael S. Tsirkin mst@redhat.com Acked-by: Rafael J. Wysocki rafael@kernel.org Cc: stable@vger.kernel.org --- drivers/pci/hotplug/acpiphp_glue.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-)
diff --git a/drivers/pci/hotplug/acpiphp_glue.c b/drivers/pci/hotplug/acpiphp_glue.c index af1c73f2bee6..c0ffb1389fda 100644 --- a/drivers/pci/hotplug/acpiphp_glue.c +++ b/drivers/pci/hotplug/acpiphp_glue.c @@ -499,7 +499,6 @@ pci_info(bus, "enable_slot bus: bridge: %d, bus->self: %p\n", bridge, bus->self) acpiphp_native_scan_bridge(dev); } } else { - LIST_HEAD(add_list); int max, pass;
acpiphp_rescan_slot(slot); @@ -513,12 +512,10 @@ pci_info(bus, "enable_slot bus: bridge: %d, bus->self: %p\n", bridge, bus->self) if (pass && dev->subordinate) { check_hotplug_bridge(slot, dev); pcibios_resource_survey_bus(dev->subordinate); - __pci_bus_size_bridges(dev->subordinate, - &add_list); } } } - __pci_bus_assign_resources(bus, &add_list, NULL); + pci_assign_unassigned_bridge_resources(bus->self); }
acpiphp_sanitize_bus(bus);