[RFCv1,6/7] PCI/MSI: Add pci_alloc_irq_vectors_iovas helper

Commit Message

Nicolin Chen Nov. 9, 2024, 5:48 a.m. UTC

Now, the common __pci_alloc_irq_vectors() accepts an array of msi_iovas,
which is a list of preset IOVAs for MSI doorbell addresses.

Add a helper that would pass in a list. A following patch will call this
to forward msi_iovas from user space.

Signed-off-by: Nicolin Chen <[e-mail]>
---
 include/linux/pci.h   | 17 +++++++++++++++++
 drivers/pci/msi/api.c | 21 +++++++++++++++++++++
 2 files changed, 38 insertions(+)

Comments

Andy Shevchenko Nov. 11, 2024, 9:34 a.m. UTC | #1

On Fri, Nov 08, 2024 at 09:48:51PM -0800, Nicolin Chen wrote:
> Now, the common __pci_alloc_irq_vectors() accepts an array of msi_iovas,
> which is a list of preset IOVAs for MSI doorbell addresses.
> 
> Add a helper that would pass in a list. A following patch will call this
> to forward msi_iovas from user space.

...

> +/**
> + * pci_alloc_irq_vectors_iovas() - Allocate multiple device interrupt
> + *                                 vectors with preset msi_iovas
> + * @dev:       the PCI device to operate on
> + * @min_vecs:  minimum required number of vectors (must be >= 1)
> + * @max_vecs:  maximum desired number of vectors
> + * @flags:     allocation flags, as in pci_alloc_irq_vectors()
> + * @msi_iovas: list of IOVAs for MSI between [min_vecs, max_vecs]
> + *
> + * Same as pci_alloc_irq_vectors(), but with the extra @msi_iovas parameter.
> + * Check that function docs, and &struct irq_affinity, for more details.
> + */

Always validate your kernel-doc descriptions

	scripts/kernel-doc -Wall -none -v ...

will give you a warning here.

Patch

diff --git a/include/linux/pci.h b/include/linux/pci.h
index 68ebb9d42f7f..6423bee3b207 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1678,6 +1678,9 @@  int pci_alloc_irq_vectors(struct pci_dev *dev, unsigned int min_vecs,
 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);
+int pci_alloc_irq_vectors_iovas(struct pci_dev *dev, unsigned int min_vecs,
+				unsigned int max_vecs, unsigned int flags,
+				dma_addr_t *msi_iovas);
 
 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,
@@ -1714,6 +1717,13 @@  pci_alloc_irq_vectors_affinity(struct pci_dev *dev, unsigned int min_vecs,
 	return -ENOSPC;
 }
 static inline int
+pci_alloc_irq_vectors_iovas(struct pci_dev *dev, unsigned int min_vecs,
+			    unsigned int max_vecs, unsigned int flags,
+			    dma_addr_t *msi_iovas)
+
+	return -ENOSPC; /* No support if !CONFIG_PCI_MSI */
+}
+static inline int
 pci_alloc_irq_vectors(struct pci_dev *dev, unsigned int min_vecs,
 		      unsigned int max_vecs, unsigned int flags)
 {
@@ -2068,6 +2078,13 @@  pci_alloc_irq_vectors_affinity(struct pci_dev *dev, unsigned int min_vecs,
 	return -ENOSPC;
 }
 static inline int
+pci_alloc_irq_vectors_iovas(struct pci_dev *dev, unsigned int min_vecs,
+			    unsigned int max_vecs, unsigned int flags,
+			    dma_addr_t *msi_iovas)
+{
+	return -ENOSPC;
+}
+static inline int
 pci_alloc_irq_vectors(struct pci_dev *dev, unsigned int min_vecs,
 		      unsigned int max_vecs, unsigned int flags)
 {
diff --git a/drivers/pci/msi/api.c b/drivers/pci/msi/api.c
index dff3d7350b38..4e90ef8f571c 100644
--- a/drivers/pci/msi/api.c
+++ b/drivers/pci/msi/api.c
@@ -327,6 +327,27 @@  int pci_alloc_irq_vectors_affinity(struct pci_dev *dev, unsigned int min_vecs,
 }
 EXPORT_SYMBOL(pci_alloc_irq_vectors_affinity);
 
+/**
+ * pci_alloc_irq_vectors_iovas() - Allocate multiple device interrupt
+ *                                 vectors with preset msi_iovas
+ * @dev:       the PCI device to operate on
+ * @min_vecs:  minimum required number of vectors (must be >= 1)
+ * @max_vecs:  maximum desired number of vectors
+ * @flags:     allocation flags, as in pci_alloc_irq_vectors()
+ * @msi_iovas: list of IOVAs for MSI between [min_vecs, max_vecs]
+ *
+ * Same as pci_alloc_irq_vectors(), but with the extra @msi_iovas parameter.
+ * Check that function docs, and &struct irq_affinity, for more details.
+ */
+int pci_alloc_irq_vectors_iovas(struct pci_dev *dev, unsigned int min_vecs,
+				unsigned int max_vecs, unsigned int flags,
+				dma_addr_t *msi_iovas)
+{
+	return __pci_alloc_irq_vectors(dev, min_vecs, max_vecs,
+				       flags, NULL, msi_iovas);
+}
+EXPORT_SYMBOL(pci_alloc_irq_vectors_iovas);
+
 /**
  * pci_irq_vector() - Get Linux IRQ number of a device interrupt vector
  * @dev: the PCI device to operate on