| |
|
 |
|
 |
|
|
|
| |
|
|
xen-devel
[Xen-devel] Re: Should shadow_fault_fast_fail abort?
On Fri, Dec 15, 2006 at 09:27:45AM +0000, Tim Deegan wrote:
> At 15:42 +1100 on 15 Dec (1166197339), Herbert Xu wrote:
> > I noticed your recent patch turned off PFEC_reserved_bit in case
> > another CPU had already modified a magic PTE. It seems that it
> > still leaves PFEC_page_present enabled. This could confuse the
> > guest if the PTE modification is such that the PTE is now present
> > and valid. In fact the guest may treat it as a protection fault.
>
> It's just a spurious page fault -- the hardware is happy to throw these
> at operating systems and so am I. :)
It's only a spurious page fault if PFEC_page_present is clear.
Otherwise the OS (Linux in particular) may treat this as a
protection error which may:
1) Kill a user-space process if in user-mode.
2) Oops the kernel otherwise.
> That does seem cleaner. Is this a problem you were seeing on a
> particular system, or just a general improvement?
I just happened to be looking at the code :)
Cheers,
--
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <herbert@xxxxxxxxxxxxxxxxxxx>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel
|
|
|
| |
|
Home