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

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

[Meng Xu]

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

***The command line I used for dom0 image is***
panic=10 panic_on_oops=1 console=hvc0,115200n8 earlyprintk=xen quiet splash


***The problem is***:
When I boot up the host machine into Xen and use "sudo screen
/dev/ttyS0 115200n8" on the remote machine to listen to the serial
port of the host machine, I can only see some garbled message.

***My question is***:
Is there anything else I should configure to use the non-standard PCI
serial port?
Is the non-standard PCI serial ports supported in current Xen version?
When Xen kernel crash, will the kernel dump information be directed to
the remote machine via the non-standard PCI serial port? (I know this
works on the legacy serial port but I'm not sure if it works for the
non-standard PCI serial port.)

Thank you very much for your help! Any suggestion is really appreciated!
If you need any further information, please let me know!
I attach the full grub entry information at the end of this email.

Best regards,

Meng

-------------------------------
The full grub entry I used is:

menuentry 'Ubuntu GNU/Linux, with Xen (credit) and Linux
3.8.0-44-generic' --class ubuntu --class gnu-linux --class gnu --class
os --class xen {

    savedefault

    insmod part_msdos

    insmod ext2

    set root='(hd0,msdos5)'

    search --no-floppy --fs-uuid --set=root 6c02f0b9-a3b4-4474-a0ab-807f019fd77e

    echo    'Loading Xen ...'

    multiboot   /boot/xen-4.6-unstable.gz placeholder
dom0_mem=8192M,max:8192M dom0_max_vcpus=8 sched=credit
com5=115200,8n1,0xf010,50  console=com5,vga

    echo    'Loading Linux 3.8.0-44-generic ...'

    module  /boot/vmlinuz-3.8.0-44-generic placeholder root=/dev/sda5
ro panic=10 panic_on_oops=1 console=hvc0,115200n8 earlyprintk=xen
quiet splash

    echo    'Loading initial ramdisk ...'

    module  /boot/initrd.img-3.8.0-44-generic

}



[1] http://wiki.xenproject.org/wiki/Xen_Serial_Console



-- 


-----------
Meng Xu
PhD Student in Computer and Information Science
University of Pennsylvania
http://www.cis.upenn.edu/~mengxu/

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

[Andrew Cooper]

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

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

[Meng Xu]

Hi Andrew,

>>
>> *** 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.

I see.

>
> You probably want
>
> com1=115200,8n1,pci
>
> as you can make no guarantees about the BDF or IO base remaining
> consistent across reboots.

I see. If I only configure com1 as you suggested, it works as well.
(Maybe it  just happened to work with the previous setting I had.)

So the following xen command line works:
placeholder dom0_mem=8192M,max:8192M dom0_max_vcpus=8 sched=credit
com1=115200,8n1,pci console=com1,vga

Thank you again for your help!

Best regards,

Meng
-- 


-----------
Meng Xu
PhD Student in Computer and Information Science
University of Pennsylvania
http://www.cis.upenn.edu/~mengxu/

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

[Meng Xu]

Sorry for the ripple... :-(
It is working now...



>
> menuentry 'Ubuntu GNU/Linux, with Xen (credit) and Linux
> 3.8.0-44-generic' --class ubuntu --class gnu-linux --class gnu --class
> os --class xen {
>
>     savedefault
>
>     insmod part_msdos
>
>     insmod ext2
>
>     set root='(hd0,msdos5)'
>
>     search --no-floppy --fs-uuid --set=root 6c02f0b9-a3b4-4474-a0ab-807f019fd77e
>
>     echo    'Loading Xen ...'
>
>     multiboot   /boot/xen-4.6-unstable.gz placeholder
> dom0_mem=8192M,max:8192M dom0_max_vcpus=8 sched=credit
> com5=115200,8n1,0xf010,50  console=com5,vga


I forgot to set up the "com1" in the xen image grub entry.
After setting the com1, the serial port works now~

>
>     echo    'Loading Linux 3.8.0-44-generic ...'
>
>     module  /boot/vmlinuz-3.8.0-44-generic placeholder root=/dev/sda5
> ro panic=10 panic_on_oops=1 console=hvc0,115200n8 earlyprintk=xen
> quiet splash
>
>     echo    'Loading initial ramdisk ...'
>
>     module  /boot/initrd.img-3.8.0-44-generic
>
> }
>
>

Finally, I pulled my leg from the serial port configuration mud...

Meng

-----------
Meng Xu
PhD Student in Computer and Information Science
University of Pennsylvania
http://www.cis.upenn.edu/~mengxu/