History log of /freebsd-current/usr.sbin/bhyve/uart_emul.h
Revision Date Author Comments
# f3003a0d 02-Apr-2024 Andrew Turner <andrew@freebsd.org>

bhyve: Add PL011 UART emulation

This will be use for arm64 guests, instead of the existing ns16550 UART
model.

Reviewed by: corvink, jhb
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D40997


# d1c5d0cf 20-Mar-2024 Mark Johnston <markj@FreeBSD.org>

bhyve: Move device model-independent UART code into a separate file

Currently bhyve implements a ns16550-compatible UART in uart_emul.c.
This file also contains generic code to manage RX FIFOs and to handle
reading from and writing to a TTY. bhyve instantiates UARTs to
implement COM devices (via pci_lpc.c) and PCI UART devices.

The arm64 port will bring with it a PL011 device model which is used as
the default console (i.e., no COM ports). To simplify its integration,
add a UART "backend" layer which lets UART device models allocate an RX
FIFO and interact with TTYs without duplicating code. In particular,
code in uart_backend.* is to be shared among device models, and the
namespace for uart_emul.* is changed to uart_ns16550_*.

This is based on andrew@'s work in
https://github.com/zxombie/freebsd/tree/bhyvearm64 but I've made a
number of changes, particularly with respect to naming and source code
organization.

No functional change intended.

Reviewed by: corvink, jhb
MFC after: 1 week
Sponsored by: Innovate UK
Differential Revision: https://reviews.freebsd.org/D40993


# b3e76948 16-Aug-2023 Warner Losh <imp@FreeBSD.org>

Remove $FreeBSD$: two-line .h pattern

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


# 4d846d26 10-May-2023 Warner Losh <imp@FreeBSD.org>

spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD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


# 621b5090 26-Jun-2019 John Baldwin <jhb@FreeBSD.org>

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


# 483d953a 04-May-2020 John Baldwin <jhb@FreeBSD.org>

Initial support for bhyve save and restore.

Save and restore (also known as suspend and resume) permits a snapshot
to be taken of a guest's state that can later be resumed. In the
current implementation, bhyve(8) creates a UNIX domain socket that is
used by bhyvectl(8) to send a request to save a snapshot (and
optionally exit after the snapshot has been taken). A snapshot
currently consists of two files: the first holds a copy of guest RAM,
and the second file holds other guest state such as vCPU register
values and device model state.

To resume a guest, bhyve(8) must be started with a matching pair of
command line arguments to instantiate the same set of device models as
well as a pointer to the saved snapshot.

While the current implementation is useful for several uses cases, it
has a few limitations. The file format for saving the guest state is
tied to the ABI of internal bhyve structures and is not
self-describing (in that it does not communicate the set of device
models present in the system). In addition, the state saved for some
device models closely matches the internal data structures which might
prove a challenge for compatibility of snapshot files across a range
of bhyve versions. The file format also does not currently support
versioning of individual chunks of state. As a result, the current
file format is not a fixed binary format and future revisions to save
and restore will break binary compatiblity of snapshot files. The
goal is to move to a more flexible format that adds versioning,
etc. and at that point to commit to providing a reasonable level of
compatibility. As a result, the current implementation is not enabled
by default. It can be enabled via the WITH_BHYVE_SNAPSHOT=yes option
for userland builds, and the kernel option BHYVE_SHAPSHOT.

Submitted by: Mihai Tiganus, Flavius Anton, Darius Mihai
Submitted by: Elena Mihailescu, Mihai Carabas, Sergiu Weisz
Relnotes: yes
Sponsored by: University Politehnica of Bucharest
Sponsored by: Matthew Grooms (student scholarships)
Sponsored by: iXsystems
Differential Revision: https://reviews.freebsd.org/D19495


# 1de7b4b8 27-Nov-2017 Pedro F. Giffuni <pfg@FreeBSD.org>

various: general adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

No functional change intended.


# ea7f1c8c 28-Oct-2013 Neel Natu <neel@FreeBSD.org>

Add support for PCI-to-ISA LPC bridge emulation. If the LPC bus is attached
to a virtual machine then we implicitly create COM1 and COM2 ISA devices.

Prior to this change the only way of attaching a COM port to the virtual
machine was by presenting it as a PCI device that is mapped at the legacy
I/O address 0x3F8 or 0x2F8.

There were some issues with the original approach:
- It did not work at all with UEFI because UEFI will reprogram the PCI device
BARs and remap the COM1/COM2 ports at non-legacy addresses.
- OpenBSD GENERIC kernel does not create a /dev/console because it expects
the uart device at the legacy 0x3F8/0x2F8 address to be an ISA device.
- It was functional with a FreeBSD guest but caused the console to appear
on /dev/ttyu2 which was not intuitive.

The uart emulation is now independent of the bus on which it resides. Thus it
is possible to have uart devices on the PCI bus in addition to the legacy
COM1/COM2 devices behind the LPC bus.

The command line option to attach ISA COM1/COM2 ports to a virtual machine is
"-s <bus>,lpc -l com1,stdio".

The command line option to create a PCI-attached uart device is:
"-s <bus>,uart[,stdio]"

The command line option to create PCI-attached COM1/COM2 device is:
"-S <bus>,uart[,stdio]". This style of creating COM ports is deprecated.

Discussed with: grehan
Reviewed by: grehan
Submitted by: Tycho Nightingale (tycho.nightingale@pluribusnetworks.com)

M share/examples/bhyve/vmrun.sh
AM usr.sbin/bhyve/legacy_irq.c
AM usr.sbin/bhyve/legacy_irq.h
M usr.sbin/bhyve/Makefile
AM usr.sbin/bhyve/uart_emul.c
M usr.sbin/bhyve/bhyverun.c
AM usr.sbin/bhyve/uart_emul.h
M usr.sbin/bhyve/pci_uart.c
M usr.sbin/bhyve/pci_emul.c
M usr.sbin/bhyve/inout.c
M usr.sbin/bhyve/pci_emul.h
M usr.sbin/bhyve/inout.h
AM usr.sbin/bhyve/pci_lpc.c
AM usr.sbin/bhyve/pci_lpc.h