Document that -singlestep command line option is deprecated

Document that the -singlestep command line option is now
deprecated, as it is replaced by either the TCG accelerator
property 'one-insn-per-tb' for system emulation or the new
'-one-insn-per-tb' option for usermode emulation, and remove
the only use of the deprecated syntax from a README.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-id: 20230417164041.684562-7-peter.maydell@linaro.org

docs/about/deprecated.rst

@@ -111,6 +111,22 @@ Use ``-machine acpi=off`` instead.
 The HAXM project has been retired (see https://github.com/intel/haxm#status).
 Use "whpx" (on Windows) or "hvf" (on macOS) instead.
 
+``-singlestep`` (since 8.1)
+'''''''''''''''''''''''''''
+
+The ``-singlestep`` option has been turned into an accelerator property,
+and given a name that better reflects what it actually does.
+Use ``-accel tcg,one-insn-per-tb=on`` instead.
+
+User-mode emulator command line arguments
+-----------------------------------------
+
+``-singlestep`` (since 8.1)
+'''''''''''''''''''''''''''
+
+The ``-singlestep`` option has been given a name that better reflects
+what it actually does. For both linux-user and bsd-user, use the
+new ``-one-insn-per-tb`` option instead.
 
 QEMU Machine Protocol (QMP) commands
 ------------------------------------

qemu-options.hx

@@ -4192,10 +4192,11 @@ SRST
 ERST
 
 DEF("singlestep", 0, QEMU_OPTION_singlestep, \
-    "-singlestep     always run in singlestep mode\n", QEMU_ARCH_ALL)
+    "-singlestep     deprecated synonym for -accel tcg,one-insn-per-tb=on\n", QEMU_ARCH_ALL)
 SRST
 ``-singlestep``
-    Run the emulation in single step mode.
+    This is a deprecated synonym for the TCG accelerator property
+    ``one-insn-per-tb``.
 ERST
 
 DEF("preconfig", 0, QEMU_OPTION_preconfig, \

tcg/tci/README

@@ -49,7 +49,7 @@ The only difference from running QEMU with TCI to running without TCI
 should be speed. Especially during development of TCI, it was very
 useful to compare runs with and without TCI. Create /tmp/qemu.log by
 
-        qemu-system-i386 -d in_asm,op_opt,cpu -D /tmp/qemu.log -singlestep
+        qemu-system-i386 -d in_asm,op_opt,cpu -D /tmp/qemu.log -accel tcg,one-insn-per-tb=on
 
 once with interpreter and once without interpreter and compare the resulting
 qemu.log files. This is also useful to see the effects of additional