bhyve: Split backends into separate files

Currently the net_backend structure definition is private to
net_backends.c, so all of the backend definitions are there. While
adding a new backend to use libslirp, it was noted that this file is
somewhat cluttered. Move the netmap and netgraph backends to their own
files and clean up includes a bit. No functional change intended.

Reviewed by: corvink, jhb
MFC after: 3 weeks
Sponsored by: Innovate UK
Differential Revision: https://reviews.freebsd.org/D42689

bhyve: fix arguments to ioctl(VMIO_SIOCSIFFLAGS)

ioctl(2)'s with integer argument shall pass command argument by value,
not by pointer. The ioctl(2) manual page is not very clear about that.
See sys/kern/sys_generic.c:sys_ioctl() near IOC_VOID.

Reviewed by: markj
Differential Revision: https://reviews.freebsd.org/D42366
Fixes: fd8b9c73a5a63a7aa438a73951d7a535b4f25d9a

bhyve: Use VMIO_SIOCSIFFLAGS instead of SIOCGIFFLAGS

Creating an IP socket to invoke the SIOCGIFFLAGS ioctl on is the only
thing preventing bhyve from working inside a bhyve jail with IPv4 and
IPv6 disabled restricting the jailed bhyve process to only access the
host network via a tap/vmnet device node.

PR: 273557
Fixes: 56be282bc999 ("bhyve: net_backends, automatically IFF_UP tap devices")
Reviewed by: markj
MFC after: 1 week

Remove $FreeBSD$: one-line .c pattern

Remove /^[\s*]*__FBSDID\("\$FreeBSD\$"\);?\s*\n/

Remove $FreeBSD$: two-line .h pattern

Remove /^\s*\*\n \*\s+\$FreeBSD\$$\n/

spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD

The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch
up to that fact and revert to their recommended match of BSD-2-Clause.

Discussed with: pfg
MFC After: 3 days
Sponsored by: Netflix

bhyve: Define an accessor for net backend private data

Use it to silence warnings about potential unaligned accesses. No
functional change intended.

MFC after: 1 week
Reviewed by: corvink, jhb
Differential Revision: https://reviews.freebsd.org/D37289

bhyve: Address some signed/unsigned comparison warnings

MFC after: 1 week

bhyve: Avoid arithmetic on void pointers

No functional change intended.

MFC after: 1 week

bhyve: Avoid arithmetic on void pointers

No functional change intended.

MFC after: 1 week

bhyve: Annotate unused function parameters

MFC after: 1 week

bhyve: Don't free an invalid pointer.

The netmap-specific data stored at be->opaque is freed by the caller
on error as part of freeing be.

Reviewed by: markj
Reported by: GCC -Wfree-nonheap-object
Differential Revision: https://reviews.freebsd.org/D36828

bhyve: Mark variables and functions as static where appropriate

Mark them const as well when it makes sense to do so. No functional
change intended.

MFC after: 1 week
Sponsored by: The FreeBSD Foundation

bhyve virtio-net: Allow backend type to be explicitly specified.

Surrently virtio-net uses the prefix of the backing interface to
choose the backend. This patch adds an additional option "type" to
choose the backend type explicitly. This allows greater flexibility
for end users to manage bhyve specific resources (such as by naming
the tap interfaces to more descriptive names). The option "type" is
optional. When it is not presented, the backend is derived from the
name of the backend interface.

For example, the line `-s 3,virtio-net,bsdvm0,type=tap` will create a
virtio-net device for the guest using the tap interface "bsdvm0".

Adding a new "type" option preserves the current legacy format in which
the first value after virtio-net names an instance of a backend.

Note that tap interfaces not following the pattern "tap*" will not be
created on demand via devfs cloning but must be created explicitly.

Reviewed by: vmaffione, jhb
Differential Revision: https://reviews.freebsd.org/D35143

bhyve: clean up trailing whitespaces

Clean up trailing whitespaces. No functional changes.

Reviewed by: jhb
Differential Revision: https://reviews.freebsd.org/D33681

bhyve: net_backends, automatically IFF_UP tap devices

If you want communications with the outside world and tell bhyve to
create an interfaces then it should be usable as well.
Rather than relying on the sysctl net.link.tap.up_on_open automatically
try to IFF_UP the opened tap device.

MFC after: 10 days
Reviewed by: markj, grehan
Differential Revision: https://reviews.freebsd.org/D31342

Refactor configuration management in bhyve.

