linux-toradex.git/kernel/irq, branch v6.2-rc2

genirq/msi: Return MSI_XA_DOMAIN_SIZE as the maximum MSI index when no domain is present

2022-12-16T14:04:04+00:00

On architectures such as s390 that do not use irq domains for MSI,
returning 0 as the maximum MSI index is a bit counter-productive,
as it indicates that no MSI can be allocated. Bad idea.

Instead, return the maximum we're willing to support in the MSI
backing store (MSI_XA_DOMAIN_SIZE), and let the arch code do its
usual thing.

Thanks to Matthew Rosato for fixing the fix.

Reported-by: Guenter Roeck 
Signed-off-by: Thomas Gleixner 
[maz: commit message]
Signed-off-by: Marc Zyngier 
Link: https://lore.kernel.org/r/87fsdgzpqs.ffs@tglx

genirq/msi: Check for the presence of an irq domain when validating msi_ctrl

2022-12-16T13:27:18+00:00

For architectures such as s390 and powerpc that do not use
irq domains for MSIs, dev->msi.domain is always NULL, so
the per-device, per-bus MSI domain is also guaranteed to
be NULL.

So checking one without checking the other is bound to result
in a splat, followed by a memory leak as we don't free the MSI
descriptors.

Add the missing check.

Reported-by: Matthew Rosato 
Signed-off-by: Marc Zyngier 
Link: https://lore.kernel.org/r/e570e70d-19bc-101b-0481-ff9a3cab3504@linux.ibm.com

genirq/msi: Provide msi_domain_alloc_irq_at()

2022-12-05T21:22:34+00:00

For supporting post MSI-X enable allocations and for the upcoming PCI/IMS
support a separate interface is required which allows not only the
allocation of a specific index, but also the allocation of any, i.e. the
next free index. The latter is especially required for IMS because IMS
completely does away with index to functionality mappings which are
often found in MSI/MSI-X implementation.

But even with MSI-X there are devices where only the first few indices have
a fixed functionality and the rest is freely assignable by software,
e.g. to queues.

msi_domain_alloc_irq_at() is also different from the range based interfaces
as it always enforces that the MSI descriptor is allocated by the core code
and not preallocated by the caller like the PCI/MSI[-X] enable code path
does.

msi_domain_alloc_irq_at() can be invoked with the index argument set to
MSI_ANY_INDEX which makes the core code pick the next free index. The irq
domain can provide a prepare_desc() operation callback in it's
msi_domain_ops to do domain specific post allocation initialization before
the actual Linux interrupt and the associated interrupt descriptor and
hierarchy alloccations are conducted.

The function also takes an optional @icookie argument which is of type
union msi_instance_cookie. This cookie is not used by the core code and is
stored in the allocated msi_desc::data::icookie. The meaning of the cookie
is completely implementation defined. In case of IMS this might be a PASID
or a pointer to a device queue, but for the MSI core it's opaque and not
used in any way.

The function returns a struct msi_map which on success contains the
allocated index number and the Linux interrupt number so the caller can
spare the index to Linux interrupt number lookup.

On failure map::index contains the error code and map::virq is 0.

Signed-off-by: Thomas Gleixner 
Reviewed-by: Kevin Tian 
Acked-by: Marc Zyngier 
Link: https://lore.kernel.org/r/20221124232326.501359457@linutronix.de

genirq/msi: Provide msi_domain_ops:: Prepare_desc()

2022-12-05T21:22:33+00:00

The existing MSI domain ops msi_prepare() and set_desc() turned out to be
unsuitable for implementing IMS support.

msi_prepare() does not operate on the MSI descriptors. set_desc() lacks
an irq_domain pointer and has a completely different purpose.

Introduce a prepare_desc() op which allows IMS implementations to amend an
MSI descriptor which was allocated by the core code, e.g. by adjusting the
iomem base or adding some data based on the allocated index. This is way
better than requiring that all IMS domain implementations preallocate the
MSI descriptor and then allocate the interrupt.

