Re: [Xen-devel] [PATCH] Check AMD SYSCFG DramModEn bit for MTRR configuration

[Wei Huang <wei.huang2@xxxxxxx>]

It is indeed very rare. But such bug, whenever it happens, is very hard
to spot. Linux kernel forces this bit to clear when read fixed MTRR. I
think we should at least print out a warning message.

-Wei
 
On Wed, 2011-03-02 at 09:20 -0600, Anish Patel wrote:
> Buggy BIOSes are more common than you think.  especially from small 
> shops, and some times they don't tend to release BIOS updates for their 
> platforms.
> 
> 
> 
> On 03/02/11 02:01, Keir Fraser wrote:
> > On 01/03/2011 21:11, "Wei Huang"<wei.huang2@xxxxxxx>  wrote:
> >
> >> This patch checks whether SYSCFG DramModEn bit is clear by BIOS. Some
> >> buggy BIOS might set this bit to 1, which causes unexpected behavior on
> >> AMD platforms. This patch also increase family check for AMD CPUs when
> >> setting fixed MTRR ranges.
> > How common are these buggy BIOSes? Can't we just get users to update their
> > BIOS?
> >
> >   -- Keir
> >
> >> Signed-off-by: Wei Huang<wei.huang2@xxxxxxx>
> >>
> >>
> >> PS: If OK, please apply it to both xen-4.1 and xen-4.0 trees.
> >>
> >> _______________________________________________
> >> Xen-devel mailing list
> >> Xen-devel@xxxxxxxxxxxxxxxxxxx
> >> http://lists.xensource.com/xen-devel
> >
> >
> > _______________________________________________
> > Xen-devel mailing list
> > Xen-devel@xxxxxxxxxxxxxxxxxxx
> > http://lists.xensource.com/xen-devel
> >
> 
> 




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