[PATCH 0/7] dmaengine: idxd: Add interrupt handle revoke support

[PATCH 0/7] dmaengine: idxd: Add interrupt handle revoke support

[Dave Jiang]

Hi Vinod,
I know this series came in late. If possible, can this be included for the 5.16
merge window please? If not possible, totally understand. Thanks!

The series adds support to refresh the interrupt handles when they become
invalid. Typically this happens during a VM live migration where a VM moves
from one machine to another. The driver will receive an interrupt to
indicate that interrupt handles need to be changed. The driver blocks the
current submissions and acquires new interrupt handles. All submissions
will be held off until the handle is refreshed. Already submitted descriptor
will error with status of "incorrect interrupt handle" and be resubmitted by the
driver.

---

Dave Jiang (7):
      dmaengine: idxd: rework descriptor free path on failure
      dmaengine: idxd: int handle management refactoring
      dmaengine: idxd: move interrupt handle assignment
      dmaengine: idxd: add helper for per interrupt handle drain
      dmaengine: idxd: create locked version of idxd_quiesce() call
      dmaengine: idxd: handle invalid interrupt handle descriptors
      dmaengine: idxd: handle interrupt handle revoked event


 drivers/dma/idxd/device.c    |  24 +++-
 drivers/dma/idxd/dma.c       |  18 ++-
 drivers/dma/idxd/idxd.h      |  13 +-
 drivers/dma/idxd/init.c      |  87 ++++++-------
 drivers/dma/idxd/irq.c       | 228 +++++++++++++++++++++++++++++++++++
 drivers/dma/idxd/registers.h |   1 +
 drivers/dma/idxd/submit.c    |  26 ++--
 drivers/dma/idxd/sysfs.c     |   1 -
 8 files changed, 333 insertions(+), 65 deletions(-)

--

[PATCH 1/7] dmaengine: idxd: rework descriptor free path on failure

[Dave Jiang]

Refactor the completion function to allow skipping of descriptor freeing on
the submission failiure path. This completely removes descriptor freeing
from the submit failure path and leave the responsibility to the caller.

Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
---
 drivers/dma/idxd/dma.c    |   10 ++++++++--
 drivers/dma/idxd/idxd.h   |    8 +-------
 drivers/dma/idxd/init.c   |    9 +++------
 drivers/dma/idxd/irq.c    |    8 ++++----
 drivers/dma/idxd/submit.c |   12 +++---------
 5 files changed, 19 insertions(+), 28 deletions(-)

diff --git a/drivers/dma/idxd/dma.c b/drivers/dma/idxd/dma.c
index c39e9483206a..1ea663215909 100644
--- a/drivers/dma/idxd/dma.c
+++ b/drivers/dma/idxd/dma.c
@@ -21,7 +21,8 @@ static inline struct idxd_wq *to_idxd_wq(struct dma_chan *c)
 }
 
 void idxd_dma_complete_txd(struct idxd_desc *desc,
-			   enum idxd_complete_type comp_type)
+			   enum idxd_complete_type comp_type,
+			   bool free_desc)
 {
 	struct dma_async_tx_descriptor *tx;
 	struct dmaengine_result res;
@@ -44,6 +45,9 @@ void idxd_dma_complete_txd(struct idxd_desc *desc,
 		tx->callback = NULL;
 		tx->callback_result = NULL;
 	}
+
+	if (free_desc)
+		idxd_free_desc(desc->wq, desc);
 }
 
 static void op_flag_setup(unsigned long flags, u32 *desc_flags)
@@ -153,8 +157,10 @@ static dma_cookie_t idxd_dma_tx_submit(struct dma_async_tx_descriptor *tx)
 	cookie = dma_cookie_assign(tx);
 
 	rc = idxd_submit_desc(wq, desc);
-	if (rc < 0)
+	if (rc < 0) {
+		idxd_free_desc(wq, desc);
 		return rc;
+	}
 
 	return cookie;
 }
diff --git a/drivers/dma/idxd/idxd.h b/drivers/dma/idxd/idxd.h
index 0cf8d3145870..3d600f8ee90b 100644
--- a/drivers/dma/idxd/idxd.h
+++ b/drivers/dma/idxd/idxd.h
@@ -579,7 +579,7 @@ int idxd_register_dma_channel(struct idxd_wq *wq);
 void idxd_unregister_dma_channel(struct idxd_wq *wq);
 void idxd_parse_completion_status(u8 status, enum dmaengine_tx_result *res);
 void idxd_dma_complete_txd(struct idxd_desc *desc,
-			   enum idxd_complete_type comp_type);
+			   enum idxd_complete_type comp_type, bool free_desc);
 