Signed-off-by: Thomas Gleixner 
Reviewed-by: Kevin Tian 
Acked-by: Marc Zyngier 
Link: https://lore.kernel.org/r/20221124232326.444560717@linutronix.de

genirq/msi: Provide BUS_DEVICE_PCI_MSI[X]

2022-12-05T21:22:32+00:00

Provide new bus tokens for the upcoming per device PCI/MSI and PCI/MSIX
interrupt domains.

Signed-off-by: Thomas Gleixner 
Reviewed-by: Kevin Tian 
Acked-by: Marc Zyngier 
Link: https://lore.kernel.org/r/20221124232325.917219885@linutronix.de

genirq/msi: Add range checking to msi_insert_desc()

2022-12-05T21:22:32+00:00

Per device domains provide the real domain size to the core code. This
allows range checking on insertion of MSI descriptors and also paves the
way for dynamic index allocations which are required e.g. for IMS. This
avoids external mechanisms like bitmaps on the device side and just
utilizes the core internal MSI descriptor storxe for it.

Signed-off-by: Thomas Gleixner 
Reviewed-by: Kevin Tian 
Acked-by: Marc Zyngier 
Link: https://lore.kernel.org/r/20221124232325.798556374@linutronix.de

genirq/msi: Provide msi_match_device_domain()

2022-12-05T18:21:01+00:00

Provide an interface to match a per device domain bus token. This allows to
query which type of domain is installed for a particular domain id. Will be
used for PCI to avoid frequent create/remove cycles for the MSI resp. MSI-X
domains.

Signed-off-by: Thomas Gleixner 
Reviewed-by: Kevin Tian 
Acked-by: Marc Zyngier 
Link: https://lore.kernel.org/r/20221124232325.738047902@linutronix.de

genirq/msi: Provide msi_create/free_device_irq_domain()

2022-12-05T18:21:01+00:00

Now that all prerequsites are in place, provide the actual interfaces for
creating and removing per device interrupt domains.

MSI device interrupt domains are created from the provided
msi_domain_template which is duplicated so that it can be modified for the
particular device.

The name of the domain and the name of the interrupt chip are composed by
"$(PREFIX)$(CHIPNAME)-$(DEVNAME)"

  $PREFIX:   The optional prefix provided by the underlying MSI parent domain
             via msi_parent_ops::prefix.
  $CHIPNAME: The name of the irq_chip in the template
  $DEVNAME:  The name of the device

The domain is further initialized through a MSI parent domain callback which
fills in the required functionality for the parent domain or domains further
down the hierarchy. This initialization can fail, e.g. when the requested
feature or MSI domain type cannot be supported.

The domain pointer is stored in the pointer array inside of msi_device_data
which is attached to the domain.

The domain can be removed via the API or left for disposal via devres when
the device is torn down. The API removal is useful e.g. for PCI to have
seperate domains for MSI and MSI-X, which are mutually exclusive and always
occupy the default domain id slot.

Signed-off-by: Thomas Gleixner 
Reviewed-by: Kevin Tian 
Acked-by: Marc Zyngier 
Link: https://lore.kernel.org/r/20221124232325.678838546@linutronix.de

genirq/msi: Split msi_create_irq_domain()

2022-12-05T18:21:01+00:00

Split the functionality of msi_create_irq_domain() so it can
be reused for creating per device irq domains.

No functional change.

Signed-off-by: Thomas Gleixner 
Reviewed-by: Kevin Tian 
Acked-by: Marc Zyngier 
Link: https://lore.kernel.org/r/20221124232325.559086358@linutronix.de

genirq/msi: Add size info to struct msi_domain_info

2022-12-05T18:21:01+00:00

To allow proper range checking especially for dynamic allocations add a
size field to struct msi_domain_info. If the field is 0 then the size is
unknown or unlimited (up to MSI_MAX_INDEX) to provide backwards
compability.

Signed-off-by: Thomas Gleixner 
Reviewed-by: Kevin Tian 
Acked-by: Marc Zyngier 
Link: https://lore.kernel.org/r/20221124232325.501144862@linutronix.de