5 files changed, 76 insertions, 38 deletions

diff --git a/drivers/dma/idxd/device.c b/drivers/dma/idxd/device.c
index 5abbcc61c528..169b7ade8919 100644
--- a/drivers/dma/idxd/device.c
+++ b/drivers/dma/idxd/device.c
@@ -299,21 +299,6 @@ void idxd_wqs_unmap_portal(struct idxd_device *idxd)
 	}
 }
 
-static void __idxd_wq_set_priv_locked(struct idxd_wq *wq, int priv)
-{
-	struct idxd_device *idxd = wq->idxd;
-	union wqcfg wqcfg;
-	unsigned int offset;
-
-	offset = WQCFG_OFFSET(idxd, wq->id, WQCFG_PRIVL_IDX);
-	spin_lock(&idxd->dev_lock);
-	wqcfg.bits[WQCFG_PRIVL_IDX] = ioread32(idxd->reg_base + offset);
-	wqcfg.priv = priv;
-	wq->wqcfg->bits[WQCFG_PRIVL_IDX] = wqcfg.bits[WQCFG_PRIVL_IDX];
-	iowrite32(wqcfg.bits[WQCFG_PRIVL_IDX], idxd->reg_base + offset);
-	spin_unlock(&idxd->dev_lock);
-}
-
 static void __idxd_wq_set_pasid_locked(struct idxd_wq *wq, int pasid)
 {
 	struct idxd_device *idxd = wq->idxd;
@@ -1423,15 +1408,14 @@ int drv_enable_wq(struct idxd_wq *wq)
 	}
 
 	/*
-	 * In the event that the WQ is configurable for pasid and priv bits.
-	 * For kernel wq, the driver should setup the pasid, pasid_en, and priv bit.
-	 * However, for non-kernel wq, the driver should only set the pasid_en bit for
-	 * shared wq. A dedicated wq that is not 'kernel' type will configure pasid and
+	 * In the event that the WQ is configurable for pasid, the driver
+	 * should setup the pasid, pasid_en bit. This is true for both kernel
+	 * and user shared workqueues. There is no need to setup priv bit in
+	 * that in-kernel DMA will also do user privileged requests.
+	 * A dedicated wq that is not 'kernel' type will configure pasid and
 	 * pasid_en later on so there is no need to setup.
 	 */
 	if (test_bit(IDXD_FLAG_CONFIGURABLE, &idxd->flags)) {
-		int priv = 0;
-
 		if (wq_pasid_enabled(wq)) {
 			if (is_idxd_wq_kernel(wq) || wq_shared(wq)) {
 				u32 pasid = wq_dedicated(wq) ? idxd->pasid : 0;
@@ -1439,10 +1423,6 @@ int drv_enable_wq(struct idxd_wq *wq)
 				__idxd_wq_set_pasid_locked(wq, pasid);
 			}
 		}
-
-		if (is_idxd_wq_kernel(wq))
-			priv = 1;
-		__idxd_wq_set_priv_locked(wq, priv);
 	}
 
 	rc = 0;
@@ -1550,6 +1530,15 @@ int idxd_device_drv_probe(struct idxd_dev *idxd_dev)
 	if (rc < 0)
 		return -ENXIO;
 
+	/*
+	 * System PASID is preserved across device disable/enable cycle, but
+	 * genconfig register content gets cleared during device reset. We
+	 * need to re-enable user interrupts for kernel work queue completion
+	 * IRQ to function.
+	 */
+	if (idxd->pasid != IOMMU_PASID_INVALID)
+		idxd_set_user_intr(idxd, 1);
+
 	rc = idxd_device_evl_setup(idxd);
 	if (rc < 0) {
 		idxd->cmd_status = IDXD_SCMD_DEV_EVL_ERR;
diff --git a/drivers/dma/idxd/dma.c b/drivers/dma/idxd/dma.c
index eb35ca313684..07623fb0f52f 100644
--- a/drivers/dma/idxd/dma.c
+++ b/drivers/dma/idxd/dma.c
@@ -75,9 +75,10 @@ static inline void idxd_prep_desc_common(struct idxd_wq *wq,
 	hw->xfer_size = len;
 	/*
 	 * For dedicated WQ, this field is ignored and HW will use the WQCFG.priv
-	 * field instead. This field should be set to 1 for kernel descriptors.
+	 * field instead. This field should be set to 0 for kernel descriptors
+	 * since kernel DMA on VT-d supports "user" privilege only.
 	 */
-	hw->priv = 1;
+	hw->priv = 0;
 	hw->completion_addr = compl;
 }
 
diff --git a/drivers/dma/idxd/idxd.h b/drivers/dma/idxd/idxd.h
index 5428a2e1b1ec..502be9db63f4 100644
--- a/drivers/dma/idxd/idxd.h
+++ b/drivers/dma/idxd/idxd.h
@@ -473,6 +473,15 @@ static inline struct idxd_device *ie_to_idxd(struct idxd_irq_entry *ie)
 	return container_of(ie, struct idxd_device, ie);
 }
 
