[Lguest] mercurial repo

[ron minnich]

On 7/26/07, Zachary Amsden <zach at vmware.com> wrote:
> ron minnich wrote:
> > Next question. I do have a working patch to allow experts to set the
> > system call #. Really, though, it makes more sense to set this in
> > sysfs or via a per-guest ioctl or some such, right? What's the fix
> > here? Plan 9 port is done, but I do need this change among others.
> >
>
> Allowing one to set the system call # is a bad idea.  You can't allow it
> to overlap with any host IRQ or architectural fault handler.  Because
> Linux uses IPIs in high numbers, and 0-0x1f are architectural faults,
> the only truly safe system call vector that you can dispatch is 0x80.

Allowing to set an arbitrary number is a bad idea. Allowing to set to
a limited but valid range is a fine idea. I am not going to ask the
plan 9 guys to rewrite their system call vector just yet. 0x40 has
worked well for them for many years.

ron