Use common qemu_set_blocking() instead.
Note that pre-patch the behavior of Win32 and Linux realizations
are inconsistent: we ignore failure for Win32, and assert success
for Linux.
How do we convert the callers?
1. Most of callers call qemu_socket_set_nonblock() on a
freshly created socket fd, in conditions when we may simply
report an error. Seems correct switching to error handling
both for Windows (pre-patch error is ignored) and Linux
(pre-patch we assert success). Anyway, we normally don't
expect errors in these cases.
Still in tests let's use &error_abort for simplicity.
What are exclusions?
2. hw/virtio/vhost-user.c - we are inside #ifdef CONFIG_LINUX,
so no damage in switching to error handling from assertion.
3. io/channel-socket.c: here we convert both old calls to
qemu_socket_set_nonblock() and qemu_socket_set_block() to
one new call. Pre-patch we assert success for Linux in
qemu_socket_set_nonblock(), and ignore all other errors here.
So, for Windows switch is a bit dangerous: we may get
new errors or crashes(when error_abort is passed) in
cases where we have silently ignored the error before
(was it correct in all such cases, if they were?) Still,
there is no other way to stricter API than take
this risk.
4. util/vhost-user-server - compiled only for Linux (see
util/meson.build), so we are safe, switching from assertion to
&error_abort.
Note: In qga/channel-posix.c we use g_warning(), where g_printerr()
would actually be a better choice. Still let's for now follow
common style of qga, where g_warning() is commonly used to print
such messages, and no call to g_printerr(). Converting everything
to use g_printerr() should better be another series.
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
In generic code we have qio_channel_set_blocking(), which takes
bool parameter, and qemu_file_set_blocking(), which as well takes
bool parameter.
At lower fd-layer we have a mess of functions:
- enough direct calls to Unix-specific g_unix_set_fd_nonblocking()
(of course, all calls are out of Windows-compatible code), which
is glib specific with GError, which we can't use, and have to
handle error-reporting by hand after the call.
and several platform-agnostic qemu_* helpers:
- qemu_socket_set_nonblock(), which asserts success for posix (still,
in most cases we can handle the error in better way) and ignores
error for win32 realization
- qemu_socket_try_set_nonblock(), providing and error, but not errp,
so we have to handle it after the call
- qemu_socket_set_block(), which simply ignores an error
Note, that *_socket_* word in original API, which we are going
to substitute was intended, because Windows support these operations
only for sockets. What leads to solution of dropping it again?
1. Having a QEMU-native wrapper with errp parameter
for g_unix_set_fd_nonblocking() for non-socket fds worth doing,
at least to unify error handling.
2. So, if try to keep _socket_ vs _file_ words, we'll have two
actually duplicated functions for Linux, which actually will
be executed successfully on any (good enough) fds, and nothing
prevent using them improperly except for the name. That doesn't
look good.
3. Naming helped us in the world where we crash on errors or
ignore them. Now, with errp parameter, callers are intended to
proper error checking. And for places where we really OK with
crash-on-error semantics (like tests), we have an explicit
&error_abort.
So, this commit starts a series, which will effectively revert
commit ff5927baa7 "util: rename qemu_*block() socket functions"
(which in turn was reverting f9e8cacc55
"oslib-posix: rename socket_set_nonblock() to qemu_set_nonblock()",
so that's a long story).
Now we don't simply rename, instead we provide the new API and
update all the callers.
This commit only introduces a new fd-layer wrapper. Next commits
will replace old API calls with it, and finally remove old API.
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Headers in include/sysemu/ are not only related to system
*emulation*, they are also used by virtualization. Rename
as system/ which is clearer.
Files renamed manually then mechanical change using sed tool.
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Tested-by: Lei Yang <leiyang@redhat.com>
Message-Id: <20241203172445.28576-1-philmd@linaro.org>
touch_all_pages() can return early, before creating threads. In this case,
however, it leaks the MemsetContext that it has allocated at the
beginning of the function.
Reported by Coverity as CID 1534922.
Fixes: 04accf43df ("oslib-posix: initialize backend memory objects in parallel", 2024-02-06)
Reviewed-by: Mark Kanda <mark.kanda@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
QEMU initializes preallocated backend memory as the objects are parsed from
the command line. This is not optimal in some cases (e.g. memory spanning
multiple NUMA nodes) because the memory objects are initialized in series.
