From f8bf2aeb651b3460a4b36fd7ba1ba1d31777d35c Mon Sep 17 00:00:00 2001 From: James Sewart Date: Tue, 10 Dec 2019 15:51:33 -0600 Subject: PCI: Fix pci_add_dma_alias() bitmask size The number of possible devfns is 256, but pci_add_dma_alias() allocated a bitmap of size 255. Fix this off-by-one error. This fixes commits 338c3149a221 ("PCI: Add support for multiple DMA aliases") and c6635792737b ("PCI: Allocate dma_alias_mask with bitmap_zalloc()"), but I doubt it was possible to see a problem because it takes 4 64-bit longs (or 8 32-bit longs) to hold 255 bits, and bitmap_zalloc() doesn't save the 255-bit size anywhere. [bhelgaas: commit log, move #define to drivers/pci/pci.h, include loop limit fix from Qian Cai: https://lore.kernel.org/r/20191218170004.5297-1-cai@lca.pw] Signed-off-by: James Sewart Signed-off-by: Bjorn Helgaas Reviewed-by: Logan Gunthorpe --- drivers/pci/search.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'drivers/pci/search.c') diff --git a/drivers/pci/search.c b/drivers/pci/search.c index bade14002fd8..e4dbdef5aef0 100644 --- a/drivers/pci/search.c +++ b/drivers/pci/search.c @@ -41,9 +41,9 @@ int pci_for_each_dma_alias(struct pci_dev *pdev, * DMA, iterate over that too. */ if (unlikely(pdev->dma_alias_mask)) { - u8 devfn; + unsigned int devfn; - for_each_set_bit(devfn, pdev->dma_alias_mask, U8_MAX) { + for_each_set_bit(devfn, pdev->dma_alias_mask, MAX_NR_DEVFNS) { ret = fn(pdev, PCI_DEVID(pdev->bus->number, devfn), data); if (ret) -- cgit v1.2.3 From 2856ba6020fc5cbf051d5a75b2abb3046072c144 Mon Sep 17 00:00:00 2001 From: Jon Derrick Date: Tue, 21 Jan 2020 06:37:47 -0700 Subject: PCI: Introduce pci_real_dma_dev() The current DMA alias implementation requires the aliased device be on the same PCI bus as the requester ID. Add an arch-specific mechanism to point to another PCI device when doing mapping and PCI DMA alias search. The default case returns the actual device. Link: https://lore.kernel.org/r/1579613871-301529-4-git-send-email-jonathan.derrick@intel.com Signed-off-by: Jon Derrick Signed-off-by: Bjorn Helgaas Cc: Christoph Hellwig --- arch/x86/pci/common.c | 10 ++++++++++ drivers/pci/pci.c | 19 ++++++++++++++++++- drivers/pci/search.c | 6 ++++++ include/linux/pci.h | 1 + 4 files changed, 35 insertions(+), 1 deletion(-) (limited to 'drivers/pci/search.c') diff --git a/arch/x86/pci/common.c b/arch/x86/pci/common.c index 1e59df041456..fe21a5c557e6 100644 --- a/arch/x86/pci/common.c +++ b/arch/x86/pci/common.c @@ -736,3 +736,13 @@ int pci_ext_cfg_avail(void) else return 0; } + +#if IS_ENABLED(CONFIG_VMD) +struct pci_dev *pci_real_dma_dev(struct pci_dev *dev) +{ + if (is_vmd(dev->bus)) + return to_pci_sysdata(dev->bus)->vmd_dev; + + return dev; +} +#endif diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index e87196cc1a7f..ab2b8bcd29bf 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -6033,7 +6033,9 @@ bool pci_devs_are_dma_aliases(struct pci_dev *dev1, struct pci_dev *dev2) return (dev1->dma_alias_mask && test_bit(dev2->devfn, dev1->dma_alias_mask)) || (dev2->dma_alias_mask && - test_bit(dev1->devfn, dev2->dma_alias_mask)); + test_bit(dev1->devfn, dev2->dma_alias_mask)) || + pci_real_dma_dev(dev1) == dev2 || + pci_real_dma_dev(dev2) == dev1; } bool pci_device_is_present(struct pci_dev *pdev) @@ -6057,6 +6059,21 @@ void pci_ignore_hotplug(struct pci_dev *dev) } EXPORT_SYMBOL_GPL(pci_ignore_hotplug); +/** + * pci_real_dma_dev - Get PCI DMA device for PCI device + * @dev: the PCI device that may have a PCI DMA alias + * + * Permits the platform to provide architecture-specific functionality to + * devices needing to alias DMA to another PCI device on another PCI bus. If + * the PCI device is on the same bus, it is recommended to use + * pci_add_dma_alias(). This is the default implementation. Architecture + * implementations can override this. + */ +struct pci_dev __weak *pci_real_dma_dev(struct pci_dev *dev) +{ + return dev; +} + resource_size_t __weak pcibios_default_alignment(void) { return 0; diff --git a/drivers/pci/search.c b/drivers/pci/search.c index bade14002fd8..efdb8b56035f 100644 --- a/drivers/pci/search.c +++ b/drivers/pci/search.c @@ -32,6 +32,12 @@ int pci_for_each_dma_alias(struct pci_dev *pdev, struct pci_bus *bus; int ret; + /* + * The device may have an explicit alias requester ID for DMA where the + * requester is on another PCI bus. + */ + pdev = pci_real_dma_dev(pdev); + ret = fn(pdev, pci_dev_id(pdev), data); if (ret) return ret; diff --git a/include/linux/pci.h b/include/linux/pci.h index c393dff2d66f..7f4e80666972 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -1202,6 +1202,7 @@ int __must_check pci_resize_resource(struct pci_dev *dev, int i, int size); int pci_select_bars(struct pci_dev *dev, unsigned long flags); bool pci_device_is_present(struct pci_dev *pdev); void pci_ignore_hotplug(struct pci_dev *dev); +struct pci_dev *pci_real_dma_dev(struct pci_dev *dev); int __printf(6, 7) pci_request_irq(struct pci_dev *dev, unsigned int nr, irq_handler_t handler, irq_handler_t thread_fn, void *dev_id, -- cgit v1.2.3