docs/devel/tcg.rst

14 Generator". For more information, please take a look at :ref:`tcg-ops-ref`.
20 -----------------------
26 Block (TB). If the state changes (e.g. privilege level), a new TB will
34 ---------------------
38 segment base value) to find the next basic block.
42 main loop. That’s where QEMU looks for the next TB to execute,
44 in memory. Then QEMU proceeds to execute this next TB, starting at the
48 callback to be re-evaluated before executing additional instructions.
66 branch to the next TB or return to the main loop.
79    correctly locate and execute the next TB. For most guests, this is
100 Next, the main loop looks for the next TB to execute using the
107 The next time this previous TB is executed and we get to that same
127 Self-modifying code and translated code invalidation
128 ----------------------------------------------------
130 Self-modifying code is a special challenge in x86 emulation because no
131 instruction cache invalidation is signaled by the application when code
134 User-mode emulation marks a host page as write-protected (if it is
135 not already read-only) every time translated code is generated for a
146 cache flushes, so some of the protection above would not be
152 -----------------
165 very often throughout the execution of a translation block---this includes
171 -------------
177 QEMU uses an address translation cache (TLB) to speed up the translation.
187 areas.  Access is faster for RAM and ROM because the translation cache also
194 ---------------------
199 limitation you can use the ``-perfmap`` or the ``-jitdump`` option to generate
200 map files. ``-perfmap`` is lightweight and produces only guest-host mappings.
201 ``-jitdump`` additionally saves JITed code and guest debug information (if
207   perf record $QEMU -perfmap $REMAINING_ARGS
210   perf record -k 1 $QEMU -jitdump $REMAINING_ARGS
211   DEBUGINFOD_URLS= perf inject -j -i perf.data -o perf.data.jitted
212   perf report -i perf.data.jitted
214 Note that qemu-system generates mappings only for ``-kernel`` files in ELF