From: Fangyu Yu The RISC-V IOMMU can optionally support Svpbmt page-based memory types in its page table format. When present,the generic page table code can use this capability to encode memory attributes (e.g. MMIO vs normal memory) in PTEs. Reviewed-by: Jason Gunthorpe Reviewed-by: Anup Patel Reviewed-by: Guo Ren Reviewed-by: Nutty Liu Reviewed-by: Kevin Tian Signed-off-by: Fangyu Yu --- drivers/iommu/riscv/iommu.c | 2 ++ include/linux/generic_pt/common.h | 4 ++++ 2 files changed, 6 insertions(+) diff --git a/drivers/iommu/riscv/iommu.c b/drivers/iommu/riscv/iommu.c index a31f50bbad35..6c324f9fdc53 100644 --- a/drivers/iommu/riscv/iommu.c +++ b/drivers/iommu/riscv/iommu.c @@ -1268,6 +1268,8 @@ static struct iommu_domain *riscv_iommu_alloc_paging_domain(struct device *dev) cfg.common.features = BIT(PT_FEAT_SIGN_EXTEND) | BIT(PT_FEAT_FLUSH_RANGE) | BIT(PT_FEAT_RISCV_SVNAPOT_64K); + if (iommu->caps & RISCV_IOMMU_CAPABILITIES_SVPBMT) + cfg.common.features |= BIT(PT_FEAT_RISCV_SVPBMT); domain->riscvpt.iommu.nid = dev_to_node(iommu->dev); domain->domain.ops = &riscv_iommu_paging_domain_ops; diff --git a/include/linux/generic_pt/common.h b/include/linux/generic_pt/common.h index fc5d0b5edadc..2683e5b38998 100644 --- a/include/linux/generic_pt/common.h +++ b/include/linux/generic_pt/common.h @@ -188,6 +188,10 @@ enum { * Support the 64k contiguous page size following the Svnapot extension. */ PT_FEAT_RISCV_SVNAPOT_64K = PT_FEAT_FMT_START, + /* + * Support Svpbmt extension: encode page-based memory type (PBMT) in PTEs. + */ + PT_FEAT_RISCV_SVPBMT, }; -- 2.50.1 From: Fangyu Yu When the RISC-V IOMMU page table format support Svpbmt, PBMT provides a way to tag mappings with page-based memory types. Encode memory type via PBMT in RISC-V IOMMU PTEs: - IOMMU_MMIO -> PBMT=IO - !IOMMU_MMIO && !IOMMU_CACHE -> PBMT=NC - otherwise -> PBMT=Normal (PBMT=0) Only touch PBMT when PT_FEAT_RISCV_SVPBMT is advertised. Reviewed-by: Jason Gunthorpe Reviewed-by: Anup Patel Reviewed-by: Guo Ren Reviewed-by: Nutty Liu Reviewed-by: Kevin Tian Signed-off-by: Fangyu Yu --- drivers/iommu/generic_pt/fmt/riscv.h | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/drivers/iommu/generic_pt/fmt/riscv.h b/drivers/iommu/generic_pt/fmt/riscv.h index a7fef6266a36..ae9a76514416 100644 --- a/drivers/iommu/generic_pt/fmt/riscv.h +++ b/drivers/iommu/generic_pt/fmt/riscv.h @@ -64,6 +64,8 @@ enum { RISCVPT_PPN64 = GENMASK_ULL(53, 10), RISCVPT_PPN64_64K = GENMASK_ULL(53, 14), RISCVPT_PBMT = GENMASK_ULL(62, 61), + RISCVPT_NC = BIT_ULL(61), + RISCVPT_IO = BIT_ULL(62), RISCVPT_N = BIT_ULL(63), /* Svnapot encodings for ppn[0] */ @@ -201,7 +203,8 @@ static inline void riscvpt_attr_from_entry(const struct pt_state *pts, { attrs->descriptor_bits = pts->entry & (RISCVPT_R | RISCVPT_W | RISCVPT_X | RISCVPT_U | - RISCVPT_G | RISCVPT_A | RISCVPT_D); + RISCVPT_G | RISCVPT_A | RISCVPT_D | RISCVPT_NC | + RISCVPT_IO); } #define pt_attr_from_entry riscvpt_attr_from_entry @@ -237,6 +240,12 @@ static inline int riscvpt_iommu_set_prot(struct pt_common *common, pte |= RISCVPT_R; if (!(iommu_prot & IOMMU_NOEXEC)) pte |= RISCVPT_X; + if (common->features & BIT(PT_FEAT_RISCV_SVPBMT)) { + if (iommu_prot & IOMMU_MMIO) + pte |= RISCVPT_IO; + else if (!(iommu_prot & IOMMU_CACHE)) + pte |= RISCVPT_NC; + } /* Caller must specify a supported combination of flags */ if (unlikely((pte & (RISCVPT_X | RISCVPT_W | RISCVPT_R)) == 0)) -- 2.50.1