This lets AioContexts be used (optionally) with a glib main loop.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

This will be used when polling the GSource attached to an AioContext.
Reviewed-by: NAnthony Liguori <aliguori@us.ibm.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

With this patch, I/O handlers (including event notifier handlers) can be
attached to a single AioContext.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Start introducing AioContext, which will let us remove globals from
aio.c/async.c, and introduce multiple I/O threads.

The bottom half functions now take an additional AioContext argument.
A bottom half is created with a specific AioContext that remains the
same throughout the lifetime.  qemu_bh_new is just a wrapper that
uses a global context.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Using bool reduces the size of the structure and improves readability.
A hole in the structure was removed.
Signed-off-by: NStefan Weil <sw@weilnetz.de>
Signed-off-by: NStefan Hajnoczi <stefanha@linux.vnet.ibm.com>

- remove qemu_calculate_timeout;

- explicitly size timeout to uint32_t;

- introduce slirp_update_timeout;

- pass NULL as timeout argument to select in case timeout is the maximum
value;
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: NPaul Brook <paul@codesourcery.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

qemu may segfault when a BH handler first deletes a BH and then (possibly
indirectly) calls a nested qemu_bh_poll(). This is because the inner instance
frees the BH and deletes it from the list that the outer one processes.

This patch deletes BHs only in the outermost qemu_bh_poll instance.

Commit 7887f620 already tried to achieve the same, but it assumed that the BH
handler would only delete its own BH. With a nested qemu_bh_poll(), this isn't
guaranteed, so that commit wasn't enough. Hope this one fixes it for real.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

qemu_malloc/qemu_free no longer exist after this commit.
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

The purpose of AsyncContexts was to protect qcow and qcow2 against reentrancy
during an emulated bdrv_read/write (which includes a qemu_aio_wait() call and
can run AIO callbacks of different requests if it weren't for AsyncContexts).

Now both qcow and qcow2 are protected by CoMutexes and AsyncContexts can be
removed.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Without this, qemu segfaults when a BH handler first deletes its BH and
then calls another function which involves a nested qemu_bh_poll() call.

This can be reproduced by generating an I/O error (e.g. with blkdebug) on
an IDE device and using rerror/werror=stop to stop the VM. When continuing
the VM, qemu segfaults.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NStefan Hajnoczi <stefanha@linux.vnet.ibm.com>

Add the possibility to use AIO and BHs without allowing foreign callbacks to be
run. Basically, you put your own AIOs and BHs in a separate context. For
details see the comments in the source.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

Instead of putting more and more stuff into vl.c, let's have the generic
functions that deal with asynchronous callbacks in their own file.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>