Merge tag 'for-joerg' of git://git.kernel.org/pub/scm/linux/kernel/git/jgg/iommufd into core

iommu: Define EINVAL as device/domain incompatibility

This series is to replace the previous EMEDIUMTYPE patch in a VFIO series:
https://lore.kernel.org/kvm/Yxnt9uQTmbqul5lf@8bytes.org/

The purpose is to regulate all existing ->attach_dev callback functions to
use EINVAL exclusively for an incompatibility error between a device and a
domain. This allows VFIO and IOMMUFD to detect such a soft error, and then
try a different domain with the same device.

Among all the patches, the first two are preparatory changes. And then one
patch to update kdocs and another three patches for the enforcement
effort.

Link: https://lore.kernel.org/r/cover.1666042872.git.nicolinc@nvidia.com

16 files changed, 60 insertions, 56 deletions

diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
index d3b39d0416fa..45299eb7e8e3 100644
--- a/drivers/iommu/amd/iommu.c
+++ b/drivers/iommu/amd/iommu.c
@@ -2155,21 +2155,13 @@ static void amd_iommu_detach_device(struct iommu_domain *dom,
 static int amd_iommu_attach_device(struct iommu_domain *dom,
 				   struct device *dev)
 {
+	struct iommu_dev_data *dev_data = dev_iommu_priv_get(dev);
 	struct protection_domain *domain = to_pdomain(dom);
-	struct iommu_dev_data *dev_data;
-	struct amd_iommu *iommu;
+	struct amd_iommu *iommu = rlookup_amd_iommu(dev);
 	int ret;
 
-	if (!check_device(dev))
-		return -EINVAL;
-
-	dev_data = dev_iommu_priv_get(dev);
 	dev_data->defer_attach = false;
 
-	iommu = rlookup_amd_iommu(dev);
-	if (!iommu)
-		return -EINVAL;
-
 	if (dev_data->domain)
 		detach_device(dev);
 
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
index 94a2e53368af..ab160198edd6 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -2433,23 +2433,14 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
 			goto out_unlock;
 		}
 	} else if (smmu_domain->smmu != smmu) {
-		dev_err(dev,
-			"cannot attach to SMMU %s (upstream of %s)\n",
-			dev_name(smmu_domain->smmu->dev),
-			dev_name(smmu->dev));
-		ret = -ENXIO;
+		ret = -EINVAL;
 		goto out_unlock;
 	} else if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1 &&
 		   master->ssid_bits != smmu_domain->s1_cfg.s1cdmax) {
-		dev_err(dev,
-			"cannot attach to incompatible domain (%u SSID bits != %u)\n",
-			smmu_domain->s1_cfg.s1cdmax, master->ssid_bits);
 		ret = -EINVAL;
 		goto out_unlock;
 	} else if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1 &&
 		   smmu_domain->stall_enabled != master->stall_enabled) {
-		dev_err(dev, "cannot attach to stall-%s domain\n",
-			smmu_domain->stall_enabled ? "enabled" : "disabled");
 		ret = -EINVAL;
 		goto out_unlock;
 	}
diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c b/drivers/iommu/arm/arm-smmu/arm-smmu.c
index 30dab1418e3f..719fbca1fe52 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu.c
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c
@@ -1150,9 +1150,6 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
 	 * different SMMUs.
 	 */
 	if (smmu_domain->smmu != smmu) {
-		dev_err(dev,
-			"cannot attach to SMMU %s whilst already attached to domain on SMMU %s\n",
-			dev_name(smmu_domain->smmu->dev), dev_name(smmu->dev));
 		ret = -EINVAL;
 		goto rpm_put;
 	}
diff --git a/drivers/iommu/arm/arm-smmu/qcom_iommu.c b/drivers/iommu/arm/arm-smmu/qcom_iommu.c
index 3869c3ecda8c..bfd7b51eb5db 100644
--- a/drivers/iommu/arm/arm-smmu/qcom_iommu.c
+++ b/drivers/iommu/arm/arm-smmu/qcom_iommu.c
@@ -381,13 +381,8 @@ static int qcom_iommu_attach_dev(struct iommu_domain *domain, struct device *dev
 	 * Sanity check the domain. We don't support domains across
 	 * different IOMMUs.
 	 */
-	if (qcom_domain->iommu != qcom_iommu) {
-		dev_err(dev, "cannot attach to IOMMU %s while already "
-			"attached to domain on IOMMU %s\n",
-			dev_name(qcom_domain->iommu->dev),
-			dev_name(qcom_iommu->dev));
+	if (qcom_domain->iommu != qcom_iommu)
 		return -EINVAL;
-	}
 
