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Subject[tip: irq/core] PCI/MSI: Sanitize MSI-X checks
The following commit has been merged into the irq/core branch of tip:

Commit-ID: bab65e48cb064d67b488efb6888c06fd977a8245
Gitweb: https://git.kernel.org/tip/bab65e48cb064d67b488efb6888c06fd977a8245
Author: Thomas Gleixner <tglx@linutronix.de>
AuthorDate: Fri, 11 Nov 2022 14:55:07 +01:00
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Thu, 17 Nov 2022 15:15:22 +01:00

PCI/MSI: Sanitize MSI-X checks

There is no point in doing the same sanity checks over and over in a loop
during MSI-X enablement. Put them in front of the loop and return early
when they fail.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/r/20221111122015.516946468@linutronix.de

---
drivers/pci/msi/msi.c | 65 +++++++++++++++++++++---------------------
1 file changed, 33 insertions(+), 32 deletions(-)

diff --git a/drivers/pci/msi/msi.c b/drivers/pci/msi/msi.c
index 380e651..794ec97 100644
--- a/drivers/pci/msi/msi.c
+++ b/drivers/pci/msi/msi.c
@@ -721,47 +721,31 @@ out_disable:
return ret;
}

-static int __pci_enable_msix(struct pci_dev *dev, struct msix_entry *entries,
- int nvec, struct irq_affinity *affd, int flags)
+static bool pci_msix_validate_entries(struct msix_entry *entries, int nvec, int hwsize)
{
- int nr_entries;
int i, j;

- if (!pci_msi_supported(dev, nvec) || dev->current_state != PCI_D0)
- return -EINVAL;
+ if (!entries)
+ return true;

- nr_entries = pci_msix_vec_count(dev);
- if (nr_entries < 0)
- return nr_entries;
- if (nvec > nr_entries && !(flags & PCI_IRQ_VIRTUAL))
- return nr_entries;
+ for (i = 0; i < nvec; i++) {
+ /* Entry within hardware limit? */
+ if (entries[i].entry >= hwsize)
+ return false;

- if (entries) {
- /* Check for any invalid entries */
- for (i = 0; i < nvec; i++) {
- if (entries[i].entry >= nr_entries)
- return -EINVAL; /* invalid entry */
- for (j = i + 1; j < nvec; j++) {
- if (entries[i].entry == entries[j].entry)
- return -EINVAL; /* duplicate entry */
- }
+ /* Check for duplicate entries */
+ for (j = i + 1; j < nvec; j++) {
+ if (entries[i].entry == entries[j].entry)
+ return false;
}
}
-
- /* Check whether driver already requested for MSI IRQ */
- if (dev->msi_enabled) {
- pci_info(dev, "can't enable MSI-X (MSI IRQ already assigned)\n");
- return -EINVAL;
- }
- return msix_capability_init(dev, entries, nvec, affd);
+ return true;
}

-int __pci_enable_msix_range(struct pci_dev *dev,
- struct msix_entry *entries, int minvec,
- int maxvec, struct irq_affinity *affd,
- int flags)
+int __pci_enable_msix_range(struct pci_dev *dev, struct msix_entry *entries, int minvec,
+ int maxvec, struct irq_affinity *affd, int flags)
{
- int rc, nvec = maxvec;
+ int hwsize, rc, nvec = maxvec;

if (maxvec < minvec)
return -ERANGE;
@@ -774,6 +758,23 @@ int __pci_enable_msix_range(struct pci_dev *dev,
if (WARN_ON_ONCE(dev->msix_enabled))
return -EINVAL;

+ if (!pci_msi_supported(dev, nvec) || dev->current_state != PCI_D0)
+ return -EINVAL;
+
+ hwsize = pci_msix_vec_count(dev);
+ if (hwsize < 0)
+ return hwsize;
+
+ if (!pci_msix_validate_entries(entries, nvec, hwsize))
+ return -EINVAL;
+
+ /* PCI_IRQ_VIRTUAL is a horrible hack! */
+ if (nvec > hwsize && !(flags & PCI_IRQ_VIRTUAL))
+ nvec = hwsize;
+
+ if (nvec < minvec)
+ return -ENOSPC;
+
rc = pci_setup_msi_context(dev);
if (rc)
return rc;
@@ -785,7 +786,7 @@ int __pci_enable_msix_range(struct pci_dev *dev,
return -ENOSPC;
}

- rc = __pci_enable_msix(dev, entries, nvec, affd, flags);
+ rc = msix_capability_init(dev, entries, nvec, affd);
if (rc == 0)
return nvec;

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