Based on a patch from Mark McLoughlin, this patch introduces a new
bottom half packet transmitter that avoids the latency imposed by
the tx_timer approach. Rather than scheduling a timer when a TX
packet comes in, schedule a bottom half to be run from the iothread.
The bottom half handler first attempts to flush the queue with
notification disabled (this is where we could race with a guest
without txburst). If we flush a full burst, reschedule immediately.
If we send short of a full burst, try to re-enable notification.
To avoid a race with TXs that may have occurred, we must then
flush again. If we find some packets to send, the guest it probably
active, so we can reschedule again.
tx_timer and tx_bh are mutually exclusive, so we can re-use the
tx_waiting flag to indicate one or the other needs to be setup.
This allows us to seamlessly migrate between timer and bh TX
handling.
The bottom half handler becomes the new default and we add a new
tx= option to virtio-net-pci. Usage:
-device virtio-net-pci,tx=timer # select timer mitigation vs "bh"
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
If virtio_net_flush_tx() is called with notification disabled, we can
race with the guest, processing packets at the same rate as they
get produced. The trouble is that this means we have no guaranteed
exit condition from the function and can spend minutes in there.
Currently flush_tx is only called with notification on, which seems
to limit us to one pass through the queue per call. An upcoming
patch changes this.
Also add an option to set this value on the command line as different
workloads may wish to use different values. We can't necessarily
support any random value, so this is a developer option: x-txburst=
Usage:
-device virtio-net-pci,x-txburst=64 # 64 packets per tx flush
One pass through the queue (256) seems to be a good default value
for this, balancing latency with throughput. We use a signed int
for x-txburst because 2^31 packets in a burst would take many, many
minutes to process and it allows us to easily return a negative
value value from virtio_net_flush_tx() to indicate a back-off
or error condition.
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Add an option to make the TX mitigation timer adjustable as a device
option. The 150us hard coded default used currently is reasonable,
but may not be suitable for all workloads, this gives us a way to
adjust it using a single binary. We can't support any random option
though, so use the "x-" prefix to indicate this is a developer
option. Usage:
-device virtio-net-pci,x-txtimer=500000,... # .5ms timeout
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
hw/virtio-net.h:
#define ETH_ALEN 6
ETH_ALEN was defined by commit 7967406801
Signed-off-by: Amos Kong <akong@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Mac feature bit isn't going to work as all network cards already have a
'mac' property to set the mac address. Remove it from mask and add in
get_features.
Reported-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Add feature bits as properties to virtio. This makes it possible to e.g. define
machine without indirect buffer support, which is required for 0.10
compatibility, or without hardware checksum support, which is required for 0.11
compatibility. Since default values for optional features are now set by qdev,
get_features callback has been modified: it sets non-optional bits, and clears
bits not supported by host.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Add a few new RX modes to better control the receive_filter. These
are all fairly obvious features that hardware could provide.
Signed-off-by: Alex Williamson <alex.williamson@hp.com>
Signed-off-by: Mark McLoughlin <markmc@redhat.com>
Change the PCI network drivers init functions to return the PCIDev, to
inform which slot has been hot-plugged.
Also record PCIDevice structure on NICInfo to locate for release on
hot-removal.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6593 c046a42c-6fe2-441c-8c8c-71466251a162
Use the control virtqueue to allow the guest to enable and manipulate
a VLAN filter table. This allows us to drop more packets the guest
doesn't want to see. We define a new VLAN class for the control
virtqueue with commands ADD and DEL with usage defined in virtio-net.h.
Signed-off-by: Alex Williamson <alex.williamson@hp.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6540 c046a42c-6fe2-441c-8c8c-71466251a162
Create a filter table and allow the guest to populate it with the
MAC class control commands. We manage the size and usage of the
filter table including enabling promiscuous and all-multi modes
as necessary. The guest should therefore assume the table is
infinite. Eventually this might allow us to bind directly to a
hardware NIC and manipulate a physical MAC filter.
The specifics of the TABLE_SET command are documented in
virtio-net.h. Separate buffers in the same command are used
for unicaste and multicast addresses for priority and
sychronization. With this we can export the VIRTIO_NET_F_CTRL_RX
feature bit.
Signed-off-by: Alex Williamson <alex.williamson@hp.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6539 c046a42c-6fe2-441c-8c8c-71466251a162
Add a new RX_MODE control virtqueue class with commands PROMISC and
ALLMULTI and usage documented in virtio-net.h allowing the guest to
manipulate packet receiving options. We don't export a feature for
this until we also add the MAC filter table.
Note, for compatibility with older guest drivers we need to default
to promiscuous.
Signed-off-by: Alex Williamson <alex.williamson@hp.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6537 c046a42c-6fe2-441c-8c8c-71466251a162
This will be used for RX mode, MAC table, VLAN table control, etc...
The control transaction consists of one or more "out" sg entries and
one or more "in" sg entries. The first out entry contains a header
defining the class and command. Additional out entries may provide
data for the command. A response via the ack entry is required
and the guest will typically be waiting for it.
Signed-off-by: Alex Williamson <alex.williamson@hp.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6536 c046a42c-6fe2-441c-8c8c-71466251a162
Makes it much easier to search too.
Signed-off-by: Alex Williamson <alex.williamson@hp.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6535 c046a42c-6fe2-441c-8c8c-71466251a162
All PCI NIC init functions return void and nothing uses the
return value from virtio_net_init().
Signed-off-by: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6291 c046a42c-6fe2-441c-8c8c-71466251a162
Implement the VIRTIO_NET_F_STATUS feature by exposing the link status
through virtio_net_config::status.
Signed-off-by: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6250 c046a42c-6fe2-441c-8c8c-71466251a162
This adds virtio-net support. This is based on the virtio-net driver
that exists in kvm-userspace. This also adds a new qemu_sendv_packet
which virtio-net requires.
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6073 c046a42c-6fe2-441c-8c8c-71466251a162
Alex Williamson