Ports enter a "throttled" state when writing to the chardev would block.
The current output VirtQueueElement is kept around until the chardev
becomes writable again.

There are several places in the virtio-serial lifecycle where the
VirtQueueElement should be thrown away.  For example, if the virtio
device is reset then virtqueue elements are no longer valid.

This patch adds the discard_throttle_data() function to unmap the
scatter-gather list and decrement vq->inuse.  This ensures that the
VirtQueueElement is freed properly.

Cc: amit.shah@redhat.com
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
Tested-by: NLadi Prosek <lprosek@redhat.com>
Reviewed-by: NLadi Prosek <lprosek@redhat.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

Add support for enabling the virtio 1.0 "emergency write"
(VIRTIO_CONSOLE_F_EMERG_WRITE) feature. The previous patch introduced
the plumbing required for this; now we expose the virtio feature to
the guest. The feature is disabled for compatibility machines to avoid
exposing a new feature to existing guests.

As required by the virtio 1.0 spec, the emergency write functionality
is available to the guest even if the guest doesn't negotatiate the
feature, as well as before feature negotation.
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NSascha Silbe <silbe@linux.vnet.ibm.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

Add the infrastructure required for the virtio 1.0 "emergency write"
(VIRTIO_CONSOLE_F_EMERG_WRITE) feature. Because we don't touch the
size of the configuration area, guests will not be able to actually
make use of this without further patches.
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NSascha Silbe <silbe@linux.vnet.ibm.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

Forcibly convert it to a vmstate wrapper;  proper conversion
comes later.
Signed-off-by: NDr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

virtio-serial-bus has had version 3 since 37f95bf3 in 0.13-rc0;
it's time to clean it up a bit.
Signed-off-by: NDr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: NAmit Shah <amit.shah@redhat.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

Commit 57cb38b3 included qapi/error.h into qemu/osdep.h to get the
Error typedef.  Since then, we've moved to include qemu/osdep.h
everywhere.  Its file comment explains: "To avoid getting into
possible circular include dependencies, this file should not include
any other QEMU headers, with the exceptions of config-host.h,
compiler.h, os-posix.h and os-win32.h, all of which are doing a
similar job to this file and are under similar constraints."
qapi/error.h doesn't do a similar job, and it doesn't adhere to
similar constraints: it includes qapi-types.h.  That's in excess of
100KiB of crap most .c files don't actually need.

Add the typedef to qemu/typedefs.h, and include that instead of
qapi/error.h.  Include qapi/error.h in .c files that need it and don't
get it now.  Include qapi-types.h in qom/object.h for uint16List.

Update scripts/clean-includes accordingly.  Update it further to match
reality: replace config.h by config-target.h, add sysemu/os-posix.h,
sysemu/os-win32.h.  Update the list of includes in the qemu/osdep.h
comment quoted above similarly.

This reduces the number of objects depending on qapi/error.h from "all
of them" to less than a third.  Unfortunately, the number depending on
qapi-types.h shrinks only a little.  More work is needed for that one.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
[Fix compilation without the spice devel packages. - Paolo]
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Move allocation to virtio functions also when loading/saving a
VirtQueueElement.  This will also let the load/save functions
keep backwards compatibility when the VirtQueueElement layout
is changed.
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

The return code of virtqueue_pop/vring_pop is unused except to check for
errors or 0.  We can thus easily move allocation inside the functions
and just return a pointer to the VirtQueueElement.

The advantage is that we will be able to allocate only the space that
is needed for the actual size of the s/g list instead of the full
VIRTQUEUE_MAX_SIZE items.  Currently VirtQueueElement takes about 48K
of memory, and this kind of allocation puts a lot of stress on malloc.
By cutting the size by two or three orders of magnitude, malloc can
use much more efficient algorithms.

The patch is pretty large, but changes to each device are testable
more or less independently.  Splitting it would mostly add churn.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>

Clean up includes so that osdep.h is included first and headers
which it implies are not included manually.

This commit was created with scripts/clean-includes.
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>
Message-id: 1453832250-766-15-git-send-email-peter.maydell@linaro.org

Signed-off-by: NCao jin <caoj.fnst@cn.fujitsu.com>
Message-Id: <1452068575-21543-1-git-send-email-caoj.fnst@cn.fujitsu.com>
Reviewed-by: NAmit Shah <amit.shah@redhat.com>
Signed-off-by: NAmit Shah <amit.shah@redhat.com>

This also fixes a minor bug:
-                virtqueue_map_sg(port->elem.out_sg, port->elem.out_addr,
-                                 port->elem.out_num, 1);
is wrong: out_sg is not written so should not be marked dirty.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: NIgor Mammedov <imammedo@redhat.com>

Commit ef546f12 ("virtio: add
feature checking helpers") introduced a helper __virtio_has_feature.
We don't want to use reserved identifiers, though, so let's
rename __virtio_has_feature to virtio_has_feature and virtio_has_feature
to virtio_vdev_has_feature.
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

Signed-off-by: NJason Wang <jasowang@redhat.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Acked-by: NPaolo Bonzini <pbonzini@redhat.com>

Don't assume a specific layout for control messages.
Required by virtio 1.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: NAmit Shah <amit.shah@redhat.com>
Reviewed-by: NJason Wang <jasowang@redhat.com>

Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NLuiz Capitulino <lcapitulino@redhat.com>

As only one place in virtio-serial-bus.c uses
DEFINE_VIRTIO_SERIAL_PROPERTIES, there is no need to expose it. Inline
it into virtio-serial-bus.c to avoid wrongly use.
Signed-off-by: NShannon Zhao <zhaoshenglong@huawei.com>
Signed-off-by: NShannon Zhao <shannon.zhao@linaro.org>
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>
Acked-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

Make features 64bit wide everywhere.

