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
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 was previously using stdin for both reading and writing to the
console, which made it difficult to redirect console output. Use
stdin for reading and stdout for writing. This makes it easier to use
bhyve as a backend for syzkaller.
As a side effect, the change fixes a minor bug which would cause bhyve
to fail with ENOTCAPABLE if configured to use nmdm for com1 and stdio
for com2.
bhyveload already uses separate descriptors, as does the bvmcons driver.
Reviewed by: jhb
MFC after: 1 month
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D19788
THRE is always asserted in LSR reads, so REG_IER writes that raise
IER_ETXRDY must also set thre_int_pending.
Reported by: Illumos, according to emaste@
https://twitter.com/ed_maste/status/1106195949087584258
MFC after: 2 weeks
will return success when the kernel is built without support of
the capability mode.
It is important to note, that I'm taking a more conservative approach
with these changes and it will be done in small steps.
Reviewed by: jhb
MFC after: 6 weeks
Differential Revision: https://reviews.freebsd.org/D18744
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.
When using -l option targeting file that can't be opened (ie. nmdm module
is not loaded and /dev/nmdm* is specified) bhyve tries to apply capsicum
capabilities to a file that was not opened.
Enclose that code in an if statement and only run it on correctly opened
descriptor also providing meaningful message in case of an error.
Submitted by: Pawel Biernacki <pawel.biernacki@gmail.com>
Reviewed by: grehan, emaste
Sponsoied by: Mysterious Code Ltd.
Differential Revision: D12985
The /etc/ttys entry for a serial console in FreeBSD/x86 is as follows:
ttyu0 "/usr/libexec/getty 3wire" vt100 onifconsole secure
The initial terminal type passed to getty(8) is "3wire" which sets the
CLOCAL flag. However reset(1) clears this flag and any programs that try
to open the terminal will hang waiting for DCD to be asserted.
Fix this by always asserting DCD and DSR in the emulated uart.
The following discussion on virtualization@ has more details:
https://lists.freebsd.org/pipermail/freebsd-virtualization/2015-June/003666.html
Reported by: jmg
Discussed with: grehan
Failing to do this will cause the kevent(2) notification to trigger
continuously and the bhyve(8) mevent thread will hog the cpu until the
characters on the backend tty device are drained.
Also, make the uart backend file descriptor non-blocking to avoid a
select(2) before every byte read from that backend.
Reviewed by: grehan
This fixes the issue of bhyve appearing to halt when using
nmdm ports for the console, until a connection is made to
the other end.
bhyveload already does this.
Reported by: Many.
MFC after: 3 weeks.
bhyveload: introduce the -c <device> parameter
to select a tty for output (or "stdio")
bhyve: allow the puc and lpc-com backends to
accept a tty in addition to "stdio"
When used in conjunction with the null-modem device,
nmdm(4), this allows attach/detach to the guest console
and multiple concurrent serial ports. kgdb on a serial
port is now functional.
Reviewed by: neel
Requested by: Almost everyone that has used bhyve
MFC after: 10.0
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
