From 42a1b73852c4a176d233a192422b5e1d0ba67cbf Mon Sep 17 00:00:00 2001
From: Dave Jiang <dave.jiang@intel.com>
Date: Wed, 11 May 2022 17:11:57 -0700
Subject: [PATCH] dmaengine: idxd: Separate user and kernel pasid enabling
Git-commit: 42a1b73852c4a176d233a192422b5e1d0ba67cbf
Patch-mainline: v5.19-rc1
References: git-fixes

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>
Link: https://lore.kernel.org/r/165231431746.986466.5666862038354800551.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/dma/idxd/cdev.c   |    4 ++--
 drivers/dma/idxd/device.c |    4 ++--
 drivers/dma/idxd/idxd.h   |   16 ++++++++++++++--
 drivers/dma/idxd/init.c   |   30 +++++++++++++++---------------
 drivers/dma/idxd/sysfs.c  |    2 +-
 5 files changed, 34 insertions(+), 22 deletions(-)

--- a/drivers/dma/idxd/cdev.c
+++ b/drivers/dma/idxd/cdev.c
@@ -99,7 +99,7 @@ static int idxd_cdev_open(struct inode *
 	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 inod
 	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)
--- a/drivers/dma/idxd/device.c
+++ b/drivers/dma/idxd/device.c
@@ -962,7 +962,7 @@ static int idxd_wqs_setup(struct idxd_de
 		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;
@@ -1267,7 +1267,7 @@ 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;
--- a/drivers/dma/idxd/idxd.h
+++ b/drivers/dma/idxd/idxd.h
@@ -241,6 +241,7 @@ 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 {
@@ -471,9 +472,20 @@ static inline bool device_pasid_enabled(
 	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 {
--- a/drivers/dma/idxd/init.c
+++ b/drivers/dma/idxd/init.c
@@ -512,18 +512,15 @@ static int idxd_probe(struct idxd_device
 	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
  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_dev
 	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)
@@ -693,7 +692,8 @@ static void idxd_remove(struct pci_dev *
 	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);
--- a/drivers/dma/idxd/sysfs.c
+++ b/drivers/dma/idxd/sysfs.c
@@ -588,7 +588,7 @@ static ssize_t wq_mode_store(struct devi
 	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;