 	return 0;
 }
diff --git a/drivers/iommu/fsl_pamu.c b/drivers/iommu/fsl_pamu.c
index 0d03f837a5d4..2eb3211c8167 100644
--- a/drivers/iommu/fsl_pamu.c
+++ b/drivers/iommu/fsl_pamu.c
@@ -211,7 +211,7 @@ int pamu_config_ppaace(int liodn, u32 omi, u32 stashid, int prot)
 		ppaace->op_encode.index_ot.omi = omi;
 	} else if (~omi != 0) {
 		pr_debug("bad operation mapping index: %d\n", omi);
-		return -EINVAL;
+		return -ENODEV;
 	}
 
 	/* configure stash id */
diff --git a/drivers/iommu/fsl_pamu_domain.c b/drivers/iommu/fsl_pamu_domain.c
index fa20f4b03e12..4408ac3c49b6 100644
--- a/drivers/iommu/fsl_pamu_domain.c
+++ b/drivers/iommu/fsl_pamu_domain.c
@@ -258,7 +258,7 @@ static int fsl_pamu_attach_device(struct iommu_domain *domain,
 	liodn = of_get_property(dev->of_node, "fsl,liodn", &len);
 	if (!liodn) {
 		pr_debug("missing fsl,liodn property at %pOF\n", dev->of_node);
-		return -EINVAL;
+		return -ENODEV;
 	}
 
 	spin_lock_irqsave(&dma_domain->domain_lock, flags);
@@ -267,7 +267,7 @@ static int fsl_pamu_attach_device(struct iommu_domain *domain,
 		if (liodn[i] >= PAACE_NUMBER_ENTRIES) {
 			pr_debug("Invalid liodn %d, attach device failed for %pOF\n",
 				 liodn[i], dev->of_node);
-			ret = -EINVAL;
+			ret = -ENODEV;
 			break;
 		}
 
diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index a934a46bb9e6..f298e51d5aa6 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -4196,19 +4196,15 @@ static int prepare_domain_attach_device(struct iommu_domain *domain,
 		return -ENODEV;
 
 	if (dmar_domain->force_snooping && !ecap_sc_support(iommu->ecap))
-		return -EOPNOTSUPP;
+		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)) {
-		dev_err(dev, "%s: iommu width (%d) is not "
-		        "sufficient for the mapped address (%llx)\n",
-		        __func__, addr_width, dmar_domain->max_addr);
-		return -EFAULT;
-	}
+	if (dmar_domain->max_addr > (1LL << addr_width))
+		return -EINVAL;
 	dmar_domain->gaw = addr_width;
 
 	/*
diff --git a/drivers/iommu/intel/pasid.c b/drivers/iommu/intel/pasid.c
index c30ddac40ee5..95d73f19ab61 100644
--- a/drivers/iommu/intel/pasid.c
+++ b/drivers/iommu/intel/pasid.c
@@ -101,8 +101,10 @@ int intel_pasid_alloc_table(struct device *dev)
 
 	might_sleep();
 	info = dev_iommu_priv_get(dev);
-	if (WARN_ON(!info || !dev_is_pci(dev) || info->pasid_table))
-		return -EINVAL;
+	if (WARN_ON(!info || !dev_is_pci(dev)))
+		return -ENODEV;
+	if (WARN_ON(info->pasid_table))
+		return -EEXIST;
 
 	pasid_table = kzalloc(sizeof(*pasid_table), GFP_KERNEL);
 	if (!pasid_table)
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index c50f68b2b656..6ca377f4fbf9 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -1976,6 +1976,18 @@ static int __iommu_attach_device(struct iommu_domain *domain,
 	return ret;
 }
 
