[RFC PATCH 01/12] hw/arm/smmu: Use enum for SMMU stage

[Mostafa Saleh <smostafa@google.com>]

Currently, translation stage is represented as an int, where 1 is stage-1 and
2 is stage-2, when nested is added, 3 would be confusing to represent nesting,
so we use an enum instead.

While keeping the same values, this is useful for:
 - Doing tricks with bit masks, where BIT(0) is stage-1 and BIT(1) is
   stage-2 and both is nested.
 - Tracing, as stage is printed as int.

Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
 hw/arm/smmu-common.c         | 14 +++++++-------
 hw/arm/smmuv3.c              | 15 ++++++++-------
 include/hw/arm/smmu-common.h | 11 +++++++++--
 3 files changed, 24 insertions(+), 16 deletions(-)

diff --git a/hw/arm/smmu-common.c b/hw/arm/smmu-common.c
index 4caedb4998..3a7c350aca 100644
--- a/hw/arm/smmu-common.c
+++ b/hw/arm/smmu-common.c
@@ -304,7 +304,7 @@ static int smmu_ptw_64_s1(SMMUTransCfg *cfg,
                           SMMUTLBEntry *tlbe, SMMUPTWEventInfo *info)
 {
     dma_addr_t baseaddr, indexmask;
-    int stage = cfg->stage;
+    SMMUStage stage = cfg->stage;
     SMMUTransTableInfo *tt = select_tt(cfg, iova);
     uint8_t level, granule_sz, inputsize, stride;
 
@@ -392,7 +392,7 @@ static int smmu_ptw_64_s1(SMMUTransCfg *cfg,
     info->type = SMMU_PTW_ERR_TRANSLATION;
 
 error:
-    info->stage = 1;
+    info->stage = SMMU_STAGE_1;
     tlbe->entry.perm = IOMMU_NONE;
     return -EINVAL;
 }
@@ -415,7 +415,7 @@ static int smmu_ptw_64_s2(SMMUTransCfg *cfg,
                           dma_addr_t ipa, IOMMUAccessFlags perm,
                           SMMUTLBEntry *tlbe, SMMUPTWEventInfo *info)
 {
-    const int stage = 2;
+    const SMMUStage stage = SMMU_STAGE_2;
     int granule_sz = cfg->s2cfg.granule_sz;
     /* ARM DDI0487I.a: Table D8-7. */
     int inputsize = 64 - cfg->s2cfg.tsz;
@@ -513,7 +513,7 @@ static int smmu_ptw_64_s2(SMMUTransCfg *cfg,
     info->type = SMMU_PTW_ERR_TRANSLATION;
 
 error:
-    info->stage = 2;
+    info->stage = SMMU_STAGE_2;
     tlbe->entry.perm = IOMMU_NONE;
     return -EINVAL;
 }
@@ -532,9 +532,9 @@ error:
 int smmu_ptw(SMMUTransCfg *cfg, dma_addr_t iova, IOMMUAccessFlags perm,
              SMMUTLBEntry *tlbe, SMMUPTWEventInfo *info)
 {
-    if (cfg->stage == 1) {
+    if (cfg->stage == SMMU_STAGE_1) {
         return smmu_ptw_64_s1(cfg, iova, perm, tlbe, info);
-    } else if (cfg->stage == 2) {
+    } else if (cfg->stage == SMMU_STAGE_2) {
         /*
          * If bypassing stage 1(or unimplemented), the input address is passed
          * directly to stage 2 as IPA. If the input address of a transaction
@@ -543,7 +543,7 @@ int smmu_ptw(SMMUTransCfg *cfg, dma_addr_t iova, IOMMUAccessFlags perm,
          */
         if (iova >= (1ULL << cfg->oas)) {
             info->type = SMMU_PTW_ERR_ADDR_SIZE;
-            info->stage = 1;
+            info->stage = SMMU_STAGE_1;
             tlbe->entry.perm = IOMMU_NONE;
             return -EINVAL;
         }
diff --git a/hw/arm/smmuv3.c b/hw/arm/smmuv3.c
index 9eb56a70f3..50e5a72d54 100644
--- a/hw/arm/smmuv3.c
+++ b/hw/arm/smmuv3.c
@@ -34,7 +34,8 @@
 #include "smmuv3-internal.h"
 #include "smmu-internal.h"
 
-#define PTW_RECORD_FAULT(cfg)   (((cfg)->stage == 1) ? (cfg)->record_faults : \
+#define PTW_RECORD_FAULT(cfg)   (((cfg)->stage == SMMU_STAGE_1) ? \
+                                 (cfg)->record_faults : \
                                  (cfg)->s2cfg.record_faults)
 
