On Thu, 2 Apr 2020 02:18:45 +0000 "Tian, Kevin" <[email protected]> wrote:
> > From: Jacob Pan <[email protected]> > > Sent: Wednesday, April 1, 2020 11:48 PM > > > > On Sat, 28 Mar 2020 10:22:41 +0000 > > "Tian, Kevin" <[email protected]> wrote: > > > > > > From: Jacob Pan <[email protected]> > > > > Sent: Saturday, March 21, 2020 7:28 AM > > > > > > > > When VT-d driver runs in the guest, PASID allocation must be > > > > performed via virtual command interface. This patch registers a > > > > custom IOASID allocator which takes precedence over the default > > > > XArray based allocator. The resulting IOASID allocation will > > > > always come from the host. This ensures that PASID namespace is > > > > system- wide. > > > > > > > > Signed-off-by: Lu Baolu <[email protected]> > > > > Signed-off-by: Liu, Yi L <[email protected]> > > > > Signed-off-by: Jacob Pan <[email protected]> > > > > --- > > > > drivers/iommu/intel-iommu.c | 84 > > > > +++++++++++++++++++++++++++++++++++++++++++++ > > > > include/linux/intel-iommu.h | 2 ++ > > > > 2 files changed, 86 insertions(+) > > > > > > > > diff --git a/drivers/iommu/intel-iommu.c > > > > b/drivers/iommu/intel-iommu.c index a76afb0fd51a..c1c0b0fb93c3 > > > > 100644 --- a/drivers/iommu/intel-iommu.c > > > > +++ b/drivers/iommu/intel-iommu.c > > > > @@ -1757,6 +1757,9 @@ static void free_dmar_iommu(struct > > intel_iommu > > > > *iommu) > > > > if (ecap_prs(iommu->ecap)) > > > > intel_svm_finish_prq(iommu); > > > > } > > > > + if (ecap_vcs(iommu->ecap) && vccap_pasid(iommu->vccap)) > > > > + > > > > ioasid_unregister_allocator(&iommu->pasid_allocator); + > > > > #endif > > > > } > > > > > > > > @@ -3291,6 +3294,84 @@ static int copy_translation_tables(struct > > > > intel_iommu *iommu) > > > > return ret; > > > > } > > > > > > > > +#ifdef CONFIG_INTEL_IOMMU_SVM > > > > +static ioasid_t intel_ioasid_alloc(ioasid_t min, ioasid_t max, > > > > void *data) > > > > > > the name is too generic... can we add vcmd in the name to clarify > > > its purpose, e.g. intel_vcmd_ioasid_alloc? > > > > > I feel the intel_ prefix is a natural extension of a generic API, > > we do that for other IOMMU APIs, right? > > other IOMMU APIs have no difference between host and guest, but > this one only applies to guest with vcmd interface. > OK, sounds good. It is more explicit, improves readability. > > > > > > +{ > > > > + struct intel_iommu *iommu = data; > > > > + ioasid_t ioasid; > > > > + > > > > + if (!iommu) > > > > + return INVALID_IOASID; > > > > + /* > > > > + * VT-d virtual command interface always uses the full > > > > 20 bit > > > > + * PASID range. Host can partition guest PASID range > > > > based on > > > > + * policies but it is out of guest's control. > > > > + */ > > > > + if (min < PASID_MIN || max > intel_pasid_max_id) > > > > + return INVALID_IOASID; > > > > + > > > > + if (vcmd_alloc_pasid(iommu, &ioasid)) > > > > + return INVALID_IOASID; > > > > + > > > > + return ioasid; > > > > +} > > > > + > > > > +static void intel_ioasid_free(ioasid_t ioasid, void *data) > > > > +{ > > > > + struct intel_iommu *iommu = data; > > > > + > > > > + if (!iommu) > > > > + return; > > > > + /* > > > > + * Sanity check the ioasid owner is done at upper > > > > layer, e.g. VFIO > > > > + * We can only free the PASID when all the devices are > > > > unbound. > > > > + */ > > > > + if (ioasid_find(NULL, ioasid, NULL)) { > > > > + pr_alert("Cannot free active IOASID %d\n", > > > > ioasid); > > > > + return; > > > > + } > > > > > > However the