docs/devel/kconfig.rst

13 SCSI adapters.  Arm, s390 and x86 boards can all present a virtio-blk
21 QEMU uses a simple domain-specific language to describe the dependencies
33   configurable and it is easy to drop unnecessary (or otherwise unwanted)
36 This domain-specific language is based on the Kconfig language that
41 is instead specified in per-target files under the ``configs/``
48 --------------------
50 Kconfig defines configurable components in files named ``hw/*/Kconfig``.
51 Note that configurable components are _not_ visible in C code as preprocessor
52 symbols; they are only visible in the Makefile.  Each configurable component
78 include it for clarity and future-proofing.  After ``bool`` the following
83   This defines a dependency for this configurable element. Dependencies
136 ------------------------------------
138 Configurable elements in QEMU fall under five broad groups.  Each group
199   for example only VFIO (passthrough) and virtio-pci devices.
202   board (and not ones which are very board-specific or that need
258 --------------------------------------------
261 a file called ``configs/TARGETNAME-softmmu.mak``.  These files
262 initialize some Kconfig variables to non-default values and provide the
267     # Default configuration for alpha-softmmu
278 The first part, consisting of commented-out ``=n`` assignments, tells
286 ``--without-default-devices`` option.  When this is done, everything defaults
298 machine, and even then only if ``--nodefaults`` is specified on the
299 command line.  Starting a VM *without* ``--nodefaults`` is allowed to
301 ``--without-default-devices`` are considered bugs in the test code:
302 the tests should either use ``--nodefaults``, and should be skipped
312 ----------------
314 In some special cases, a configurable element depends on host features
324 and also listed as follows in the top-level meson.build's host_kconfig