Allow the initialization to occur in parallel (asynchronously). In order to
ensure optimal thread placement, asynchronous initialization requires prealloc
context threads to be in use.
Signed-off-by: Mark Kanda <mark.kanda@oracle.com>
Message-ID: <20240131165327.3154970-2-mark.kanda@oracle.com>
Tested-by: Mario Casquero <mcasquer@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
... and implement it under POSIX. When a ThreadContext is provided,
create new threads via the context such that these new threads obtain a
properly configured CPU affinity.
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Message-Id: <20221014134720.168738-6-david@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Setting the CPU affinity of QEMU threads is a bit problematic, because
QEMU doesn't always have permissions to set the CPU affinity itself,
for example, with seccomp after initialized by QEMU:
-sandbox enable=on,resourcecontrol=deny
General information about CPU affinities can be found in the man page of
taskset:
CPU affinity is a scheduler property that "bonds" a process to a given
set of CPUs on the system. The Linux scheduler will honor the given CPU
affinity and the process will not run on any other CPUs.
While upper layers are already aware of how to handle CPU affinities for
long-lived threads like iothreads or vcpu threads, especially short-lived
threads, as used for memory-backend preallocation, are more involved to
handle. These threads are created on demand and upper layers are not even
able to identify and configure them.
Introduce the concept of a ThreadContext, that is essentially a thread
used for creating new threads. All threads created via that context
thread inherit the configured CPU affinity. Consequently, it's
sufficient to create a ThreadContext and configure it once, and have all
threads created via that ThreadContext inherit the same CPU affinity.
The CPU affinity of a ThreadContext can be configured two ways:
(1) Obtaining the thread id via the "thread-id" property and setting the
CPU affinity manually (e.g., via taskset).
(2) Setting the "cpu-affinity" property and letting QEMU try set the
CPU affinity itself. This will fail if QEMU doesn't have permissions
to do so anymore after seccomp was initialized.
A simple QEMU example to set the CPU affinity to host CPU 0,1,6,7 would be:
qemu-system-x86_64 -S \
-object thread-context,id=tc1,cpu-affinity=0-1,cpu-affinity=6-7
And we can query it via HMP/QMP:
(qemu) qom-get tc1 cpu-affinity
[
0,
1,
6,
7
]
But note that due to dynamic library loading this example will not work
before we actually make use of thread_context_create_thread() in QEMU
code, because the type will otherwise not get registered. We'll wire
this up next to make it work.
In general, the interface behaves like pthread_setaffinity_np(): host
CPU numbers that are currently not available are ignored; only host CPU
numbers that are impossible with the current kernel will fail. If the
list of host CPU numbers does not include a single CPU that is
available, setting the CPU affinity will fail.
A ThreadContext can be reused, simply by reconfiguring the CPU affinity.
Note that the CPU affinity of previously created threads will not get
adjusted.
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Acked-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20221014134720.168738-4-david@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Let's
* give the function a "qemu_*" style name
* make sure the parameters in the implementation match the prototype
* rename smp_cpus to max_threads, which makes the semantics of that
parameter clearer
... and add a function documentation.
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Message-Id: <20221014134720.168738-2-david@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Commit 06680b15b4 moved qemu_*_exec_dir() to cutils but forgot
to move the macOS dyld(3) include, resulting in the following
error (when building with Homebrew GCC on macOS Monterey 12.4):
[313/1197] Compiling C object libqemuutil.a.p/util_cutils.c.o
FAILED: libqemuutil.a.p/util_cutils.c.o
../../util/cutils.c:1039:13: error: implicit declaration of function '_NSGetExecutablePath' [-Werror=implicit-function-declaration]
1039 | if (_NSGetExecutablePath(fpath, &len) == 0) {
| ^~~~~~~~~~~~~~~~~~~~
../../util/cutils.c:1039:13: error: nested extern declaration of '_NSGetExecutablePath' [-Werror=nested-externs]
Fix by moving the include line to cutils.
