linux-kernel - [PATCH v3 4/6] iommu/io-pgtable-arm: add support for non-strict mode

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Date:   Thu, 12 Jul 2018 14:18:30 +0800
From:   Zhen Lei <thunder.leizhen@...wei.com>
To:     Jean-Philippe Brucker <jean-philippe.brucker@....com>,
        Robin Murphy <robin.murphy@....com>,
        Will Deacon <will.deacon@....com>,
        Joerg Roedel <joro@...tes.org>,
        linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
        iommu <iommu@...ts.linux-foundation.org>,
        linux-kernel <linux-kernel@...r.kernel.org>
CC:     Zhen Lei <thunder.leizhen@...wei.com>
Subject: [PATCH v3 4/6] iommu/io-pgtable-arm: add support for non-strict mode

To support the non-strict mode, now we only tlbi and sync for the strict
mode. But for the non-leaf case, always follow strict mode.

Use the lowest bit of the iova parameter to pass the strict mode:
0, IOMMU_STRICT;
1, IOMMU_NON_STRICT;
Treat 0 as IOMMU_STRICT, so that the unmap operation can compatible with
other IOMMUs which still use strict mode.

Signed-off-by: Zhen Lei <thunder.leizhen@...wei.com>
---
 drivers/iommu/io-pgtable-arm.c | 23 ++++++++++++++---------
 1 file changed, 14 insertions(+), 9 deletions(-)

diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
index 010a254..9234db3 100644
--- a/drivers/iommu/io-pgtable-arm.c
+++ b/drivers/iommu/io-pgtable-arm.c
@@ -292,7 +292,7 @@ static void __arm_lpae_set_pte(arm_lpae_iopte *ptep, arm_lpae_iopte pte,
 
 static size_t __arm_lpae_unmap(struct arm_lpae_io_pgtable *data,
 			       unsigned long iova, size_t size, int lvl,
-			       arm_lpae_iopte *ptep);
+			       arm_lpae_iopte *ptep, int strict);
 
 static void __arm_lpae_init_pte(struct arm_lpae_io_pgtable *data,
 				phys_addr_t paddr, arm_lpae_iopte prot,
@@ -334,7 +334,7 @@ static int arm_lpae_init_pte(struct arm_lpae_io_pgtable *data,
 		size_t sz = ARM_LPAE_BLOCK_SIZE(lvl, data);
 
 		tblp = ptep - ARM_LPAE_LVL_IDX(iova, lvl, data);
-		if (WARN_ON(__arm_lpae_unmap(data, iova, sz, lvl, tblp) != sz))
+		if (WARN_ON(__arm_lpae_unmap(data, iova, sz, lvl, tblp, IOMMU_STRICT) != sz))
 			return -EINVAL;
 	}
 
@@ -531,7 +531,7 @@ static void arm_lpae_free_pgtable(struct io_pgtable *iop)
 static size_t arm_lpae_split_blk_unmap(struct arm_lpae_io_pgtable *data,
 				       unsigned long iova, size_t size,
 				       arm_lpae_iopte blk_pte, int lvl,
-				       arm_lpae_iopte *ptep)
+				       arm_lpae_iopte *ptep, int strict)
 {
 	struct io_pgtable_cfg *cfg = &data->iop.cfg;
 	arm_lpae_iopte pte, *tablep;
@@ -576,15 +576,18 @@ static size_t arm_lpae_split_blk_unmap(struct arm_lpae_io_pgtable *data,
 	}
 
 	if (unmap_idx < 0)
-		return __arm_lpae_unmap(data, iova, size, lvl, tablep);
+		return __arm_lpae_unmap(data, iova, size, lvl, tablep, strict);
 
 	io_pgtable_tlb_add_flush(&data->iop, iova, size, size, true);
+	if (!strict)
+		io_pgtable_tlb_sync(&data->iop);
+
 	return size;
 }
 
 static size_t __arm_lpae_unmap(struct arm_lpae_io_pgtable *data,
 			       unsigned long iova, size_t size, int lvl,
-			       arm_lpae_iopte *ptep)
+			       arm_lpae_iopte *ptep, int strict)
 {
 	arm_lpae_iopte pte;
 	struct io_pgtable *iop = &data->iop;
@@ -609,7 +612,7 @@ static size_t __arm_lpae_unmap(struct arm_lpae_io_pgtable *data,
 			io_pgtable_tlb_sync(iop);
 			ptep = iopte_deref(pte, data);
 			__arm_lpae_free_pgtable(data, lvl + 1, ptep);
-		} else {
+		} else if (strict) {
 			io_pgtable_tlb_add_flush(iop, iova, size, size, true);
 		}
 
@@ -620,25 +623,27 @@ static size_t __arm_lpae_unmap(struct arm_lpae_io_pgtable *data,
 		 * minus the part we want to unmap
 		 */
 		return arm_lpae_split_blk_unmap(data, iova, size, pte,
-						lvl + 1, ptep);
+						lvl + 1, ptep, strict);
 	}
 
 	/* Keep on walkin' */
 	ptep = iopte_deref(pte, data);
-	return __arm_lpae_unmap(data, iova, size, lvl + 1, ptep);
+	return __arm_lpae_unmap(data, iova, size, lvl + 1, ptep, strict);
 }
 
 static size_t arm_lpae_unmap(struct io_pgtable_ops *ops, unsigned long iova,
 			     size_t size)
 {
+	int strict = ((iova & IOMMU_STRICT_MODE_MASK) == IOMMU_STRICT);
 	struct arm_lpae_io_pgtable *data = io_pgtable_ops_to_data(ops);
 	arm_lpae_iopte *ptep = data->pgd;
 	int lvl = ARM_LPAE_START_LVL(data);
 
+	iova &= ~IOMMU_STRICT_MODE_MASK;
 	if (WARN_ON(iova >= (1ULL << data->iop.cfg.ias)))
 		return 0;
 
-	return __arm_lpae_unmap(data, iova, size, lvl, ptep);
+	return __arm_lpae_unmap(data, iova, size, lvl, ptep, strict);
 }
 
 static phys_addr_t arm_lpae_iova_to_phys(struct io_pgtable_ops *ops,
-- 
1.8.3