From: Matt Evans Date: Thu, 23 Apr 2026 17:30:51 +0000 (-0700) Subject: PCI/P2PDMA: Avoid returning a provider for non_mappable_bars X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=951ebc18d181af1d90deddbc0ef3269061d6e03c;p=thirdparty%2Flinux.git PCI/P2PDMA: Avoid returning a provider for non_mappable_bars Extend the checks in pcim_p2pdma_init() and pcim_p2pdma_provider() to exclude functions that have pdev->non_mappable_bars set. Consumers such as VFIO were previously able to map these for access by the CPU or P2P. Update the comment on non_mappable_bars to show it refers to any access, not just userspace CPU access. Fixes: 372d6d1b8ae3c ("PCI/P2PDMA: Refactor to separate core P2P functionality from memory allocation") Suggested-by: Alex Williamson Signed-off-by: Matt Evans Signed-off-by: Bjorn Helgaas Reviewed-by: Niklas Schnelle Reviewed-by: Alex Williamson Link: https://patch.msgid.link/20260423173051.1999679-1-mattev@meta.com --- diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c index 7c898542af8d5..adb17a4f69396 100644 --- a/drivers/pci/p2pdma.c +++ b/drivers/pci/p2pdma.c @@ -262,6 +262,9 @@ int pcim_p2pdma_init(struct pci_dev *pdev) struct pci_p2pdma *p2p; int i, ret; + if (pdev->non_mappable_bars) + return -EOPNOTSUPP; + p2p = rcu_dereference_protected(pdev->p2pdma, 1); if (p2p) return 0; @@ -318,7 +321,8 @@ struct p2pdma_provider *pcim_p2pdma_provider(struct pci_dev *pdev, int bar) { struct pci_p2pdma *p2p; - if (!(pci_resource_flags(pdev, bar) & IORESOURCE_MEM)) + if (!(pci_resource_flags(pdev, bar) & IORESOURCE_MEM) || + pdev->non_mappable_bars) return NULL; p2p = rcu_dereference_protected(pdev->p2pdma, 1); diff --git a/include/linux/pci.h b/include/linux/pci.h index 2c4454583c115..1e6802017d6b8 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -508,7 +508,7 @@ struct pci_dev { unsigned int no_command_memory:1; /* No PCI_COMMAND_MEMORY */ unsigned int rom_bar_overlap:1; /* ROM BAR disable broken */ unsigned int rom_attr_enabled:1; /* Display of ROM attribute enabled? */ - unsigned int non_mappable_bars:1; /* BARs can't be mapped to user-space */ + unsigned int non_mappable_bars:1; /* BARs can't be mapped by CPU or peers */ pci_dev_flags_t dev_flags; atomic_t enable_cnt; /* pci_enable_device has been called */