Re: [Qemu-devel] Re: How to get target system display with qemu -nographic option?

[David Barrett]

Ah, you're going well outside my area of familiarity -- I've never set 
up a console terminal over a serial line physically nor virtually.

However, I notice you're using the "-append" line -- I made that mistake 
as well, but learned that you can only use "-append" if you're also 
using "-kernel" and "-initrd".  Basically, you can wholly specify the 
kernel in the qemu command line, or you need to go with the kernel 
defined by GRUB, but you can't selectively override grub using the 
command line.

Other than that, I'm not sure how to help.  Good luck!

-david

Atoosah wrote:
> Thank you guys for the explanation. I don't want to ssh as that will 
> modify the behavior of my kernel. The option -monitor requires a device, 
> and so "none" would be viewed as a device (which does not exist).
>
> My goal is to run qemu and have my guests display available via the 
> serial line (for example /dev/ttyS0). In order to do this, it seems to 
> me that the guests grub.conf file console parameter needs to be modified 
> (similar to below); on the host,  qemu needs to be started with 
> "console" option (as shown below); finally, another terminal should be 
> opened with serial port capabilities (such as minicom).  Is this 
> correct? If so, how do I get minicom to connect?
>
> - I've modified my guest kernel /boot/grub/grub.conf file as follows:
> title Fedora ...
> console=ttyS0,38400n8
>
> - To start qemu the options I use are:
> qemu -hda mydisk.img -m 512 -append "root=/dev/hda console=ttyS0" 
> -nographic -serial pty
>
> - My minicom settings are similar to my grub.conf file, i.e. "Comm 
> Parameters" are 38400 8N1
> If I start qemu in one terminal and minicom in the other, should my 
> guests display automatically show up in the minicom screen? If not, how 
> do I get minicom to connect to /dev/ttyS0? So far, my minicom shows as 
> offline. (I've also tried GtkTerm, with no success).
>
> Thanks again.
>
>
>     Ah, "graphics" means "display" -- it doesn't matter whether your guest
>     VM is running X or using a simple terminal, it all looks like one big
>     graphic to qemu.
>
>     Said another way, "-nographic" disables the display entirely, whether
>     that display is used for graphics or text.
>
>     I don't know what you're trying to do with /etc/inittab.  That doesn't
>     mean it's wrong, it just means I've never found it necessary to go that
>     route.  I'm guessing you should probably undo all your changes there and
>     just stick with whatever was the default, and then use the "-nographic
>     -monitor none" option I mention above.
>
>     -david
>
>     On the guest. When you use -nographic, you get a (vritual) pc without
>     a monitor, but with a serial port. If your Fedora is not set up to
>     have a login on the serial port, you will see nothing when you connect
>     a serial cable to the port. You can have login prompts both on serial
>     and on screen.
>
>     You could also ssh into the guest instead.