[Qemu-devel] [PATCH -V2 1/4] target-ppc: Update slb array with correct index values.

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

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

Without this, a value of rb=0 and rs=0 results in replacing the 0th
index. This can be observed when using gdb remote debugging support.

(gdb) x/10i do_fork
   0xc000000000085330 <do_fork>:        Cannot access memory at address 0xc000000000085330
(gdb)

This is because when we do the slb sync via kvm_cpu_synchronize_state,
we overwrite the slb entry (0th entry) for 0xc000000000085330

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 target-ppc/kvm.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/target-ppc/kvm.c b/target-ppc/kvm.c
index 30a870e..a629447 100644
--- a/target-ppc/kvm.c
+++ b/target-ppc/kvm.c
@@ -1034,8 +1034,18 @@ int kvm_arch_get_registers(CPUState *cs)
         /* Sync SLB */
 #ifdef TARGET_PPC64
         for (i = 0; i < 64; i++) {
-            ppc_store_slb(env, sregs.u.s.ppc64.slb[i].slbe,
-                               sregs.u.s.ppc64.slb[i].slbv);
+            target_ulong rb = sregs.u.s.ppc64.slb[i].slbe;
+            /*
+             * KVM_GET_SREGS doesn't retun slb entry with slot information
+             * same as index. So don't depend on the slot information in
+             * the returned value.
+             */
+            rb &= ~0xfff;
+            /*
+             * use the array index as the slot
+             */
+            rb |= i;
+            ppc_store_slb(env, rb, sregs.u.s.ppc64.slb[i].slbv);
         }
 #endif
 
-- 
1.8.1.2