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Filename Latest commit message Latest commit date
Thomas Gleixner 3b4220c2bf PCI/MSI: Enable and mask MSI-X early
commit 438553958ba19296663c6d6583d208dfb6792830 upstream.

The ordering of MSI-X enable in hardware is dysfunctional:

 1) MSI-X is disabled in the control register
 2) Various setup functions
 3) pci_msi_setup_msi_irqs() is invoked which ends up accessing
    the MSI-X table entries
 4) MSI-X is enabled and masked in the control register with the
    comment that enabling is required for some hardware to access
    the MSI-X table

Step #4 obviously contradicts #3. The history of this is an issue with the
NIU hardware. When #4 was introduced the table access actually happened in
msix_program_entries() which was invoked after enabling and masking MSI-X.

This was changed in commit d71d6432e1 ("PCI/MSI: Kill redundant call of
irq_set_msi_desc() for MSI-X interrupts") which removed the table write
from msix_program_entries().

Interestingly enough nobody noticed and either NIU still works or it did
not get any testing with a kernel 3.19 or later.

Nevertheless this is inconsistent and there is no reason why MSI-X can't be
enabled and masked in the control register early on, i.e. move step #4
above to step #1. This preserves the NIU workaround and has no side effects
on other hardware.

Fixes: d71d6432e1 ("PCI/MSI: Kill redundant call of irq_set_msi_desc() for MSI-X interrupts")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Ashok Raj <ashok.raj@intel.com>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210729222542.344136412@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-08-18 08:57:02 +02:00
arch x86/resctrl: Fix default monitoring groups reporting 2021-08-18 08:57:02 +02:00
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drivers PCI/MSI: Enable and mask MSI-X early 2021-08-18 08:57:02 +02:00
fs ceph: reduce contention in ceph_check_delayed_caps() 2021-08-18 08:56:57 +02:00
include genirq: Provide IRQCHIP_AFFINITY_PRE_STARTUP 2021-08-18 08:57:02 +02:00
init
ipc
kernel genirq/timings: Prevent potential array overflow in __irq_timings_store() 2021-08-18 08:57:02 +02:00
lib
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net vsock/virtio: avoid potential deadlock when vsock device remove 2021-08-18 08:57:01 +02:00
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sound ASoC: cs42l42: Fix LRCLK frame start edge 2021-08-18 08:56:58 +02:00
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Makefile Linux 5.4.141 2021-08-15 13:08:06 +02:00
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    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.