The command line option '-singlestep' and its HMP equivalent the 'singlestep' command are very confusingly named, because they have nothing to do with single-stepping the guest (either via the gdb stub or by emulation of guest CPU architectural debug facilities). What they actually do is put TCG into a mode where it puts only one guest instruction into each translation block. This is useful for some circumstances such as when you want the -d debug logging to be easier to interpret, or if you have a finicky guest binary that wants to see interrupts delivered at something other than the end of a basic block. The confusing name is made worse by the fact that our documentation for these is so minimal as to be useless for telling users what they really do. This series: * changes the command line interface: for user-mode emulators, the new option is '-one-insn-per-tb', and for system mode emulators it is a TCG accel property '-accel tcg,one-insn-per-tb=on' * updates all the places which currently directly touch the 'singlestep' global variable to instead get the current accelerator and query/set the QOM property (except the one internal to TCG itself in curr_cflags()) * documents that the old -singlestep option is deprecated * adds a new HMP command 'one-insn-per-tb', and deprecates the old 'singlestep' command. (Strictly we don't need to deprecate HMP commands, but I'd already written the code for v1 of this series and it's a minor user convenience.) * moves the 'is one-insn-per-tb on?' info from 'info status' to 'info jit' * deprecates the 'singlestep' member of the QMP StatusInfo type, with no replacement. (We have a sketch of a design of how we might provide this in QMP if we need to, but I'm pretty sure nobody using QMP is actually using the info in the 'singlestep' field, especially since it's always been wrongly documented and there's no write interface, only a read one.) Changes v2->v3: * curr_cflags() is a hot path, so use a global variable so it doesn't have to fetch the current accelerator object. (NB: I haven't done the tcg_global_cflags thing suggested in review of v2; justification in the below-the-fold part of the patch 3 commit message notes.) * put the new line in test-hmp.c in its proper alphabetical order place in patch 8 * in patch 10 don't provide a replacement field in the QMP StatusInfo type, just deprecate the old one * I finally tested that bsd-user compiles, and fixed the missing-close-bracket error in that patch :-) Patches still needing review: 3, 7, 10 thanks -- PMM Peter Maydell (10): make one-insn-per-tb an accel option softmmu: Don't use 'singlestep' global in QMP and HMP commands accel/tcg: Use one_insn_per_tb global instead of old singlestep global linux-user: Add '-one-insn-per-tb' option equivalent to '-singlestep' bsd-user: Add '-one-insn-per-tb' option equivalent to '-singlestep' Document that -singlestep command line option is deprecated accel/tcg: Report one-insn-per-tb in 'info jit', not 'info status' hmp: Add 'one-insn-per-tb' command equivalent to 'singlestep' qapi/run-state.json: Fix missing newline at end of file hmp: Deprecate 'singlestep' member of StatusInfo docs/about/deprecated.rst | 39 +++++++++++++++++++++++++++++++++++++ docs/user/main.rst | 14 +++++++++++-- qapi/run-state.json | 16 +++++++++++---- accel/tcg/internal.h | 2 ++ include/exec/cpu-common.h | 2 -- include/monitor/hmp.h | 2 +- accel/tcg/cpu-exec.c | 2 +- accel/tcg/monitor.c | 14 +++++++++++++ accel/tcg/tcg-all.c | 23 ++++++++++++++++++++++ bsd-user/main.c | 14 ++++++++----- linux-user/main.c | 18 +++++++++++------ softmmu/globals.c | 1 - softmmu/runstate-hmp-cmds.c | 25 ++++++++++++++++++------ softmmu/runstate.c | 10 +++++++++- softmmu/vl.c | 17 ++++++++++++++-- tests/qtest/test-hmp.c | 1 + hmp-commands.hx | 25 ++++++++++++++++++++---- qemu-options.hx | 12 ++++++++++-- tcg/tci/README | 2 +- 19 files changed, 201 insertions(+), 38 deletions(-) -- 2.34.1
