We erronously ignored data from guest on the serial channel if no client is
connected. This leads to an assert when the guest writes a second time, since
there is still data unconsumed by us (the host).
Fix by reading data anyway, and discarding it after parsing (and reading) whole
messages from the guest.
Net affect is that any messages the agent sends while no client is connected
get discarded, but only full messages are discarded.
This fixes an abort if booting a winxp guest with vdagent without a connected
client.
updates taken from spice vga mode updates, i.e. non cacheable, glz compressed
(depends on whatever settings you apply to the server) opaque draw operations.
+ completed the SpiceCoreInterface implementation (timers)
v1->v2:
removed test_util.c (Hans)
replaced mallocz with calloc (Hans)
We are keeping track of tokens for sending agent data to the client, but
the client send an initial value of ~0, and never gives us new send tokens
so this is all rather useless -> remove it.
Note that it is kept in the migration data struct for compatibility reasons.
read_from_vdi_port(), called from vdagent_char_device_wakeup() may
fail to consume all data because no buffers are available in the
read_bufs ring. When this happens we would fail to ever read more data
from the agent on the guest as the port is throttled and stays throttled
until we've consumed all data from the current buffer.
This patch re-enables the call to read_from_vdi_port() from
vdi_read_buf_release(), so that we will try the read again when space
becomes available in the read_bufs ring.
Together with another nasty hack in the linux guest virtio_console
driver, where it waits for a write to be acked by the host before
continuing with the next one, this can lead to a linux guest
getting stuck / hang (until the write is read by the spice-server
which never happens becaus of the above issues).
Note that even with this patch, the guest will still gets stuck due to
a bug in watch_update_mask in spice-core in qemu, which causes writing
to the client to never resume once it blocked. A patch for this has been
submitted to qemu.
read_from_vdi_port() MUST always be called in a while loop until it returns 0.
This is needed because it can cause new data available events and its
recursion protection causes those to get lost. Calling it until it returns 0
ensures that all data has been consumed.
Example scenario where we can fail to read the available data otherwise:
- server/reds.c: vdagent_char_device_wakeup get called
by hw/spice-vmc.c because data has arrived from the guest,
- hw/spice-vmc.c: vmc_read get calls
- If the vmc_read call depletes the current buffer it calls
virtio_serial_throttle_port(&svc->port, false)
- This causes vmc_have_data to get called, which if in the
mean time another buffer has arrived causes
vdagent_char_device_wakeup to gets called again
(so recursively)
- vdagent_char_device_wakeup is protected against recursive
calling and ignores the second call (a nasty hack)
- if no other data arrives, the arrived data will not get read
This patch adds a channel event callback to the spice core interface.
This new callback will be called for three events:
(1) A new connection has been established.
(2) The channel is ready (i.e. authentication is done,
link message verification passed all tests, channel
is ready to use).
(3) Channel was disconnected.
Qemu will use this to send notifications to the management app.
When drawing a drawable with a NULL src bitmap that means we should
be using the previously generated self_bitmap. Not doing this causes
a segfault due to accessing the NULL.
The self_bitmap is the size of self_bitmap_area, not the bbox.
This is especially important since we later copy the self_bitmap_area
into the new bitmap, and if that is larger than bbox then we will
overwrite random memory.
We really need to flush the ring to ensure that we push something on the
release ring. If we don't do this and the ring is not pushed for other
reasons we will timeout in the guest driver waiting for the ring.
We've changed how resources are released so they are now being
freed continuosly, rather than on OOM, since we want to free as early
possible to avoid fragmentation. So, OOM situations should be a bit
less common now and signify a real memory shortage, so we should try
to free up more resources.
When upgrading a cluster of machines you typically do this by
upgrading a set of machines at a time, making the new machines run
the new software version, but in a fashion compatible with the old
versions (in terms of e.g. migration). Then when all machines are
upgrades, any new features in the new version can be enabled.
This API allows qemu to limit the set of features that spice uses to
those compatible with an older version, in order to do an upgrade like
this. Right now it doesn't really do much, since we don't keep compat
with 0.4.0 atm (although that may be added later).
There is no guarantee that any future version of spice support
being compatible with any previous version. However, we will always
support compatibility with the previous major version so that clusters
can be upgraded step by step.
This will prevent: 1) rendering problems (commands sent to the client in the wrong order)
2) sending commands for surfaces that haven't been created yet on the client side.
This used to be a callback for the vdi_port "data ready" interrupt,
which did indicate either data ready to read or data ready to write, but
this is no longer the case now that virtio-serial is used.
This seemingly simple fix prevents a race that needs to be fixed with
another patch, see freedesktop bz #29903