Replace the existing ad-hoc configuration via various global variables
with a small database of key-value pairs. The database supports
heirarchical keys using a MIB-like syntax to name the path to a given
key. Values are always stored as strings. The API used to manage
configuation values does include wrappers to handling boolean values.
Other values use non-string types require parsing by consumers.

The configuration values are stored in a tree using nvlists. Leaf
nodes hold string values. Configuration values are permitted to
reference other configuration values using '%(name)'. This permits
constructing template configurations.

All existing command line arguments now set configuration values. For
devices, the "-s" option parses its option argument to generate a list
of key-value pairs for the given device.

A new '-o' command line option permits setting an individual
configuration variable. The key name is always given as a full path
of dot-separated components.

A new '-k' command line option parses a simple configuration file.
This configuration file holds a flat list of 'key=value' lines where
the 'key' is the full path of a configuration variable. Lines
starting with a '#' are comments.

In general, bhyve starts by parsing command line options in sequence
and applying those settings to configuration values. Once this is
complete, bhyve then begins initializing its state based on the
configuration values. This means that subsequent configuration
options or files may override or supplement previously given settings.

A special 'config.dump' configuration value can be set to true to help
debug configuration issues. When this value is set, bhyve will print
out the configuration variables as a flat list of 'key=value' lines.

Most command line argments map to a single configuration variable,
e.g. '-w' sets the 'x86.strictmsr' value to false. A few command
line arguments have less obvious effects:

- Multiple '-p' options append their values (as a comma-seperated
list) to "vcpu.N.cpuset" values (where N is a decimal vcpu number).

- For '-s' options, a pci.<bus>.<slot>.<function> node is created.
The first argument to '-s' (the device type) is used as the value of
a "device" variable. Additional comma-separated arguments are then
parsed into 'key=value' pairs and used to set additional variables
under the device node. A PCI device emulation driver can provide
its own hook to override the parsing of the additonal '-s' arguments
after the device type.

After the configuration phase as completed, the init_pci hook
then walks the "pci.<bus>.<slot>.<func>" nodes. It uses the
"device" value to find the device model to use. The device
model's init routine is passed a reference to its nvlist node
in the configuration tree which it can query for specific
variables.

The result is that a lot of the string parsing is removed from
the device models and centralized. In addition, adding a new
variable just requires teaching the model to look for the new
variable.

- For '-l' options, a similar model is used where the string is
parsed into values that are later read during initialization.
One key note here is that the serial ports use the commonly
used lowercase names from existing documentation and examples
(e.g. "lpc.com1") instead of the uppercase names previously
used internally in bhyve.

Reviewed by: grehan
MFC after: 3 months
Differential Revision: https://reviews.freebsd.org/D26035

bhyve: Fix processing of netgraph backend options.

After r360820, additional parameters are passed through the argument 'opts', and the name of the backend through the argument 'devname'. So, there is no need to skip the backend name from the 'opts' argument.

Add a new bhyve network backend that allow to connect the VM to the netgraph(4) network.
The backend uses the socket API with the PF_NETGRAPH protocol family, which is provided by the ng_socket(4).

To use the new backend, provide the following bhyve option:
-s X:Y:Z,[virtio-net|e1000],netgraph,socket=[ng_socket name],path=[destination node],hook=[our socket src hook],peerhook=[dst node hook]

Reviewed by: vmaffione, lutz_donnerhacke.de
Approved by: vmaffione (mentor)
Sponsored by: vstack.com
Differential Revision: https://reviews.freebsd.org/D24620

bhyve: Pass the full string of options to the network backends.

Reviewed by: vmaffione
Approved by: vmaffione (mentor)
Sponsored by: vstack.com
Differential Revision: https://reviews.freebsd.org/D24735

bhyve: enable virtio-net mergeable rx buffers for tap(4)

This patch adds a new netbe_peek_recvlen() function to the net
backend API. The new function allows the virtio-net receive code
to know in advance how many virtio descriptors chains will be
needed to receive the next packet. As a result, the implementation
of the virtio-net mergeable rx buffers feature becomes efficient,
so that we can enable it also with the tap(4) backend. For the
tap(4) backend, a bounce buffer is introduced to implement the
peeck_recvlen() callback, which implies an additional packet copy
on the receive datapath. In the future, it should be possible to
remove the bounce buffer (and so the additional copy), by
obtaining the length of the next packet from kevent data.

