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...@linux.intel.com> Signed-off-by: Liu, Yi L <yi.l....@intel.com> Signed-off-by: Jacob Pan <jacob.jun....@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 b8aa6479b87f..2f0bf7cc70ce 100644 --- a/drivers/iommu/intel-iommu.c +++ b/drivers/iommu/intel-iommu.c @@ -1758,6 +1758,9 @@ 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 } @@ -3294,6 +3297,84 @@ 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) +{ + 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; + } + 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. + */ + if (ecap_vcs(iommu->ecap) && vccap_pasid(iommu->vccap)) { + pr_info("Register custom PASID allocator\n"); + iommu->pasid_allocator.alloc = intel_ioasid_alloc; + iommu->pasid_allocator.free = intel_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; @@ -3411,6 +3492,9 @@ 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 0df734db19a9..7955afc1ec94 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> @@ -561,6 +562,7 @@ 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 _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu