kernel.git/drivers/pci/msi, branch linux-6.16.y

PCI/MSI: Prevent recursive locking in pci_msix_write_tph_tag()

2025-07-10T21:41:08Z

pci_msix_write_tph_tag() takes the per device MSI descriptor mutex and then invokes msi_domain_get_virq(), which takes the same mutex again. That obviously results in a system hang which is exposed by a softlockup or lockdep warning. Move the lock guard after the invocation of msi_domain_get_virq() to fix this. [ tglx: Massage changelog by adding a proper explanation and removing the not really useful stacktrace ] Fixes: d5124a9957b2 ("PCI/MSI: Provide a sane mechanism for TPH") Reported-by: Jorge Lopez Suggested-by: Thomas Gleixner Signed-off-by: Himanshu Madhani Signed-off-by: Thomas Gleixner Tested-by: Jorge Lopez Link: https://lore.kernel.org/all/20250708222530.1041477-1-himanshu.madhani@oracle.com

PCI/MSI: Size device MSI domain with the maximum number of vectors

2025-06-04T09:19:25Z

Zenghui reports that since 1396e89e09f0 ("genirq/msi: Move prepare() call to per-device allocation"), his Multi-MSI capable device isn't working anymore. This is a consequence of 15c72f824b32 ("PCI/MSI: Add support for per device MSI[X] domains"), which always creates a MSI domain of size 1, even in the presence of Multi-MSI. While this was somehow working until then, moving the .prepare() call ends up sizing the ITS table with a tiny value for this device, and making the endpoint driver unhappy. Instead, always create the domain and call the .prepare() helper with the maximum expected size. Fixes: 1396e89e09f0 ("genirq/msi: Move prepare() call to per-device allocation") Fixes: 15c72f824b32 ("PCI/MSI: Add support for per device MSI[X] domains") Reported-by: Zenghui Yu Signed-off-by: Marc Zyngier Signed-off-by: Thomas Gleixner Tested-by: Zenghui Yu Reviewed-by: Lorenzo Pieralisi Link: https://lore.kernel.org/all/20250603141801.915305-1-maz@kernel.org Closes: https://lore.kernel.org/r/0b1d7aec-1eac-a9cd-502a-339e216e08a1@huawei.com

Merge tag 'irq-msi-2025-05-25' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2025-05-27T15:15:26Z

Pull MSI updates from Thomas Gleixner: "Updates for the MSI subsystem (core code and PCI): - Switch the MSI descriptor locking to lock guards - Replace a broken and naive implementation of PCI/MSI-X control word updates in the PCI/TPH driver with a properly serialized variant in the PCI/MSI core code. - Remove the MSI descriptor abuse in the SCCI/UFS/QCOM driver by replacing the direct access to the MSI descriptors with the proper API function calls. People will never understand that APIs exist for a reason... - Provide core infrastructre for the upcoming PCI endpoint library extensions. Currently limited to ARM GICv3+, but in theory extensible to other architectures. - Provide a MSI domain::teardown() callback, which allows drivers to undo the effects of the prepare() callback. - Move the MSI domain::prepare() callback invocation to domain creation time to avoid redundant (and in case of ARM/GIC-V3-ITS confusing) invocations on every allocation. In combination with the new teardown callback this removes some ugly hacks in the GIC-V3-ITS driver, which pretended to work around the short comings of the core code so far. With this update the code is correct by design and implementation. - Make the irqchip MSI library globally available, provide a MSI parent domain creation helper and convert a bunch of (PCI/)MSI drivers over to the modern MSI parent mechanism. This is the first step to get rid of at least one incarnation of the three PCI/MSI management schemes. - The usual small cleanups and improvements" * tag 'irq-msi-2025-05-25' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (33 commits) PCI/MSI: Use bool for MSI enable state tracking PCI: tegra: Convert to MSI parent infrastructure PCI: xgene: Convert to MSI parent infrastructure PCI: apple: Convert to MSI parent infrastructure irqchip/msi-lib: Honour the MSI_FLAG_NO_AFFINITY flag irqchip/mvebu: Convert to msi_create_parent_irq_domain() helper irqchip/gic: Convert to msi_create_parent_irq_domain() helper genirq/msi: Add helper for creating MSI-parent irq domains irqchip: Make irq-msi-lib.h globally available irqchip/gic-v3-its: Use allocation size from the prepare call genirq/msi: Engage the .msi_teardown() callback on domain removal genirq/msi: Move prepare() call to per-device allocation irqchip/gic-v3-its: Implement .msi_teardown() callback genirq/msi: Add .msi_teardown() callback as the reverse of .msi_prepare() irqchip/gic-v3-its: Add support for device tree msi-map and msi-mask dt-bindings: PCI: pci-ep: Add support for iommu-map and msi-map irqchip/gic-v3-its: Set IRQ_DOMAIN_FLAG_MSI_IMMUTABLE for ITS irqdomain: Add IRQ_DOMAIN_FLAG_MSI_IMMUTABLE and irq_domain_is_msi_immutable() platform-msi: Add msi_remove_device_irq_domain() in platform_device_msi_free_irqs_all() genirq/msi: Rename msi_[un]lock_descs() ...

PCI/MSI: Use bool for MSI enable state tracking

2025-05-21T19:28:53Z

Convert pci_msi_enable and pci_msi_enabled() to use bool type for clarity. No functional changes, only code cleanup. Signed-off-by: Hans Zhang Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/all/20250516165223.125083-2-18255117159@163.com

PCI/MSI: Add an option to write MSIX ENTRY_DATA before any reads

2025-04-15T06:32:18Z

Commit 7d5ec3d36123 ("PCI/MSI: Mask all unused MSI-X entries") introduced a readl() from ENTRY_VECTOR_CTRL before the writel() to ENTRY_DATA. This is correct, however some hardware, like the Sun Neptune chips, the NIU module, will cause an error and/or fatal trap if any MSIX table entry is read before the corresponding ENTRY_DATA field is written to. Add an optional early writel() in msix_prepare_msi_desc(). Fixes: 7d5ec3d36123 ("PCI/MSI: Mask all unused MSI-X entries") Signed-off-by: Jonathan Currier Signed-off-by: Thomas Gleixner Cc: stable@vger.kernel.org Link: https://lore.kernel.org/all/20241117234843.19236-2-dullfire@yahoo.com

PCI/MSI: Provide a sane mechanism for TPH

2025-04-09T18:47:30Z

The PCI/TPH driver fiddles with the MSI-X control word of an active interrupt completely unserialized against concurrent operations issued from the interrupt core. It also brings the PCI/MSI-X internal cached control word out of sync. Provide a function, which has the required serialization and keeps the control word cache in sync. Unfortunately this requires to look up and lock the interrupt descriptor, which should be only done in the interrupt core code. But confining this particular oddity in the PCI/MSI core is the lesser of all evil. A interrupt core implementation would require a larger pile of infrastructure and indirections for dubious value. Signed-off-by: Thomas Gleixner Acked-by: Bjorn Helgaas Link: https://lore.kernel.org/all/20250319105506.683663807@linutronix.de

PCI/MSI: Switch msix_capability_init() to guard(msi_desc_lock)

2025-04-09T18:47:30Z

Split the lock protected functionality of msix_capability_init() out into a helper function and use guard(msi_desc_lock) to replace the lock/unlock pair. Simplify the error path in the helper function by utilizing a custom cleanup to get rid of the remaining gotos. No functional change intended. Signed-off-by: Thomas Gleixner Acked-by: Bjorn Helgaas Link: https://lore.kernel.org/all/20250319105506.564105011@linutronix.de

PCI/MSI: Switch msi_capability_init() to guard(msi_desc_lock)

2025-04-09T18:47:30Z

Split the lock protected functionality of msi_capability_init() out into a helper function and use guard(msi_desc_lock) to replace the lock/unlock pair. No functional change intended. Signed-off-by: Thomas Gleixner Acked-by: Bjorn Helgaas Link: https://lore.kernel.org/all/20250319105506.504992208@linutronix.de

PCI/MSI: Use __free() for affinity masks

2025-04-09T18:47:30Z

Let cleanup handle the freeing of the affinity mask. That prepares for switching the MSI descriptor locking to a guard(). No functional change. Signed-off-by: Thomas Gleixner Acked-by: Bjorn Helgaas Link: https://lore.kernel.org/all/20250319105506.444764312@linutronix.de

PCI/MSI: Set pci_dev:: Msi_enabled late

2025-04-09T18:47:29Z

The comment claiming that pci_dev::msi_enabled has to be set across setup is a leftover from ancient code versions. Nothing in the setup code requires the flag to be set anymore. Set it in the success path and remove the extra goto label. Signed-off-by: Thomas Gleixner Acked-by: Bjorn Helgaas Link: https://lore.kernel.org/all/20250319105506.383222333@linutronix.de