> -----Original Message----- > From: Alex Williamson [mailto:alex.william...@redhat.com] > Sent: Tuesday, January 21, 2014 7:06 PM > To: Bhushan Bharat-R65777 > Cc: Sethi Varun-B16395; io...@lists.linux-foundation.org; linux- > ker...@vger.kernel.org > Subject: Re: [RFC PATCH] vfio/iommu_type1: Multi-IOMMU domain support > > On Tue, 2014-01-21 at 07:27 +0000, bharat.bhus...@freescale.com wrote: > > > + domain->domain = iommu_domain_alloc(domain->bus); > > > + if (!domain->domain) { > > > + ret = -EIO; > > > + goto out_free; > > > + } > > > + > > > + ret = iommu_attach_group(domain->domain, iommu_group); > > > + if (ret) > > > + goto out_domain; > > > + > > > + INIT_LIST_HEAD(&domain->group_list); > > > + list_add(&group->next, &domain->group_list); > > > + > > > + if (!allow_unsafe_interrupts && > > > + !iommu_domain_has_cap(domain->domain, IOMMU_CAP_INTR_REMAP)) { > > > + pr_warn("%s: No interrupt remapping support. Use the module > > > +param > > > \"allow_unsafe_interrupts\" to enable VFIO IOMMU support on this > > > platform\n", > > > + __func__); > > > + ret = -EPERM; > > > + goto out_detach; > > > + } > > > + > > > + if (iommu_domain_has_cap(domain->domain, IOMMU_CAP_CACHE_COHERENCY)) > > > + domain->prot |= IOMMU_CACHE; > > > + > > > + /* Try to match an existing compatible domain. */ > > > + list_for_each_entry(d, &iommu->domain_list, next) { > > > + if (d->bus == domain->bus && d->prot == domain->prot) { > > > > Are not we talking about allowing a domain to support different bus type if > domain/iommu-group properties matches. > > This is where I was suggesting to Varun that we could test iommu_ops instead > of > bus_type. > > > > + iommu_detach_group(domain->domain, iommu_group); > > > + if (!iommu_attach_group(d->domain, iommu_group)) { > > > + list_add(&group->next, &d->group_list); > > > + iommu_domain_free(domain->domain); > > > + kfree(domain); > > > + mutex_unlock(&iommu->lock); > > > + return 0; > > > + } > > > + > > > + ret = iommu_attach_group(domain->domain, iommu_group); > > > + if (ret) > > > + goto out_domain; > > > + } > > > + } > > > + > > > + /* replay mappings on new domains */ > > > + ret = vfio_iommu_replay(iommu, domain); > > > > IIUC; We created a new domain because an already existing domain does > > not have same attribute; say domain->prot; But in vfio_iommu_replay() we > > pick > up any domain, first domain, and create mapping accordingly. > > Should not we use attributes of this domain otherwise we may get "reserved > > bit > faults"? > > We use an existing domain to get the iova to physical mappings, should those > not > be consistent regardless of the domain we pick? We're not using any of the > low > level attributes that could cause something like a reserved bit fault. > Thanks,
You are right, we use dma->addr etc from any domain and but uses "prot" from the domain passed to replay function(). So effectively the only difference (from dma mapping perspective) between domains in a container is "prot" Thanks -Bharat > > Alex > >
