> From: Paul Durrant [mailto:[email protected]] > Sent: Wednesday, August 1, 2018 4:34 PM > > > -----Original Message----- > > From: Xen-devel [mailto:[email protected]] On > Behalf > > Of Jan Beulich > > Sent: 01 August 2018 09:21 > > To: Roger Pau Monne <[email protected]> > > Cc: Kevin Tian <[email protected]>; Stefano Stabellini > > <[email protected]>; Wei Liu <[email protected]>; George Dunlap > > <[email protected]>; Andrew Cooper > > <[email protected]>; Ian Jackson <[email protected]>; > Tim > > (Xen.org) <[email protected]>; Julien Grall <[email protected]>; xen-devel > > <[email protected]> > > Subject: Re: [Xen-devel] [PATCH 2/4] iommu: generalize > > iommu_inclusive_mapping > > > > >>> On 31.07.18 at 17:33, <[email protected]> wrote: > > > On Tue, Jul 31, 2018 at 08:39:22AM -0600, Jan Beulich wrote: > > >> >>> On 27.07.18 at 17:31, <[email protected]> wrote: > > >> > Introduce a new iommu=inclusive generic option that supersedes > > >> > iommu_inclusive_mapping. This should be a non-functional change > on > > >> > Intel hardware, while AMD hardware will gain the same functionality > of > > >> > mapping almost everything below the 4GB boundary. > > >> > > >> So first of all - what's the motivation behind this change? So far we > > >> had no need for hacks line the VT-d side one on AMD. I don't think > > >> this should be widened without there being indication of a problem > > >> with non-niche AMD systems. > > > > > > OK, I can leave the default on for Intel and off for everything else, > > > but I will introduce the generic dom0-iommu= option anyway. > > > > Hmm, I've always been wishing we'd change to a default of off for > > VT-d as well - imo we shouldn't by default assume broken firmware. > > Kevin? > > I suspect that a seriously large number of Xen users will find their systems > fail to boot if the default is changed. I'm testing on a Dell R730 with (to my > knowledge) up-to-date firmware. Not exactly a rare system and turning off > inclusive mapping will cause it to wedge during boot. > > Paul
Though I agree with Jan in concept, the reality means we have to keep default on as before. :-) Thanks Kevin _______________________________________________ Xen-devel mailing list [email protected] https://lists.xenproject.org/mailman/listinfo/xen-devel