Fixes: 06680b15b4 ("include: move qemu_*_exec_dir() to cutils")
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 20220809222046.30812-1-f4bug@amsat.org
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
A recent commit moved some Haiku-specific code parts from oslib-posix.c
to cutils.c, but failed to move the corresponding header #include
statement, too, so "make vm-build-haiku.x86_64" is currently broken.
Fix it by moving the header #include, too.
Fixes: 06680b15b4 ("include: move qemu_*_exec_dir() to cutils")
Message-Id: <20220718172026.139004-1-thuth@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
The qemu_*block() functions are meant to be be used with sockets (the
win32 implementation expects SOCKET)
Over time, those functions where used with Win32 SOCKET or
file-descriptors interchangeably. But for portability, they must only be
used with socket-like file-descriptors. FDs can use
g_unix_set_fd_nonblocking() instead.
Rename the functions with "socket" in the name to prevent bad usages.
This is effectively reverting commit f9e8cacc55 ("oslib-posix:
rename socket_set_nonblock() to qemu_set_nonblock()").
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Replace the global variables with inlined helper functions. getpagesize() is very
likely annotated with a "const" function attribute (at least with glibc), and thus
optimization should apply even better.
This avoids the need for a constructor initialization too.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20220323155743.1585078-12-marcandre.lureau@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The qemu_try_memalign() functions for POSIX and Windows used to be
significantly different, but these days they are identical except for
the actual allocation function called, and the POSIX version already
has to have ifdeffery for different allocation functions.
Move to a single implementation in memalign.c, which uses the Windows
_aligned_malloc if we detect that function in meson.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20220226180723.1706285-7-peter.maydell@linaro.org
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Currently qemu_try_memalign()'s behaviour if asked to allocate
0 bytes is rather variable:
* on Windows, we will assert
* on POSIX platforms, we get the underlying behaviour of
the posix_memalign() or equivalent function, which may be
either "return a valid non-NULL pointer" or "return NULL"
Explictly check for 0 byte allocations, so we get consistent
behaviour across platforms. We handle them by incrementing the size
so that we return a valid non-NULL pointer that can later be passed
to qemu_vfree(). This is permitted behaviour for the
posix_memalign() API and is the most usual way that underlying
malloc() etc implementations handle a zero-sized allocation request,
because it won't trip up calling code that assumes NULL means an
error. (This includes our own qemu_memalign(), which will abort on
NULL.)
This change is a preparation for sharing the qemu_try_memalign() code
between Windows and POSIX.
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>
We implement qemu_memalign() in both oslib-posix.c and oslib-win32.c,
but the two versions are essentially the same: they call
qemu_try_memalign(), and abort() after printing an error message if
it fails. The only difference is that the win32 version prints the
GetLastError() value whereas the POSIX version prints
strerror(errno). However, this is a bug in the win32 version: in
commit dfbd0b873a in 2020 we changed the implementation of
qemu_try_memalign() from using VirtualAlloc() (which sets the
GetLastError() value) to using _aligned_malloc() (which sets errno),
but didn't update the error message to match.
Replace the two separate functions with a single version in a
new memalign.c file, which drops the unnecessary extra qemu_oom_check()
function and instead prints a more useful message including the
requested size and alignment as well as the errno string.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20220226180723.1706285-4-peter.maydell@linaro.org
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Temporarily modifying the SIGBUS handler is really nasty, as we might be
unlucky and receive an MCE SIGBUS while having our handler registered.
Unfortunately, there is no way around messing with SIGBUS when
MADV_POPULATE_WRITE is not applicable or not around.
Let's forward SIGBUS that don't belong to us to the already registered
handler and document the situation.
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20211217134611.31172-8-david@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Add a mutex to protect the SIGBUS case, as we cannot mess concurrently
with the sigbus handler and we have to manage the global variable
sigbus_memset_context. The MADV_POPULATE_WRITE path can run
concurrently.
Note that page_mutex and page_cond are shared between concurrent
invocations, which shouldn't be a problem.
This is a preparation for future virtio-mem prealloc code, which will call
os_mem_prealloc() asynchronously from an iothread when handling guest
requests.
Reviewed-by: Pankaj Gupta <pankaj.gupta@ionos.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20211217134611.31172-7-david@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Steve Sistare