On 2018/8/9 18:54, Robin Murphy wrote:

On 06/08/18 13:27, Zhen Lei wrote:

quoted

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.

Signed-off-by: Zhen Lei <redacted>
---
  drivers/iommu/io-pgtable-arm.c | 27 ++++++++++++++++++---------
  drivers/iommu/io-pgtable.h     |  3 +++
  2 files changed, 21 insertions(+), 9 deletions(-)

diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
index 010a254..bb61bef 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, bool strict);

  static void __arm_lpae_init_pte(struct arm_lpae_io_pgtable *data,
                  phys_addr_t paddr, arm_lpae_iopte prot,

@@ -319,6 +319,7 @@ static int arm_lpae_init_pte(struct arm_lpae_io_pgtable *data,
                   arm_lpae_iopte prot, int lvl,
                   arm_lpae_iopte *ptep)
  {
+    size_t unmapped;
      arm_lpae_iopte pte = *ptep;

      if (iopte_leaf(pte, lvl)) {

@@ -334,7 +335,8 @@ 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))
+        unmapped = __arm_lpae_unmap(data, iova, sz, lvl, tblp, true);
+        if (WARN_ON(unmapped != sz))

What's the extra local variable for?

in order to remove the warning: more than 80 characters a line

quoted

              return -EINVAL;
      }

@@ -576,15 +578,17 @@ 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, true);

      io_pgtable_tlb_add_flush(&data->iop, iova, size, size, true);
+    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, bool strict)
  {
      arm_lpae_iopte pte;
      struct io_pgtable *iop = &data->iop;

@@ -609,7 +613,7 @@ 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) {

Since this is the only place we ever actually evaluate "strict", can't we just test iop->cfg.quirks directly at this point instead of playing pass-the-parcel with the extra argument?

Wonderful, you're right!

Robin.

quoted

              io_pgtable_tlb_add_flush(iop, iova, size, size, true);
          }

@@ -625,12 +629,13 @@ static size_t __arm_lpae_unmap(struct arm_lpae_io_pgtable *data,

      /* 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)
  {
+    bool 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);

@@ -638,7 +643,9 @@ static size_t arm_lpae_unmap(struct io_pgtable_ops *ops, unsigned long iova,
      if (WARN_ON(iova >= (1ULL << data->iop.cfg.ias)))
          return 0;

-    return __arm_lpae_unmap(data, iova, size, lvl, ptep);
+    strict = !(data->iop.cfg.quirks & IO_PGTABLE_QUIRK_NON_STRICT);
+
+    return __arm_lpae_unmap(data, iova, size, lvl, ptep, strict);
  }

  static phys_addr_t arm_lpae_iova_to_phys(struct io_pgtable_ops *ops,

@@ -771,7 +778,8 @@ static void arm_lpae_restrict_pgsizes(struct io_pgtable_cfg *cfg)
      u64 reg;
      struct arm_lpae_io_pgtable *data;

-    if (cfg->quirks & ~(IO_PGTABLE_QUIRK_ARM_NS | IO_PGTABLE_QUIRK_NO_DMA))
+    if (cfg->quirks & ~(IO_PGTABLE_QUIRK_ARM_NS | IO_PGTABLE_QUIRK_NO_DMA |
+            IO_PGTABLE_QUIRK_NON_STRICT))
          return NULL;

      data = arm_lpae_alloc_pgtable(cfg);

@@ -863,7 +871,8 @@ static void arm_lpae_restrict_pgsizes(struct io_pgtable_cfg *cfg)
      struct arm_lpae_io_pgtable *data;

      /* The NS quirk doesn't apply at stage 2 */
-    if (cfg->quirks & ~IO_PGTABLE_QUIRK_NO_DMA)
+    if (cfg->quirks & ~(IO_PGTABLE_QUIRK_NO_DMA |
+        IO_PGTABLE_QUIRK_NON_STRICT))
          return NULL;

      data = arm_lpae_alloc_pgtable(cfg);

diff --git a/drivers/iommu/io-pgtable.h b/drivers/iommu/io-pgtable.h
index 2df7909..beb14a3 100644
--- a/drivers/iommu/io-pgtable.h
+++ b/drivers/iommu/io-pgtable.h

@@ -71,12 +71,15 @@ struct io_pgtable_cfg {
       *    be accessed by a fully cache-coherent IOMMU or CPU (e.g. for a
       *    software-emulated IOMMU), such that pagetable updates need not
       *    be treated as explicit DMA data.
+     * IO_PGTABLE_QUIRK_NON_STRICT: Put off TLBs invalidation and release
+     *    memory first.
       */
      #define IO_PGTABLE_QUIRK_ARM_NS        BIT(0)
      #define IO_PGTABLE_QUIRK_NO_PERMS    BIT(1)
      #define IO_PGTABLE_QUIRK_TLBI_ON_MAP    BIT(2)
      #define IO_PGTABLE_QUIRK_ARM_MTK_4GB    BIT(3)
      #define IO_PGTABLE_QUIRK_NO_DMA        BIT(4)
+    #define IO_PGTABLE_QUIRK_NON_STRICT    BIT(5)
      unsigned long            quirks;
      unsigned long            pgsize_bitmap;
      unsigned int            ias;

-- 
1.8.3

.

-- 
Thanks!
BestRegards