diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index ac62c8f9294b..009bb0112cc0 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -748,7 +748,13 @@ static void spapr_cpu_reset(void *opaque)
         env->external_htab = (void *)1;
     }
     env->htab_base = -1;
-    env->htab_mask = HTAB_SIZE(spapr) - 1;
+    /*
+     * htab_mask is the mask used to normalize hash value to PTEG index.
+     * htab_shift is log2 of hash table size.
+     * We have 8 hpte per group, and each hpte is 16 bytes.
+     * ie have 128 bytes per hpte entry.
+     */
+    env->htab_mask = (1ULL << ((spapr)->htab_shift - 7)) - 1;
     env->spr[SPR_SDR1] = (target_ulong)(uintptr_t)spapr->htab |
         (spapr->htab_shift - 18);
 }
diff --git a/hw/ppc/spapr_hcall.c b/hw/ppc/spapr_hcall.c
index f755a5392317..c6e123b11ab0 100644
--- a/hw/ppc/spapr_hcall.c
+++ b/hw/ppc/spapr_hcall.c
@@ -40,6 +40,17 @@ static target_ulong compute_tlbie_rb(target_ulong v, target_ulong r,
     return rb;
 }
 
+static inline bool valid_pte_index(CPUPPCState *env, target_ulong pte_index)
+{
+    /*
+     * hash value/pteg group index is normalized by htab_mask
+     */
+    if (((pte_index & ~7ULL) / HPTES_PER_GROUP) & ~env->htab_mask) {
+        return false;
+    }
+    return true;
+}
+
 static target_ulong h_enter(PowerPCCPU *cpu, sPAPREnvironment *spapr,
                             target_ulong opcode, target_ulong *args)
 {
@@ -91,7 +102,7 @@ static target_ulong h_enter(PowerPCCPU *cpu, sPAPREnvironment *spapr,
 
     pteh &= ~0x60ULL;
 
-    if ((pte_index * HASH_PTE_SIZE_64) & ~env->htab_mask) {
+    if (!valid_pte_index(env, pte_index)) {
         return H_PARAMETER;
     }
     if (likely((flags & H_EXACT) == 0)) {
@@ -136,7 +147,7 @@ static RemoveResult remove_hpte(CPUPPCState *env, target_ulong ptex,
     hwaddr hpte;
     target_ulong v, r, rb;
 
-    if ((ptex * HASH_PTE_SIZE_64) & ~env->htab_mask) {
+    if (!valid_pte_index(env, ptex)) {
         return REMOVE_PARM;
     }
 
@@ -262,7 +273,7 @@ static target_ulong h_protect(PowerPCCPU *cpu, sPAPREnvironment *spapr,
     hwaddr hpte;
     target_ulong v, r, rb;
 
-    if ((pte_index * HASH_PTE_SIZE_64) & ~env->htab_mask) {
+    if (!valid_pte_index(env, pte_index)) {
         return H_PARAMETER;
     }
 
@@ -299,7 +310,7 @@ static target_ulong h_read(PowerPCCPU *cpu, sPAPREnvironment *spapr,
     uint8_t *hpte;
     int i, ridx, n_entries = 1;
 
-    if ((pte_index * HASH_PTE_SIZE_64) & ~env->htab_mask) {
+    if (!valid_pte_index(env, pte_index)) {
         return H_PARAMETER;
     }
 
diff --git a/target-ppc/cpu.h b/target-ppc/cpu.h
index bb847676a52e..b0f66e5104dd 100644
--- a/target-ppc/cpu.h
+++ b/target-ppc/cpu.h
@@ -961,6 +961,7 @@ struct CPUPPCState {
 #endif
     /* segment registers */
     hwaddr htab_base;
+    /* mask used to normalize hash value to PTEG index */
     hwaddr htab_mask;
     target_ulong sr[32];
     /* externally stored hash table */
diff --git a/target-ppc/kvm.c b/target-ppc/kvm.c
index 781b72f1ea5a..c771ec11ed28 100644
--- a/target-ppc/kvm.c
+++ b/target-ppc/kvm.c
@@ -1029,7 +1029,9 @@ int kvm_arch_get_registers(CPUState *cs)
             return ret;
         }
 
