[pve-devel] [PATCH pve-kernel/master 1/2] fix #5926: cherry-pick ACS-quirk fix from linux-stable/6.11.7

[Stoiko Ivanov]

the latest linux-stable pull I found in ubuntu-oracular was for 6.11.5
- this fix here seems targeted enough. see also the discussion
upstream:
https://lore.kernel.org/all/20241029163317.GA216411@nvidia.com/

Signed-off-by: Stoiko Ivanov <s.ivanov at proxmox.com>
---
 ...nable_acs-support-for-the-ACS-quirks.patch | 68 +++++++++++++++++++
 1 file changed, 68 insertions(+)
 create mode 100644 patches/kernel/0016-PCI-Fix-pci_enable_acs-support-for-the-ACS-quirks.patch

diff --git a/patches/kernel/0016-PCI-Fix-pci_enable_acs-support-for-the-ACS-quirks.patch b/patches/kernel/0016-PCI-Fix-pci_enable_acs-support-for-the-ACS-quirks.patch
new file mode 100644
index 000000000000..81123616f983
--- /dev/null
+++ b/patches/kernel/0016-PCI-Fix-pci_enable_acs-support-for-the-ACS-quirks.patch
@@ -0,0 +1,68 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Jason Gunthorpe <jgg at nvidia.com>
+Date: Wed, 16 Oct 2024 20:52:33 -0300
+Subject: [PATCH] PCI: Fix pci_enable_acs() support for the ACS quirks
+
+[ Upstream commit f3c3ccc4fe49dbc560b01d16bebd1b116c46c2b4 ]
+
+There are ACS quirks that hijack the normal ACS processing and deliver to
+to special quirk code. The enable path needs to call
+pci_dev_specific_enable_acs() and then pci_dev_specific_acs_enabled() will
+report the hidden ACS state controlled by the quirk.
+
+The recent rework got this out of order and we should try to call
+pci_dev_specific_enable_acs() regardless of any actual ACS support in the
+device.
+
+As before command line parameters that effect standard PCI ACS don't
+interact with the quirk versions, including the new config_acs= option.
+
+Link: https://lore.kernel.org/r/0-v1-f96b686c625b+124-pci_acs_quirk_fix_jgg@nvidia.com
+Fixes: 47c8846a49ba ("PCI: Extend ACS configurability")
+Reported-by: Jiri Slaby <jirislaby at kernel.org>
+Closes: https://lore.kernel.org/all/e89107da-ac99-4d3a-9527-a4df9986e120@kernel.org
+Closes: https://bugzilla.suse.com/show_bug.cgi?id=1229019
+Tested-by: Steffen Dirkwinkel <me at steffen.cc>
+Signed-off-by: Jason Gunthorpe <jgg at nvidia.com>
+Signed-off-by: Bjorn Helgaas <bhelgaas at google.com>
+Signed-off-by: Sasha Levin <sashal at kernel.org>
+(cherry picked from commit 8803132f857d1959f99c6ef98cf74776a52987e4)
+Signed-off-by: Stoiko Ivanov <s.ivanov at proxmox.com>
+---
+ drivers/pci/pci.c | 14 +++++++++-----
+ 1 file changed, 9 insertions(+), 5 deletions(-)
+
+diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
+index ffaaca0978cbc..a89436d481f07 100644
+--- a/drivers/pci/pci.c
++++ b/drivers/pci/pci.c
+@@ -1067,8 +1067,15 @@ static void pci_std_enable_acs(struct pci_dev *dev, struct pci_acs *caps)
+ static void pci_enable_acs(struct pci_dev *dev)
+ {
+ 	struct pci_acs caps;
++	bool enable_acs = false;
+ 	int pos;
+ 
++	/* If an iommu is present we start with kernel default caps */
++	if (pci_acs_enable) {
++		if (pci_dev_specific_enable_acs(dev))
++			enable_acs = true;
++	}
++
+ 	pos = dev->acs_cap;
+ 	if (!pos)
+ 		return;
+@@ -1077,11 +1084,8 @@ static void pci_enable_acs(struct pci_dev *dev)
+ 	pci_read_config_word(dev, pos + PCI_ACS_CTRL, &caps.ctrl);
+ 	caps.fw_ctrl = caps.ctrl;
+ 
+-	/* If an iommu is present we start with kernel default caps */
+-	if (pci_acs_enable) {
+-		if (pci_dev_specific_enable_acs(dev))
+-			pci_std_enable_acs(dev, &caps);
+-	}
++	if (enable_acs)
++		pci_std_enable_acs(dev, &caps);
+ 
+ 	/*
+ 	 * Always apply caps from the command line, even if there is no iommu.
-- 
2.39.5