 /* cdev */
 int idxd_cdev_register(void);
@@ -603,10 +603,4 @@ static inline void perfmon_init(void) {}
 static inline void perfmon_exit(void) {}
 #endif
 
-static inline void complete_desc(struct idxd_desc *desc, enum idxd_complete_type reason)
-{
-	idxd_dma_complete_txd(desc, reason);
-	idxd_free_desc(desc->wq, desc);
-}
-
 #endif
diff --git a/drivers/dma/idxd/init.c b/drivers/dma/idxd/init.c
index eb09bc591c31..ef549cef8480 100644
--- a/drivers/dma/idxd/init.c
+++ b/drivers/dma/idxd/init.c
@@ -717,10 +717,8 @@ static void idxd_flush_pending_llist(struct idxd_irq_entry *ie)
 	if (!head)
 		return;
 
-	llist_for_each_entry_safe(desc, itr, head, llnode) {
-		idxd_dma_complete_txd(desc, IDXD_COMPLETE_ABORT);
-		idxd_free_desc(desc->wq, desc);
-	}
+	llist_for_each_entry_safe(desc, itr, head, llnode)
+		idxd_dma_complete_txd(desc, IDXD_COMPLETE_ABORT, true);
 }
 
 static void idxd_flush_work_list(struct idxd_irq_entry *ie)
@@ -729,8 +727,7 @@ static void idxd_flush_work_list(struct idxd_irq_entry *ie)
 
 	list_for_each_entry_safe(desc, iter, &ie->work_list, list) {
 		list_del(&desc->list);
-		idxd_dma_complete_txd(desc, IDXD_COMPLETE_ABORT);
-		idxd_free_desc(desc->wq, desc);
+		idxd_dma_complete_txd(desc, IDXD_COMPLETE_ABORT, true);
 	}
 }
 
diff --git a/drivers/dma/idxd/irq.c b/drivers/dma/idxd/irq.c
index 3261ea247e83..573a2f6d0f7f 100644
--- a/drivers/dma/idxd/irq.c
+++ b/drivers/dma/idxd/irq.c
@@ -195,11 +195,11 @@ static void irq_process_pending_llist(struct idxd_irq_entry *irq_entry)
 			 * and 0xff, which DSA_COMP_STATUS_MASK can mask out.
 			 */
 			if (unlikely(desc->completion->status == IDXD_COMP_DESC_ABORT)) {
-				complete_desc(desc, IDXD_COMPLETE_ABORT);
+				idxd_dma_complete_txd(desc, IDXD_COMPLETE_ABORT, true);
 				continue;
 			}
 
-			complete_desc(desc, IDXD_COMPLETE_NORMAL);
+			idxd_dma_complete_txd(desc, IDXD_COMPLETE_NORMAL, true);
 		} else {
 			spin_lock(&irq_entry->list_lock);
 			list_add_tail(&desc->list,
@@ -239,11 +239,11 @@ static void irq_process_work_list(struct idxd_irq_entry *irq_entry)
 		 * and 0xff, which DSA_COMP_STATUS_MASK can mask out.
 		 */
 		if (unlikely(desc->completion->status == IDXD_COMP_DESC_ABORT)) {
-			complete_desc(desc, IDXD_COMPLETE_ABORT);
+			idxd_dma_complete_txd(desc, IDXD_COMPLETE_ABORT, true);
 			continue;
 		}
 
