int intel_pasid_setup_nested()

in intel/pasid.c [825:925]

• 75 lines of code
• 12 McCabe index (conditional complexity)

int intel_pasid_setup_nested(struct intel_iommu *iommu, struct device *dev,
			     pgd_t *gpgd, u32 pasid,
			     struct iommu_gpasid_bind_data_vtd *pasid_data,
			     struct dmar_domain *domain, int addr_width)
{
	struct pasid_entry *pte;
	struct dma_pte *pgd;
	int ret = 0;
	u64 pgd_val;
	int agaw;
	u16 did;

	if (!ecap_nest(iommu->ecap)) {
		pr_err_ratelimited("IOMMU: %s: No nested translation support\n",
				   iommu->name);
		return -EINVAL;
	}

	if (!(domain->flags & DOMAIN_FLAG_NESTING_MODE)) {
		pr_err_ratelimited("Domain is not in nesting mode, %x\n",
				   domain->flags);
		return -EINVAL;
	}

	pte = intel_pasid_get_entry(dev, pasid);
	if (WARN_ON(!pte))
		return -EINVAL;

	/*
	 * Caller must ensure PASID entry is not in use, i.e. not bind the
	 * same PASID to the same device twice.
	 */
	if (pasid_pte_is_present(pte))
		return -EBUSY;

	pasid_clear_entry(pte);

	/* Sanity checking performed by caller to make sure address
	 * width matching in two dimensions:
	 * 1. CPU vs. IOMMU
	 * 2. Guest vs. Host.
	 */
	switch (addr_width) {
#ifdef CONFIG_X86
	case ADDR_WIDTH_5LEVEL:
		if (!cpu_feature_enabled(X86_FEATURE_LA57) ||
		    !cap_5lp_support(iommu->cap)) {
			dev_err_ratelimited(dev,
					    "5-level paging not supported\n");
			return -EINVAL;
		}

		pasid_set_flpm(pte, 1);
		break;
#endif
	case ADDR_WIDTH_4LEVEL:
		pasid_set_flpm(pte, 0);
		break;
	default:
		dev_err_ratelimited(dev, "Invalid guest address width %d\n",
				    addr_width);
		return -EINVAL;
	}

	/* First level PGD is in GPA, must be supported by the second level */
	if ((uintptr_t)gpgd > domain->max_addr) {
		dev_err_ratelimited(dev,
				    "Guest PGD %lx not supported, max %llx\n",
				    (uintptr_t)gpgd, domain->max_addr);
		return -EINVAL;
	}
	pasid_set_flptr(pte, (uintptr_t)gpgd);

	ret = intel_pasid_setup_bind_data(iommu, pte, pasid_data);
	if (ret)
		return ret;

	/* Setup the second level based on the given domain */
	pgd = domain->pgd;

	agaw = iommu_skip_agaw(domain, iommu, &pgd);
	if (agaw < 0) {
		dev_err_ratelimited(dev, "Invalid domain page table\n");
		return -EINVAL;
	}
	pgd_val = virt_to_phys(pgd);
	pasid_set_slptr(pte, pgd_val);
	pasid_set_fault_enable(pte);

	did = domain->iommu_did[iommu->seq_id];
	pasid_set_domain_id(pte, did);

	pasid_set_address_width(pte, agaw);
	pasid_set_page_snoop(pte, !!ecap_smpwc(iommu->ecap));

	pasid_set_translation_type(pte, PASID_ENTRY_PGTT_NESTED);
	pasid_set_present(pte);
	pasid_flush_caches(iommu, pte, pasid, did);

	return ret;
}