This is a note to let you know that I've just added the patch titled
PCI/MSI: Deal with devices lying about their MSI mask capability
to the 4.19-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-msi-deal-with-devices-lying-about-their-msi-mask-capability.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 2226667a145db2e1f314d7f57fd644fe69863ab9 Mon Sep 17 00:00:00 2001
From: Marc Zyngier <maz@xxxxxxxxxx>
Date: Thu, 4 Nov 2021 18:01:29 +0000
Subject: PCI/MSI: Deal with devices lying about their MSI mask capability
From: Marc Zyngier <maz@xxxxxxxxxx>
commit 2226667a145db2e1f314d7f57fd644fe69863ab9 upstream.
It appears that some devices are lying about their mask capability,
pretending that they don't have it, while they actually do.
The net result is that now that we don't enable MSIs on such
endpoint.
Add a new per-device flag to deal with this. Further patches will
make use of it, sadly.
Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Reviewed-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20211104180130.3825416-2-maz@xxxxxxxxxx
Cc: Bjorn Helgaas <helgaas@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/pci/msi.c | 3 +++
include/linux/pci.h | 2 ++
2 files changed, 5 insertions(+)
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -569,6 +569,9 @@ msi_setup_entry(struct pci_dev *dev, int
goto out;
pci_read_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS, &control);
+ /* Lies, damned lies, and MSIs */
+ if (dev->dev_flags & PCI_DEV_FLAGS_HAS_MSI_MASKING)
+ control |= PCI_MSI_FLAGS_MASKBIT;
entry->msi_attrib.is_msix = 0;
entry->msi_attrib.is_64 = !!(control & PCI_MSI_FLAGS_64BIT);
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -205,6 +205,8 @@ enum pci_dev_flags {
PCI_DEV_FLAGS_NO_FLR_RESET = (__force pci_dev_flags_t) (1 << 10),
/* Don't use Relaxed Ordering for TLPs directed at this device */
PCI_DEV_FLAGS_NO_RELAXED_ORDERING = (__force pci_dev_flags_t) (1 << 11),
+ /* Device does honor MSI masking despite saying otherwise */
+ PCI_DEV_FLAGS_HAS_MSI_MASKING = (__force pci_dev_flags_t) (1 << 12),
};
enum pci_irq_reroute_variant {
Patches currently in stable-queue which might be from maz@xxxxxxxxxx are
queue-4.19/pci-add-msi-masking-quirk-for-nvidia-ion-ahci.patch
queue-4.19/pci-msi-deal-with-devices-lying-about-their-msi-mask-capability.patch
queue-4.19/irq-mips-avoid-nested-irq_enter.patch
