linux-kernel - [tip: irq/msi] PCI/MSI: Sanitize MSI-X table map handling

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Date:   Thu, 09 Dec 2021 16:07:00 -0000
From:   "tip-bot2 for Thomas Gleixner" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Juergen Gross <jgross@...e.com>,
        Jason Gunthorpe <jgg@...dia.com>,
        Bjorn Helgaas <bhelgaas@...gle.com>, x86@...nel.org,
        linux-kernel@...r.kernel.org
Subject: [tip: irq/msi] PCI/MSI: Sanitize MSI-X table map handling

The following commit has been merged into the irq/msi branch of tip:

Commit-ID:     85aa607e79f8343f1ea028b29bdf8b6bc99c729a
Gitweb:        https://git.kernel.org/tip/85aa607e79f8343f1ea028b29bdf8b6bc99c729a
Author:        Thomas Gleixner <tglx@...utronix.de>
AuthorDate:    Mon, 06 Dec 2021 23:27:54 +01:00
Committer:     Thomas Gleixner <tglx@...utronix.de>
CommitterDate: Thu, 09 Dec 2021 11:52:22 +01:00

PCI/MSI: Sanitize MSI-X table map handling

Unmapping the MSI-X base mapping in the loops which allocate/free MSI
descriptors is daft and in the way of allowing runtime expansion of MSI-X
descriptors.

Store the mapping in struct pci_dev and free it after freeing the MSI-X
descriptors.

Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Tested-by: Juergen Gross <jgross@...e.com>
Reviewed-by: Jason Gunthorpe <jgg@...dia.com>
Acked-by: Bjorn Helgaas <bhelgaas@...gle.com>
Link: https://lore.kernel.org/r/20211206210224.871651518@linutronix.de

---
 drivers/pci/msi/msi.c | 18 ++++++++----------
 include/linux/pci.h   |  1 +
 2 files changed, 9 insertions(+), 10 deletions(-)

diff --git a/drivers/pci/msi/msi.c b/drivers/pci/msi/msi.c
index 8926a6c..465fe9e 100644
--- a/drivers/pci/msi/msi.c
+++ b/drivers/pci/msi/msi.c
@@ -241,14 +241,14 @@ static void free_msi_irqs(struct pci_dev *dev)
 	pci_msi_teardown_msi_irqs(dev);
 
 	list_for_each_entry_safe(entry, tmp, msi_list, list) {
-		if (entry->pci.msi_attrib.is_msix) {
-			if (list_is_last(&entry->list, msi_list))
-				iounmap(entry->pci.mask_base);
-		}
-
 		list_del(&entry->list);
 		free_msi_entry(entry);
 	}
+
+	if (dev->msix_base) {
+		iounmap(dev->msix_base);
+		dev->msix_base = NULL;
+	}
 }
 
 static void pci_intx_for_msi(struct pci_dev *dev, int enable)
@@ -501,10 +501,6 @@ static int msix_setup_entries(struct pci_dev *dev, void __iomem *base,
 	for (i = 0, curmsk = masks; i < nvec; i++) {
 		entry = alloc_msi_entry(&dev->dev, 1, curmsk);
 		if (!entry) {
-			if (!i)
-				iounmap(base);
-			else
-				free_msi_irqs(dev);
 			/* No enough memory. Don't try again */
 			ret = -ENOMEM;
 			goto out;
@@ -602,12 +598,14 @@ static int msix_capability_init(struct pci_dev *dev, struct msix_entry *entries,
 		goto out_disable;
 	}
 
+	dev->msix_base = base;
+
 	/* Ensure that all table entries are masked. */
 	msix_mask_all(base, tsize);
 
 	ret = msix_setup_entries(dev, base, entries, nvec, affd);
 	if (ret)
-		goto out_disable;
+		goto out_free;
 
 	ret = pci_msi_setup_msi_irqs(dev, nvec, PCI_CAP_ID_MSIX);
 	if (ret)
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 18a75c8..8cb1036 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -473,6 +473,7 @@ struct pci_dev {
 	u8		ptm_granularity;
 #endif
 #ifdef CONFIG_PCI_MSI
+	void __iomem	*msix_base;
 	const struct attribute_group **msi_irq_groups;
 #endif
 	struct pci_vpd	vpd;