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* [PATCH v2] PCI: acpiphp: Reassign resources on bridge if necessary
@ 2023-04-24 19:15 Igor Mammedov
  2023-04-24 20:47 ` Michael S. Tsirkin
                   ` (4 more replies)
  0 siblings, 5 replies; 15+ messages in thread
From: Igor Mammedov @ 2023-04-24 19:15 UTC (permalink / raw)
  To: linux-kernel
  Cc: imammedo, mst, rafael, lenb, bhelgaas, linux-acpi, linux-pci,
	helgaas, mika.westerberg

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.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
---
tested in QEMU with Q35 machine on PCIE root port and also
with nested conventional bridge attached to root port.

v2:
  * fixup subject to match expected style
  * drop no longer needed __pci_bus_size_bridges() to avoid
    memory leak (Bjorn Helgaas <helgaas@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 5b1f271c6034..328d1e416014 100644
--- a/drivers/pci/hotplug/acpiphp_glue.c
+++ b/drivers/pci/hotplug/acpiphp_glue.c
@@ -498,7 +498,6 @@ static void enable_slot(struct acpiphp_slot *slot, bool bridge)
 				acpiphp_native_scan_bridge(dev);
 		}
 	} else {
-		LIST_HEAD(add_list);
 		int max, pass;
 
 		acpiphp_rescan_slot(slot);
@@ -512,12 +511,10 @@ static void enable_slot(struct acpiphp_slot *slot, bool bridge)
 				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);
-- 
2.39.1


^ permalink raw reply related	[flat|nested] 15+ messages in thread

end of thread, other threads:[~2023-05-31 15:24 UTC | newest]

Thread overview: 15+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2023-04-24 19:15 [PATCH v2] PCI: acpiphp: Reassign resources on bridge if necessary Igor Mammedov
2023-04-24 20:47 ` Michael S. Tsirkin
2023-05-09 12:44 ` Igor Mammedov
2023-05-22 11:06 ` Igor Mammedov
2023-05-22 11:52   ` Rafael J. Wysocki
2023-05-22 19:21     ` Michael S. Tsirkin
2023-05-22 21:51 ` Bjorn Helgaas
2023-05-22 21:54   ` Michael S. Tsirkin
2023-05-22 21:55   ` Rafael J. Wysocki
2023-05-23 15:42   ` Bjorn Helgaas
2023-05-30 17:12 ` Bjorn Helgaas
2023-05-30 18:16   ` Michael S. Tsirkin
2023-05-30 18:55     ` Bjorn Helgaas
2023-05-30 19:06       ` Michael S. Tsirkin
2023-05-31 15:22       ` Igor Mammedov

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