> -----Original Message----- > From: Tian, Kevin [mailto:kevin.t...@intel.com] > Sent: 07 August 2018 10:03 > To: Paul Durrant <paul.durr...@citrix.com>; Jan Beulich > <jbeul...@suse.com> > Cc: George Dunlap <george.dun...@citrix.com>; xen-devel <xen- > de...@lists.xenproject.org> > Subject: RE: [PATCH v5 09/15] vtd: add lookup_page method to iommu_ops > > > From: Paul Durrant [mailto:paul.durr...@citrix.com] > > Sent: Tuesday, August 7, 2018 4:56 PM > > > > > -----Original Message----- > > > From: Tian, Kevin [mailto:kevin.t...@intel.com] > > > Sent: 07 August 2018 09:48 > > > To: Paul Durrant <paul.durr...@citrix.com>; Jan Beulich > > > <jbeul...@suse.com> > > > Cc: George Dunlap <george.dun...@citrix.com>; xen-devel <xen- > > > de...@lists.xenproject.org> > > > Subject: RE: [PATCH v5 09/15] vtd: add lookup_page method to > > iommu_ops > > > > > > > From: Paul Durrant [mailto:paul.durr...@citrix.com] > > > > Sent: Tuesday, August 7, 2018 4:37 PM > > > > > > > > > -----Original Message----- > > > > > From: Tian, Kevin [mailto:kevin.t...@intel.com] > > > > > Sent: 07 August 2018 09:33 > > > > > To: Jan Beulich <jbeul...@suse.com>; Paul Durrant > > > > > <paul.durr...@citrix.com> > > > > > Cc: George Dunlap <george.dun...@citrix.com>; xen-devel <xen- > > > > > de...@lists.xenproject.org> > > > > > Subject: RE: [PATCH v5 09/15] vtd: add lookup_page method to > > > > iommu_ops > > > > > > > > > > > From: Jan Beulich [mailto:jbeul...@suse.com] > > > > > > Sent: Tuesday, August 7, 2018 4:30 PM > > > > > > > > > > > > >>> On 07.08.18 at 10:21, <paul.durr...@citrix.com> wrote: > > > > > > >> From: Tian, Kevin [mailto:kevin.t...@intel.com] > > > > > > >> Sent: 07 August 2018 04:25 > > > > > > >> > > > > > > >> > From: Paul Durrant [mailto:paul.durr...@citrix.com] > > > > > > >> > Sent: Saturday, August 4, 2018 1:22 AM > > > > > > >> > > > > > > > >> > --- a/xen/drivers/passthrough/vtd/iommu.c > > > > > > >> > +++ b/xen/drivers/passthrough/vtd/iommu.c > > > > > > >> > @@ -1830,6 +1830,39 @@ static int __must_check > > > > > > >> > intel_iommu_unmap_page(struct domain *d, > > > > > > >> > return dma_pte_clear_one(d, bfn_to_baddr(bfn)); > > > > > > >> > } > > > > > > >> > > > > > > > >> > +static int intel_iommu_lookup_page(struct domain *d, bfn_t > > bfn, > > > > > > mfn_t > > > > > > >> > *mfn, > > > > > > >> > + unsigned int *flags) > > > > > > >> > > > > > > >> Not looking at later patches yet... but in concept bfn address > > > > > > >> space is per device instead of per domain. > > > > > > > > > > > > > > Not in this case. Xen has always maintained a single IOMMU > > address > > > > per > > > > > > > virtual machine. That is what BFN refers to. > > > > > > > > > > > > Nut is that a model we can maintain mid and long term? In > > particular > > > > > > on ARM, where Julien has told me a single system could have > > multiple > > > > > > _different_ IOMMUs, I could easily see the address spaces > diverging. > > > > > > > > > > > > > > > > multiple IOMMUs is another thing. > > > > > > > > > > what I questioned is that even one IOMMU needs to support > mulitiple > > > > > address spaces. That is the point of an IOMMU... > > > > > > > > Indeed and that is why we use it to enforce domain separation. I see no > > > > need, as yet, to enforce separation within a domain. That need may > > arise > > > > later and the code can be modified at that point. > > > > > > > > > > but then you need completely different set of APIs at that time... > > > > Ok. Would you be happy if I add the option to supply a an SBDF in the map > > and unmap hypercalls but ignore the value for now? Or even have a 'global' > > flag but return -EOPNOTSUPP if it is not specified. That would avoid the > > need to add new hypercalls for per-device mapping. > > > > that would be better! maybe also worthy of a capability query interface > to tell whether global or per-bdf mapping is supported?
I could make it an option to the 'enable' hypercall. A caller could try to enable per-device mappings first and, if that fails, fall back to global. Paul > > Thanks > Kevin _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
