> -----Original Message----- > From: Jan Beulich [mailto:jbeul...@suse.com] > Sent: 25 September 2017 16:31 > To: Paul Durrant <paul.durr...@citrix.com> > Cc: Andrew Cooper <andrew.coop...@citrix.com>; xen- > de...@lists.xenproject.org > Subject: RE: [Xen-devel] [PATCH v7 01/12] x86/mm: allow a privileged PV > domain to map guest mfns > > >>> On 25.09.17 at 16:56, <paul.durr...@citrix.com> wrote: > >> -----Original Message----- > >> From: Xen-devel [mailto:xen-devel-boun...@lists.xen.org] On Behalf Of > Jan > >> Beulich > >> Sent: 25 September 2017 15:50 > >> To: Paul Durrant <paul.durr...@citrix.com> > >> Cc: Andrew Cooper <andrew.coop...@citrix.com>; xen- > >> de...@lists.xenproject.org > >> Subject: Re: [Xen-devel] [PATCH v7 01/12] x86/mm: allow a privileged PV > >> domain to map guest mfns > >> > >> >>> On 25.09.17 at 16:42, <paul.durr...@citrix.com> wrote: > >> >> From: Jan Beulich [mailto:jbeul...@suse.com] > >> >> Sent: 25 September 2017 14:03 > >> >> >>> On 18.09.17 at 17:31, <paul.durr...@citrix.com> wrote: > >> >> The other aspect I don't understand is why this is needed for PV > >> >> Dom0, but not for PVH. The answer here can't be "because PVH > >> >> Dom0 isn't supported yet", because it eventually will be, and then > >> >> there will still be the problem of PVH supposedly having no notion > >> >> of MFNs (be their own or foreign guest ones). The answer also > >> >> can't be "since it would use XENMAPSPACE_gmfn_foreign", as > >> >> that's acting in terms of GFN too. > >> > > >> > The hypercall is PV-only. For a PVH/HVM tools domain things are > handled > >> by > >> > doing an add-to-physmap to gfns specified by the tools domain. I have > >> tested > >> > both PV and HVM clients of my new memory op. > >> > >> And how is this add-to-physmap any better superpage shattering > >> wise than the old mechansim? > > > > Because the calling domain can make an intelligent choice about what gfns > to > > use? > > And why was an intelligent choice not possible with the old > mechanism? The calling domain is the tool stack one in both > cases, isn't it?
True, I suppose. Paul > > Jan _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org https://lists.xen.org/xen-devel