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/[email protected]
Signed-off-by: Igor Mammedov <[email protected]>
Signed-off-by: Bjorn Helgaas <[email protected]>
Acked-by: Michael S. Tsirkin <[email protected]>
Acked-by: Rafael J. Wysocki <[email protected]>
Cc: [email protected]
---
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);
--
2.39.3