linux-stable.git/kernel/irq/msi.c, branch linux-6.1.y

x86/apic/msi: Fix misconfigured non-maskable MSI quirk

2023-12-08T07:51:20+00:00

commit b56ebe7c896dc78b5865ec2c4b1dae3c93537517 upstream.

commit ef8dd01538ea ("genirq/msi: Make interrupt allocation less
convoluted"), reworked the code so that the x86 specific quirk for affinity
setting of non-maskable PCI/MSI interrupts is not longer activated if
necessary.

This could be solved by restoring the original logic in the core MSI code,
but after a deeper analysis it turned out that the quirk flag is not
required at all.

The quirk is only required when the PCI/MSI device cannot mask the MSI
interrupts, which in turn also prevents reservation mode from being enabled
for the affected interrupt.

This allows ot remove the NOMASK quirk bit completely as msi_set_affinity()
can instead check whether reservation mode is enabled for the interrupt,
which gives exactly the same answer.

Even in the momentary non-existing case that the reservation mode would be
not set for a maskable MSI interrupt this would not cause any harm as it
just would cause msi_set_affinity() to go needlessly through the
functionaly equivalent slow path, which works perfectly fine with maskable
interrupts as well.

Rework msi_set_affinity() to query the reservation mode and remove all
NOMASK quirk logic from the core code.

[ tglx: Massaged changelog ]

Fixes: ef8dd01538ea ("genirq/msi: Make interrupt allocation less convoluted")
Suggested-by: Thomas Gleixner 
Signed-off-by: Koichiro Den 
Signed-off-by: Thomas Gleixner 
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20231026032036.2462428-1-den@valinux.co.jp
Signed-off-by: Greg Kroah-Hartman

x86/pci/xen: populate MSI sysfs entries

2023-05-30T13:03:22+00:00

commit 335b4223466dd75f9f3ea4918187afbadd22e5c8 upstream.

Commit bf5e758f02fc ("genirq/msi: Simplify sysfs handling") reworked the
creation of sysfs entries for MSI IRQs. The creation used to be in
msi_domain_alloc_irqs_descs_locked after calling ops->domain_alloc_irqs.
Then it moved into __msi_domain_alloc_irqs which is an implementation of
domain_alloc_irqs. However, Xen comes with the only other implementation
of domain_alloc_irqs and hence doesn't run the sysfs population code
anymore.

Commit 6c796996ee70 ("x86/pci/xen: Fixup fallout from the PCI/MSI
overhaul") set the flag MSI_FLAG_DEV_SYSFS for the xen msi_domain_info
but that doesn't actually have an effect because Xen uses it's own
domain_alloc_irqs implementation.

Fix this by making use of the fallback functions for sysfs population.

Fixes: bf5e758f02fc ("genirq/msi: Simplify sysfs handling")
Signed-off-by: Maximilian Heyne 
Reviewed-by: Juergen Gross 
Link: https://lore.kernel.org/r/20230503131656.15928-1-mheyne@amazon.de
Signed-off-by: Juergen Gross 
Signed-off-by: Greg Kroah-Hartman

genirq/msi: Shutdown managed interrupts with unsatifiable affinities

2022-04-10T19:06:30+00:00

When booting with maxcpus=, interrupt controllers
such as the GICv3 ITS may not be able to satisfy the affinity of
some managed interrupts, as some of the HW resources are simply
not available.

The same thing happens when loading a driver using managed interrupts
while CPUs are offline.

In order to deal with this, do not try to activate such interrupt
if there is no online CPU capable of handling it. Instead, place
it in shutdown state. Once a capable CPU shows up, it will be
activated.

Reported-by: John Garry 
Reported-by: David Decotigny 
Signed-off-by: Marc Zyngier 
Signed-off-by: Thomas Gleixner 
Tested-by: John Garry 
Link: https://lore.kernel.org/r/20220405185040.206297-2-maz@kernel.org

genirq/msi: Populate sysfs entry only once

2022-01-10T18:22:10+00:00

The MSI entries for multi-MSI are populated en bloc for the MSI descriptor,
but the current code invokes the population inside the per interrupt loop
which triggers a warning in the sysfs code and causes the interrupt
allocation to fail.

Move it outside of the loop so it works correctly for single and multi-MSI.