-		complete_desc(desc, IDXD_COMPLETE_NORMAL);
+		idxd_dma_complete_txd(desc, IDXD_COMPLETE_NORMAL, true);
 	}
 }
 
diff --git a/drivers/dma/idxd/submit.c b/drivers/dma/idxd/submit.c
index de76fb4abac2..ea11809dbb32 100644
--- a/drivers/dma/idxd/submit.c
+++ b/drivers/dma/idxd/submit.c
@@ -129,7 +129,7 @@ static void llist_abort_desc(struct idxd_wq *wq, struct idxd_irq_entry *ie,
 	spin_unlock(&ie->list_lock);
 
 	if (found)
-		complete_desc(found, IDXD_COMPLETE_ABORT);
+		idxd_dma_complete_txd(found, IDXD_COMPLETE_ABORT, false);
 }
 
 int idxd_submit_desc(struct idxd_wq *wq, struct idxd_desc *desc)
@@ -139,15 +139,11 @@ int idxd_submit_desc(struct idxd_wq *wq, struct idxd_desc *desc)
 	void __iomem *portal;
 	int rc;
 
-	if (idxd->state != IDXD_DEV_ENABLED) {
-		idxd_free_desc(wq, desc);
+	if (idxd->state != IDXD_DEV_ENABLED)
 		return -EIO;
-	}
 
-	if (!percpu_ref_tryget_live(&wq->wq_active)) {
-		idxd_free_desc(wq, desc);
+	if (!percpu_ref_tryget_live(&wq->wq_active))
 		return -ENXIO;
-	}
 
 	portal = idxd_wq_portal_addr(wq);
 
@@ -182,8 +178,6 @@ int idxd_submit_desc(struct idxd_wq *wq, struct idxd_desc *desc)
 			/* abort operation frees the descriptor */
 			if (ie)
 				llist_abort_desc(wq, ie, desc);
-			else
-				idxd_free_desc(wq, desc);
 			return rc;
 		}
 	}

[PATCH 2/7] dmaengine: idxd: int handle management refactoring

[Dave Jiang]

Attach int_handle to irq_entry. This removes the separate management of int
handles and reduces the confusion of interating through int handles that is
off by 1 count.

Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
---
 drivers/dma/idxd/device.c |    8 ++++
 drivers/dma/idxd/idxd.h   |   10 ++++-
 drivers/dma/idxd/init.c   |   86 ++++++++++++++++++++++++---------------------
 drivers/dma/idxd/submit.c |    6 ++-
 drivers/dma/idxd/sysfs.c  |    1 -
 5 files changed, 64 insertions(+), 47 deletions(-)

diff --git a/drivers/dma/idxd/device.c b/drivers/dma/idxd/device.c
index fab412349f7f..f381319615fd 100644
--- a/drivers/dma/idxd/device.c
+++ b/drivers/dma/idxd/device.c
@@ -1206,6 +1206,13 @@ int __drv_enable_wq(struct idxd_wq *wq)
 		goto err;
 	}
 
+	/*
+	 * Device has 1 misc interrupt and N interrupts for descriptor completion. To
+	 * assign WQ to interrupt, we will take the N+1 interrupt since vector 0 is
+	 * for the misc interrupt.
+	 */
+	wq->ie = &idxd->irq_entries[wq->id + 1];
+
 	rc = idxd_wq_enable(wq);
 	if (rc < 0) {
 		dev_dbg(dev, "wq %d enabling failed: %d\n", wq->id, rc);
@@ -1256,6 +1263,7 @@ void __drv_disable_wq(struct idxd_wq *wq)
 	idxd_wq_drain(wq);
 	idxd_wq_reset(wq);
 
+	wq->ie = NULL;
 	wq->client_count = 0;
 }
 
diff --git a/drivers/dma/idxd/idxd.h b/drivers/dma/idxd/idxd.h
index 3d600f8ee90b..355159d4ee68 100644
--- a/drivers/dma/idxd/idxd.h
+++ b/drivers/dma/idxd/idxd.h
@@ -10,6 +10,7 @@
 #include <linux/cdev.h>
 #include <linux/idr.h>
 #include <linux/pci.h>
+#include <linux/ioasid.h>
 #include <linux/perf_event.h>
 #include <uapi/linux/idxd.h>
 #include "registers.h"
@@ -64,6 +65,7 @@ extern struct idxd_device_driver idxd_drv;
 extern struct idxd_device_driver idxd_dmaengine_drv;
 extern struct idxd_device_driver idxd_user_drv;
 
