[PATCH v2 4/6] hw/arm/smmuv3: Align stream table base address to table size

[Simon Veith <sveith@amazon.de>]

Per the specification, and as observed in hardware, the SMMUv3 aligns
the SMMU_STRTAB_BASE address to the size of the table by masking out the
respective least significant bits in the ADDR field.

Apply this masking logic to our smmu_find_ste() lookup function per the
specification.

ref. ARM IHI 0070C, section 6.3.23.

Signed-off-by: Simon Veith <sveith@amazon.de>
Cc: Eric Auger <eric.auger@redhat.com>
Cc: qemu-devel@nongnu.org
Cc: qemu-arm@nongnu.org
---
Changed in v2:

* Now using MAKE_64BIT_MASK()
* Eliminated unnecessary branches by using MAX()
* Removed unnecessary range check against DMA_ADDR_BITS

 hw/arm/smmuv3.c | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/hw/arm/smmuv3.c b/hw/arm/smmuv3.c
index 727558b..31ac3ca 100644
--- a/hw/arm/smmuv3.c
+++ b/hw/arm/smmuv3.c
@@ -376,8 +376,9 @@ bad_ste:
 static int smmu_find_ste(SMMUv3State *s, uint32_t sid, STE *ste,
                          SMMUEventInfo *event)
 {
-    dma_addr_t addr;
+    dma_addr_t addr, strtab_base;
     uint32_t log2size;
+    int strtab_size_shift;
     int ret;
 
     trace_smmuv3_find_ste(sid, s->features, s->sid_split);
@@ -391,10 +392,16 @@ static int smmu_find_ste(SMMUv3State *s, uint32_t sid, STE *ste,
     }
     if (s->features & SMMU_FEATURE_2LVL_STE) {
         int l1_ste_offset, l2_ste_offset, max_l2_ste, span;
-        dma_addr_t strtab_base, l1ptr, l2ptr;
+        dma_addr_t l1ptr, l2ptr;
         STEDesc l1std;
 
-        strtab_base = s->strtab_base & SMMU_BASE_ADDR_MASK;
+        /*
+         * Align strtab base address to table size. For this purpose, assume it
+         * is not bounded by SMMU_IDR1_SIDSIZE.
+         */
+        strtab_size_shift = MAX(5, (int)log2size - s->sid_split - 1 + 3);
+        strtab_base = s->strtab_base & SMMU_BASE_ADDR_MASK &
+                      ~MAKE_64BIT_MASK(0, strtab_size_shift);
         l1_ste_offset = sid >> s->sid_split;
         l2_ste_offset = sid & ((1 << s->sid_split) - 1);
         l1ptr = (dma_addr_t)(strtab_base + l1_ste_offset * sizeof(l1std));
@@ -433,7 +440,10 @@ static int smmu_find_ste(SMMUv3State *s, uint32_t sid, STE *ste,
         }
         addr = l2ptr + l2_ste_offset * sizeof(*ste);
     } else {
-        addr = (s->strtab_base & SMMU_BASE_ADDR_MASK) + sid * sizeof(*ste);
+        strtab_size_shift = log2size + 5;
+        strtab_base = s->strtab_base & SMMU_BASE_ADDR_MASK &
+                      ~MAKE_64BIT_MASK(0, strtab_size_shift);
+        addr = strtab_base + sid * sizeof(*ste);
     }
 
     if (smmu_get_ste(s, addr, ste, event)) {
-- 
2.7.4