Verified the fix with reproducer described in
https://lore.kernel.org/linux-
pci/[email protected]/T/#m40d277dcdb9be64a1609a82412d1aa906263e201
using a plucky image:
qemu-system-x86_64 --enable-kvm -m 5G -cpu host \
-smp sockets=1,cores=2,threads=2 \
-snapshot -vga none -display none -nographic \
-drive if=none,file=/opt/vm/ubuntu-24.04-with-linux-net.qcow2,id=hda \
-device virtio-blk,drive=hda \
-device virtio-net,netdev=eth0,addr=03 -netdev user,id=eth0 \
-device virtio-net,netdev=eth1,addr=04 -netdev
socket,id=eth1,mcast=230.0.0.1:1234
git clone git://dpdk.org/dpdk
cd dpdk/
meson build-static --werror --default-library=static --debug
ninja -C build-static
echo 3 > /proc/sys/vm/drop_caches
echo 256 >
/sys/devices/system/node/node0/hugepages/hugepages-2048kB/nr_hugepages
modprobe vfio-pci
lspci
python3 ./usertools/dpdk-devbind.py --noiommu-mode -b vfio-pci 0000:00:04.0
./build-static/app/dpdk-testpmd -l 1,2 --socket-mem 512,0 -a 0000:00:04.0 -- -i
Kernel 6.14.0-23-generic showed expected behavior, 6.14.0-24-generic
which included the faulty commit
4d4c10f763d7808fbade28d83d237411603bca05 PCI: Explicitly put devices
into D0 when initializing
reproduced the bug, while 6.14.0-27-generic with this fix included
worked fine again.
** Tags removed: verification-needed-plucky-linux
** Tags added: verification-done-plucky-linux
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https://bugs.launchpad.net/bugs/2117494
Title:
[Regression Updates] "PCI: Explicitly put devices into D0 when
initializing" breaks pci-pass-through in QEMU/KVM
Status in linux package in Ubuntu:
Fix Released
Status in linux source package in Noble:
Fix Committed
Status in linux source package in Plucky:
Fix Committed
Bug description:
[SRU Justification]
Impact: Reported regression to PCI pass-through in QEMU/KVM
(https://lists.ubuntu.com/archives/kernel-team/2025-July/161565.html)
which was caused by changes to fix suspend/resume on disks with BIOS
password set (bug #2110090).
Fix: Upstream fix from 6.16-rc3 addressing the issue (see below)
Testcase: Requires to set up a VM with PCI pass-through.
Regression potential: Things related to PCI power management (devices
not being initialized or not properly resuming after suspend).
--- original description ---
From: Thomas Lamprecht <[email protected]>
Subject: Re: [PATCH 1/1][SRU][N] PCI: Explicitly put devices into D0 when
initializing
...
FYI: This causes regressions on PCI passthrough to QEMU/KVM, among other
things. A colleague found that the following patch on top fixes it here:
commit 907a7a2e5bf40c6a359b2f6cc53d6fdca04009e0
Author: Mario Limonciello <[email protected]>
Date: Wed Jun 11 18:31:16 2025 -0500
PCI/PM: Set up runtime PM even for devices without PCI PM
4d4c10f763d7 ("PCI: Explicitly put devices into D0 when initializing")
intended to put PCI devices into D0, but in doing so unintentionally
changed runtime PM initialization not to occur on devices that don't
support PCI PM. This caused a regression in vfio-pci due to an imbalance
with its use.
Adjust the logic in pci_pm_init() so that even if PCI PM isn't supported
runtime PM is still initialized.
Fixes: 4d4c10f763d7 ("PCI: Explicitly put devices into D0 when
initializing")
Reported-by: Giovanni Cabiddu <[email protected]>
Closes:
https://lore.kernel.org/linux-pci/[email protected]/T/#m7e8929d6421690dc8bd6dc639d86c2b4db27cbc4
Reported-by: Nicolas Dichtel <[email protected]>
Closes:
https://lore.kernel.org/linux-pci/[email protected]/T/#m40d277dcdb9be64a1609a82412d1aa906263e201
Signed-off-by: Mario Limonciello <[email protected]>
Signed-off-by: Bjorn Helgaas <[email protected]>
Tested-by: Giovanni Cabiddu <[email protected]>
Tested-by: Nicolas Dichtel <[email protected]>
Reviewed-by: Kuppuswamy Sathyanarayanan
<[email protected]>
Acked-by: Rafael J. Wysocki <[email protected]>
Cc: Alex Williamson <[email protected]>
Link: https://patch.msgid.link/[email protected]
Same holds for the Plucky backport in patch mail id:
<[email protected]>
To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2117494/+subscriptions
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