On migration a full 64bit guest_features field is sent if one of the
high bits is set, in addition to the lower 32bit guest_features field
which must stay for compatibility reasons.  That way we send the lower
32 feature bits twice, but the code is simpler because we don't have
to split and compose the 64bit features into two 32bit fields.
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

VIRTIO_PCI_QUEUE_MAX is not only used for pci, so rename it be generic.

Cc: Amit Shah <amit.shah@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NJason Wang <jasowang@redhat.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

There are a number of ffs(3) callers that do roughly:

  bit = ffs(val);
  if (bit) {
      do_something(bit - 1);
  }

This pattern can be converted to ctz32() like this:

  zeroes = ctz32(val);
  if (zeroes != 32) {
      do_something(zeroes);
  }
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
Message-id: 1427124571-28598-6-git-send-email-stefanha@redhat.com
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

commit 9b70c179
    virtio-serial: switch to standard-headers

changes virtio_console_config size from 8 to 12 bytes:
it adds an optional 4 byte emerg_wr field.

As this crosses a power of two boundary, this changes the PCI BAR size,
which breaks migration compatibility with old qemu machine types.
It's probably a problem for other transports as well.

As a temporary fix, as we don't yet support this new field anyway,
simply make the config size smaller at init time.

Long terms we probably want something along the lines
of virtio_net_set_config_size.
Reported-by: NCole Robinson <crobinso@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Tested-by: NCole Robinson <crobinso@redhat.com>

Users of virtio-serial may want to know when a port becomes writable.  A
port can stop accepting writes if the guest port is open but not being
read from.  In this case, data gets queued up in the virtqueue, and
after the vq is full, writes to the port do not succeed.

When the guest reads off a vq element, and adds a new one for the host
to put data in, we can tell users the port is available for more writes,
via the new ->guest_writable() callback.
Reviewed-by: NMarkus Armbruster <armbru@redhat.com>
Signed-off-by: NAmit Shah <amit.shah@redhat.com>

Commit d0a0bfe6 added checks for port
names, but didn't add a check to ensure port->name is non-NULL.  This
results in a SIGSEGV when adding a port when one of the previously-added
ports didn't have the 'name' property set.

https://bugzilla.redhat.com/show_bug.cgi?id=1192775Reported-by: Nvivian zhang <vivianzhang@redhat.com>
Reviewed-by: NMarkus Armbruster <armbru@redhat.com>
Signed-off-by: NAmit Shah <amit.shah@redhat.com>

virtio-serial.h pulls that in already.
Reported-by: NThomas Huth <thuth@linux.vnet.ibm.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

Add a helper function for checking whether a bit is set in the guest
features for a vdev as well as one that works on a feature bit set.

Convert code that open-coded this: It cleans up the code and makes it
easier to extend the guest feature bits.
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

Add virtio_{add,clear}_feature helper functions for manipulating a
feature bits variable. This has some benefits over open coding:
- add check that the bit is in a sane range
- make it obvious at a glance what is going on
- have a central point to change when we want to extend feature bits

Convert existing code manipulating features to use the new helpers.
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

Drop duplicate code.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

Warning from the Sparse static analysis tool:

hw/char/virtio-serial-bus.c:31:3:
 warning: symbol 'vserdevices' was not declared. Should it be static?

Cc: Amit Shah <amit.shah@redhat.com>
Cc: Anthony Liguori <aliguori@amazon.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: NStefan Weil <sw@weilnetz.de>
Signed-off-by: NMichael Tokarev <mjt@tls.msk.ru>

The 'config' field in the VirtIOSerial structure keeps a copy of the virtio
console's config space as visible to the guest, that is to say, in guest
endianness.  This is fiddly to maintain, because on some targets, such as
powerpc, the "guest endianness" can change when a new guest OS boots.

In fact, there's no need to maintain such a guest view of config space -
instead we can reconstruct it from host-format data when it is accessed
with get_config.
Signed-off-by: NDavid Gibson <david@gibson.dropbear.id.au>
Reviewed-by: NAlexander Graf <agraf@suse.de>
Signed-off-by: NAmit Shah <amit.shah@redhat.com>

A number of places in the virtio_serial driver retrieve the number of ports
from vser->config.max_nr_ports, which is guest-endian.  But for internal
users, we already have a host-endian copy of the number of ports in
vser->serial.max_virtserial_ports.  Using that instead of the config field
removes the need for easy-to-forget byteswapping.

