linux-kernel - [tip: irq/urgent] PCI/MSI: Remove over-zealous hardware size check in pci_msix_validate

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Date:   Sun, 16 Apr 2023 12:18:08 -0000
From:   "tip-bot2 for Thomas Gleixner" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     David Laight <David.Laight@...lab.com>,
        Thomas Gleixner <tglx@...utronix.de>, stable@...r.kernel.org,
        x86@...nel.org, linux-kernel@...r.kernel.org, maz@...nel.org
Subject: [tip: irq/urgent] PCI/MSI: Remove over-zealous hardware size check in
 pci_msix_validate_entries()

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

Commit-ID:     e3c026be4d3ca046799fde55ccbae9d0f059fb93
Gitweb:        https://git.kernel.org/tip/e3c026be4d3ca046799fde55ccbae9d0f059fb93
Author:        Thomas Gleixner <tglx@...utronix.de>
AuthorDate:    Mon, 10 Apr 2023 21:14:45 +02:00
Committer:     Thomas Gleixner <tglx@...utronix.de>
CommitterDate: Sun, 16 Apr 2023 14:11:51 +02:00

PCI/MSI: Remove over-zealous hardware size check in pci_msix_validate_entries()

pci_msix_validate_entries() validates the entries array which is handed in
by the caller for a MSI-X interrupt allocation. Aside of consistency
failures it also detects a failure when the size of the MSI-X hardware table
in the device is smaller than the size of the entries array.

That's wrong for the case of range allocations where the caller provides
the minimum and the maximum number of vectors to allocate, when the
hardware size is greater or equal than the mininum, but smaller than the
maximum.

Remove the hardware size check completely from that function and just
ensure that the entires array up to the maximum size is consistent.

The limitation and range checking versus the hardware size happens
independently of that afterwards anyway because the entries array is
optional.

Fixes: 4644d22eb673 ("PCI/MSI: Validate MSI-X contiguous restriction early")
Reported-by: David Laight <David.Laight@...lab.com>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Cc: stable@...r.kernel.org
Link: https://lore.kernel.org/r/87v8i3sg62.ffs@tglx

---
 drivers/pci/msi/msi.c |  9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/drivers/pci/msi/msi.c b/drivers/pci/msi/msi.c
index 1f71662..ef1d885 100644
--- a/drivers/pci/msi/msi.c
+++ b/drivers/pci/msi/msi.c
@@ -750,8 +750,7 @@ out_disable:
 	return ret;
 }
 
-static bool pci_msix_validate_entries(struct pci_dev *dev, struct msix_entry *entries,
-				      int nvec, int hwsize)
+static bool pci_msix_validate_entries(struct pci_dev *dev, struct msix_entry *entries, int nvec)
 {
 	bool nogap;
 	int i, j;
@@ -762,10 +761,6 @@ static bool pci_msix_validate_entries(struct pci_dev *dev, struct msix_entry *en
 	nogap = pci_msi_domain_supports(dev, MSI_FLAG_MSIX_CONTIGUOUS, DENY_LEGACY);
 
 	for (i = 0; i < nvec; i++) {
-		/* Entry within hardware limit? */
-		if (entries[i].entry >= hwsize)
-			return false;
-
 		/* Check for duplicate entries */
 		for (j = i + 1; j < nvec; j++) {
 			if (entries[i].entry == entries[j].entry)
@@ -805,7 +800,7 @@ int __pci_enable_msix_range(struct pci_dev *dev, struct msix_entry *entries, int
 	if (hwsize < 0)
 		return hwsize;
 
-	if (!pci_msix_validate_entries(dev, entries, nvec, hwsize))
+	if (!pci_msix_validate_entries(dev, entries, nvec))
 		return -EINVAL;
 
 	if (hwsize < nvec) {