virtio_net: support per queue interrupt coalesce command

Add interrupt_coalesce config in send_queue and receive_queue to cache user
config.

Send per virtqueue interrupt moderation config to underlying device in
order to have more efficient interrupt moderation and cpu utilization of
guest VM.

Additionally, address all the VQs when updating the global configuration,
as now the individual VQs configuration can diverge from the global
configuration.

Signed-off-by: Gavin Li <gavinl@nvidia.com>
Reviewed-by: Dragos Tatulea <dtatulea@nvidia.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Heng Qi <hengqi@linux.alibaba.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Link: https://lore.kernel.org/r/20230731070656.96411-3-gavinl@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: virtio_net: implement exact header length guest feature

Virtio spec introduced a feature VIRTIO_NET_F_GUEST_HDRLEN which when
set implicates that device benefits from knowing the exact size
of the header. For compatibility, to signal to the device that
the header is reliable driver also needs to set this feature.
Without this feature set by driver, device has to figure
out the header size itself.

Quoting the original virtio spec:
"hdr_len is a hint to the device as to how much of the header needs to
be kept to copy into each packet"

"a hint" might not be clear for the reader what does it mean, if it is
"maybe like that" of "exactly like that". This feature just makes it
crystal clear and let the device count on the hdr_len being filled up
by the exact length of header.

Also note the spec already has following note about hdr_len:
"Due to various bugs in implementations, this field is not useful
as a guarantee of the transport header size."

Without this feature the device needs to parse the header in core
data path handling. Accurate information helps the device to eliminate
such header parsing and directly use the hardware accelerators
for GSO operation.

virtio_net_hdr_from_skb() fills up hdr_len to skb_headlen(skb).
The driver already complies to fill the correct value. Introduce the
feature and advertise it.

Note that virtio spec also includes following note for device
implementation:
"Caution should be taken by the implementation so as to prevent
a malicious driver from attacking the device by setting
an incorrect hdr_len."

There is a plan to support this feature in our emulated device.
A device of SolidRun offers this feature bit. They claim this feature
will save the device a few cycles for every GSO packet.

Link: https://docs.oasis-open.org/virtio/virtio/v1.2/cs01/virtio-v1.2-cs01.html#x1-230006x3
Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Reviewed-by: Parav Pandit <parav@nvidia.com>
Reviewed-by: Alvaro Karsz <alvaro.karsz@solid-run.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Willem de Bruijn <willemb@google.com>
Link: https://lore.kernel.org/r/20230309094559.917857-1-jiri@resnulli.us
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

uapi/linux/virtio_net.h: Added USO types.

Added new GSO type for USO: VIRTIO_NET_HDR_GSO_UDP_L4.
Feature VIRTIO_NET_F_HOST_USO allows to enable NETIF_F_GSO_UDP_L4.
Separated VIRTIO_NET_F_GUEST_USO4 & VIRTIO_NET_F_GUEST_USO6 features
required for Windows guests.

Signed-off-by: Andrew Melnychenko <andrew@daynix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: virtio_net: fix notification coalescing comments

Fix wording in comments for the notifications coalescing feature.

Signed-off-by: Alvaro Karsz <alvaro.karsz@solid-run.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Link: https://lore.kernel.org/r/20220823073947.14774-1-alvaro.karsz@solid-run.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: virtio_net: notifications coalescing support

New VirtIO network feature: VIRTIO_NET_F_NOTF_COAL.

Control a Virtio network device notifications coalescing parameters
using the control virtqueue.

A device that supports this fetature can receive
VIRTIO_NET_CTRL_NOTF_COAL control commands.

- VIRTIO_NET_CTRL_NOTF_COAL_TX_SET:
Ask the network device to change the following parameters:
- tx_usecs: Maximum number of usecs to delay a TX notification.
- tx_max_packets: Maximum number of packets to send before a
TX notification.

- VIRTIO_NET_CTRL_NOTF_COAL_RX_SET:
Ask the network device to change the following parameters:
- rx_usecs: Maximum number of usecs to delay a RX notification.
- rx_max_packets: Maximum number of packets to receive before a
RX notification.

