[PATCH v2] target/ppc: Fix ISA v3.0 (POWER9) slbia implementation

[Nicholas Piggin]

The new ISA v3.0 slbia variants have not been implemented for TCG,
which can lead to crashing when a POWER9 machine boots Linux using
the hash MMU, for example ("disable_radix" kernel command line).

Add them.

Signed-off-by: Nicholas Piggin <address@hidden>
---
Changes in v2:
- Rewrite changelog.
- Remove stray slbie hunk that crept in

I don't think the slbie invalidation is necessary, as explained on the
list.

 target/ppc/helper.h     |  2 +-
 target/ppc/mmu-hash64.c | 56 +++++++++++++++++++++++++++++++++++------
 target/ppc/translate.c  |  5 +++-
 3 files changed, 54 insertions(+), 9 deletions(-)

diff --git a/target/ppc/helper.h b/target/ppc/helper.h
index ee1498050d..2dfa1c6942 100644
--- a/target/ppc/helper.h
+++ b/target/ppc/helper.h
@@ -615,7 +615,7 @@ DEF_HELPER_FLAGS_3(store_slb, TCG_CALL_NO_RWG, void, env, 
tl, tl)
 DEF_HELPER_2(load_slb_esid, tl, env, tl)
 DEF_HELPER_2(load_slb_vsid, tl, env, tl)
 DEF_HELPER_2(find_slb_vsid, tl, env, tl)
-DEF_HELPER_FLAGS_1(slbia, TCG_CALL_NO_RWG, void, env)
+DEF_HELPER_FLAGS_2(slbia, TCG_CALL_NO_RWG, void, env, i32)
 DEF_HELPER_FLAGS_2(slbie, TCG_CALL_NO_RWG, void, env, tl)
 DEF_HELPER_FLAGS_2(slbieg, TCG_CALL_NO_RWG, void, env, tl)
 #endif
diff --git a/target/ppc/mmu-hash64.c b/target/ppc/mmu-hash64.c
index 373d44de74..e5baabf0e1 100644
--- a/target/ppc/mmu-hash64.c
+++ b/target/ppc/mmu-hash64.c
@@ -95,9 +95,10 @@ void dump_slb(PowerPCCPU *cpu)
     }
 }
 
-void helper_slbia(CPUPPCState *env)
+void helper_slbia(CPUPPCState *env, uint32_t ih)
 {
     PowerPCCPU *cpu = env_archcpu(env);
+    int starting_entry;
     int n;
 
     /*
@@ -111,18 +112,59 @@ void helper_slbia(CPUPPCState *env)
      * expected that slbmte is more common than slbia, and slbia is usually
      * going to evict valid SLB entries, so that tradeoff is unlikely to be a
      * good one.
+     *
+     * ISA v2.05 introduced IH field with values 0,1,2,6. These all invalidate
+     * the same SLB entries (everything but entry 0), but differ in what
+     * "lookaside information" is invalidated. TCG can ignore this and flush
+     * everything.
+     *
+     * ISA v3.0 introduced additional values 3,4,7, which change what SLBs are
+     * invalidated.
      */
 
-    /* XXX: Warning: slbia never invalidates the first segment */
-    for (n = 1; n < cpu->hash64_opts->slb_size; n++) {
-        ppc_slb_t *slb = &env->slb[n];
+    env->tlb_need_flush |= TLB_NEED_LOCAL_FLUSH;
+
+    starting_entry = 1; /* default for IH=0,1,2,6 */
+
+    if (env->mmu_model == POWERPC_MMU_3_00) {
+        switch (ih) {
+        case 0x7:
+            /* invalidate no SLBs, but all lookaside information */
+            return;
 
-        if (slb->esid & SLB_ESID_V) {
-            slb->esid &= ~SLB_ESID_V;
+        case 0x3:
+        case 0x4:
+            /* also considers SLB entry 0 */
+            starting_entry = 0;
+            break;
+
+        case 0x5:
+            /* treat undefined values as ih==0, and warn */
+            qemu_log_mask(LOG_GUEST_ERROR,
+                          "slbia undefined IH field %u.\n", ih);
+            break;
+
+        default:
+            /* 0,1,2,6 */
+            break;
         }
     }
 
-    env->tlb_need_flush |= TLB_NEED_LOCAL_FLUSH;
+    for (n = starting_entry; n < cpu->hash64_opts->slb_size; n++) {
+        ppc_slb_t *slb = &env->slb[n];
+
+        if (!(slb->esid & SLB_ESID_V)) {
+            continue;
+        }
+        if (env->mmu_model == POWERPC_MMU_3_00) {
+            if (ih == 0x3 && (slb->vsid & SLB_VSID_C) == 0) {
+                /* preserves entries with a class value of 0 */
+                continue;
+            }
+        }
+
+        slb->esid &= ~SLB_ESID_V;
+    }
 }
 
 static void __helper_slbie(CPUPPCState *env, target_ulong addr,
diff --git a/target/ppc/translate.c b/target/ppc/translate.c
index eb0ddba850..e514732a09 100644
--- a/target/ppc/translate.c
+++ b/target/ppc/translate.c
@@ -5027,12 +5027,15 @@ static void gen_tlbsync(DisasContext *ctx)
 /* slbia */
 static void gen_slbia(DisasContext *ctx)
 {
+    uint32_t ih = (ctx->opcode >> 21) & 0x7;
+    TCGv_i32 t0 = tcg_const_i32(ih);
+
 #if defined(CONFIG_USER_ONLY)
     GEN_PRIV;
 #else
     CHK_SV;
 
-    gen_helper_slbia(cpu_env);
+    gen_helper_slbia(cpu_env, t0);
 #endif /* defined(CONFIG_USER_ONLY) */
 }
 
-- 
2.23.0