[RFC PATCH v2 3/9] iommufd: Add RISC-V IOMMU cache invalidation data type

[Gong Shuai]

From: Wu Fei <wu.fei9 at sanechips.com.cn>

Add IOMMU_VIOMMU_INVALIDATE_DATA_RISCV and
struct iommu_viommu_riscv_invalidate to carry RISC-V IOTINVAL
commands from user space. Define the command payload in the uAPI
instead of relying on the driver internal struct
riscv_iommu_command.

The vIOMMU cache invalidation support added later uses this format
to forward guest IOTINVAL commands to the physical IOMMU.

Signed-off-by: Wu Fei <wu.fei9 at sanechips.com.cn>
Co-developed-by: Gong Shuai <gong.shuai at sanechips.com.cn>
Signed-off-by: Gong Shuai <gong.shuai at sanechips.com.cn>
---
 include/uapi/linux/iommufd.h | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/include/uapi/linux/iommufd.h b/include/uapi/linux/iommufd.h
index 5b5ca6e41063..aa65d494b992 100644
--- a/include/uapi/linux/iommufd.h
+++ b/include/uapi/linux/iommufd.h
@@ -918,10 +918,12 @@ struct iommu_hwpt_get_dirty_bitmap {
  *                                        Data Type
  * @IOMMU_HWPT_INVALIDATE_DATA_VTD_S1: Invalidation data for VTD_S1
  * @IOMMU_VIOMMU_INVALIDATE_DATA_ARM_SMMUV3: Invalidation data for ARM SMMUv3
+ * @IOMMU_VIOMMU_INVALIDATE_DATA_RISCV: Invalidation data for RISC-V IOMMU
  */
 enum iommu_hwpt_invalidate_data_type {
 	IOMMU_HWPT_INVALIDATE_DATA_VTD_S1 = 0,
 	IOMMU_VIOMMU_INVALIDATE_DATA_ARM_SMMUV3 = 1,
+	IOMMU_VIOMMU_INVALIDATE_DATA_RISCV = 2,
 };
 
 /**
@@ -982,6 +984,31 @@ struct iommu_viommu_arm_smmuv3_invalidate {
 	__aligned_le64 cmd[2];
 };
 
+/**
+ * struct iommu_viommu_riscv_invalidate - RISC-V IOMMU cache invalidation
+ *         (IOMMU_VIOMMU_INVALIDATE_DATA_RISCV)
+ * @cmd: 128-bit cache invalidation command that runs in the IOMMU command
+ *       queue, in the format defined by the "IOMMU Page-table cache
+ *       invalidation" section of the RISC-V IOMMU specification. Must be
+ *       little-endian.
+ *
+ * Supported command list only when passing in a vIOMMU via @hwpt_id:
+ *     IOTINVAL.VMA
+ *
+ * The isolation operands are owned by the kernel, which overwrites them
+ * before the command is issued:
+ *     GV = 1 and GSCID = the GSCID assigned to the vIOMMU
+ *     PSCV = 1 and PSCID = 0
+ *
+ * All other reserved bits must be 0.
+ *
+ * -EIO will be returned if the command is not supported, -EINVAL if it is
+ * malformed.
+ */
+struct iommu_viommu_riscv_invalidate {
+	__aligned_le64 cmd[2];
+};
+
 /**
  * struct iommu_hwpt_invalidate - ioctl(IOMMU_HWPT_INVALIDATE)
  * @size: sizeof(struct iommu_hwpt_invalidate)
-- 
2.53.0