VirtIO spec. patch:
https://lists.oasis-open.org/archives/virtio-comment/202206/msg00100.html

Signed-off-by: Alvaro Karsz <alvaro.karsz@solid-run.com>
Message-Id: <20220718091102.498774-1-alvaro.karsz@solid-run.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Jason Wang <jasowang@redhat.com>

virtio_net: use LE accessors for speed/duplex

Speed and duplex config fields depend on VIRTIO_NET_F_SPEED_DUPLEX
which being 63>31 depends on VIRTIO_F_VERSION_1.

Accordingly, use LE accessors for these fields.

Reported-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

virtio_net: correct tags for config space fields

Tag config space fields as having virtio endian-ness.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

virtio-net: Introduce hash report feature

The feature VIRTIO_NET_F_HASH_REPORT extends the
layout of the packet and requests the device to
calculate hash on incoming packets and report it
in the packet header.

Signed-off-by: Yuri Benditovich <yuri.benditovich@daynix.com>
Link: https://lore.kernel.org/r/20200302115003.14877-4-yuri.benditovich@daynix.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

virtio-net: Introduce RSS receive steering feature

RSS (Receive-side scaling) defines hash calculation
rules and decision on receive virtqueue according to
the calculated hash, provided mask to apply and
provided indirection table containing indices of
receive virqueues. The driver sends the control
command to enable multiqueue and provide parameters
for receive steering.

Signed-off-by: Yuri Benditovich <yuri.benditovich@daynix.com>
Link: https://lore.kernel.org/r/20200302115003.14877-3-yuri.benditovich@daynix.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

virtio-net: Introduce extended RSC feature

VIRTIO_NET_F_RSC_EXT feature bit indicates that the device
is able to provide extended RSC information. When the feature
is negotiatede and 'gso_type' field in received packet is not
GSO_NONE, the device reports number of coalesced packets in
'csum_start' field and number of duplicated acks in 'csum_offset'
field and sets VIRTIO_NET_HDR_F_RSC_INFO in 'flags' field.

Signed-off-by: Yuri Benditovich <yuri.benditovich@daynix.com>
Link: https://lore.kernel.org/r/20200302115003.14877-2-yuri.benditovich@daynix.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

virtio_net: Introduce VIRTIO_NET_F_STANDBY feature bit

This feature bit can be used by hypervisor to indicate virtio_net device to
act as a standby for another device with the same MAC address.

VIRTIO_NET_F_STANDBY is defined as bit 62 as it is a device feature bit.

Signed-off-by: Sridhar Samudrala <sridhar.samudrala@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

virtio_net: propagate linkspeed/duplex settings from the hypervisor

The ability to set speed and duplex for virtio_net is useful in various
scenarios as described here:

16032be virtio_net: add ethtool support for set and get of settings

However, it would be nice to be able to set this from the hypervisor,
such that virtio_net doesn't require custom guest ethtool commands.

Introduce a new feature flag, VIRTIO_NET_F_SPEED_DUPLEX, which allows
the hypervisor to export a linkspeed and duplex setting. The user can
subsequently overwrite it later if desired via: 'ethtool -s'.

Note that VIRTIO_NET_F_SPEED_DUPLEX is defined as bit 63, the intention
is that device feature bits are to grow down from bit 63, since the
transports are starting from bit 24 and growing up.

Signed-off-by: Jason Baron <jbaron@akamai.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: virtio-dev@lists.oasis-open.org
Signed-off-by: David S. Miller <davem@davemloft.net>

virtio_net: add _UAPI prefix to virtio_net header guards

This gives better namespacing and prevents conflicts with no-uapi version
of virtio_net header that will be introduced in the following patch.

Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

virtio_net: Update the feature bit to comply with spec

A draft version of the MTU Advice feature bit was specified as 25. This
bit is not within the allowed range for network device feature bits, and
should be changed to be feature bit 3 to fully comply with the spec.