In particular this fixes a bug on incoming migration, where we don't adjust
the endianness vser->config correctly, because it hasn't yet been loaded
from the migration stream when virtio_serial_load_device() is called.
Signed-off-by: NDavid Gibson <david@gibson.dropbear.id.au>
Reviewed-by: NAlexander Graf <agraf@suse.de>
Signed-off-by: NAmit Shah <amit.shah@redhat.com>

It seems "name" is not mandatory, and the following command line (based
on one generated by current libvirt) will crash qemu at start:

qemu-system-x86_64 \
    -device virtio-serial-pci \
    -device virtserialport,name=foo \
    -device virtconsole

Program received signal SIGSEGV, Segmentation fault.
__strcmp_ssse3 () at ../sysdeps/x86_64/strcmp.S:210
210        movlpd    (%rsi), %xmm2
Missing separate debuginfos, use: debuginfo-install
python-libs-2.7.5-13.fc20.x86_64
(gdb) bt
 #0  __strcmp_ssse3 () at ../sysdeps/x86_64/strcmp.S:210
 #1  0x000055555566bdc6 in find_port_by_name (name=0x0) at /home/elmarco/src/qemu/hw/char/virtio-serial-bus.c:67
Signed-off-by: NMarc-André Lureau <marcandre.lureau@gmail.com>
Reviewed-by: NAmos Kong <akong@redhat.com>
Signed-off-by: NAmit Shah <amit.shah@redhat.com>

Signed-off-by: NIgor Mammedov <imammedo@redhat.com>
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NAndreas Färber <afaerber@suse.de>

Before adding new ports to VirtIOSerial devices, check if there's a
conflict in the 'name' parameter.  This ensures two virtserialports with
identical names are not initialized.

Reported-by: <mazhang@redhat.com>
Signed-off-by: NAmit Shah <amit.shah@redhat.com>
Reviewed-by: NMarkus Armbruster <armbru@redhat.com>

To ensure two virtserialports don't get added to the system with the
same 'name' parameter, we need to access all the ports on all the
devices added, and compare the names.

We currently don't have a list of all VirtIOSerial devices added to the
system.  This commit adds a simple linked list in which devices are put
when they're initialized, and removed when they go away.
Signed-off-by: NAmit Shah <amit.shah@redhat.com>
Reviewed-by: NMarkus Armbruster <armbru@redhat.com>

We keep port 0 reserved for compat with older guests, where only
virtio-console was expected.  Even if a system is started without a
virtio-console port, port #0 is kept aside.  However, after a
virtconsole port is unplugged, port id 0 became available, and the next
hotplug of a virtserialport caused failure due to it not being a console
port.

Steps to reproduce:

$ ./x86_64-softmmu/qemu-system-x86_64 -m 512 -cpu host -enable-kvm -device virtio-serial-pci -monitor stdio  -vnc :1
QEMU 2.0.91 monitor - type 'help' for more information
(qemu) device_add virtconsole,id=p1
(qemu) device_del p1
(qemu) device_add virtserialport,id=p1
Port number 0 on virtio-serial devices reserved for virtconsole devices for backward compatibility.
Device 'virtserialport' could not be initialized
(qemu) quit
Reported-by: Ndengmin <mdeng@redhat.com>
Reviewed-by: NAmos Kong <akong@redhat.com>
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NAmit Shah <amit.shah@redhat.com>

We also fix max_nr_ports at reset time as the device endianness may have
changed.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Reviewed-by: NAnthony Liguori <aliguori@us.ibm.com>
[ pass VirtIODevice * to memory accessors,
  fix max_nr_ports at reset time,
  Greg Kurz <gkurz@linux.vnet.ibm.com> ]
Signed-off-by: NGreg Kurz <gkurz@linux.vnet.ibm.com>
Reviewed-by: NAlexander Graf <agraf@suse.de>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

Signed-off-by: NGreg Kurz <gkurz@linux.vnet.ibm.com>
Reviewed-by: NAlexander Graf <agraf@suse.de>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

In order to migrate virtio subsections, they should be streamed after
the device itself. We need the device specific code to be called from
the common migration code to achieve this. This patch introduces load
and save methods for this purpose.
Suggested-by: NAndreas Färber <afaerber@suse.de>
Signed-off-by: NGreg Kurz <gkurz@linux.vnet.ibm.com>
Reviewed-by: NAlexander Graf <agraf@suse.de>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

The device configuration is set at realize time and never changes. It
should not be migrated as it is done today. For the sake of compatibility,
let's just skip them at load time.
Signed-off-by: NAlexander Graf <agraf@suse.de>
[ added missing casts to uint16_t *,
  added From, SoB and commit message,
  Greg Kurz <gkurz@linux.vnet.ibm.com> ]
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NGreg Kurz <gkurz@linux.vnet.ibm.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

Its only contents are a dead memcpy.  Since it is optional,
drop the function altogether.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NMichael Tokarev <mjt@tls.msk.ru>

Signed-off-by: NAndreas Färber <afaerber@suse.de>