sanity check is not done in default_free. Is there a > > > reason why using vcmd adds such new requirement? > > > > > Since we don't support nested guest. This vcmd allocator is only > > used by the guest IOMMU driver not VFIO. We expect IOMMU driver to > > have control of the free()/unbind() ordering. > > > > For default_free, it can come from user space and host VFIO which > > can be out of order. But we will solve that issue with the blocking > > notifier. > > > > > > + vcmd_free_pasid(iommu, ioasid); > > > > +} > > > > + > > > > +static void register_pasid_allocator(struct intel_iommu *iommu) > > > > +{ > > > > + /* > > > > + * If we are running in the host, no need for custom > > > > allocator > > > > + * in that PASIDs are allocated from the host > > > > system-wide. > > > > + */ > > > > + if (!cap_caching_mode(iommu->cap)) > > > > + return; > > > > > > is it more accurate to check against vcmd capability? > > > > > I think this is sufficient. The spec says if vcmd is present, we > > must use it but not the other way. > > No, what about an vIOMMU implementation reports CM but not > VCMD? > I didn't get the rationale why we check an indirect capability > when there is already one well defined for the purpose. > We _do_ check ecap_vcs() later on. Just an ordering thing, my thinking was a quick check if we are running in a host. ... if (ecap_vcs(iommu->ecap) && vccap_pasid(iommu->vccap)) { > > > [...] > > > > > > which one? the first or last? > > > > > All allocators share the same ops, so first=last. IOASID code will > > inspect the ops function and see if they are shared with others then > > use the same ops. > > ok, got you. > > > > [...] > > > > > > since you register an allocator for every vIOMMU, means previously > > > registered allocators should also be unregistered here? > > > > [...] > > > > + } > > > > + } > > > > +} > > > > +#endif > > > > + > > > > static int __init init_dmars(void) > > > > { > > > > struct dmar_drhd_unit *drhd; > > > > @@ -3408,6 +3489,9 @@ static int __init init_dmars(void) > > > > */ > > > > for_each_active_iommu(iommu, drhd) { > > > > iommu_flush_write_buffer(iommu); > > > > +#ifdef CONFIG_INTEL_IOMMU_SVM > > > > + register_pasid_allocator(iommu); > > > > +#endif > > > > iommu_set_root_entry(iommu); > > > > iommu->flush.flush_context(iommu, 0, 0, 0, > > > > DMA_CCMD_GLOBAL_INVL); > > > > iommu->flush.flush_iotlb(iommu, 0, 0, 0, > > > > DMA_TLB_GLOBAL_FLUSH); > > > > diff --git a/include/linux/intel-iommu.h > > > > b/include/linux/intel-iommu.h index 9cbf5357138b..9c357a325c72 > > > > 100644 --- a/include/linux/intel-iommu.h > > > > +++ b/include/linux/intel-iommu.h > > > > @@ -19,6 +19,7 @@ > > > > #include <linux/iommu.h> > > > > #include <linux/io-64-nonatomic-lo-hi.h> > > > > #include <linux/dmar.h> > > > > +#include <linux/ioasid.h> > > > > > > > > #include <asm/cacheflush.h> > > > > #include <asm/iommu.h> > > > > @@ -563,6 +564,7 @@ struct intel_iommu { > > > > #ifdef CONFIG_INTEL_IOMMU_SVM > > > > struct page_req_dsc *prq; > > > > unsigned char prq_name[16]; /* Name for PRQ > > > > interrupt */ > > > > + struct ioasid_allocator_ops pasid_allocator; /* Custom > > > > allocator for PASIDs */ > > > > #endif > > > > struct q_inval *qi; /* Queued invalidation > > > > info */ u32 *iommu_state; /* Store iommu states between suspend > > > > and resume.*/ > > > > -- > > > > 2.7.4 > > > > > > > [Jacob Pan] [Jacob Pan] _______________________________________________ iommu mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/iommu
