[RFC PATCH 10/12] hw/arm/smmu: Refactor SMMU OAS

[Mostafa Saleh]

SMMUv3 OAS is hardcoded to 44 bits, for nested configurations that
can be a problem as stage-2 might be shared with the CPU which might
have different PARANGE, and according to SMMU manual ARM IHI 0070F.b:
    6.3.6 SMMU_IDR5, OAS must match the system physical address size.

This patch doesn't change the SMMU OAS, but refactors the code to
make it easier to do that:
- Rely everywhere on IDR5 for reading OAS instead of using the macro so
  it is easier just change IDR5 and it propagages correctly.
- Make the code work if OAS is 52 bits.
- Remove unused functions/macros: pa_range/MAX_PA

Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
 hw/arm/smmu-common.c     |  7 ++++---
 hw/arm/smmuv3-internal.h | 15 ++-------------
 hw/arm/smmuv3.c          | 35 ++++++++++++++++++++++++++++-------
 3 files changed, 34 insertions(+), 23 deletions(-)

diff --git a/hw/arm/smmu-common.c b/hw/arm/smmu-common.c
index da8776ecec..a4196ddd22 100644
--- a/hw/arm/smmu-common.c
+++ b/hw/arm/smmu-common.c
@@ -359,7 +359,8 @@ static int smmu_ptw_64_s1(SMMUTransCfg *cfg,
     inputsize = 64 - tt->tsz;
     level = 4 - (inputsize - 4) / stride;
     indexmask = VMSA_IDXMSK(inputsize, stride, level);
-    baseaddr = extract64(tt->ttb, 0, 48);
+
+    baseaddr = extract64(tt->ttb, 0, cfg->oas);
     baseaddr &= ~indexmask;
 
     while (level < VMSA_LEVELS) {
@@ -472,8 +473,8 @@ static int smmu_ptw_64_s2(SMMUTransCfg *cfg,
      * Get the ttb from concatenated structure.
      * The offset is the idx * size of each ttb(number of ptes * (sizeof(pte))
      */
-    uint64_t baseaddr = extract64(cfg->s2cfg.vttb, 0, 48) + (1 << stride) *
-                                  idx * sizeof(uint64_t);
+    uint64_t baseaddr = extract64(cfg->s2cfg.vttb, 0, cfg->s2cfg.eff_ps) +
+                                  (1 << stride) * idx * sizeof(uint64_t);
     dma_addr_t indexmask = VMSA_IDXMSK(inputsize, stride, level);
 
     baseaddr &= ~indexmask;
diff --git a/hw/arm/smmuv3-internal.h b/hw/arm/smmuv3-internal.h
index e4dd11e1e6..a7d53b3854 100644
--- a/hw/arm/smmuv3-internal.h
+++ b/hw/arm/smmuv3-internal.h
@@ -592,23 +592,12 @@ static inline int oas2bits(int oas_field)
         return 44;
     case 5:
         return 48;
+    case 6:
+        return 52;
     }
     return -1;
 }
 
-static inline int pa_range(STE *ste)
-{
-    int oas_field = MIN(STE_S2PS(ste), SMMU_IDR5_OAS);
-
-    if (!STE_S2AA64(ste)) {
-        return 40;
-    }
-
-    return oas2bits(oas_field);
-}
-
-#define MAX_PA(ste) ((1 << pa_range(ste)) - 1)
-
 /* CD fields */
 
 #define CD_VALID(x)   extract32((x)->word[0], 31, 1)
diff --git a/hw/arm/smmuv3.c b/hw/arm/smmuv3.c
index 288e7cf1ae..2a29e3bccb 100644
--- a/hw/arm/smmuv3.c
+++ b/hw/arm/smmuv3.c
@@ -411,10 +411,10 @@ static bool s2t0sz_valid(SMMUTransCfg *cfg)
     }
 
     if (cfg->s2cfg.granule_sz == 16) {
-        return (cfg->s2cfg.tsz >= 64 - oas2bits(SMMU_IDR5_OAS));
+        return (cfg->s2cfg.tsz >= 64 - cfg->s2cfg.eff_ps);
     }
 
-    return (cfg->s2cfg.tsz >= MAX(64 - oas2bits(SMMU_IDR5_OAS), 16));
+    return (cfg->s2cfg.tsz >= MAX(64 - cfg->s2cfg.eff_ps, 16));
 }
 
