[Qemu-devel] [PATCH -V8 1/3] target-ppc: Fix htab_mask calculation

["Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>]

From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>

Correctly update the htab_mask using the return value of
KVM_PPC_ALLOCATE_HTAB ioctl. Also we don't update sdr1
on GET_SREGS for HV. So don't update htab_mask if sdr1
is found to be zero. Fix the pte index calculation to be
same as that found in the kernel

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 hw/ppc/spapr.c          | 8 +++++++-
 target-ppc/cpu.h        | 1 +
 target-ppc/mmu_helper.c | 4 +++-
 3 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 267a47d6cc4d..e99a66170661 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -731,7 +731,13 @@ static void spapr_cpu_reset(void *opaque)
 
     env->external_htab = (uint8_t *)spapr->htab;
     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/target-ppc/cpu.h b/target-ppc/cpu.h
index 26acdba847fa..82db9a442be5 100644
--- a/target-ppc/cpu.h
+++ b/target-ppc/cpu.h
@@ -955,6 +955,7 @@ 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/mmu_helper.c b/target-ppc/mmu_helper.c
index 04a840b01697..c39cb7b89ee0 100644
--- a/target-ppc/mmu_helper.c
+++ b/target-ppc/mmu_helper.c
@@ -2025,7 +2025,9 @@ void ppc_store_sdr1(CPUPPCState *env, target_ulong value)
                         " stored in SDR1\n", htabsize);
                 htabsize = 28;
             }
-            env->htab_mask = (1ULL << (htabsize + 18)) - 1;
+            if (htabsize) {
+                env->htab_mask = (1ULL << (htabsize + 18 - 7)) - 1;
+            }
             env->htab_base = value & SDR_64_HTABORG;
         } else
 #endif /* defined(TARGET_PPC64) */
-- 
1.8.3.2