Messages in this thread Patch in this message |  | | Subject | Re: [PATCH v11 10/10] iommu/vt-d: Add custom allocator for IOASID | From | Auger Eric <> | Date | Thu, 9 Apr 2020 12:31:04 +0200 |
| |
Hi Jacob,
On 4/3/20 8:42 PM, Jacob Pan wrote: > 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 <baolu.lu@linux.intel.com> > Signed-off-by: Liu, Yi L <yi.l.liu@intel.com> > Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com> > --- > 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 045c5c08d71d..ff3f0386951f 100644 > --- a/drivers/iommu/intel-iommu.c > +++ b/drivers/iommu/intel-iommu.c > @@ -1732,6 +1732,9 @@ 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 > } > > @@ -3266,6 +3269,84 @@ static int copy_translation_tables(struct intel_iommu *iommu) > return ret; > } > > +#ifdef CONFIG_INTEL_IOMMU_SVM > +static ioasid_t intel_vcmd_ioasid_alloc(ioasid_t min, ioasid_t max, void *data) > +{ > + 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_vcmd_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; > + } > + 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; > + > + if (!sm_supported(iommu)) { > + pr_warn("VT-d Scalable Mode not enabled, no PASID allocation\n"); > + return; > + } > + > + /* > + * Register a custom PASID allocator if we are running in a guest, > + * guest PASID must be obtained via virtual command interface. > + * There can be multiple vIOMMUs in each guest but only one allocator > + * is active. All vIOMMU allocators will eventually be calling the same > + * host allocator. > + */ nit: I prefer if (!ecap_vcs(iommu->ecap) || !vccap_pasid(iommu->vccap)) returns; as it removes indents. > + if (ecap_vcs(iommu->ecap) && vccap_pasid(iommu->vccap)) { > + pr_info("Register custom PASID allocator\n"); > + iommu->pasid_allocator.alloc = intel_vcmd_ioasid_alloc; > + iommu->pasid_allocator.free = intel_vcmd_ioasid_free; > + iommu->pasid_allocator.pdata = (void *)iommu; > + if (ioasid_register_allocator(&iommu->pasid_allocator)) { > + pr_warn("Custom PASID allocator failed, scalable mode disabled\n"); > + /* > + * Disable scalable mode on this IOMMU if there > + * is no custom allocator. Mixing SM capable vIOMMU > + * and non-SM vIOMMU are not supported. > + */ > + intel_iommu_sm = 0; > + } > + } > +} > +#endif > + > static int __init init_dmars(void) > { > struct dmar_drhd_unit *drhd; > @@ -3383,6 +3464,9 @@ 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 f652db3198d9..e122cb30388e 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> > @@ -588,6 +589,7 @@ 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.*/ > Besides Reviewed-by: Eric Auger <eric.auger@redhat.com>
Thanks
Eric
|  |