[RFC PATCH v3 09/18] hw/arm/smmu-common: Rework TLB lookup for nesting

[Mostafa Saleh]

In the previous patch, comine_tlb() was added which combines 2 TLB
entries into one, which chooses the granule and level from the
smallest entry.

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

However, the lookup for an IOVA in nested configuration is done with
stage-1 granule, 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 | 24 ++++++++++++++++++++++--
 1 file changed, 22 insertions(+), 2 deletions(-)

diff --git a/hw/arm/smmu-common.c b/hw/arm/smmu-common.c
index 0d6945fa54..c67af3bc6d 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 +90,24 @@ SMMUTLBEntry *smmu_iotlb_lookup(SMMUState *bs, SMMUTransCfg 
*cfg,
         }
         level++;
     }
+    return entry;
+}
+
+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++;
-- 
2.44.0.769.g3c40516874-goog