096fc36180
A common case for KVM test programs is that the test program acts as the hypervisor, creating, running and destroying the virtual machine, and providing the guest object code from its own object code. In this case, the VM is not running an OS, but only the functions loaded into it by the hypervisor test program, and conveniently, loaded at the same virtual addresses. Normally to resolve addresses, MMAP events are needed to map addresses back to the object code and debug symbols for that object code. Currently, there is no way to get such mapping information from guests but, in the scenario described above, the guest has the same mappings as the hypervisor, so support for that scenario can be achieved. To support that, copy the host thread's maps to the guest thread's maps. Note, we do not discover the guest until we encounter a guest event, which works well because it is not until then that we know that the host thread's maps have been set up. Typically the main function for the guest object code is called "guest_code", hence the name chosen for this feature. Note, that is just a convention, the function could be named anything, and the tools do not care. This is primarily aimed at supporting Intel PT, or similar, where trace data can be recorded for a guest. Refer to the final patch in this series "perf intel-pt: Add guest_code support" for an example. Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Ian Rogers <irogers@google.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Leo Yan <leo.yan@linaro.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: kvm@vger.kernel.org Link: https://lore.kernel.org/r/20220517131011.6117-4-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.