-        ppc_store_sdr1(env, sregs.u.s.sdr1);
+        if (!env->external_htab) {
+            ppc_store_sdr1(env, sregs.u.s.sdr1);
+        }
 
         /* Sync SLB */
 #ifdef TARGET_PPC64
diff --git a/target-ppc/machine.c b/target-ppc/machine.c
index 12c174f7f3e6..2d46ceccca3a 100644
--- a/target-ppc/machine.c
+++ b/target-ppc/machine.c
@@ -70,7 +70,9 @@ static int cpu_load_old(QEMUFile *f, void *opaque, int version_id)
         qemu_get_betls(f, &env->pb[i]);
     for (i = 0; i < 1024; i++)
         qemu_get_betls(f, &env->spr[i]);
-    ppc_store_sdr1(env, sdr1);
+    if (!env->external_htab) {
+        ppc_store_sdr1(env, sdr1);
+    }
     qemu_get_be32s(f, &env->vscr);
     qemu_get_be64s(f, &env->spe_acc);
     qemu_get_be32s(f, &env->spe_fscr);
@@ -179,9 +181,10 @@ static int cpu_post_load(void *opaque, int version_id)
         env->IBAT[1][i+4] = env->spr[SPR_IBAT4U + 2*i + 1];
     }
 
-    /* Restore htab_base and htab_mask variables */
-    ppc_store_sdr1(env, env->spr[SPR_SDR1]);
-
+    if (!env->external_htab) {
+        /* Restore htab_base and htab_mask variables */
+        ppc_store_sdr1(env, env->spr[SPR_SDR1]);
+    }
     hreg_compute_hflags(env);
     hreg_compute_mem_idx(env);
 
diff --git a/target-ppc/misc_helper.c b/target-ppc/misc_helper.c
index 616aab6fb67d..dc2ebfc4524b 100644
--- a/target-ppc/misc_helper.c
+++ b/target-ppc/misc_helper.c
@@ -38,7 +38,9 @@ void helper_store_dump_spr(CPUPPCState *env, uint32_t sprn)
 
 void helper_store_sdr1(CPUPPCState *env, target_ulong val)
 {
-    ppc_store_sdr1(env, val);
+    if (!env->external_htab) {
+        ppc_store_sdr1(env, val);
+    }
 }
 
 void helper_store_hid0_601(CPUPPCState *env, target_ulong val)
diff --git a/target-ppc/mmu_helper.c b/target-ppc/mmu_helper.c
index 04a840b01697..8e2f8e736a12 100644
--- a/target-ppc/mmu_helper.c
+++ b/target-ppc/mmu_helper.c
@@ -2014,6 +2014,7 @@ void ppc_tlb_invalidate_one(CPUPPCState *env, target_ulong addr)
 void ppc_store_sdr1(CPUPPCState *env, target_ulong value)
 {
     LOG_MMU("%s: " TARGET_FMT_lx "\n", __func__, value);
+    assert(!env->external_htab);
     if (env->spr[SPR_SDR1] != value) {
         env->spr[SPR_SDR1] = value;
 #if defined(TARGET_PPC64)
@@ -2025,7 +2026,7 @@ void ppc_store_sdr1(CPUPPCState *env, target_ulong value)
                         " stored in SDR1\n", htabsize);
                 htabsize = 28;
             }
-            env->htab_mask = (1ULL << (htabsize + 18)) - 1;
+            env->htab_mask = (1ULL << (htabsize + 18 - 7)) - 1;
             env->htab_base = value & SDR_64_HTABORG;
         } else
 #endif /* defined(TARGET_PPC64) */
