Re: HVM disc corruption (was Re: Xen won't start its device backend?)

[Reinoud Zandijk <reinoud%NetBSD.org@localhost>]

Hi,

On Wed, May 27, 2015 at 09:39:19PM +0100, Roger Pau Monn? wrote:
> El 27/05/15 a les 21.29, Reinoud Zandijk ha escrit:
> > It then reads the disklabel fine. Inspecting the code it seems to open the
> > disc with O_BINARY, with a possible O_DIRECT / O_DSYNC. Reading it seems
> > to do on a 512 block boundary for files opened with O_DIRECT and it uses
> > lseek() in combination with the qemu_read(fd, buf, cnt) function.
> > 
> > Is there any special behaviour on raw devices for such flags / functions
> > that could trigger the bug?
> 
> FWIW I had to craft the following patch for FreeBSD:
> 
> http://git.qemu.org/?p=qemu.git;a=patch;h=3cad83075c7b847fe0eb6e61316fdf50984d4570

Do you have suggestions on how to debug this? Somehow i don't have a network
connection yet :-/ With that i could just dump the devices and see what
changes? Would that help?

With regards,
Reinoud