Reviewed by: grehan, aleksandr.fedorov@itglobal.com
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D23472

bhyve: move virtio-net header processing to pci_virtio_net

This patch cleans up the API between the net frontends (e1000,
virtio-net) and the net backends (tap and netmap).
We move the virtio-net header stripping/prepending to the
virtio-net code, where this functionality belongs.
In this way, the netbe_send() and netbe_recv() signatures
can have const struct iov * rather than struct iov *.

Reviewed by: grehan, bcr, aleksandr.fedorov@itglobal.com
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D23342

bhyve: add wrapper for debug printf statements

Add printf() wrapper to use CR/CRLF terminators depending on whether
stdio is mapped to a tty open in raw mode.
Try to use the wrapper everywhere.
For now we leave the custom DPRINTF/WPRINTF defined by device
models, but we may remove them in the future.

Reviewed by: grehan, jhb
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D22657

bhyve: uniform printf format string newlines

Some of the printf statements only use LF to get a newline. However, a CR character is also required for the serial console to print debug logs in a nice way.
Fix those code locations that only use LF, by adding a CR character.

Reviewed by: markj, aleksandr.fedorov@itglobal.com
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D22552

bhyve: add support for virtio-net mergeable rx buffers

Mergeable rx buffers is a virtio-net feature that allows the hypervisor
to use multiple RX descriptor chains to receive a single receive packet.
Without this feature, a TSO-enabled guest is compelled to publish only
64K (or 32K) long chains, and each of these large buffers is consumed
to receive a single packet, even a very short one. This is a waste of
memory, as a RX queue has room for 256 chains, which means up to 16MB
of buffer memory for each (single-queue) vtnet device.
With the feature on, the guest can publish 2K long chains, and the
hypervisor will merge them as needed.

This change also enables the feature in the netmap backend, which
supports virtio-net offloads. We plan to add support for the
tap backend too.
Note that differently from QEMU/KVM, here we implement one-copy receive,
while QEMU uses two copies.

Reviewed by: jhb
MFC after: 3 weeks
Differential Revision: https://reviews.freebsd.org/D21007

bhyve: add backend rx backpressure to virtio-net

If a VM is flooded with more ingress packets than the guest OS
can handle, the current virtio-net code will keep reading those
packets and drop most of them as no space is available in the
receive queue. This is an undesirable receive livelock, which
is a waste of CPU and memory resources and potentially opens to
DoS attacks.
With this change, virtio-net uses the new netbe_rx_disable()
function to disable ingress operation in the backend while the
guest is short on RX buffers. Once the guest makes more buffers
available to the RX virtqueue, ingress operation is enabled again
by calling netbe_rx_enable().

Reviewed by: bryanv, jhb
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D20987

bhyve: fix mistake introduced by r352841

MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D20973

bhyve: support for enabling/disabling the net backend

Extend the net backend interface with two functions, namely netbe_rx_disable()
and netbe_rx_enable(), which can be used by the net device emulators to stop
the backend from invoking the receive callback. This is useful for device
emulators, i.e., on hardware resets or to implement receive backpressure.
The mevent module has been extendede to support the addition of a disabled
event. To prevent race conditions, the net backends will start with receive
operation disabled. A follow-up patch will use the new functionalities in
the virtio-net device.

Reviewed by: jhb, markj
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D20973

usr.sbin/bhyve: close backend file descriptor during tap init error

Coverity CID: 1402953
Reviewed by: scottl, markj, aleksandr.fedorov -at- itglobal.com
Approved by: vmaffione, jhb
Differential Revision: https://reviews.freebsd.org/D20913

bhyve: net_backends.c: add missing __FBSDID

Reviewed by: jhb
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D20883

bhyve: add missing license identifiers in net_utils and net_backend

Reviewed by: jhb, markj, imp
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D20874

bhyve: abstraction for network backends

Bhyve can currently emulate two virtual NICs, namely virtio-net and e1000,
and connect to the host network through two backends, namely tap and netmap.
However, there is no interface between virtual NIC functionalities and
backend functionalities. As a result, the backend code is duplicated between
the two virtual NIC implementations and also within the same virtual NIC.
Also, e1000 cannot currently use netmap as a backend.
This patch introduces a network backend API between virtio-net/e1000 and
tap/netmap, to improve code reuse and add missing functionalities.
Virtual NICs and backends can negotiate virtio-net features, such as checksum
offload and TSO. If the backend supports the features, it will propagate this
information to the guest, so that the latter can make use of them. Currently,
only netmap VALE ports support the features, but support should be added to
tap in the future.

Reviewed by: jhb, bryanv
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D20659