Commit bab65e48 authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

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: default avatarThomas Gleixner <tglx@linutronix.de>
Reviewed-by: default avatarJason Gunthorpe <jgg@nvidia.com>
Acked-by: default avatarBjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/r/20221111122015.516946468@linutronix.de
parent 12910ffd

drivers/pci/msi/msi.c

+33 −32
Original line number Diff line number Diff line
@@ -721,47 +721,31 @@ static int msix_capability_init(struct pci_dev *dev, struct msix_entry *entries, 
	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;



	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;

	if (!entries)

		return true;



	if (entries) {

		/* Check for any invalid entries */

	for (i = 0; i < nvec; i++) {

			if (entries[i].entry >= nr_entries)

				return -EINVAL;		/* invalid entry */

		/* 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)

					return -EINVAL;	/* duplicate entry */

				return false;

		}

	}

	return true;

}



	/* 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);

}



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;