Fixes: bf5e758f02fc ("genirq/msi: Simplify sysfs handling")
Reported-by: Borislav Petkov 
Signed-off-by: Thomas Gleixner 
Tested-by: Borislav Petkov 
Link: https://lore.kernel.org/r/87leznqx2a.ffs@tglx

genirq/msi: Convert storage to xarray

2021-12-16T21:22:20+00:00

The current linked list storage for MSI descriptors is suboptimal in
several ways:

  1) Looking up a MSI desciptor requires a O(n) list walk in the worst case

  2) The upcoming support of runtime expansion of MSI-X vectors would need
     to do a full list walk to figure out whether a particular index is
     already associated.

  3) Runtime expansion of sparse allocations is even more complex as the
     current implementation assumes an ordered list (increasing MSI index).

Use an xarray which solves all of the above problems nicely.

Signed-off-by: Thomas Gleixner 
Tested-by: Michael Kelley 
Tested-by: Nishanth Menon 
Reviewed-by: Greg Kroah-Hartman 
Reviewed-by: Jason Gunthorpe 
Link: https://lore.kernel.org/r/20211206210749.280627070@linutronix.de

genirq/msi: Simplify sysfs handling

2021-12-16T21:22:20+00:00

The sysfs handling for MSI is a convoluted maze and it is in the way of
supporting dynamic expansion of the MSI-X vectors because it only supports
a one off bulk population/free of the sysfs entries.

Change it to do:

   1) Creating an empty sysfs attribute group when msi_device_data is
      allocated

   2) Populate the entries when the MSI descriptor is initialized

   3) Free the entries when a MSI descriptor is detached from a Linux
      interrupt.

   4) Provide functions for the legacy non-irqdomain fallback code to
      do a bulk population/free. This code won't support dynamic
      expansion.

This makes the code simpler and reduces the number of allocations as the
empty attribute group can be shared.

Signed-off-by: Thomas Gleixner 
Tested-by: Michael Kelley 
Tested-by: Nishanth Menon 
Reviewed-by: Greg Kroah-Hartman 
Reviewed-by: Jason Gunthorpe 
Link: https://lore.kernel.org/r/20211206210749.224917330@linutronix.de

genirq/msi: Mop up old interfaces

2021-12-16T21:22:20+00:00

Get rid of the old iterators, alloc/free functions and adjust the core code
accordingly.

Signed-off-by: Thomas Gleixner 
Tested-by: Michael Kelley 
Tested-by: Nishanth Menon 
Reviewed-by: Jason Gunthorpe 
Link: https://lore.kernel.org/r/20211206210749.117395027@linutronix.de

genirq/msi: Convert to new functions

2021-12-16T21:22:20+00:00

Use the new iterator functions and add locking where required.

Signed-off-by: Thomas Gleixner 
Tested-by: Michael Kelley 
Tested-by: Nishanth Menon 
Reviewed-by: Jason Gunthorpe 
Link: https://lore.kernel.org/r/20211206210749.063705667@linutronix.de

genirq/msi: Make interrupt allocation less convoluted

2021-12-16T21:22:20+00:00

There is no real reason to do several loops over the MSI descriptors
instead of just doing one loop. In case of an error everything is undone
anyway so it does not matter whether it's a partial or a full rollback.

Signed-off-by: Thomas Gleixner 
Tested-by: Michael Kelley 
Tested-by: Nishanth Menon 
Reviewed-by: Jason Gunthorpe 
Link: https://lore.kernel.org/r/20211206210749.010234767@linutronix.de

platform-msi: Simplify platform device MSI code

2021-12-16T21:22:19+00:00

The allocation code is overly complex. It tries to have the MSI index space
packed, which is not working when an interrupt is freed. There is no
requirement for this. The only requirement is that the MSI index is unique.

Move the MSI descriptor allocation into msi_domain_populate_irqs() and use
the Linux interrupt number as MSI index which fulfils the unique
requirement.

This requires to lock the MSI descriptors which makes the lock order
reverse to the regular MSI alloc/free functions vs. the domain
mutex. Assign a seperate lockdep class for these MSI device domains.

Signed-off-by: Thomas Gleixner 
Tested-by: Nishanth Menon 
Reviewed-by: Jason Gunthorpe 
Link: https://lore.kernel.org/r/20211206210748.956731741@linutronix.de