This filter was added back in 2017 for QEMU 2.11 but it was never
properly documented, so let's explain how it works and add a couple of
examples.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Message-Id: <20200921173016.27935-1-berto@igalia.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
All our supported build platforms have Python 3.6 or newer nowadays, and
there are some useful features in Python 3.6 which are not available in
3.5 yet (e.g. the type hint annotations which will allow us to statically
type the QAPI parser), so let's bump the minimum Python version to 3.6 now.
Signed-off-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20200923162908.95372-1-thuth@redhat.com>
Message-Id: <20200925154027.12672-16-alex.bennee@linaro.org>
Updated MAINTAINERS for CAN bus related emulation as well.
Signed-off-by: Pavel Pisa <pisa@cmp.felk.cvut.cz>
Message-Id: <6d1b8db69efc4e5cfad702d2150e1960e8f63572.1600069689.git.pisa@cmp.felk.cvut.cz>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Move the whole contents of the overview doc comment from object.h
to qom.rst.
This makes the documentation source easier to read and edit, and
also solves the backslash escaping issue at the typecasting macro
examples.
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Message-Id: <20200910221526.10041-10-ehabkost@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
it's was deprecated since 3.1
Support for invalid topologies is removed, the user must ensure
that topologies described with -smp include all possible cpus,
i.e. (sockets * cores * threads) == maxcpus or QEMU will
exit with error.
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Acked-by:
Message-Id: <20200911133202.938754-1-imammedo@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
it was actually removed in 5.0,
commit 68a86dc15c (numa: remove deprecated -mem-path fallback to anonymous RAM)
clean up forgotten remnants in docs.
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Message-Id: <20200911084410.788171-3-imammedo@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
it was deprecated since 4.1
commit 4bb4a2732e (numa: deprecate implict memory distribution between nodes)
Users of existing VMs, wishing to preserve the same RAM distribution,
should configure it explicitly using ``-numa node,memdev`` options.
Current RAM distribution can be retrieved using HMP command
`info numa` and if separate memory devices (pc|nv-dimm) are present
use `info memory-device` and subtract device memory from output of
`info numa`.
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Message-Id: <20200911084410.788171-2-imammedo@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Build all executables by default except for the known-broken ones.
This also allows running qemu-iotests without manually building
socket_scm_helper.
Reported-by: Max Reitz <mreitz@redhat.com>
Tested-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Update the documentation of QAPI document comment syntax to match
the new rST backend requirements. The principal changes are:
* whitespace is now significant, and multiline definitions
must have their second and subsequent lines indented to
match the first line
* general rST format markup is permitted, not just the small
set of markup the old texinfo generator handled. For most
things (notably bulleted and itemized lists) the old format
was the same as rST is.
* Specific things that might trip people up:
- instead of *bold* and _italic_ rST has **bold** and *italic*
- lists need a preceding and following blank line
- a lone literal '*' will need to be backslash-escaped to
avoid a rST syntax error
* the old leading '|' for example (literal text) blocks is
replaced by the standard rST '::' literal block.
* we support arbitrary levels of sub- and sub-sub-heading, not
just a main and sub-heading like the old texinfo generator
* lists can now be nested
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <20200925162316.21205-18-peter.maydell@linaro.org>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
[Commit message improved slightly]
Signed-off-by: Markus Armbruster <armbru@redhat.com>
The automatic dependency handling for Sphinx manuals only makes the output
depend on the input documentation files. This means that if you edit
the Python source of an extension then the documentation won't be
rebuilt.
Create a list of all the source files for the extensions and add
it to the dependencies for the manuals. This is similar to how we
handle the qapi_gen_depends list.
Because we don't try to identify which manuals are using which
Sphinx extensions, a change to the source of one extension will
always rebuild the entire manual set, not merely the manuals
which have changed. This is acceptable because we don't change
the extensions all that often.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <20200925162316.21205-15-peter.maydell@linaro.org>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
[Re rebuilding the enitre manual set being acceptable "because we
don't change the extensions all that often": we also rebuild it when
the QAPI generator code the qapidoc extension depends on changes.
This will inconvenience QAPI developers. Can't be helped now.]
Signed-off-by: Markus Armbruster <armbru@redhat.com>
We're going to want to use SPHINX_ARGS in both docs/meson.build
and tests/qapi-schema/meson.build. Move the definition up to the
top level file so it is available to both subdirectories.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <20200925162316.21205-14-peter.maydell@linaro.org>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Convert qemu-qmp-ref to rST format. This includes dropping
the plain-text, pdf and info format outputs for this document;
as with all our other Sphinx-based documentation, we provide
HTML and manpage only.
The qemu-qmp-ref.rst is somewhat more stripped down than
the .texi was, because we do not (currently) attempt to
generate indexes for the commands, events and data types
being documented.
Again, we drop the direct link from index.html.in now that
the QMP ref is part of the interop manual.
This commit removes the code from the root meson.build file that
handled the various Texinfo-based outputs, because we no longer
generate any documentation except for the Sphinx HTML manuals and the
manpages, and the code can't handle having an empty list of files
to process.. We'll do further cleanup of the remainders of
Texinfo support in subsequent commits.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <20200925162316.21205-10-peter.maydell@linaro.org>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
[Unicode legacy literal dumbed down to plain string literal, TODO
comment on displaying QEMU version added, "make html" fixed,
storage-daemon/qapi/meson.build updated]
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Convert qemu-ga-ref to rST format. This includes dropping
the plain-text, pdf and info format outputs for this document;
as with all our other Sphinx-based documentation, we provide
HTML and manpage only.
The qemu-ga-ref.rst is somewhat more stripped down than
the .texi was, because we do not (currently) attempt to
generate indexes for the commands, events and data types
being documented.
As the GA ref is now part of the Sphinx 'interop' manual,
we can delete the direct link from index.html.in.
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <20200925162316.21205-9-peter.maydell@linaro.org>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
[Unicode legacy literal dumbed down to plain string literal, TODO
comment on displaying QEMU version added]
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Some of our documentation is auto-generated from documentation
comments in the JSON schema.
For Sphinx, rather than creating a file to include, the most natural
way to handle this is to have a small custom Sphinx extension which
processes the JSON file and inserts documentation into the rST
file being processed.
This is the same approach that kerneldoc and hxtool use.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <20200925162316.21205-8-peter.maydell@linaro.org>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
[Comment and doc string formatting tweaked, unused method dropped,
a few line breaks tweaked to follow PEP 8 more closely, MAINTAINERS
section QAPI updated]
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Make the handling of indentation in doc comments more sophisticated,
so that when we see a section like:
Notes: some text
some more text
indented line 3
we save it for the doc-comment processing code as:
some text
some more text
indented line 3
and when we see a section with the heading on its own line:
Notes:
some text
some more text
indented text
we also accept that and save it in the same form.
If we detect that the comment document text is not indented as much
as we expect it to be, we throw a parse error. (We don't complain
about over-indented sections, because for rST this can be legitimate
markup.)
The golden reference for the doc comment text is updated to remove
the two 'wrong' indents; these now form a test case that we correctly
stripped leading whitespace from an indented multi-line argument
definition.
We update the documentation in docs/devel/qapi-code-gen.txt to
describe the new indentation rules.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <20200925162316.21205-6-peter.maydell@linaro.org>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
[Whitespace between sentences tweaked]
Signed-off-by: Markus Armbruster <armbru@redhat.com>
These were deprecated since 4.0, remove both HMP and QMP variants.
Users should use device_add command instead. To get list of
possible CPUs and options, use 'info hotpluggable-cpus' HMP
or query-hotpluggable-cpus QMP command.
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Acked-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Acked-by: Cornelia Huck <cohuck@redhat.com>
Message-Id: <20200915120403.1074579-1-imammedo@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
The virtiofsd --help output documents the cache=auto default value but
the man page does not. Fix this.
Signed-off-by: Harry G. Coin <hgcoin@gmail.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20200916112250.760245-1-stefanha@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
lm32 and unicore32 are softmmut targets, and not linux-user targets.
Signed-off-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20200923080015.77373-1-thuth@redhat.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
clang's C11 atomic_fetch_*() functions only take a C11 atomic type
pointer argument. QEMU uses direct types (int, etc) and this causes a
compiler error when a QEMU code calls these functions in a source file
that also included <stdatomic.h> via a system header file:
$ CC=clang CXX=clang++ ./configure ... && make
../util/async.c:79:17: error: address argument to atomic operation must be a pointer to _Atomic type ('unsigned int *' invalid)
Avoid using atomic_*() names in QEMU's atomic.h since that namespace is
used by <stdatomic.h>. Prefix QEMU's APIs with 'q' so that atomic.h
and <stdatomic.h> can co-exist. I checked /usr/include on my machine and
searched GitHub for existing "qatomic_" users but there seem to be none.
