[V3,24/35] PCI/MSI: Provide MSI_FLAG_MSIX_CONTIGUOUS

Commit Message

Thomas Gleixner Dec. 10, 2021, 10:19 p.m. UTC

From: Thomas Gleixner <[e-mail]>

Provide a domain info flag which makes the core code check for a contiguous
MSI-X index on allocation. That's simpler than checking it at some other
domain callback in architecture code.

Signed-off-by: Thomas Gleixner <[e-mail]>
Reviewed-by: Greg Kroah-Hartman <[e-mail]>
Reviewed-by: Jason Gunthorpe <[e-mail]>
Acked-by: Bjorn Helgaas <[e-mail]>

---
 drivers/pci/msi/irqdomain.c |   16 ++++++++++++++--
 include/linux/msi.h         |    2 ++
 2 files changed, 16 insertions(+), 2 deletions(-)

Patch

--- a/drivers/pci/msi/irqdomain.c
+++ b/drivers/pci/msi/irqdomain.c
@@ -89,9 +89,21 @@  static int pci_msi_domain_check_cap(stru
 	if (pci_msi_desc_is_multi_msi(desc) &&
 	    !(info->flags & MSI_FLAG_MULTI_PCI_MSI))
 		return 1;
-	else if (desc->pci.msi_attrib.is_msix && !(info->flags & MSI_FLAG_PCI_MSIX))
-		return -ENOTSUPP;
 
+	if (desc->pci.msi_attrib.is_msix) {
+		if (!(info->flags & MSI_FLAG_PCI_MSIX))
+			return -ENOTSUPP;
+
+		if (info->flags & MSI_FLAG_MSIX_CONTIGUOUS) {
+			unsigned int idx = 0;
+
+			/* Check for gaps in the entry indices */
+			for_each_msi_entry(desc, dev) {
+				if (desc->msi_index != idx++)
+					return -ENOTSUPP;
+			}
+		}
+	}
 	return 0;
 }
 
--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -361,6 +361,8 @@  enum {
 	MSI_FLAG_LEVEL_CAPABLE		= (1 << 6),
 	/* Populate sysfs on alloc() and destroy it on free() */
 	MSI_FLAG_DEV_SYSFS		= (1 << 7),
+	/* MSI-X entries must be contiguous */
+	MSI_FLAG_MSIX_CONTIGUOUS	= (1 << 8),
 };
 
 int msi_domain_set_affinity(struct irq_data *data, const struct cpumask *mask,