[PATCH] dmaengine: idxd: Separate user and kernel pasid enabling

[PATCH] dmaengine: idxd: Separate user and kernel pasid enabling

[Dave Jiang]

The idxd driver always gated the pasid enabling under a single knob and
this assumption is incorrect. The pasid used for kernel operation can be
independently toggled and has no dependency on the user pasid (and vice
versa). Split the two so they are independent "enabled" flags.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
---
 drivers/dma/idxd/cdev.c   |    4 ++--
 drivers/dma/idxd/device.c |    6 +++---
 drivers/dma/idxd/idxd.h   |   16 ++++++++++++++--
 drivers/dma/idxd/init.c   |   30 +++++++++++++++---------------
 drivers/dma/idxd/sysfs.c  |    2 +-
 5 files changed, 35 insertions(+), 23 deletions(-)

diff --git a/drivers/dma/idxd/cdev.c b/drivers/dma/idxd/cdev.c
index b670b75885ad..28796df62ea6 100644
--- a/drivers/dma/idxd/cdev.c
+++ b/drivers/dma/idxd/cdev.c
@@ -99,7 +99,7 @@ static int idxd_cdev_open(struct inode *inode, struct file *filp)
 	ctx->wq = wq;
 	filp->private_data = ctx;
 
-	if (device_pasid_enabled(idxd)) {
+	if (device_user_pasid_enabled(idxd)) {
 		sva = iommu_sva_bind_device(dev, current->mm, NULL);
 		if (IS_ERR(sva)) {
 			rc = PTR_ERR(sva);
@@ -152,7 +152,7 @@ static int idxd_cdev_release(struct inode *node, struct file *filep)
 	if (wq_shared(wq)) {
 		idxd_device_drain_pasid(idxd, ctx->pasid);
 	} else {
-		if (device_pasid_enabled(idxd)) {
+		if (device_user_pasid_enabled(idxd)) {
 			/* The wq disable in the disable pasid function will drain the wq */
 			rc = idxd_wq_disable_pasid(wq);
 			if (rc < 0)
diff --git a/drivers/dma/idxd/device.c b/drivers/dma/idxd/device.c
index d1dba2a3af5d..d576268374d0 100644
--- a/drivers/dma/idxd/device.c
+++ b/drivers/dma/idxd/device.c
@@ -965,7 +965,7 @@ static int idxd_wqs_setup(struct idxd_device *idxd)
 		if (!wq->group)
 			continue;
 
-		if (wq_shared(wq) && !device_swq_supported(idxd)) {
+		if (wq_shared(wq) && !wq_shared_supported(wq)) {
 			idxd->cmd_status = IDXD_SCMD_WQ_NO_SWQ_SUPPORT;
 			dev_warn(dev, "No shared wq support but configured.\n");
 			return -EINVAL;
@@ -1266,7 +1266,7 @@ int drv_enable_wq(struct idxd_wq *wq)
 
 	/* Shared WQ checks */
 	if (wq_shared(wq)) {
-		if (!device_swq_supported(idxd)) {
+		if (!wq_shared_supported(wq)) {
 			idxd->cmd_status = IDXD_SCMD_WQ_NO_SVM;
 			dev_dbg(dev, "PASID not enabled and shared wq.\n");
 			goto err;
@@ -1296,7 +1296,7 @@ int drv_enable_wq(struct idxd_wq *wq)
 	if (test_bit(IDXD_FLAG_CONFIGURABLE, &idxd->flags)) {
 		int priv = 0;
 
-		if (device_pasid_enabled(idxd)) {
+		if (wq_pasid_enabled(wq)) {
 			if (is_idxd_wq_kernel(wq) || wq_shared(wq)) {
 				u32 pasid = wq_dedicated(wq) ? idxd->pasid : 0;
 
diff --git a/drivers/dma/idxd/idxd.h b/drivers/dma/idxd/idxd.h
index 24e6a0824c64..fed0dfc1eaa8 100644
--- a/drivers/dma/idxd/idxd.h
+++ b/drivers/dma/idxd/idxd.h
@@ -239,6 +239,7 @@ enum idxd_device_flag {
 	IDXD_FLAG_CONFIGURABLE = 0,
 	IDXD_FLAG_CMD_RUNNING,
 	IDXD_FLAG_PASID_ENABLED,
+	IDXD_FLAG_USER_PASID_ENABLED,
 };
 
 struct idxd_dma_dev {
@@ -469,9 +470,20 @@ static inline bool device_pasid_enabled(struct idxd_device *idxd)
 	return test_bit(IDXD_FLAG_PASID_ENABLED, &idxd->flags);
 }
 
