On Sat, Jan 30, 2016 at 12:06:51PM +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 | 17 ++++++++++------- > drivers/pci/pci.c | 21 +++++++++++++++++++++ > drivers/pci/pci.h | 2 ++ > drivers/pci/probe.c | 1 + > drivers/pci/quirks.c | 15 ++++++--------- > drivers/pci/search.c | 14 +++++++++----- > include/linux/pci.h | 12 +++++------- > 7 files changed, 54 insertions(+), 28 deletions(-) Looks good to me. Acked-by: Joerg Roedel <jroedel@xxxxxxx> -- 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
