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PCI/MSI: Provide MSI_FLAG_MSIX_CONTIGUOUS
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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 <tglx@linutronix.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/r/20211210221814.662401116@linutronix.de
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Thomas Gleixner committed Dec 16, 2021
1 parent 173ffad commit 7a82344
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Showing 2 changed files with 16 additions and 2 deletions.
16 changes: 14 additions & 2 deletions drivers/pci/msi/irqdomain.c
Original file line number Diff line number Diff line change
Expand Up @@ -89,9 +89,21 @@ static int pci_msi_domain_check_cap(struct irq_domain *domain,
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;
}

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2 changes: 2 additions & 0 deletions include/linux/msi.h
Original file line number Diff line number Diff line change
Expand Up @@ -362,6 +362,8 @@ 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,
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