On Wed, May 01, 2019 at 02:20:56PM +0100, Robin Murphy wrote: > On 2019-05-01 1:55 pm, Bjorn Helgaas wrote: > > On Wed, May 01, 2019 at 12:30:38PM +0100, Lorenzo Pieralisi wrote: > > > On Fri, Apr 12, 2019 at 08:43:32AM +0530, Srinath Mannam wrote: > > > > Few SOCs have limitation that their PCIe host can't allow few inbound > > > > address ranges. Allowed inbound address ranges are listed in dma-ranges > > > > DT property and this address ranges are required to do IOVA mapping. > > > > Remaining address ranges have to be reserved in IOVA mapping. > > > > > > > > PCIe Host driver of those SOCs has to list resource entries of allowed > > > > address ranges given in dma-ranges DT property in sorted order. This > > > > sorted list of resources will be processed and reserve IOVA address for > > > > inaccessible address holes while initializing IOMMU domain. > > > > > > > > This patch set is based on Linux-5.0-rc2. > > > > > > > > Changes from v3: > > > > - Addressed Robin Murphy review comments. > > > > - pcie-iproc: parse dma-ranges and make sorted resource list. > > > > - dma-iommu: process list and reserve gaps between entries > > > > > > > > Changes from v2: > > > > - Patch set rebased to Linux-5.0-rc2 > > > > > > > > Changes from v1: > > > > - Addressed Oza review comments. > > > > > > > > Srinath Mannam (3): > > > > PCI: Add dma_ranges window list > > > > iommu/dma: Reserve IOVA for PCIe inaccessible DMA address > > > > PCI: iproc: Add sorted dma ranges resource entries to host bridge > > > > > > > > drivers/iommu/dma-iommu.c | 19 ++++++++++++++++ > > > > drivers/pci/controller/pcie-iproc.c | 44 ++++++++++++++++++++++++++++++++++++- > > > > drivers/pci/probe.c | 3 +++ > > > > include/linux/pci.h | 1 + > > > > 4 files changed, 66 insertions(+), 1 deletion(-) > > > > > > Bjorn, Joerg, > > > > > > this series should not affect anything in the mainline other than its > > > consumer (ie patch 3); if that's the case should we consider it for v5.2 > > > and if yes how are we going to merge it ? > > > > I acked the first one > > > > Robin reviewed the second > > (https://lore.kernel.org/lkml/e6c812d6-0cad-4cfd-defd-d7ec427a6538@xxxxxxx) > > (though I do agree with his comment about DMA_BIT_MASK()), Joerg was OK > > with it if Robin was > > (https://lore.kernel.org/lkml/20190423145721.GH29810@xxxxxxxxxx). > > > > Eric reviewed the third (and pointed out a typo). > > > > My Kconfiggery never got fully answered -- it looks to me as though it's > > possible to build pcie-iproc without the DMA hole support, and I thought > > the whole point of this series was to deal with those holes > > (https://lore.kernel.org/lkml/20190418234241.GF126710@xxxxxxxxxx). I would > > have expected something like making pcie-iproc depend on IOMMU_SUPPORT. > > But Srinath didn't respond to that, so maybe it's not an issue and it > > should only affect pcie-iproc anyway. > > Hmm, I'm sure I had at least half-written a reply on that point, but I > can't seem to find it now... anyway, the gist is that these inbound > windows are generally set up to cover the physical address ranges of DRAM > and anything else that devices might need to DMA to. Thus if you're not > using an IOMMU, the fact that devices can't access the gaps in between > doesn't matter because there won't be anything there anyway; it only > needs mitigating if you do use an IOMMU and start giving arbitrary > non-physical addresses to the endpoint. So basically there is no strict IOMMU_SUPPORT dependency. > > So bottom line, I'm fine with merging it for v5.2. Do you want to merge > > it, Lorenzo, or ...? > > This doesn't look like it will conflict with the other DMA ops and MSI > mapping changes currently in-flight for iommu-dma, so I have no > objection to it going through the PCI tree for 5.2. I will update the DMA_BIT_MASK() according to your review and fix the typo Eric pointed out and push out a branch - we shall see if we can include it for v5.2. Thanks, Lorenzo
