Hi,
Sorry for necrobumping this thread. I just wanted to follow up on this
and ask if there is still interest in this plugin API extension or if it
is going to be dropped in favor of the Lorelei patches (which would also
fulfill my original use case).
Thanks for your time,
Florian
On 06/10/2025 15:21, Florian Hofhammer wrote:
> Hi,
>
> As originally discussed in the thread at
> https://lists.nongnu.org/archive/html/qemu-devel/2025-08/msg00656.html
> and later proposed in a patch at
> https://lists.nongnu.org/archive/html/qemu-devel/2025-09/msg02218.html,
> I am sending an updated version of my patch based on the previous
> feedback.
>
> Notable changes to v1:
> - Added a setjmp() in the syscall handling path to allow redirecting
> the PC via cpu_loop_exit() also in syscall callbacks. The previous
> version would only work in instruction execution / memory access
> callback contexts, as the setjmp() corresponding to the longjmp() in
> cpu_loop_exit() was only live in those contexts.
> - Added a flag to make sure the new API function is only called in
> contexts where it makes sense, i.e., during execution of guest code.
> - Added a test that checks the new functionality by skipping a
> non-existent sentinel syscall.
>
> I made it an RFC patch this time as I am not entirely sure if my
> setting/handling of the new flag makes sense the way it is. I briefly
> looked into making the QEMU_PLUGIN_CB_* flags actual flags via a
> bitfield instead of enum values, but that would have required touching
> a lot of code all over the place, so I'm not sure this is the way to go.
>
> Happy to get feedback and your thoughts on the patches!
>
> Thanks,
> Florian
>
>
> Florian Hofhammer (2):
> plugins: Add PC diversion API function
> tests/tcg: add test for qemu_plugin_set_pc API
>
> include/qemu/qemu-plugin.h | 15 +++++++
> linux-user/aarch64/cpu_loop.c | 2 +-
> linux-user/alpha/cpu_loop.c | 2 +-
> linux-user/arm/cpu_loop.c | 2 +-
> linux-user/hexagon/cpu_loop.c | 2 +-
> linux-user/hppa/cpu_loop.c | 4 ++
> linux-user/i386/cpu_loop.c | 8 ++--
> linux-user/include/special-errno.h | 8 ++++
> linux-user/loongarch64/cpu_loop.c | 5 ++-
> linux-user/m68k/cpu_loop.c | 2 +-
> linux-user/microblaze/cpu_loop.c | 2 +-
> linux-user/mips/cpu_loop.c | 5 ++-
> linux-user/openrisc/cpu_loop.c | 2 +-
> linux-user/ppc/cpu_loop.c | 6 ++-
> linux-user/riscv/cpu_loop.c | 2 +-
> linux-user/s390x/cpu_loop.c | 2 +-
> linux-user/sh4/cpu_loop.c | 2 +-
> linux-user/sparc/cpu_loop.c | 4 +-
> linux-user/syscall.c | 8 ++++
> linux-user/xtensa/cpu_loop.c | 3 ++
> plugins/api.c | 17 +++++++-
> plugins/core.c | 25 ++++++-----
> tests/tcg/multiarch/Makefile.target | 42 +++++++++++++++++++
> .../tcg/multiarch/test-plugin-skip-syscalls.c | 26 ++++++++++++
> tests/tcg/plugins/syscall.c | 6 +++
> 25 files changed, 170 insertions(+), 32 deletions(-)
> create mode 100644 tests/tcg/multiarch/test-plugin-skip-syscalls.c
>