[RFC PATCH 2/3] target/ppc: SMT support for the HID SPR

[Nicholas Piggin <npiggin@gmail.com>]

HID is a per-core shared register, skiboot sets this (e.g., setting
HILE) on one thread and that must affect all threads of the core.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 target/ppc/cpu_init.c    |  2 +-
 target/ppc/helper.h      |  1 +
 target/ppc/misc_helper.c | 21 +++++++++++++++++++++
 target/ppc/spr_common.h  |  1 +
 target/ppc/translate.c   | 16 ++++++++++++++++
 5 files changed, 40 insertions(+), 1 deletion(-)

diff --git a/target/ppc/cpu_init.c b/target/ppc/cpu_init.c
index dc3a65a575..a1b01dc479 100644
--- a/target/ppc/cpu_init.c
+++ b/target/ppc/cpu_init.c
@@ -5373,7 +5373,7 @@ static void register_book3s_ids_sprs(CPUPPCState *env)
     spr_register_hv(env, SPR_HID0, "HID0",
                  SPR_NOACCESS, SPR_NOACCESS,
                  SPR_NOACCESS, SPR_NOACCESS,
-                 &spr_read_generic, &spr_write_generic,
+                 &spr_read_generic, &spr_core_write_generic,
                  0x00000000);
     spr_register_hv(env, SPR_TSCR, "TSCR",
                  SPR_NOACCESS, SPR_NOACCESS,
diff --git a/target/ppc/helper.h b/target/ppc/helper.h
index fda40b8a60..719752b38a 100644
--- a/target/ppc/helper.h
+++ b/target/ppc/helper.h
@@ -704,6 +704,7 @@ DEF_HELPER_3(store_dcr, void, env, tl, tl)
 
 DEF_HELPER_2(load_dump_spr, void, env, i32)
 DEF_HELPER_2(store_dump_spr, void, env, i32)
+DEF_HELPER_3(spr_core_write_generic, void, env, i32, tl)
 DEF_HELPER_3(spr_write_CTRL, void, env, i32, tl)
 
 DEF_HELPER_4(fscr_facility_check, void, env, i32, i32, i32)
diff --git a/target/ppc/misc_helper.c b/target/ppc/misc_helper.c
index 1f1af21f33..0da335472e 100644
--- a/target/ppc/misc_helper.c
+++ b/target/ppc/misc_helper.c
@@ -43,6 +43,27 @@ void helper_store_dump_spr(CPUPPCState *env, uint32_t sprn)
              env->spr[sprn]);
 }
 
+void helper_spr_core_write_generic(CPUPPCState *env, uint32_t sprn,
+                                   target_ulong val)
+{
+    CPUState *cs = env_cpu(env);
+    CPUState *ccs;
+    uint32_t nr_threads = cs->nr_threads;
+    uint32_t core_id = env->spr[SPR_PIR] & ~(nr_threads - 1);
+
+    assert(core_id == env->spr[SPR_PIR] - env->spr[SPR_TIR]);
+
+    if (nr_threads == 1) {
+        env->spr[sprn] = val;
+        return;
+    }
+
+    THREAD_SIBLING_FOREACH(cs, ccs) {
+        CPUPPCState *cenv = &POWERPC_CPU(ccs)->env;
+        cenv->spr[sprn] = val;
+    }
+}
+
 void helper_spr_write_CTRL(CPUPPCState *env, uint32_t sprn,
                            target_ulong val)
 {
diff --git a/target/ppc/spr_common.h b/target/ppc/spr_common.h
index 4c0f2bed77..aae66ee966 100644
--- a/target/ppc/spr_common.h
+++ b/target/ppc/spr_common.h
@@ -82,6 +82,7 @@ void spr_noaccess(DisasContext *ctx, int gprn, int sprn);
 void spr_read_generic(DisasContext *ctx, int gprn, int sprn);
 void spr_write_generic(DisasContext *ctx, int sprn, int gprn);
 void spr_write_generic32(DisasContext *ctx, int sprn, int gprn);
+void spr_core_write_generic(DisasContext *ctx, int sprn, int gprn);
 void spr_write_MMCR0(DisasContext *ctx, int sprn, int gprn);
 void spr_write_MMCR1(DisasContext *ctx, int sprn, int gprn);
 void spr_write_PMC(DisasContext *ctx, int sprn, int gprn);
diff --git a/target/ppc/translate.c b/target/ppc/translate.c
index ef186396b4..f7a5ecc0c1 100644
--- a/target/ppc/translate.c
+++ b/target/ppc/translate.c
@@ -448,6 +448,22 @@ void spr_write_generic32(DisasContext *ctx, int sprn, int gprn)
 #endif
 }
 
+void spr_core_write_generic(DisasContext *ctx, int sprn, int gprn)
+{
+    if (!(ctx->flags & POWERPC_FLAG_SMT)) {
+        spr_write_generic(ctx, sprn, gprn);
+        return;
+    }
+
+    if (!gen_serialize(ctx)) {
+        return;
+    }
+
+    gen_helper_spr_core_write_generic(cpu_env, tcg_constant_i32(sprn),
+                                      cpu_gpr[gprn]);
+    spr_store_dump_spr(sprn);
+}
+
 static void spr_write_CTRL_ST(DisasContext *ctx, int sprn, int gprn)
 {
     /* This does not implement >1 thread */
-- 
2.40.1