* Guenter Roeck (li...@roeck-us.net) wrote: > On Tue, Jul 09, 2013 at 04:22:52PM -0700, Chris Wright wrote: > > * Guenter Roeck (li...@roeck-us.net) wrote: > > > On Tue, Jul 09, 2013 at 03:05:39PM -0600, Bjorn Helgaas wrote: > > > > [+cc Joerg, David, iommu list] > > > > > > > > On Tue, Jul 9, 2013 at 2:24 PM, Guenter Roeck <li...@roeck-us.net> > > > > wrote: > > > > > I started seeing this problem after updating the BIOS trying fix > > > > > another issue, > > > > > though I may have missed it earlier. > > > > > > > > > > I understand this is a BIOS bug. Would be great if someone can pass > > > > > this on > > > > > to Intel BIOS engineers. > > > > > > > > Maybe. It'd be nice if Linux handled it better, though. > > > > > > > If anyone has an idea how to do that, I'll be happy to write a patch. > > > > I'm not sure there's much you can do. The BIOS is saying there's a DMAR > > unit, and then saying the registers are at addr 0x0. The kernel is > > simply warning you about the invalid DMAR table entry. > > > > One thing I've seen is the BIOS zeroing the base register address when > > VT-d is disabled in BIOS. So, Guenter, a "fix" may be simply enabling > > VT-d in the BIOS. > > Ah, yes, I think I may have that disabled. I'll check it tonight. > > Does that really warrant a traceback, or would a warning message be more > appropriate (possibly telling the user to enable VT-d) ?
Bottom line, the BIOS is providing what we're seeing as invalid tables. If it's a BIOS attempt to disable VT-d is hard to glean from invalid tables, and not all BIOS give interface to enable/disable VT-d. It is a warning message, BTW. Guess I'd be inclined to leave as it is. thanks, -chris -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