+/**
+ * iommu_attach_device - Attach an IOMMU domain to a device
+ * @domain: IOMMU domain to attach
+ * @dev: Device that will be attached
+ *
+ * Returns 0 on success and error code on failure
+ *
+ * Note that EINVAL can be treated as a soft failure, indicating
+ * that certain configuration of the domain is incompatible with
+ * the device. In this case attaching a different domain to the
+ * device may succeed.
+ */
 int iommu_attach_device(struct iommu_domain *domain, struct device *dev)
 {
 	struct iommu_group *group;
@@ -2102,6 +2114,18 @@ static int __iommu_attach_group(struct iommu_domain *domain,
 	return ret;
 }
 
+/**
+ * iommu_attach_group - Attach an IOMMU domain to an IOMMU group
+ * @domain: IOMMU domain to attach
+ * @group: IOMMU group that will be attached
+ *
+ * Returns 0 on success and error code on failure
+ *
+ * Note that EINVAL can be treated as a soft failure, indicating
+ * that certain configuration of the domain is incompatible with
+ * the group. In this case attaching a different domain to the
+ * group may succeed.
+ */
 int iommu_attach_group(struct iommu_domain *domain, struct iommu_group *group)
 {
 	int ret;
diff --git a/drivers/iommu/ipmmu-vmsa.c b/drivers/iommu/ipmmu-vmsa.c
index 3b30c0752274..22230cc15dcd 100644
--- a/drivers/iommu/ipmmu-vmsa.c
+++ b/drivers/iommu/ipmmu-vmsa.c
@@ -628,8 +628,6 @@ static int ipmmu_attach_device(struct iommu_domain *io_domain,
 		 * Something is wrong, we can't attach two devices using
 		 * different IOMMUs to the same domain.
 		 */
-		dev_err(dev, "Can't attach IPMMU %s to domain on IPMMU %s\n",
-			dev_name(mmu->dev), dev_name(domain->mmu->dev));
 		ret = -EINVAL;
 	} else
 		dev_info(dev, "Reusing IPMMU context %u\n", domain->context_id);
diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index 2ab2ecfe01f8..b383c8327f9c 100644
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c
@@ -609,7 +609,7 @@ static int mtk_iommu_domain_finalise(struct mtk_iommu_domain *dom,
 	dom->iop = alloc_io_pgtable_ops(ARM_V7S, &dom->cfg, data);
 	if (!dom->iop) {
 		dev_err(data->dev, "Failed to alloc io pgtable\n");
-		return -EINVAL;
+		return -ENOMEM;
 	}
 
 	/* Update our support page sizes bitmap */
@@ -668,7 +668,7 @@ static int mtk_iommu_attach_device(struct iommu_domain *domain,
 		ret = mtk_iommu_domain_finalise(dom, frstdata, region_id);
 		if (ret) {
 			mutex_unlock(&dom->mutex);
-			return -ENODEV;
+			return ret;
 		}
 		dom->bank = &data->bank[bankid];
 	}
diff --git a/drivers/iommu/omap-iommu.c b/drivers/iommu/omap-iommu.c
index 07ee2600113c..2fd7702c6709 100644
--- a/drivers/iommu/omap-iommu.c
+++ b/drivers/iommu/omap-iommu.c
@@ -1414,7 +1414,7 @@ static int omap_iommu_attach_init(struct device *dev,
 
 	odomain->num_iommus = omap_iommu_count(dev);
 	if (!odomain->num_iommus)
-		return -EINVAL;
+		return -ENODEV;
 
 	odomain->iommus = kcalloc(odomain->num_iommus, sizeof(*iommu),
 				  GFP_ATOMIC);
@@ -1464,7 +1464,7 @@ omap_iommu_attach_dev(struct iommu_domain *domain, struct device *dev)
 
 	if (!arch_data || !arch_data->iommu_dev) {
 		dev_err(dev, "device doesn't have an associated iommu\n");
-		return -EINVAL;
+		return -ENODEV;
 	}
 
 	spin_lock(&omap_domain->lock);
@@ -1472,7 +1472,7 @@ omap_iommu_attach_dev(struct iommu_domain *domain, struct device *dev)
 	/* only a single client device can be attached to a domain */
 	if (omap_domain->dev) {
 		dev_err(dev, "iommu domain is already attached\n");
-		ret = -EBUSY;
+		ret = -EINVAL;
 		goto out;
 	}
 
diff --git a/drivers/iommu/sprd-iommu.c b/drivers/iommu/sprd-iommu.c
index fadd2c907222..e02793375598 100644
--- a/drivers/iommu/sprd-iommu.c
+++ b/drivers/iommu/sprd-iommu.c
@@ -237,10 +237,8 @@ static int sprd_iommu_attach_device(struct iommu_domain *domain,
 	struct sprd_iommu_domain *dom = to_sprd_domain(domain);
 	size_t pgt_size = sprd_iommu_pgt_size(domain);
 
