[RFC PATCH v5 10/10] iommu/riscv: Add IOTINVAL.GVMA invalidations

[fangyu.yu@linux.alibaba.com]

From: Fangyu Yu <fangyu.yu@linux.alibaba.com>

Previously, only IOTINVAL.VMA was issued, which is insufficient for
second-stage address translation consistency.

Signed-off-by: Fangyu Yu <fangyu.yu@linux.alibaba.com>
---
 drivers/iommu/riscv/iommu.c | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/drivers/iommu/riscv/iommu.c b/drivers/iommu/riscv/iommu.c
index e3791e912af3..a764a172c588 100644
--- a/drivers/iommu/riscv/iommu.c
+++ b/drivers/iommu/riscv/iommu.c
@@ -830,6 +830,15 @@ static int riscv_iommu_iodir_set_mode(struct riscv_iommu_device *iommu,
 	riscv_iommu_cmd_inval_vma(&cmd);
 	riscv_iommu_cmd_send(iommu, &cmd);
 
+	/*
+	 * Per the RISC-V IOMMU spec (sec. 5.5), the IOMMU may retain
+	 * cached translations across mode switches. IOTINVAL.VMA only
+	 * covers first-stage leaf PTEs, so use a global IOTINVAL.GVMA
+	 * to flush stale second-stage translations.
+	 */
+	riscv_iommu_cmd_inval_gvma(&cmd);
+	riscv_iommu_cmd_send(iommu, &cmd);
+
 	/* IOFENCE.C */
 	riscv_iommu_cmd_sync(iommu, RISCV_IOMMU_IOTINVAL_TIMEOUT);
 
@@ -1175,12 +1184,15 @@ static void riscv_iommu_iodir_iotinval(struct riscv_iommu_device *iommu,
 		/*
 		 * else: IOTINVAL.VMA with GV=1,AV=PSCV=0,and
 		 * GSCID=DC.iohgatp.GSCID
-		 *
+		 */
+		riscv_iommu_cmd_send(iommu, &cmd);
+		/*
 		 * IOTINVAL.GVMA with GV=1,AV=0,and
 		 * GSCID=DC.iohgatp.GSCID
-		 * TODO: For now, the Second-Stage feature have not yet been merged,
-		 * also issue IOTINVAL.GVMA once second-stage support is merged.
 		 */
+		riscv_iommu_cmd_inval_gvma(&cmd);
+		riscv_iommu_cmd_inval_set_gscid(&cmd,
+			FIELD_GET(RISCV_IOMMU_DC_IOHGATP_GSCID, iohgatp));
 	}
 	riscv_iommu_cmd_send(iommu, &cmd);
 }
-- 
2.50.1