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
