From 3f1ce8e85ee06dbe6a8b2e037e9b35f6b32e9ab3 Mon Sep 17 00:00:00 2001 From: Jean-Philippe Brucker Date: Fri, 18 Sep 2020 12:18:48 +0200 Subject: iommu/arm-smmu-v3: Share process page tables With Shared Virtual Addressing (SVA), we need to mirror CPU TTBR, TCR, MAIR and ASIDs in SMMU contexts. Each SMMU has a single ASID space split into two sets, shared and private. Shared ASIDs correspond to those obtained from the arch ASID allocator, and private ASIDs are used for "classic" map/unmap DMA. A possible conflict happens when trying to use a shared ASID that has already been allocated for private use by the SMMU driver. This will be addressed in a later patch by replacing the private ASID. At the moment we return -EBUSY. Each mm_struct shared with the SMMU will have a single context descriptor. Add a refcount to keep track of this. It will be protected by the global SVA lock. Introduce a new arm-smmu-v3-sva.c file and the CONFIG_ARM_SMMU_V3_SVA option to let users opt in SVA support. Signed-off-by: Jean-Philippe Brucker Reviewed-by: Jonathan Cameron Link: https://lore.kernel.org/r/20200918101852.582559-9-jean-philippe@linaro.org Signed-off-by: Will Deacon --- drivers/iommu/Kconfig | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'drivers/iommu/Kconfig') diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig index bef5d75e306b..82fa56238c96 100644 --- a/drivers/iommu/Kconfig +++ b/drivers/iommu/Kconfig @@ -308,6 +308,16 @@ config ARM_SMMU_V3 Say Y here if your system includes an IOMMU device implementing the ARM SMMUv3 architecture. +config ARM_SMMU_V3_SVA + bool "Shared Virtual Addressing support for the ARM SMMUv3" + depends on ARM_SMMU_V3 + help + Support for sharing process address spaces with devices using the + SMMUv3. + + Say Y here if your system supports SVA extensions such as PCIe PASID + and PRI. + config S390_IOMMU def_bool y if S390 && PCI depends on S390 && PCI -- cgit