This patch series adds several new API functions focused on enabling use cases around reading and writing guest memory from QEMU plugins. To support these new APIs, some utility functionality around retrieving information about address spaces is added as well.
The new qemu_plugin_write_register utilizes gdb_write_register, which is now declared in gdbstub.h for this purpose instead of being static. qemu_plugin_write_memory_vaddr utilizes cpu_memory_rw_debug much the same as the existing read_memory_vaddr function does. The read and write_hwaddr functions are the most different. These functions use address_space_rw, which works well in most cases. There is an important caveat that for writes, the page being written will be set dirty by the write operation. This dirty setting requires locking the page range, which can contend with an already held lock in page_collection_lock when called in a tb translate callback with a write to the instruction memory in the tb. The doc comments warn against doing this, and it's unlikely anyone would want to do this. I've also added two test plugins: one that implements a simple hypercall interface that guest code can use to communicate with the plugin in a structured way with a test to ensure that this hypercall works and writing virtual memory works. And one that implements a simple patch utility to patch memory at runtime. The test for the second plugin ensures the patch applies successfully to instruction memory, and can use both hw and vaddr methods. novafacing (8): Expose gdb_write_register function to consumers of gdbstub Add register write API Add address space API Add memory virtual address write API Add memory hardware address read/write API Add patcher plugin and test Add hypercalls plugin and test Update plugin version and add notes gdbstub/gdbstub.c | 2 +- include/exec/gdbstub.h | 14 + include/qemu/plugin.h | 6 + include/qemu/qemu-plugin.h | 217 ++++++- plugins/api.c | 213 ++++++- tests/tcg/Makefile.target | 2 + tests/tcg/plugins/hypercalls.c | 552 ++++++++++++++++++ tests/tcg/plugins/meson.build | 2 +- tests/tcg/plugins/patch.c | 324 ++++++++++ tests/tcg/x86_64/Makefile.softmmu-target | 36 +- tests/tcg/x86_64/system/hypercalls-target.c | 45 ++ tests/tcg/x86_64/system/patch-target.c | 32 + .../tcg/x86_64/system/validate-hypercalls.py | 40 ++ tests/tcg/x86_64/system/validate-patch.py | 39 ++ 14 files changed, 1501 insertions(+), 23 deletions(-) create mode 100644 tests/tcg/plugins/hypercalls.c create mode 100644 tests/tcg/plugins/patch.c create mode 100644 tests/tcg/x86_64/system/hypercalls-target.c create mode 100644 tests/tcg/x86_64/system/patch-target.c create mode 100755 tests/tcg/x86_64/system/validate-hypercalls.py create mode 100755 tests/tcg/x86_64/system/validate-patch.py -- 2.49.0