-	if (dom->sdev) {
-		pr_err("There's already a device attached to this domain.\n");
+	if (dom->sdev)
 		return -EINVAL;
-	}
 
 	dom->pgt_va = dma_alloc_coherent(sdev->dev, pgt_size, &dom->pgt_pa, GFP_KERNEL);
 	if (!dom->pgt_va)
diff --git a/drivers/iommu/tegra-gart.c b/drivers/iommu/tegra-gart.c
index e5ca3cf1a949..ed53279d1106 100644
--- a/drivers/iommu/tegra-gart.c
+++ b/drivers/iommu/tegra-gart.c
@@ -112,7 +112,7 @@ static int gart_iommu_attach_dev(struct iommu_domain *domain,
 	spin_lock(&gart->dom_lock);
 
 	if (gart->active_domain && gart->active_domain != domain) {
-		ret = -EBUSY;
+		ret = -EINVAL;
 	} else if (dev_iommu_priv_get(dev) != domain) {
 		dev_iommu_priv_set(dev, domain);
 		gart->active_domain = domain;
diff --git a/drivers/iommu/virtio-iommu.c b/drivers/iommu/virtio-iommu.c
index 8b1b5c270e50..5b8fe9bfa9a5 100644
--- a/drivers/iommu/virtio-iommu.c
+++ b/drivers/iommu/virtio-iommu.c
@@ -670,7 +670,7 @@ static int viommu_domain_finalise(struct viommu_endpoint *vdev,
 		dev_err(vdev->dev,
 			"granule 0x%lx larger than system page size 0x%lx\n",
 			viommu_page_size, PAGE_SIZE);
-		return -EINVAL;
+		return -ENODEV;
 	}
 
 	ret = ida_alloc_range(&viommu->domain_ids, viommu->first_domain,
@@ -697,7 +697,7 @@ static int viommu_domain_finalise(struct viommu_endpoint *vdev,
 		if (ret) {
 			ida_free(&viommu->domain_ids, vdomain->id);
 			vdomain->viommu = NULL;
-			return -EOPNOTSUPP;
+			return ret;
 		}
 	}
 
@@ -734,8 +734,7 @@ static int viommu_attach_dev(struct iommu_domain *domain, struct device *dev)
 		 */
 		ret = viommu_domain_finalise(vdev, domain);
 	} else if (vdomain->viommu != vdev->viommu) {
-		dev_err(dev, "cannot attach to foreign vIOMMU\n");
-		ret = -EXDEV;
+		ret = -EINVAL;
 	}
 	mutex_unlock(&vdomain->mutex);
 
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 7d2648058e43..68d7d304cdb7 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -278,6 +278,18 @@ struct iommu_ops {
 /**
  * struct iommu_domain_ops - domain specific operations
  * @attach_dev: attach an iommu domain to a device
+ *  Return:
+ * * 0		- success
+ * * EINVAL	- can indicate that device and domain are incompatible due to
+ *		  some previous configuration of the domain, in which case the
+ *		  driver shouldn't log an error, since it is legitimate for a
+ *		  caller to test reuse of existing domains. Otherwise, it may
+ *		  still represent some other fundamental problem
+ * * ENOMEM	- out of memory
+ * * ENOSPC	- non-ENOMEM type of resource allocation failures
+ * * EBUSY	- device is attached to a domain and cannot be changed
+ * * ENODEV	- device specific errors, not able to be attached
+ * * <others>	- treated as ENODEV by the caller. Use is discouraged
  * @detach_dev: detach an iommu domain from a device
  * @set_dev_pasid: set an iommu domain to a pasid of device
  * @map: map a physically contiguous memory region to an iommu domain