+static inline void idxd_set_user_intr(struct idxd_device *idxd, bool enable)
+{
+	union gencfg_reg reg;
+
+	reg.bits = ioread32(idxd->reg_base + IDXD_GENCFG_OFFSET);
+	reg.user_int_en = enable;
+	iowrite32(reg.bits, idxd->reg_base + IDXD_GENCFG_OFFSET);
+}
+
 extern struct bus_type dsa_bus_type;
 
 extern bool support_enqcmd;
diff --git a/drivers/dma/idxd/init.c b/drivers/dma/idxd/init.c
index 1aa823974cda..0eb1c827a215 100644
--- a/drivers/dma/idxd/init.c
+++ b/drivers/dma/idxd/init.c
@@ -550,14 +550,59 @@ static struct idxd_device *idxd_alloc(struct pci_dev *pdev, struct idxd_driver_d
 
 static int idxd_enable_system_pasid(struct idxd_device *idxd)
 {
-	return -EOPNOTSUPP;
+	struct pci_dev *pdev = idxd->pdev;
+	struct device *dev = &pdev->dev;
+	struct iommu_domain *domain;
+	ioasid_t pasid;
+	int ret;
+
+	/*
+	 * Attach a global PASID to the DMA domain so that we can use ENQCMDS
+	 * to submit work on buffers mapped by DMA API.
+	 */
+	domain = iommu_get_domain_for_dev(dev);
+	if (!domain)
+		return -EPERM;
+
+	pasid = iommu_alloc_global_pasid(dev);
+	if (pasid == IOMMU_PASID_INVALID)
+		return -ENOSPC;
+
+	/*
+	 * DMA domain is owned by the driver, it should support all valid
+	 * types such as DMA-FQ, identity, etc.
+	 */
+	ret = iommu_attach_device_pasid(domain, dev, pasid);
+	if (ret) {
+		dev_err(dev, "failed to attach device pasid %d, domain type %d",
+			pasid, domain->type);
+		iommu_free_global_pasid(pasid);
+		return ret;
+	}
+
+	/* Since we set user privilege for kernel DMA, enable completion IRQ */
+	idxd_set_user_intr(idxd, 1);
+	idxd->pasid = pasid;
+
+	return ret;
 }
 
 static void idxd_disable_system_pasid(struct idxd_device *idxd)
 {
+	struct pci_dev *pdev = idxd->pdev;
+	struct device *dev = &pdev->dev;
+	struct iommu_domain *domain;
+
+	domain = iommu_get_domain_for_dev(dev);
+	if (!domain)
+		return;
+
+	iommu_detach_device_pasid(domain, dev, idxd->pasid);
+	iommu_free_global_pasid(idxd->pasid);
 
-	iommu_sva_unbind_device(idxd->sva);
+	idxd_set_user_intr(idxd, 0);
 	idxd->sva = NULL;
+	idxd->pasid = IOMMU_PASID_INVALID;
 }
 
 static int idxd_enable_sva(struct pci_dev *pdev)
@@ -600,8 +645,9 @@ static int idxd_probe(struct idxd_device *idxd)
 		} else {
 			set_bit(IDXD_FLAG_USER_PASID_ENABLED, &idxd->flags);
 
-			if (idxd_enable_system_pasid(idxd))
-				dev_warn(dev, "No in-kernel DMA with PASID.\n");
+			rc = idxd_enable_system_pasid(idxd);
+			if (rc)
+				dev_warn(dev, "No in-kernel DMA with PASID. %d\n", rc);
 			else
 				set_bit(IDXD_FLAG_PASID_ENABLED, &idxd->flags);
 		}
diff --git a/drivers/dma/idxd/sysfs.c b/drivers/dma/idxd/sysfs.c
index 293739ac5596..63f6966c51aa 100644
--- a/drivers/dma/idxd/sysfs.c
+++ b/drivers/dma/idxd/sysfs.c
@@ -948,13 +948,6 @@ static ssize_t wq_name_store(struct device *dev,
 	if (strlen(buf) > WQ_NAME_SIZE || strlen(buf) == 0)
 		return -EINVAL;
 
-	/*
-	 * This is temporarily placed here until we have SVM support for
-	 * dmaengine.
-	 */
-	if (wq->type == IDXD_WQT_KERNEL && device_pasid_enabled(wq->idxd))
-		return -EOPNOTSUPP;
-
 	input = kstrndup(buf, count, GFP_KERNEL);
 	if (!input)
 		return -ENOMEM;