 /*
@@ -435,8 +435,11 @@ static bool s2_pgtable_config_valid(uint8_t sl0, uint8_t 
t0sz, uint8_t gran)
     return nr_concat <= VMSA_MAX_S2_CONCAT;
 }
 
-static int decode_ste_s2_cfg(SMMUTransCfg *cfg, STE *ste)
+static int decode_ste_s2_cfg(SMMUv3State *s, SMMUTransCfg *cfg,
+                             STE *ste)
 {
+    uint8_t oas = FIELD_EX32(s->idr[5], IDR5, OAS);
+
     if (STE_S2AA64(ste) == 0x0) {
         qemu_log_mask(LOG_UNIMP,
                       "SMMUv3 AArch32 tables not supported\n");
@@ -469,7 +472,15 @@ static int decode_ste_s2_cfg(SMMUTransCfg *cfg, STE *ste)
     }
 
     /* For AA64, The effective S2PS size is capped to the OAS. */
-    cfg->s2cfg.eff_ps = oas2bits(MIN(STE_S2PS(ste), SMMU_IDR5_OAS));
+    cfg->s2cfg.eff_ps = oas2bits(MIN(STE_S2PS(ste), oas));
+    /*
+     * For SMMUv3.1 and later, when OAS == IAS == 52, the stage 2 input
+     * range is further limited to 48 bits unless STE.S2TG indicates a
+     * 64KB granule.
+     */
+    if (cfg->s2cfg.granule_sz != 16) {
+        cfg->s2cfg.eff_ps = MIN(cfg->s2cfg.eff_ps, 48);
+    }
     /*
      * It is ILLEGAL for the address in S2TTB to be outside the range
      * described by the effective S2PS value.
@@ -545,6 +556,7 @@ static int decode_ste(SMMUv3State *s, SMMUTransCfg *cfg,
                       STE *ste, SMMUEventInfo *event)
 {
     uint32_t config;
+    uint8_t oas = FIELD_EX32(s->idr[5], IDR5, OAS);
     int ret;
 
     if (!STE_VALID(ste)) {
@@ -591,8 +603,8 @@ static int decode_ste(SMMUv3State *s, SMMUTransCfg *cfg,
          * Stage-1 OAS defaults to OAS even if not enabled as it would be used
          * in input address check for stage-2.
          */
-        cfg->oas = oas2bits(SMMU_IDR5_OAS);
-        ret = decode_ste_s2_cfg(cfg, ste);
+        cfg->oas = oas2bits(oas);
+        ret = decode_ste_s2_cfg(s, cfg, ste);
         if (ret) {
             goto bad_ste;
         }
@@ -718,6 +730,7 @@ static int decode_cd(SMMUv3State *s, SMMUTransCfg *cfg,
     int i;
     SMMUTranslationStatus status;
     SMMUTLBEntry *entry;
+    uint8_t oas = FIELD_EX32(s->idr[5], IDR5, OAS);
 
     if (!CD_VALID(cd) || !CD_AARCH64(cd)) {
         goto bad_cd;
@@ -736,7 +749,7 @@ static int decode_cd(SMMUv3State *s, SMMUTransCfg *cfg,
     cfg->aa64 = true;
 
     cfg->oas = oas2bits(CD_IPS(cd));
-    cfg->oas = MIN(oas2bits(SMMU_IDR5_OAS), cfg->oas);
+    cfg->oas = MIN(oas2bits(oas), cfg->oas);
     cfg->tbi = CD_TBI(cd);
     cfg->asid = CD_ASID(cd);
     cfg->affd = CD_AFFD(cd);
@@ -765,6 +778,14 @@ static int decode_cd(SMMUv3State *s, SMMUTransCfg *cfg,
             goto bad_cd;
         }
 
+        /*
+         * An address greater than 48 bits in size can only be output from a
+         * TTD when, in SMMUv3.1 and later, the effective IPS is 52 and a 64KB
+         * granule is in use for that translation table
+         */
+        if (tt->granule_sz != 16) {
+            cfg->oas = MIN(cfg->oas, 48);
+        }
         tt->tsz = tsz;
         tt->ttb = CD_TTB(cd, i);
 
-- 
2.44.0.396.g6e790dbe36-goog