[PATCH v2 3/6] hw/arm/smmuv3: Check stream IDs against actual table LOG2SIZE

[Simon Veith <sveith@amazon.de>]

When checking whether a stream ID is in range of the stream table, we
have so far been only checking it against our implementation limit
(SMMU_IDR1_SIDSIZE). However, the guest can program the
STRTAB_BASE_CFG.LOG2SIZE field to a size that is smaller than this
limit.

Check the stream ID against this limit as well to match the hardware
behavior of raising C_BAD_STREAMID events in case the limit is exceeded.
Also, ensure that we do not go one entry beyond the end of the table by
checking that its index is strictly smaller than the table size.

ref. ARM IHI 0070C, section 6.3.24.

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:

* Also check that stream ID is strictly lower than the table size

 hw/arm/smmuv3.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/hw/arm/smmuv3.c b/hw/arm/smmuv3.c
index eef9a18..727558b 100644
--- a/hw/arm/smmuv3.c
+++ b/hw/arm/smmuv3.c
@@ -377,11 +377,15 @@ static int smmu_find_ste(SMMUv3State *s, uint32_t sid, STE *ste,
                          SMMUEventInfo *event)
 {
     dma_addr_t addr;
+    uint32_t log2size;
     int ret;
 
     trace_smmuv3_find_ste(sid, s->features, s->sid_split);
-    /* Check SID range */
-    if (sid > (1 << SMMU_IDR1_SIDSIZE)) {
+    log2size = FIELD_EX32(s->strtab_base_cfg, STRTAB_BASE_CFG, LOG2SIZE);
+    /*
+     * Check SID range against both guest-configured and implementation limits
+     */
+    if (sid >= (1 << MIN(log2size, SMMU_IDR1_SIDSIZE))) {
         event->type = SMMU_EVT_C_BAD_STREAMID;
         return -EINVAL;
     }
-- 
2.7.4