Re: [Qemu-devel] [PATCH] hw: improve multiboot module loading

[Ralf Ramsauer]

On 07.04.2011 um 10:38, Alexander Graf wrote:
> 
> Also, I just realized that you did miss another small part that needs change. 
> A few lines above, there is code to interpret the modules right before that 
> as well:
> 
>    if (initrd_filename) {
>        const char *r = initrd_filename;
>        mbs.mb_buf_size += strlen(r) + 1;
>        mbs.mb_mods_avail = 1;
>        while ((r = strchr(r, ','))) {
>           mbs.mb_mods_avail++;
>           r++;
>        }
>        mbs.mb_buf_size += MB_MOD_SIZE * mbs.mb_mods_avail;
>    }
> 
> This code would need some change as well, as now the mb_buf_size field is 
> incorrect. It doesn't really hurt, but is bad style to not use the exact 
> amount of memory we need to.

You're right, I didn't look at this section. But now i had a deeper look into 
the code, and I noticed the the mb_buf size seems to be incorrect anyway.

Look at this line:

mbs.mb_buf_size += strlen(r) + 1;

If I start qemu with the option -initrd "mod1 arg=bla, mod2 arg=foo, mod3 
arg=bar", then r contains
"mod1 arg=bla, mod2 arg=foo, mod3 arg=bar", so the commas and spaces after the 
comma are counted for the size of the multiboot command line.
Yes, this doesn't really hurt, but it's nevertheless not the exact amount of 
memory. I'll try to fix it.

--
Ralf