Hi Jacek, When you post updated versions, please post the whole series with a new version number. I think there are three postings of [v2 1/2], and I think they're different. In any case, it's hard for me to keep them straight. On Tue, Jan 26, 2016 at 06:12:15PM +0100, Jacek Lawrynowicz wrote: > This patch solves IOMMU support issues with PCIe non-transparent bridges > that use Requester ID look-up tables (LUT), e.g. PEX8733. Before exiting > the bridge, packet's RID is rewritten according to LUT programmed by > a driver. Modified packets are then passed to a destination bus and > processed upstream. The problem is that such packets seem to come from > non-existent nodes that are hidden behind NTB and are not discoverable > by a destination node, so IOMMU discards them. Adding DMA alias for a > given LUT entry allows IOMMU to create a proper mapping that enables > inter-node communication. > > The current DMA alias implementation supports only single alias, so it's > not possible to connect more than two nodes when IOMMU is enabled. This > implementation enables all possible aliases on a given bus (256) that > are stored in a bitset. Alias devfn is directly translated to a bit > number. The bitset is not allocated for devices that have no need for > DMA aliases. > > More details can be found in following article: > http://www.plxtech.com/files/pdf/technical/expresslane/RTC_Enabling%20MulitHostSystemDesigns.pdf > > Signed-off-by: Jacek Lawrynowicz <jacek.lawrynowicz@xxxxxxxxx> > Acked-By: David Woodhouse <David.Woodhouse@xxxxxxxxx> > --- > drivers/iommu/iommu.c | 11 ++++------- > drivers/pci/pci.c | 27 +++++++++++++++++++++++++++ > drivers/pci/pci.h | 2 ++ > drivers/pci/probe.c | 1 + > drivers/pci/quirks.c | 15 ++++++--------- > drivers/pci/search.c | 14 +++++++++----- > include/linux/pci.h | 14 +++++++------- > 7 files changed, 56 insertions(+), 28 deletions(-) > > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c > index 0e3b009..93a89ed 100644 > --- a/drivers/iommu/iommu.c > +++ b/drivers/iommu/iommu.c > @@ -660,8 +660,8 @@ static struct iommu_group *get_pci_function_alias_group(struct pci_dev *pdev, > } > > /* > - * Look for aliases to or from the given device for exisiting groups. The > - * dma_alias_devfn only supports aliases on the same bus, therefore the search > + * Look for aliases to or from the given device for exisiting groups. DMA s/exisiting/existing/ (Not your change, but might as well fix the typo since you're touching the line anyway.) > + * aliases are only supported on the same bus, therefore the search > * space is quite small (especially since we're really only looking at pcie > * device, and therefore only expect multiple slots on the root complex or > * downstream switch ports). It's conceivable though that a pair of > @@ -686,11 +686,8 @@ static struct iommu_group *get_pci_alias_group(struct pci_dev *pdev, > continue; > > /* We alias them or they alias us */ > - if (((pdev->dev_flags & PCI_DEV_FLAGS_DMA_ALIAS_DEVFN) && > - pdev->dma_alias_devfn == tmp->devfn) || > - ((tmp->dev_flags & PCI_DEV_FLAGS_DMA_ALIAS_DEVFN) && > - tmp->dma_alias_devfn == pdev->devfn)) { > - > + if (pci_dma_alias_is_enabled(pdev, tmp->devfn) || > + pci_dma_alias_is_enabled(tmp, pdev->devfn)) { I was hoping for something that took two pci_dev pointers and returned true if they were aliases of each other, e.g., bool pci_dma_aliases(struct pci_dev *dev1, struct pci_dev *dev2); > group = get_pci_alias_group(tmp, devfns); > if (group) { > pci_dev_put(tmp); > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c > index 602eb42..cd38767 100644 > --- a/drivers/pci/pci.c > +++ b/drivers/pci/pci.c > @@ -4568,6 +4568,33 @@ int pci_set_vga_state(struct pci_dev *dev, bool decode, > return 0; > } > > +/** > + * pci_enable_dma_alias - Allows to set multiple devfn aliases for given device > + * @dev: the PCI device for which alias is added > + * @devfn: alias slot and function > + * > + * This helper encodes 8-bit devfn as bit number in dma_alias_mask. > + * It should be called early, preferably as PCI fixup header quirk. > + */ > +void pci_enable_dma_alias(struct pci_dev *dev, u8 devfn) I kind of liked "pci_add_dma_alias()." "Enable" suggests that we can turn them on and off, which isn't really the case here. > +{ > + if (!dev->dma_alias_mask) > + dev->dma_alias_mask = kcalloc(BITS_TO_LONGS(U8_MAX), > + sizeof(long), GFP_KERNEL); > + if (!dev->dma_alias_mask) { > + dev_warn(&dev->dev, "Unable to allocate DMA alias mask.\n"); > + return; > + } > + if (dev->dma_alias_mask) > + set_bit(devfn, dev->dma_alias_mask); > +} Bjorn -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
