[PATCH v4 09/19] hw/arm/smmu-common: Rework TLB lookup for nesting

[Mostafa Saleh]

In the next patch, combine_tlb() will be added which combines 2 TLB
entries into one for nested translations, which chooses the granule
and level from the smallest entry.

This means that with nested translation, an entry can be cached with
the granule of stage-2 and not stage-1.

However, currently, the lookup for an IOVA is done with input stage
granule, which is stage-1 for nested configuration, which will not
work with the above logic.
This patch reworks lookup in that case, so it falls back to stage-2
granule if no entry is found using stage-1 granule.

Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
 hw/arm/smmu-common.c | 36 ++++++++++++++++++++++++++++++++++--
 1 file changed, 34 insertions(+), 2 deletions(-)

diff --git a/hw/arm/smmu-common.c b/hw/arm/smmu-common.c
index 21982621c0..0840b5cffd 100644
--- a/hw/arm/smmu-common.c
+++ b/hw/arm/smmu-common.c
@@ -66,8 +66,10 @@ SMMUIOTLBKey smmu_get_iotlb_key(int asid, int vmid, uint64_t 
iova,
     return key;
 }
 
-SMMUTLBEntry *smmu_iotlb_lookup(SMMUState *bs, SMMUTransCfg *cfg,
-                                SMMUTransTableInfo *tt, hwaddr iova)
+static SMMUTLBEntry *smmu_iotlb_lookup_all_levels(SMMUState *bs,
+                                                  SMMUTransCfg *cfg,
+                                                  SMMUTransTableInfo *tt,
+                                                  hwaddr iova)
 {
     uint8_t tg = (tt->granule_sz - 10) / 2;
     uint8_t inputsize = 64 - tt->tsz;
@@ -88,6 +90,36 @@ SMMUTLBEntry *smmu_iotlb_lookup(SMMUState *bs, SMMUTransCfg 
*cfg,
         }
         level++;
     }
+    return entry;
+}
+
+/**
+ * smmu_iotlb_lookup - Look up for a TLB entry.
+ * @bs: SMMU state which includes the TLB instance
+ * @cfg: Configuration of the translation
+ * @tt: Translation table info (granule and tsz)
+ * @iova: IOVA address to lookup
+ *
+ * returns a valid entry on success, otherwise NULL.
+ * In case of nested translation, tt can be updated to include
+ * the granule of the found entry as it might different from
+ * the IOVA granule.
+ */
+SMMUTLBEntry *smmu_iotlb_lookup(SMMUState *bs, SMMUTransCfg *cfg,
+                                SMMUTransTableInfo *tt, hwaddr iova)
+{
+    SMMUTLBEntry *entry = NULL;
+
+    entry = smmu_iotlb_lookup_all_levels(bs, cfg, tt, iova);
+    /*
+     * For nested translation also try the s2 granule, as the TLB will insert
+     * it if the size of s2 tlb entry was smaller.
+     */
+    if (!entry && (cfg->stage == SMMU_NESTED) &&
+        (cfg->s2cfg.granule_sz != tt->granule_sz)) {
+        tt->granule_sz = cfg->s2cfg.granule_sz;
+        entry = smmu_iotlb_lookup_all_levels(bs, cfg, tt, iova);
+    }
 
     if (entry) {
         cfg->iotlb_hits++;
-- 
2.45.2.803.g4e1b14247a-goog