This patch was generated using:
$ git grep -h -o '\<atomic\(64\)\?_[a-z0-9_]\+' include/qemu/atomic.h | \
sort -u >/tmp/changed_identifiers
$ for identifier in $(</tmp/changed_identifiers); do
sed -i "s%\<$identifier\>%q$identifier%g" \
$(git grep -I -l "\<$identifier\>")
done
I manually fixed line-wrap issues and misaligned rST tables.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20200923105646.47864-1-stefanha@redhat.com>
The sentence explaining the deprecation schedule is ambiguous. Make it
clear that a feature deprecated in the Nth release is guaranteed to
remain available in the N+1th release. Removal can occur in the N+2nd
release or later.
As an example of this in action, see commit
25956af3fe ("block: Finish deprecation of
'qemu-img convert -n -o'"). The feature was deprecated in QEMU 4.2.0. It
was present in the 5.0.0 release and removed in the 5.1.0 release.
Suggested-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20200915150734.711426-1-stefanha@redhat.com>
it's was deprecated since 3.1
Support for invalid topologies is removed, the user must ensure
that topologies described with -smp include all possible cpus,
i.e. (sockets * cores * threads) == maxcpus or QEMU will
exit with error.
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Message-Id: <20200911133202.938754-1-imammedo@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Hyper-V TLFS prior to version 6.0 had a mistake in it: special value
'0xffffffff' for CPUID 0x40000004.EBX was called 'never to retry', this
looked weird (like why it's not '0' which supposedly have the same effect?)
but nobody raised the question. In TLFS version 6.0 the mistake was
corrected to 'never notify' which sounds logical. Fix QEMU accordingly.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20200515114847.74523-1-vkuznets@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Some machines don't have much differences a part from the flash model
being used. Introduce new machine properties to change them from the
command line.
For instance, to start the ast2500-evb machine with a different FMC
chip and a 64M SPI chip, use :
-M ast2500-evb,fmc-model=mx25l25635e,spi-model=mx66u51235f
Cc: 郁雷 <yulei.sh@bytedance.com>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Tested-by: Lei YU <yulei.sh@bytedance.com>
Message-Id: <20200915054859.2338477-1-clg@kaod.org>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
I found that there are many spelling errors in the comments of qemu,
so I used the spellcheck tool to check the spelling errors
and finally found some spelling errors in the docs folder.
Signed-off-by: zhaolichang <zhaolichang@huawei.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <20200917075029.313-4-zhaolichang@huawei.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
According to
<https://docutils.sourceforge.io/docs/ref/rst/directives.html#parsed-literal>,
"inline markup is recognized and there is no protection from parsing.
Backslash-escapes may be necessary to prevent unintended parsing".
The qemu(1) manual page (formatted with Sphinx 2.2.2) has several overlong
lines on my system. A stand-alone backslash at EOL serves as line
continuation in a "parsed-literal" block. Therefore, escape the
backslashes that we want to appear as such in the formatted documentation.
Cc: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20200908172111.19072-1-lersek@redhat.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Deprecate our lm32 target support. Michael Walle (former lm32 maintainer)
suggested that we do this in 2019:
https://www.mail-archive.com/qemu-devel@nongnu.org/msg605024.html
because the only public user of the architecture is the many-years-dead
milkymist project. (The Linux port to lm32 was never merged upstream.)
In commit 4b4d96c776 (March 2020) we marked it as 'orphan' in
the MAINTAINERS file, but didn't officially deprecate it. Mark it
deprecated now, with the intention of removing it from QEMU in
mid-2021 before the 6.1 release.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Acked-by: Michael Walle <michael@walle.cc>
Message-id: 20200827113259.25064-1-peter.maydell@linaro.org
Deprecate our Unicore32 target support:
* the Linux kernel dropped support for unicore32 in commit
05119217a9bd199c for its 5.9 release (with rationale in the
cover letter: https://lkml.org/lkml/2020/8/3/232 )
* there is apparently no upstream toolchain that can create unicore32
binaries
* the maintainer doesn't seem to have made any contributions to
QEMU since the port first landed in 2012
* nobody else seems to have made changes to the unicore code except
for generic cleanups either
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-id: 20200825172719.19422-1-peter.maydell@linaro.org
Make the list of MPS2 boards consistent in the phrasing of each
entry, use the correct casing of "Arm", and move the mps2-an511
entry so the list is in numeric order.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 20200903202048.15370-4-peter.maydell@linaro.org
Implement a model of the MPS2 with the AN500 firmware. This is
similar to the AN385, with the following differences:
* Cortex-M7 CPU
* PSRAM is at 0x6000_0000
* Ethernet is at 0xa000_0000
* No zbt_boot_ctrl remapping of the low 16K
(but QEMU doesn't implement this anyway)
* no "block RAM" at 0x01000000
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 20200903202048.15370-3-peter.maydell@linaro.org
Implement a model of the MPS2 with the AN386 firmware. This is
essentially identical to the AN385 firmware, but it has a
Cortex-M4 rather than a Cortex-M3.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 20200903202048.15370-2-peter.maydell@linaro.org
We deprecated the support for KVM on 32-bit Arm hosts in time
for release 5.0, which means that our deprecation policy allows
us to drop it in release 5.2. Remove the code.