-static inline bool device_swq_supported(struct idxd_device *idxd)
+static inline bool device_user_pasid_enabled(struct idxd_device *idxd)
 {
-	return (support_enqcmd && device_pasid_enabled(idxd));
+	return test_bit(IDXD_FLAG_USER_PASID_ENABLED, &idxd->flags);
+}
+
+static inline bool wq_pasid_enabled(struct idxd_wq *wq)
+{
+	return (is_idxd_wq_kernel(wq) && device_pasid_enabled(wq->idxd)) ||
+	       (is_idxd_wq_user(wq) && device_user_pasid_enabled(wq->idxd));
+}
+
+static inline bool wq_shared_supported(struct idxd_wq *wq)
+{
+	return (support_enqcmd && wq_pasid_enabled(wq));
 }
 
 enum idxd_portal_prot {
diff --git a/drivers/dma/idxd/init.c b/drivers/dma/idxd/init.c
index 993a5dcca24f..355fb3ef4cbf 100644
--- a/drivers/dma/idxd/init.c
+++ b/drivers/dma/idxd/init.c
@@ -512,18 +512,15 @@ static int idxd_probe(struct idxd_device *idxd)
 	dev_dbg(dev, "IDXD reset complete\n");
 
 	if (IS_ENABLED(CONFIG_INTEL_IDXD_SVM) && sva) {
-		rc = iommu_dev_enable_feature(dev, IOMMU_DEV_FEAT_SVA);
-		if (rc == 0) {
-			rc = idxd_enable_system_pasid(idxd);
-			if (rc < 0) {
-				iommu_dev_disable_feature(dev, IOMMU_DEV_FEAT_SVA);
-				dev_warn(dev, "Failed to enable PASID. No SVA support: %d\n", rc);
-			} else {
-				set_bit(IDXD_FLAG_PASID_ENABLED, &idxd->flags);
-			}
-		} else {
-			dev_warn(dev, "Unable to turn on SVA feature.\n");
-		}
+		if (iommu_dev_enable_feature(dev, IOMMU_DEV_FEAT_SVA))
+			dev_warn(dev, "Unable to turn on user SVA feature.\n");
+		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");
+		else
+			set_bit(IDXD_FLAG_PASID_ENABLED, &idxd->flags);
 	} else if (!sva) {
 		dev_warn(dev, "User forced SVA off via module param.\n");
 	}
@@ -561,7 +558,8 @@ static int idxd_probe(struct idxd_device *idxd)
  err:
 	if (device_pasid_enabled(idxd))
 		idxd_disable_system_pasid(idxd);
-	iommu_dev_disable_feature(dev, IOMMU_DEV_FEAT_SVA);
+	if (device_user_pasid_enabled(idxd))
+		iommu_dev_disable_feature(dev, IOMMU_DEV_FEAT_SVA);
 	return rc;
 }
 
@@ -574,7 +572,8 @@ static void idxd_cleanup(struct idxd_device *idxd)
 	idxd_cleanup_internals(idxd);
 	if (device_pasid_enabled(idxd))
 		idxd_disable_system_pasid(idxd);
-	iommu_dev_disable_feature(dev, IOMMU_DEV_FEAT_SVA);
+	if (device_user_pasid_enabled(idxd))
+		iommu_dev_disable_feature(dev, IOMMU_DEV_FEAT_SVA);
 }
 
 static int idxd_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
@@ -691,7 +690,8 @@ static void idxd_remove(struct pci_dev *pdev)
 	free_irq(irq_entry->vector, irq_entry);
 	pci_free_irq_vectors(pdev);
 	pci_iounmap(pdev, idxd->reg_base);
-	iommu_dev_disable_feature(&pdev->dev, IOMMU_DEV_FEAT_SVA);
+	if (device_user_pasid_enabled(idxd))
+		iommu_dev_disable_feature(&pdev->dev, IOMMU_DEV_FEAT_SVA);
 	pci_disable_device(pdev);
 	destroy_workqueue(idxd->wq);
 	perfmon_pmu_remove(idxd);
diff --git a/drivers/dma/idxd/sysfs.c b/drivers/dma/idxd/sysfs.c
index 7e628e31ce24..d482e708f0fa 100644
--- a/drivers/dma/idxd/sysfs.c
+++ b/drivers/dma/idxd/sysfs.c
@@ -588,7 +588,7 @@ static ssize_t wq_mode_store(struct device *dev,
 	if (sysfs_streq(buf, "dedicated")) {
 		set_bit(WQ_FLAG_DEDICATED, &wq->flags);
 		wq->threshold = 0;
-	} else if (sysfs_streq(buf, "shared") && device_swq_supported(idxd)) {
+	} else if (sysfs_streq(buf, "shared")) {
 		clear_bit(WQ_FLAG_DEDICATED, &wq->flags);
 	} else {
 		return -EINVAL;

Re: [PATCH] dmaengine: idxd: Separate user and kernel pasid enabling

[Vinod Koul]

On 11-05-22, 17:11, Dave Jiang wrote:
> The idxd driver always gated the pasid enabling under a single knob and
> this assumption is incorrect. The pasid used for kernel operation can be
> independently toggled and has no dependency on the user pasid (and vice
> versa). Split the two so they are independent "enabled" flags.

Applied, thanks

-- 
~Vinod