tcg: add "-accel tcg,tb-size" and deprecate "-tb-size"

-tb-size fits nicely in the new framework for accelerator-specific options.  It
is a very niche option, so insta-deprecate it.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

accel/tcg/tcg-all.c

@@ -34,11 +34,13 @@
 #include "include/qapi/error.h"
 #include "include/qemu/error-report.h"
 #include "include/hw/boards.h"
+#include "qapi/qapi-builtin-visit.h"
 
 typedef struct TCGState {
     AccelState parent_obj;
 
     bool mttcg_enabled;
+    unsigned long tb_size;
 } TCGState;
 
 #define TYPE_TCG_ACCEL ACCEL_CLASS_NAME("tcg")
@@ -46,8 +48,6 @@ typedef struct TCGState {
 #define TCG_STATE(obj) \
         OBJECT_CHECK(TCGState, (obj), TYPE_TCG_ACCEL)
 
-unsigned long tcg_tb_size;
-
 /* mask must never be zero, except for A20 change call */
 static void tcg_handle_interrupt(CPUState *cpu, int mask)
 {
@@ -126,7 +126,7 @@ static int tcg_init(MachineState *ms)
 {
     TCGState *s = TCG_STATE(current_machine->accelerator);
 
-    tcg_exec_init(tcg_tb_size * 1024 * 1024);
+    tcg_exec_init(s->tb_size * 1024 * 1024);
     cpu_interrupt_handler = tcg_handle_interrupt;
     mttcg_enabled = s->mttcg_enabled;
     return 0;
@@ -167,6 +167,33 @@ static void tcg_set_thread(Object *obj, const char *value, Error **errp)
     }
 }
 
+static void tcg_get_tb_size(Object *obj, Visitor *v,
+                            const char *name, void *opaque,
+                            Error **errp)
+{
+    TCGState *s = TCG_STATE(obj);
+    uint32_t value = s->tb_size;
+
+    visit_type_uint32(v, name, &value, errp);
+}
+
+static void tcg_set_tb_size(Object *obj, Visitor *v,
+                            const char *name, void *opaque,
+                            Error **errp)
+{
+    TCGState *s = TCG_STATE(obj);
+    Error *error = NULL;
+    uint32_t value;
+
+    visit_type_uint32(v, name, &value, &error);
+    if (error) {
+        error_propagate(errp, error);
+        return;
+    }
+
+    s->tb_size = value;
+}
+
 static void tcg_accel_class_init(ObjectClass *oc, void *data)
 {
     AccelClass *ac = ACCEL_CLASS(oc);
@@ -178,6 +205,13 @@ static void tcg_accel_class_init(ObjectClass *oc, void *data)
                                   tcg_get_thread,
                                   tcg_set_thread,
                                   NULL);
+
+    object_class_property_add(oc, "tb-size", "int",
+        tcg_get_tb_size, tcg_set_tb_size,
+        NULL, NULL, &error_abort);
+    object_class_property_set_description(oc, "tb-size",
+        "TCG translation block cache size", &error_abort);
+
 }
 
 static const TypeInfo tcg_accel_type = {

include/sysemu/accel.h

@@ -64,8 +64,6 @@ typedef struct AccelClass {
 #define ACCEL_GET_CLASS(obj) \
     OBJECT_GET_CLASS(AccelClass, (obj), TYPE_ACCEL)
 
-extern unsigned long tcg_tb_size;
-
 AccelClass *accel_find(const char *opt_name);
 int accel_init_machine(AccelState *accel, MachineState *ms);
 

qemu-deprecated.texi

@@ -142,6 +142,12 @@ QEMU 4.1 has three options, please migrate to one of these three:
       to do is specify the kernel they want to boot with the -kernel option
  3. ``-bios <file>`` - Tells QEMU to load the specified file as the firmwrae.
 
+@subsection -tb-size option (since 5.0)
+
+QEMU 5.0 introduced an alternative syntax to specify the size of the translation
+block cache, @option{-accel tcg,tb-size=}.  The new syntax deprecates the
+previously available @option{-tb-size} option.
+
 @section QEMU Machine Protocol (QMP) commands
 
 @subsection change (since 2.5.0)

qemu-options.hx

@@ -118,8 +118,9 @@ Select CPU model (@code{-cpu help} for list and additional feature selection)
 ETEXI
 
 DEF("accel", HAS_ARG, QEMU_OPTION_accel,
-    "-accel [accel=]accelerator[,thread=single|multi]\n"
+    "-accel [accel=]accelerator[,prop[=value][,...]]\n"
     "                select accelerator (kvm, xen, hax, hvf, whpx or tcg; use 'help' for a list)\n"
+    "                tb-size=n (TCG translation block cache size)\n"
     "                thread=single|multi (enable multi-threaded TCG)\n", QEMU_ARCH_ALL)
 STEXI
 @item -accel @var{name}[,prop=@var{value}[,...]]
@@ -129,6 +130,8 @@ kvm, xen, hax, hvf, whpx or tcg can be available. By default, tcg is used. If th
 more than one accelerator specified, the next one is used if the previous one
 fails to initialize.
 @table @option
+@item tb-size=@var{n}
+Controls the size (in MiB) of the TCG translation block cache.
 @item thread=single|multi
 Controls number of TCG threads. When the TCG is multi-threaded there will be one
 thread per vCPU therefor taking advantage of additional host cores. The default
@@ -3923,7 +3926,8 @@ DEF("tb-size", HAS_ARG, QEMU_OPTION_tb_size, \
 STEXI
 @item -tb-size @var{n}
 @findex -tb-size
-Set TB size.
+Set TCG translation block cache size.  Deprecated, use @samp{-accel tcg,tb-size=@var{n}}
+instead.
 ETEXI
 
 DEF("incoming", HAS_ARG, QEMU_OPTION_incoming, \

vl.c

@@ -2727,6 +2727,7 @@ static int do_configure_accelerator(void *opaque, QemuOpts *opts, Error **errp)
         return 0;
     }
     accel = ACCEL(object_new_with_class(OBJECT_CLASS(ac)));
+    object_apply_compat_props(OBJECT(accel));
     qemu_opt_foreach(opts, accelerator_set_property,
                      accel,
                      &error_fatal);
@@ -2738,6 +2739,7 @@ static int do_configure_accelerator(void *opaque, QemuOpts *opts, Error **errp)
                      acc, strerror(-ret));
         return 0;
     }
+
     return 1;
 }
 
@@ -3590,10 +3592,8 @@ int main(int argc, char **argv, char **envp)
                 error_report("TCG is disabled");
                 exit(1);
 #endif
-                if (qemu_strtoul(optarg, NULL, 0, &tcg_tb_size) < 0) {
-                    error_report("Invalid argument to -tb-size");
-                    exit(1);
-                }
+                warn_report("The -tb-size option is deprecated, use -accel tcg,tb-size instead");
+                object_register_sugar_prop(ACCEL_CLASS_NAME("tcg"), "tb-size", optarg);
                 break;
             case QEMU_OPTION_icount:
                 icount_opts = qemu_opts_parse_noisily(qemu_find_opts("icount"),