[PATCH v3 06/10] accel/tcg: Move post-load tb_flush to vm_change_state hook

[Richard Henderson <richard.henderson@linaro.org>]

We need not call tb_flush once per cpu, only once per vmload.

By moving the call from cpu_common_post_load to a tcg-specific
vm_change_state_handler, we do even better than that: we only
flush when called from HMP triggered loadvm, when we had old
state to flush.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 accel/tcg/tcg-all.c  | 21 +++++++++++++++++++++
 hw/core/cpu-system.c |  9 ---------
 2 files changed, 21 insertions(+), 9 deletions(-)

diff --git a/accel/tcg/tcg-all.c b/accel/tcg/tcg-all.c
index 5125e1a4e2..18ea0c58b0 100644
--- a/accel/tcg/tcg-all.c
+++ b/accel/tcg/tcg-all.c
@@ -38,6 +38,8 @@
 #include "qemu/target-info.h"
 #ifndef CONFIG_USER_ONLY
 #include "hw/boards.h"
+#include "exec/tb-flush.h"
+#include "system/runstate.h"
 #endif
 #include "accel/accel-ops.h"
 #include "accel/accel-cpu-ops.h"
@@ -82,6 +84,23 @@ static void tcg_accel_instance_init(Object *obj)
 
 bool one_insn_per_tb;
 
+#ifndef CONFIG_USER_ONLY
+static void tcg_vm_change_state(void *opaque, bool running, RunState state)
+{
+    if (state == RUN_STATE_RESTORE_VM) {
+        /*
+         * loadvm will update the content of RAM, bypassing the usual
+         * mechanisms that ensure we flush TBs for writes to memory
+         * we've translated code from, so we must flush all TBs.
+         *
+         * vm_stop() has just stopped all cpus, so we are exclusive.
+         */
+        assert(!running);
+        tb_flush__exclusive_or_serial();
+    }
+}
+#endif
+
 static int tcg_init_machine(AccelState *as, MachineState *ms)
 {
     TCGState *s = TCG_STATE(as);
@@ -124,6 +143,8 @@ static int tcg_init_machine(AccelState *as, MachineState *ms)
     default:
         g_assert_not_reached();
     }
+
+    qemu_add_vm_change_state_handler(tcg_vm_change_state, NULL);
 #endif
 
     tcg_allowed = true;
diff --git a/hw/core/cpu-system.c b/hw/core/cpu-system.c
index 09c928c1f9..f601a083d1 100644
--- a/hw/core/cpu-system.c
+++ b/hw/core/cpu-system.c
@@ -23,7 +23,6 @@
 #include "system/address-spaces.h"
 #include "exec/cputlb.h"
 #include "system/memory.h"
-#include "exec/tb-flush.h"
 #include "qemu/target-info.h"
 #include "hw/qdev-core.h"
 #include "hw/qdev-properties.h"
@@ -207,14 +206,6 @@ static int cpu_common_post_load(void *opaque, int version_id)
         cpu_reset_interrupt(cpu, 0x01);
 
         tlb_flush(cpu);
-
-        /*
-         * loadvm has just updated the content of RAM, bypassing the
-         * usual mechanisms that ensure we flush TBs for writes to
-         * memory we've translated code from. So we must flush all TBs,
-         * which will now be stale.
-         */
-        tb_flush(cpu);
     }
 
     return 0;
-- 
2.43.0