This is a note to let you know that I've just added the patch titled
PCI: Avoid FLR for AMD FCH AHCI adapters
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
pci-avoid-flr-for-amd-fch-ahci-adapters.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 63ba51db24ed1b8f8088a897290eb6c036c5435d Mon Sep 17 00:00:00 2001
From: Damien Le Moal <damien.lemoal@xxxxxxxxxxxxxxxxxx>
Date: Sat, 28 Jan 2023 10:39:51 +0900
Subject: PCI: Avoid FLR for AMD FCH AHCI adapters
From: Damien Le Moal <damien.lemoal@xxxxxxxxxxxxxxxxxx>
commit 63ba51db24ed1b8f8088a897290eb6c036c5435d upstream.
PCI passthrough to VMs does not work with AMD FCH AHCI adapters: the guest
OS fails to correctly probe devices attached to the controller due to FIS
communication failures:
ata4: softreset failed (1st FIS failed)
...
ata4.00: qc timeout after 5000 msecs (cmd 0xec)
ata4.00: failed to IDENTIFY (I/O error, err_mask=0x4)
Forcing the "bus" reset method before unbinding & binding the adapter to
the vfio-pci driver solves this issue, e.g.:
echo "bus" > /sys/bus/pci/devices/<ID>/reset_method
gives a working guest OS, indicating that the default FLR reset method
doesn't work correctly.
Apply quirk_no_flr() to AMD FCH AHCI devices to work around this issue.
Link: https://lore.kernel.org/r/20230128013951.523247-1-damien.lemoal@xxxxxxxxxxxxxxxxxx
Reported-by: Niklas Cassel <niklas.cassel@xxxxxxx>
Signed-off-by: Damien Le Moal <damien.lemoal@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/pci/quirks.c | 1 +
1 file changed, 1 insertion(+)
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -5328,6 +5328,7 @@ static void quirk_no_flr(struct pci_dev
DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_AMD, 0x1487, quirk_no_flr);
DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_AMD, 0x148c, quirk_no_flr);
DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_AMD, 0x149c, quirk_no_flr);
+DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_AMD, 0x7901, quirk_no_flr);
DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x1502, quirk_no_flr);
DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x1503, quirk_no_flr);
Patches currently in stable-queue which might be from damien.lemoal@xxxxxxxxxxxxxxxxxx are
queue-5.15/pci-avoid-flr-for-amd-fch-ahci-adapters.patch
