Re: Question about Xen serial console on non-standard PCI serial ports

[Andrew Cooper <andrew.cooper3@citrix.com>]

On 11/11/15 17:53, Meng Xu wrote:
> Hi all,
>
> We bought a new machine which has no legacy serial ports on the
> motherboard. But we added two PCI serial ports onto the motherboard.
>
> We are trying to configure Xen serial console on the non-standard PCI
> serial port.
> (We have successfully configure Xen serial console on the legacy
> serial port before.)
>
> We followed the manual on [1].
> We connect the ttyS4 to the serial port of a remote machine.
>
> The following command run on the host machine (the new machine I want
> to configure).
> ***The "setserial -g /dev/ttyS*" shows:***
> /dev/ttyS4, UART: 16650V2, Port: 0xf010, IRQ: 50
> /dev/ttyS5, UART: 16650V2, Port: 0xf000, IRQ: 52
>
> *** The PCI serial device is listed in "lspci -v" as below:***
>
> 81:00.0 Serial controller: MosChip Semiconductor Technology Ltd. PCIe
> 9922 Multi-I/O Controller (prog-if 02 [16550])
>
>     Subsystem: Device a000:1000
>
>     Flags: bus master, fast devsel, latency 0, IRQ 50
>
>     I/O ports at f010 [size=8]
>
>     Memory at fbe03000 (32-bit, non-prefetchable) [size=4K]
>
>     Memory at fbe02000 (32-bit, non-prefetchable) [size=4K]
>
>     Capabilities: [50] MSI: Enable- Count=1/8 Maskable- 64bit+
>
>     Capabilities: [78] Power Management version 3
>
>     Capabilities: [80] Express Legacy Endpoint, MSI 00
>
>     Capabilities: [100] Virtual Channel
>
>     Capabilities: [800] Advanced Error Reporting
>
>     Kernel driver in use: serial
>
> 81:00.1 Serial controller: MosChip Semiconductor Technology Ltd. PCIe
> 9922 Multi-I/O Controller (prog-if 02 [16550])
>
>     Subsystem: Device a000:1000
>
>     Flags: bus master, fast devsel, latency 0, IRQ 52
>
>     I/O ports at f000 [size=8]
>
>     Memory at fbe01000 (32-bit, non-prefetchable) [size=4K]
>
>     Memory at fbe00000 (32-bit, non-prefetchable) [size=4K]
>
>     Capabilities: [50] MSI: Enable- Count=1/8 Maskable- 64bit+
>
>     Capabilities: [78] Power Management version 3
>
>     Capabilities: [80] Express Legacy Endpoint, MSI 00
>
>     Capabilities: [100] Advanced Error Reporting
>
>     Kernel driver in use: serial
>
> *** The command line I used for xen image is***
> dom0_mem=8192M,max:8192M dom0_max_vcpus=8 sched=credit
> com5=115200,8n1,0xf010,50  console=com5,vga

Xen doesn't have a com5 command line option.

You probably want

com1=115200,8n1,pci

as you can make no guarantees about the BDF or IO base remaining
consistent across reboots.

~Andrew