[PATCH 18/20] iommu/vt-d: Enhance compatibility check for paging domain attach

Lu Baolu
2024-05-29T05:36:29Z

The driver now supports domain_alloc_paging, ensuring that a valid device
pointer is provided whenever a paging domain is allocated. Additionally,
the dmar_domain attributes are set up at the time of allocation.

Consistent with the established semantics in the IOMMU core, if a domain is
attached to a device and found to be incompatible with the IOMMU hardware
capabilities, the operation will return an -EINVAL error. This implicitly
advises the caller to allocate a new domain for the device and attempt the
domain attachment again.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
drivers/iommu/intel/iommu.c | 39 ++++++++++++++++++-------------------
drivers/iommu/intel/pasid.c | 28 +-------------------------
2 files changed, 20 insertions(+), 47 deletions(-)

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 693a6d7c79ed..e9393f5c2c50 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -3826,27 +3826,26 @@ int prepare_domain_attach_device(struct iommu_domain *domain,
if (domain->dirty_ops && !ssads_supported(iommu))
return -EINVAL;

- /* check if this iommu agaw is sufficient for max mapped address */
- addr_width = agaw_to_width(iommu->agaw);
- if (addr_width > cap_mgaw(iommu->cap))
- addr_width = cap_mgaw(iommu->cap);
-
- if (dmar_domain->max_addr > (1LL << addr_width))
+ if (dmar_domain->iommu_coherency !=
+ iommu_paging_structure_coherency(iommu))
return -EINVAL;
- dmar_domain->gaw = addr_width;
-
- /*
- * Knock out extra levels of page tables if necessary
- */
- while (iommu->agaw < dmar_domain->agaw) {
- struct dma_pte *pte;
-
- pte = dmar_domain->pgd;
- if (dma_pte_present(pte)) {
- dmar_domain->pgd = phys_to_virt(dma_pte_addr(pte));
- iommu_free_page(pte);
- }
- dmar_domain->agaw--;
+
+ if (domain->type & __IOMMU_DOMAIN_PAGING) {
+ if (dmar_domain->iommu_superpage !=
+ iommu_superpage_capability(iommu, dmar_domain->use_first_level))
+ return -EINVAL;
+
+ if (dmar_domain->use_first_level &&
+ (!sm_supported(iommu) || !ecap_flts(iommu->ecap)))
+ return -EINVAL;
+
+ /* check if this iommu agaw is sufficient for max mapped address */
+ addr_width = agaw_to_width(iommu->agaw);
+ if (addr_width > cap_mgaw(iommu->cap))
+ addr_width = cap_mgaw(iommu->cap);
+
+ if (dmar_domain->gaw > addr_width || dmar_domain->agaw > iommu->agaw)
+ return -EINVAL;
}

if (sm_supported(iommu) && !dev_is_real_dma_subdevice(dev) &&
diff --git a/drivers/iommu/intel/pasid.c b/drivers/iommu/intel/pasid.c
index abce19e2ad6f..573e1b8e3cfb 100644
--- a/drivers/iommu/intel/pasid.c
+++ b/drivers/iommu/intel/pasid.c
@@ -345,25 +345,6 @@ int intel_pasid_setup_first_level(struct intel_iommu *iommu,
return 0;
}

-/*
- * Skip top levels of page tables for iommu which has less agaw
- * than default. Unnecessary for PT mode.
- */
-static int iommu_skip_agaw(struct dmar_domain *domain,
- struct intel_iommu *iommu,
- struct dma_pte **pgd)
-{
- int agaw;
-
- for (agaw = domain->agaw; agaw > iommu->agaw; agaw--) {
- *pgd = phys_to_virt(dma_pte_addr(*pgd));
- if (!dma_pte_present(*pgd))
- return -EINVAL;
- }
-
- return agaw;
-}
-
/*
* Set up the scalable mode pasid entry for second only translation type.
*/
@@ -374,7 +355,6 @@ int intel_pasid_setup_second_level(struct intel_iommu *iommu,
struct pasid_entry *pte;
struct dma_pte *pgd;
u64 pgd_val;
- int agaw;
u16 did;

/*
@@ -388,12 +368,6 @@ int intel_pasid_setup_second_level(struct intel_iommu *iommu,
}

pgd = domain->pgd;
- agaw = iommu_skip_agaw(domain, iommu, &pgd);
- if (agaw < 0) {
- dev_err(dev, "Invalid domain page table\n");
- return -EINVAL;
- }
-
pgd_val = virt_to_phys(pgd);
did = domain_id_iommu(domain, iommu);

@@ -412,7 +386,7 @@ int intel_pasid_setup_second_level(struct intel_iommu *iommu,
pasid_clear_entry(pte);
pasid_set_domain_id(pte, did);
pasid_set_slptr(pte, pgd_val);
- pasid_set_address_width(pte, agaw);
+ pasid_set_address_width(pte, domain->agaw);
pasid_set_translation_type(pte, PASID_ENTRY_PGTT_SL_ONLY);
pasid_set_fault_enable(pte);
pasid_set_page_snoop(pte, !!ecap_smpwc(iommu->ecap));
--
2.34.1