diff options
| author | Thomas Gleixner <tglx@linutronix.de> | 2022-11-25 00:26:24 +0100 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2022-12-05 22:22:34 +0100 |
| commit | 34026364df8eca05ee32e706a2c014511a19af02 (patch) | |
| tree | 149fb12fa7947b157f1ff25313ca07c6884754b3 /include/linux/pci.h | |
| parent | 73bd063ca03493f44e0700cc08824093da9741bc (diff) | |
| download | linux-34026364df8eca05ee32e706a2c014511a19af02.tar.bz2 | |
PCI/MSI: Provide post-enable dynamic allocation interfaces for MSI-X
MSI-X vectors can be allocated after the initial MSI-X enablement, but this
needs explicit support of the underlying interrupt domains.
Provide a function to query the ability and functions to allocate/free
individual vectors post-enable.
The allocation can either request a specific index in the MSI-X table or
with the index argument MSI_ANY_INDEX it allocates the next free vector.
The return value is a struct msi_map which on success contains both index
and the Linux interrupt number. In case of failure index is negative and
the Linux interrupt number is 0.
The allocation function is for a single MSI-X index at a time as that's
sufficient for the most urgent use case VFIO to get rid of the 'disable
MSI-X, reallocate, enable-MSI-X' cycle which is prone to lost interrupts
and redirections to the legacy and obviously unhandled INTx.
As single index allocation is also sufficient for the use cases Jason
Gunthorpe pointed out: Allocation of a MSI-X or IMS vector for a network
queue. See Link below.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/all/20211126232735.547996838@linutronix.de
Link: https://lore.kernel.org/r/20221124232326.731233614@linutronix.de
Diffstat (limited to 'include/linux/pci.h')
| -rw-r--r-- | include/linux/pci.h | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/include/linux/pci.h b/include/linux/pci.h index 243e48f79e82..68b14ba93df2 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -38,6 +38,7 @@ #include <linux/interrupt.h> #include <linux/io.h> #include <linux/resource_ext.h> +#include <linux/msi_api.h> #include <uapi/linux/pci.h> #include <linux/pci_ids.h> @@ -1559,6 +1560,11 @@ int pci_alloc_irq_vectors_affinity(struct pci_dev *dev, unsigned int min_vecs, unsigned int max_vecs, unsigned int flags, struct irq_affinity *affd); +bool pci_msix_can_alloc_dyn(struct pci_dev *dev); +struct msi_map pci_msix_alloc_irq_at(struct pci_dev *dev, unsigned int index, + const struct irq_affinity_desc *affdesc); +void pci_msix_free_irq(struct pci_dev *pdev, struct msi_map map); + void pci_free_irq_vectors(struct pci_dev *dev); int pci_irq_vector(struct pci_dev *dev, unsigned int nr); const struct cpumask *pci_irq_get_affinity(struct pci_dev *pdev, int vec); |