From bab65e48cb064d67b488efb6888c06fd977a8245 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Fri, 11 Nov 2022 14:55:07 +0100 Subject: [PATCH] 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 Reviewed-by: Jason Gunthorpe Acked-by: Bjorn Helgaas 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 380e65155b93..794ec97c5b70 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;