[PATCH 3/6] iommu/vt-d: Check if SVA is supported when attaching the SVA domain

[Lu Baolu <baolu.lu@linux.intel.com>]

From: Jason Gunthorpe <jgg@nvidia.com>

Attach of a SVA domain should fail if SVA is not supported, move the check
for SVA support out of IOMMU_DEV_FEAT_SVA and into attach.

Also check when allocating a SVA domain to match other drivers.

Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Yi Liu <yi.l.liu@intel.com>
Tested-by: Zhangfei Gao <zhangfei.gao@linaro.org>
Link: https://lore.kernel.org/r/20250228092631.3425464-3-baolu.lu@linux.intel.com
---
 drivers/iommu/intel/iommu.c | 37 +------------------------------
 drivers/iommu/intel/svm.c   | 43 +++++++++++++++++++++++++++++++++++++
 2 files changed, 44 insertions(+), 36 deletions(-)

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index e7152ea77393..58bff6fe3a93 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -3862,41 +3862,6 @@ static struct iommu_group *intel_iommu_device_group(struct device *dev)
 	return generic_device_group(dev);
 }
 
-static int intel_iommu_enable_sva(struct device *dev)
-{
-	struct device_domain_info *info = dev_iommu_priv_get(dev);
-	struct intel_iommu *iommu;
-
-	if (!info || dmar_disabled)
-		return -EINVAL;
-
-	iommu = info->iommu;
-	if (!iommu)
-		return -EINVAL;
-
-	if (!(iommu->flags & VTD_FLAG_SVM_CAPABLE))
-		return -ENODEV;
-
-	if (!info->pasid_enabled || !info->ats_enabled)
-		return -EINVAL;
-
-	/*
-	 * Devices having device-specific I/O fault handling should not
-	 * support PCI/PRI. The IOMMU side has no means to check the
-	 * capability of device-specific IOPF.  Therefore, IOMMU can only
-	 * default that if the device driver enables SVA on a non-PRI
-	 * device, it will handle IOPF in its own way.
-	 */
-	if (!info->pri_supported)
-		return 0;
-
-	/* Devices supporting PRI should have it enabled. */
-	if (!info->pri_enabled)
-		return -EINVAL;
-
-	return 0;
-}
-
 static int context_flip_pri(struct device_domain_info *info, bool enable)
 {
 	struct intel_iommu *iommu = info->iommu;
@@ -4017,7 +3982,7 @@ intel_iommu_dev_enable_feat(struct device *dev, enum iommu_dev_features feat)
 		return intel_iommu_enable_iopf(dev);
 
 	case IOMMU_DEV_FEAT_SVA:
-		return intel_iommu_enable_sva(dev);
+		return 0;
 
 	default:
 		return -ENODEV;
diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c
index f5569347591f..ba93123cb4eb 100644
--- a/drivers/iommu/intel/svm.c
+++ b/drivers/iommu/intel/svm.c
@@ -110,6 +110,41 @@ static const struct mmu_notifier_ops intel_mmuops = {
 	.free_notifier = intel_mm_free_notifier,
 };
 
+static int intel_iommu_sva_supported(struct device *dev)
+{
+	struct device_domain_info *info = dev_iommu_priv_get(dev);
+	struct intel_iommu *iommu;
+
+	if (!info || dmar_disabled)
+		return -EINVAL;
+
+	iommu = info->iommu;
+	if (!iommu)
+		return -EINVAL;
+
+	if (!(iommu->flags & VTD_FLAG_SVM_CAPABLE))
+		return -ENODEV;
+
+	if (!info->pasid_enabled || !info->ats_enabled)
+		return -EINVAL;
+
+	/*
+	 * Devices having device-specific I/O fault handling should not
+	 * support PCI/PRI. The IOMMU side has no means to check the
+	 * capability of device-specific IOPF.  Therefore, IOMMU can only
+	 * default that if the device driver enables SVA on a non-PRI
+	 * device, it will handle IOPF in its own way.
+	 */
+	if (!info->pri_supported)
+		return 0;
+
+	/* Devices supporting PRI should have it enabled. */
+	if (!info->pri_enabled)
+		return -EINVAL;
+
+	return 0;
+}
+
 static int intel_svm_set_dev_pasid(struct iommu_domain *domain,
 				   struct device *dev, ioasid_t pasid,
 				   struct iommu_domain *old)
@@ -121,6 +156,10 @@ static int intel_svm_set_dev_pasid(struct iommu_domain *domain,
 	unsigned long sflags;
 	int ret = 0;
 
+	ret = intel_iommu_sva_supported(dev);
+	if (ret)
+		return ret;
+
 	dev_pasid = domain_add_dev_pasid(domain, dev, pasid);
 	if (IS_ERR(dev_pasid))
 		return PTR_ERR(dev_pasid);
@@ -161,6 +200,10 @@ struct iommu_domain *intel_svm_domain_alloc(struct device *dev,
 	struct dmar_domain *domain;
 	int ret;
 
+	ret = intel_iommu_sva_supported(dev);
+	if (ret)
+		return ERR_PTR(ret);
+
 	domain = kzalloc(sizeof(*domain), GFP_KERNEL);
 	if (!domain)
 		return ERR_PTR(-ENOMEM);
-- 
2.43.0