In the flush_queued_data() function, we expect port to be valid. Assert
only for port and not port || discard.
Reported-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Individual ports can now signal to the virtio-serial core to stop
sending data if the ports cannot immediately handle new data. When a
port later unthrottles, any data queued up in the virtqueue are sent to
the port.
Disable throttling once a port is closed (and we discard all the
unconsumed buffers in the vq).
The guest kernel can reclaim the buffers when it receives the port close
event or when a port is being removed. Ensure we free up the buffers
before we send out any events to the guest.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Before the earlier patch, we relied on incorrect virtio api usage to
signal to the guest that a particular buffer wasn't consumed by the
host.
After fixing that, we now just discard the data the guest sends us while
a host port is disconnected or doesn't have a handler registered for
consuming data.
This commit really doesn't change anything from the current behaviour,
just makes the code slightly better by spinning off data handling to
ports in another function.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
We cannot indicate to the guest how much data was consumed by an app for
out_bufs. So we just have to assume the apps will consume all the data
that are handed over to them.
Fix the virtio api abuse in control_out() and handle_output().
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Current guests don't send more than one iov but it can change later.
Ensure we handle that case.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
CC: Avi Kivity <avi@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Current control messages are small enough to not be split into multiple
buffers but we could run into such a situation in the future or a
malicious guest could cause such a situation.
So handle the entire iov request for control messages.
Also ensure the size of the control request is >= what we expect
otherwise we risk accessing memory that we don't own.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
CC: Avi Kivity <avi@redhat.com>
Reported-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
The virtio-net code uses iov_fill() which fills an iov from a linear
buffer. The virtio-serial-bus code does something similar in an
open-coded function.
Create a new iov.c file that has iov_from_buf().
Convert virtio-net and virtio-serial-bus over to use this functionality.
virtio-net used ints to hold sizes, the new function is going to use
size_t types.
Later commits will add the opposite functionality -- going from an iov
to a linear buffer.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
If adding of ports or devices in the guest fails we can send out a QMP
event so that management software can deal with it.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
The check for a 0-sized write request to a guest port is not necessary;
the while loop below won't be executed in this case and all will be
fine.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
The virtio-serial code doesn't mix declarations and definitions, so
separate them out on different lines.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Allow the port 'id's to be set by a user on the command line. This is
needed by management apps that will want a stable port numbering scheme
for hot-plug/unplug and migration.
Since the port numbers are shared with the guest (to identify ports in
control messages), we just send a control message to the guest
indicating addition of new ports (hot-plug) or notifying the guest of
the available ports when the guest sends us a DEVICE_READY control
message.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
If the host connection to a port is closed on the destination machine
after migration, whereas the connection was open on the source, the
guest has to be informed of that.
Similar for a host connection open on the destination.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
If some ports that were hot-plugged on the source are not available on
the destination, fail migration instead of trying to deref a NULL
pointer.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Reported-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
The number of ports on the source as well as the destination machines
should match. If they don't, it means some ports that got hotplugged on
the source aren't instantiated on the destination. Or that ports that
were hot-unplugged on the source are created on the destination.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Reported-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
The target could be started with max_nr_ports for a virtio-serial device
lesser than what was available on the source machine. Fail the migration
in such a case.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Reported-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
error_report() terminates the message with a newline. Strip it it
from its arguments.
This fixes a few error messages lacking a newline:
net_handle_fd_param()'s "No file descriptor named %s found", and
tap_open()'s "vnet_hdr=1 requested, but no kernel support for
IFF_VNET_HDR available" (all three versions).
There's one place that passes arguments without newlines
intentionally: load_vmstate(). Fix it up.
Since commit 98b19252cf, all
serial devices declare MULTIPORT feature.
To allow 0.12 compatibility, we should clear this when
max_nr_ports is 1.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
This commit enables one to use multiple virtio-serial devices and to
assign ports to arbitrary devices like this:
-device virtio-serial,id=foo -device virtio-serial,id=bar \
-device virtserialport,bus=foo.0,name=foo \
-device virtserialport,bus=bar.0,name=bar
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
The port 'id' or number is internal state between the guest kernel and
our bus implementation. This is invocation-dependent and isn't part of
the guest-host ABI.
To correcly enumerate and map ports between the host and the guest, the
'name' property is used.
Example:
-device virtserialport,name=org.qemu.port.0
This invocation will get us a char device in the guest at:
/dev/virtio-ports/org.qemu.port.0
which can be a symlink to
/dev/vport0p3
This 'name' property is exposed by the guest kernel in a sysfs
attribute:
/sys/kernel/virtio-ports/vport0p3/name
A simple udev script can pick up this name and create the symlink
mentioned above.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Via control channel messages, the guest can tell us whether a port got
opened or closed. Similarly, we can also indicate to the guest of host
port open/close events.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
This commit converts the virtio-console device to create a new
virtio-serial bus that can host console and generic serial ports. The
file hosting this code is now called virtio-serial-bus.c.
The virtio console is now a very simple qdev device that sits on the
virtio-serial-bus and communicates between the bus and qemu's chardevs.
This commit also includes a few changes to the virtio backing code for
pci and s390 to spawn the virtio-serial bus.
As a result of the qdev conversion, we get rid of a lot of legacy code.
The old-style way of instantiating a virtio console using
-virtioconsole ...
is maintained, but the new, preferred way is to use
-device virtio-serial -device virtconsole,chardev=...
With this commit, multiple devices as well as multiple ports with a
single device can be supported.
For multiple ports support, each port gets an IO vq pair. Since the
guest needs to know in advance how many vqs a particular device will
need, we have to set this number as a property of the virtio-serial
device and also as a config option.
In addition, we also spawn a pair of control IO vqs. This is an internal
channel meant for guest-host communication for things like port
open/close, sending port properties over to the guest, etc.
This commit is a part of a series of other commits to get the full
implementation of multiport support. Future commits will add other
support as well as ride on the savevm version that we bump up here.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
