[PATCH v3 1/2] iommu/riscv: Advertise Svpbmt support to generic page table

[fangyu . yu]

From: Fangyu Yu <fangyu.yu@xxxxxxxxxxxxxxxxx>

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.

Signed-off-by: Fangyu Yu <fangyu.yu@xxxxxxxxxxxxxxxxx>
Reviewed-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
Reviewed-by: Anup Patel <anup@xxxxxxxxxxxxxx>
Reviewed-by: Guo Ren <guoren@xxxxxxxxxx>
Reviewed-by: Nutty Liu <nutty.liu@xxxxxxxxxxx>
Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx>
---
 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