 /**
@@ -402,7 +403,7 @@ static bool s2_pgtable_config_valid(uint8_t sl0, uint8_t t0sz, uint8_t gran)
 
 static int decode_ste_s2_cfg(SMMUTransCfg *cfg, STE *ste)
 {
-    cfg->stage = 2;
+    cfg->stage = SMMU_STAGE_2;
 
     if (STE_S2AA64(ste) == 0x0) {
         qemu_log_mask(LOG_UNIMP,
@@ -678,7 +679,7 @@ static int decode_cd(SMMUTransCfg *cfg, CD *cd, SMMUEventInfo *event)
 
     /* we support only those at the moment */
     cfg->aa64 = true;
-    cfg->stage = 1;
+    cfg->stage = SMMU_STAGE_1;
 
     cfg->oas = oas2bits(CD_IPS(cd));
     cfg->oas = MIN(oas2bits(SMMU_IDR5_OAS), cfg->oas);
@@ -762,7 +763,7 @@ static int smmuv3_decode_config(IOMMUMemoryRegion *mr, SMMUTransCfg *cfg,
         return ret;
     }
 
-    if (cfg->aborted || cfg->bypassed || (cfg->stage == 2)) {
+    if (cfg->aborted || cfg->bypassed || (cfg->stage == SMMU_STAGE_2)) {
         return 0;
     }
 
@@ -882,7 +883,7 @@ static IOMMUTLBEntry smmuv3_translate(IOMMUMemoryRegion *mr, hwaddr addr,
         goto epilogue;
     }
 
-    if (cfg->stage == 1) {
+    if (cfg->stage == SMMU_STAGE_1) {
         /* Select stage1 translation table. */
         tt = select_tt(cfg, addr);
         if (!tt) {
@@ -919,7 +920,7 @@ static IOMMUTLBEntry smmuv3_translate(IOMMUMemoryRegion *mr, hwaddr addr,
              * nesting is not supported. So it is sufficient to check the
              * translation stage to know the TLB stage for now.
              */
-            event.u.f_walk_eabt.s2 = (cfg->stage == 2);
+            event.u.f_walk_eabt.s2 = (cfg->stage == SMMU_STAGE_2);
             if (PTW_RECORD_FAULT(cfg)) {
                 event.type = SMMU_EVT_F_PERMISSION;
                 event.u.f_permission.addr = addr;
@@ -935,7 +936,7 @@ static IOMMUTLBEntry smmuv3_translate(IOMMUMemoryRegion *mr, hwaddr addr,
 
     if (smmu_ptw(cfg, aligned_addr, flag, cached_entry, &ptw_info)) {
         /* All faults from PTW has S2 field. */
-        event.u.f_walk_eabt.s2 = (ptw_info.stage == 2);
+        event.u.f_walk_eabt.s2 = (ptw_info.stage == SMMU_STAGE_2);
         g_free(cached_entry);
         switch (ptw_info.type) {
         case SMMU_PTW_ERR_WALK_EABT:
diff --git a/include/hw/arm/smmu-common.h b/include/hw/arm/smmu-common.h
index 5ec2e6c1a4..b3c881f0ee 100644
--- a/include/hw/arm/smmu-common.h
+++ b/include/hw/arm/smmu-common.h
@@ -49,8 +49,15 @@ typedef enum {
     SMMU_PTW_ERR_PERMISSION,  /* Permission fault */
 } SMMUPTWEventType;
 
+/* SMMU Stage */
+typedef enum {
+    SMMU_STAGE_1 = 1,
+    SMMU_STAGE_2,
+    SMMU_NESTED,
+} SMMUStage;
+
 typedef struct SMMUPTWEventInfo {
-    int stage;
+    SMMUStage stage;
     SMMUPTWEventType type;
     dma_addr_t addr; /* fetched address that induced an abort, if any */
 } SMMUPTWEventInfo;
@@ -88,7 +95,7 @@ typedef struct SMMUS2Cfg {
  */
 typedef struct SMMUTransCfg {
     /* Shared fields between stage-1 and stage-2. */
-    int stage;                 /* translation stage */
+    SMMUStage stage;           /* translation stage */
     bool disabled;             /* smmu is disabled */
     bool bypassed;             /* translation is bypassed */
     bool aborted;              /* translation is aborted */
-- 
2.44.0.396.g6e790dbe36-goog