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[ Upstream commit 40613da52b ]
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
Signed-off-by: Sasha Levin <sashal@kernel.org>
Linux kernel
============
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In order to build the documentation, use ``make htmldocs`` or
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https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.