Message-ID: <20211206210439.021277807@linutronix.de>
From:   Thomas Gleixner <tglx@linutronix.de>
To:     LKML <linux-kernel@vger.kernel.org>
Cc:     Bjorn Helgaas <helgaas@kernel.org>, Marc Zygnier <maz@kernel.org>,
        Alex Williamson <alex.williamson@redhat.com>,
        Kevin Tian <kevin.tian@intel.com>,
        Jason Gunthorpe <jgg@nvidia.com>,
        Megha Dey <megha.dey@intel.com>,
        Ashok Raj <ashok.raj@intel.com>, linux-pci@vger.kernel.org,
        Cedric Le Goater <clg@kaod.org>,
        xen-devel@lists.xenproject.org, Juergen Gross <jgross@suse.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Will Deacon <will@kernel.org>,
        Santosh Shilimkar <ssantosh@kernel.org>,
        iommu@lists.linux-foundation.org, dmaengine@vger.kernel.org,
        Stuart Yoder <stuyoder@gmail.com>,
        Laurentiu Tudor <laurentiu.tudor@nxp.com>,
        Nishanth Menon <nm@ti.com>, Tero Kristo <kristo@kernel.org>,
        linux-arm-kernel@lists.infradead.org,
        Vinod Koul <vkoul@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Robin Murphy <robin.murphy@arm.com>,
        Sinan Kaya <okaya@kernel.org>
Subject: [patch V2 25/36] PCI/MSI: Provide MSI_FLAG_MSIX_CONTIGUOUS
References: <20211206210307.625116253@linutronix.de>
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Date:   Mon,  6 Dec 2021 23:39:36 +0100 (CET)
Precedence: bulk

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

--- 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
@@ -376,6 +376,8 @@ 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,