Date:   Thu, 16 Dec 2021 21:40:54 -0000
From:   "tip-bot2 for Thomas Gleixner" <tip-bot2@linutronix.de>
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To:     linux-tip-commits@vger.kernel.org
Subject: [tip: irq/msi] PCI/MSI: Provide MSI_FLAG_MSIX_CONTIGUOUS
Cc:     Thomas Gleixner <tglx@linutronix.de>,
        "Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
        Jason Gunthorpe <jgg@nvidia.com>,
        Bjorn Helgaas <bhelgaas@google.com>, x86@kernel.org,
        linux-kernel@vger.kernel.org
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The following commit has been merged into the irq/msi branch of tip:

Commit-ID:     7a823443e9b4ed1ff4a3026d184f09d23fd6d9c9
Gitweb:        https://git.kernel.org/tip/7a823443e9b4ed1ff4a3026d184f09d23fd6d9c9
Author:        Thomas Gleixner <tglx@linutronix.de>
AuthorDate:    Fri, 10 Dec 2021 23:19:20 +01:00
Committer:     Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Thu, 16 Dec 2021 22:16:40 +01:00

PCI/MSI: Provide MSI_FLAG_MSIX_CONTIGUOUS

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


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

diff --git a/drivers/pci/msi/irqdomain.c b/drivers/pci/msi/irqdomain.c
index 4224202..180b2a1 100644
--- a/drivers/pci/msi/irqdomain.c
+++ b/drivers/pci/msi/irqdomain.c
@@ -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;
 }
 
diff --git a/include/linux/msi.h b/include/linux/msi.h
index b3d3b0b..d206239 100644
--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -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,