To repeat the rationale from the deprecation note: the Linux
kernel dropped support for 32-bit Arm KVM hosts in 5.7.
Running 32-bit guests on a 64-bit Arm host remains supported.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-id: 20200904154156.31943-2-peter.maydell@linaro.org
We have an exploding complexity problem in the testing so lets just
move the more involved plugins into contrib. tests/plugins still exist
for the basic plugins that exercise the API. We restore the old
pre-meson style Makefile for contrib as it also doubles as a guide for
out-of-tree plugin builds.
While we are at it add some examples to the documentation and a
specific plugins build target.
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20200909112742.25730-11-alex.bennee@linaro.org>
It's buggy and we are not sure anyone uses it.
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
Message-Id: <20200909112742.25730-6-alex.bennee@linaro.org>
Most of the Makefile bits are obsolete and can be removed.
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Section markup in definition documentation makes no sense and can
produce invalid Texinfo. Reject.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20200320091805.5585-2-armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Commit 480324ec8d "docs/qdev-device-use: Clean up the sentences
related to -usbdevice" deleted the information on syntax that no
longer works. Unfortunately, the resulting text suggests you can
configure USB block devices with -drive, and USB network devices with
-net, which is misleading.
Instead of rephrasing the now misleading text, I'm putting the
information back, and just make clear it's about old versions of QEMU.
Cc: Thomas Huth <thuth@redhat.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20200806081147.3123652-4-armbru@redhat.com>
Commit 4d8bb958fa0..231aaf3a821 integrated the contents of
docs/qmp-events.txt into QAPI schema doc comments. It left dangling
references to qmp-events.txt behind. Fix to point to the QEMU QMP
reference manual generated from the QAPI schema.
Add a similar reference for commands.
Cc: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20200806081147.3123652-2-armbru@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Currently QAPI generates a type and function for free'ing it:
typedef struct QCryptoBlockCreateOptions QCryptoBlockCreateOptions;
void qapi_free_QCryptoBlockCreateOptions(QCryptoBlockCreateOptions *obj);
This is used in the traditional manner:
QCryptoBlockCreateOptions *opts = NULL;
opts = g_new0(QCryptoBlockCreateOptions, 1);
....do stuff with opts...
qapi_free_QCryptoBlockCreateOptions(opts);
Since bumping the min glib to 2.48, QEMU has incrementally adopted the
use of g_auto/g_autoptr. This allows the compiler to run a function to
free a variable when it goes out of scope, the benefit being the
compiler can guarantee it is freed in all possible code ptahs.
This benefit is applicable to QAPI types too, and given the seriously
long method names for some qapi_free_XXXX() functions, is much less
typing. This change thus makes the code generator emit:
G_DEFINE_AUTOPTR_CLEANUP_FUNC(QCryptoBlockCreateOptions,
qapi_free_QCryptoBlockCreateOptions)
The above code example now becomes
g_autoptr(QCryptoBlockCreateOptions) opts = NULL;
opts = g_new0(QCryptoBlockCreateOptions, 1);
....do stuff with opts...
Note, if the local pointer needs to live beyond the scope holding the
variable, then g_steal_pointer can be used. This is useful to return the
pointer to the caller in the success codepath, while letting it be freed
in all error codepaths.
return g_steal_pointer(&opts);
The crypto/block.h header needs updating to avoid symbol clash now that
the g_autoptr support is a standard QAPI feature.
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20200723153845.2934357-1-berrange@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
We do not need to ask cmake for the dependencies, so just use the
pkg-config mechanism. Keep "auto" for SDL so that it tries using
sdl-config too.
The documentation is adjusted to use SDL2_image as the example,
rather than SDL which does not use the "pkg-config" method.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>