Fixes 14de9d114a82 ('virtio-net: Add initial MTU advice feature')
Signed-off-by: Aaron Conole <aconole@redhat.com>
Suggested-by: "Michael S. Tsirkin" <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

virtio-net: Add initial MTU advice feature

This commit adds the feature bit and associated mtu device entry for the
virtio network device. When a virtio device comes up, it checks the
feature bit for the VIRTIO_NET_F_MTU feature. If such feature bit is
enabled, the driver will read the advised MTU and use it as the initial
value.

Signed-off-by: Aaron Conole <aconole@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

virtio_net: document VIRTIO_NET_CTRL_GUEST_OFFLOADS

Document VIRTIO_NET_CTRL_GUEST_OFFLOADS and the
relevant feature bits.

Will allow ethtool control of the offloads down the road.

Reported-by: Yan Vugenfirer <yan@daynix.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

virtio_net: unconditionally define struct virtio_net_hdr_v1.

This was introduced in commit ed9ecb0415b97b5f9f91f146e1977bb372c74c6d,
but only defined if !VIRTIO_NET_NO_LEGACY. We should always define
it: easier for users to have conditional legacy code.

Suggested-by: "Michael S. Tsirkin" <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

virtio: Don't expose legacy net features when VIRTIO_NET_NO_LEGACY defined.

In particular, the virtio header always has the u16 num_buffers field.
We define a new 'struct virtio_net_hdr_v1' for this (rather than
simply calling it 'struct virtio_net_hdr', to avoid nasty type errors
if some parts of a project define VIRTIO_NET_NO_LEGACY and some don't.

Transitional devices (which can't define VIRTIO_NET_NO_LEGACY) will
have to keep using struct virtio_net_hdr_mrg_rxbuf, which has the same
byte layout as struct virtio_net_hdr_v1.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

virtio_net: v1.0 endianness

Based on patches by Rusty Russell, Cornelia Huck.
Note: more code changes are needed for 1.0 support
(due to different header size).
So we don't advertize support for 1.0 yet.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

uapi: Convert some uses of 6 to ETH_ALEN

Use the #define where appropriate.

Add #include <linux/if_ether.h>
where appropriate too.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

virtio-net: put virtio net header inline with data

For small packets we can simplify xmit processing
by linearizing buffers with the header:
most packets seem to have enough head room
we can use for this purpose.
Since existing hypervisors require that header
is the first s/g element, we need a feature bit
for this.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

virtio: don't expose u16 in userspace api

Programs using virtio headers outside of kernel will no longer
build because u16 type does not exist in userspace. All user ABI
must use __u16 typedef instead.

Bug introduce by:
commit 986a4f4d452dec004697f667439d27c3fda9c928
Author: Jason Wang <jasowang@redhat.com>
Date: Fri Dec 7 07:04:56 2012 +0000

virtio_net: multiqueue support

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

virtio-net: introduce a new control to set macaddr

Currently we write MAC address to pci config space byte by byte,
this means that we have an intermediate step where mac is wrong.
This patch introduced a new control command to set MAC address,
it's atomic.

VIRTIO_NET_F_CTRL_MAC_ADDR is a new feature bit for compatibility.

Signed-off-by: Amos Kong <akong@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

virtio_net: multiqueue support

This patch adds the multiqueue (VIRTIO_NET_F_MQ) support to virtio_net
driver. VIRTIO_NET_F_MQ capable device could allow the driver to do packet
transmission and reception through multiple queue pairs and does the packet
steering to get better performance. By default, one one queue pair is used, user
could change the number of queue pairs by ethtool in the next patch.

When multiple queue pairs is used and the number of queue pairs is equal to the
number of vcpus. Driver does the following optimizations to implement per-cpu
virt queue pairs:

- select the txq based on the smp processor id.
- smp affinity hint to the cpu that owns the queue pairs.

This could be used with the flow steering support of the device to guarantee the
packets of a single flow is handled by the same cpu.

Signed-off-by: Krishna Kumar <krkumar2@in.ibm.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

UAPI: (Scripted) Disintegrate include/linux

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Michael Kerrisk <mtk.manpages@gmail.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Dave Jones <davej@redhat.com>