+#define INVALID_INT_HANDLE	-1
 struct idxd_irq_entry {
 	struct idxd_device *idxd;
 	int id;
@@ -75,6 +77,9 @@ struct idxd_irq_entry {
 	 * and irq thread processing error descriptor.
 	 */
 	spinlock_t list_lock;
+	int int_handle;
+	struct idxd_wq *wq;
+	ioasid_t pasid;
 };
 
 struct idxd_group {
@@ -171,6 +176,7 @@ struct idxd_wq {
 	struct wait_queue_head err_queue;
 	struct idxd_device *idxd;
 	int id;
+	struct idxd_irq_entry *ie;
 	enum idxd_wq_type type;
 	struct idxd_group *group;
 	int client_count;
@@ -266,6 +272,8 @@ struct idxd_device {
 	unsigned int pasid;
 
 	int num_groups;
+	int irq_cnt;
+	bool request_int_handles;
 
 	u32 msix_perm_offset;
 	u32 wqcfg_offset;
@@ -292,8 +300,6 @@ struct idxd_device {
 	struct workqueue_struct *wq;
 	struct work_struct work;
 
-	int *int_handles;
-
 	struct idxd_pmu *idxd_pmu;
 };
 
diff --git a/drivers/dma/idxd/init.c b/drivers/dma/idxd/init.c
index ef549cef8480..bae32a30081d 100644
--- a/drivers/dma/idxd/init.c
+++ b/drivers/dma/idxd/init.c
@@ -81,6 +81,7 @@ static int idxd_setup_interrupts(struct idxd_device *idxd)
 		dev_err(dev, "Not MSI-X interrupt capable.\n");
 		return -ENOSPC;
 	}
+	idxd->irq_cnt = msixcnt;
 
 	rc = pci_alloc_irq_vectors(pdev, msixcnt, msixcnt, PCI_IRQ_MSIX);
 	if (rc != msixcnt) {
@@ -103,7 +104,18 @@ static int idxd_setup_interrupts(struct idxd_device *idxd)
 	for (i = 0; i < msixcnt; i++) {
 		idxd->irq_entries[i].id = i;
 		idxd->irq_entries[i].idxd = idxd;
+		/*
+		 * Association of WQ should be assigned starting with irq_entry 1.
+		 * irq_entry 0 is for misc interrupts and has no wq association
+		 */
+		if (i > 0)
+			idxd->irq_entries[i].wq = idxd->wqs[i - 1];
 		idxd->irq_entries[i].vector = pci_irq_vector(pdev, i);
+		idxd->irq_entries[i].int_handle = INVALID_INT_HANDLE;
+		if (device_pasid_enabled(idxd) && i > 0)
+			idxd->irq_entries[i].pasid = idxd->pasid;
+		else
+			idxd->irq_entries[i].pasid = INVALID_IOASID;
 		spin_lock_init(&idxd->irq_entries[i].list_lock);
 	}
 
@@ -135,22 +147,14 @@ static int idxd_setup_interrupts(struct idxd_device *idxd)
 		}
 
 		dev_dbg(dev, "Allocated idxd-msix %d for vector %d\n", i, irq_entry->vector);
-		if (idxd->hw.cmd_cap & BIT(IDXD_CMD_REQUEST_INT_HANDLE)) {
-			/*
-			 * The MSIX vector enumeration starts at 1 with vector 0 being the
-			 * misc interrupt that handles non I/O completion events. The
-			 * interrupt handles are for IMS enumeration on guest. The misc
-			 * interrupt vector does not require a handle and therefore we start
-			 * the int_handles at index 0. Since 'i' starts at 1, the first
-			 * int_handles index will be 0.
-			 */
-			rc = idxd_device_request_int_handle(idxd, i, &idxd->int_handles[i - 1],
+		if (idxd->request_int_handles) {
+			rc = idxd_device_request_int_handle(idxd, i, &irq_entry->int_handle,
 							    IDXD_IRQ_MSIX);
 			if (rc < 0) {
 				free_irq(irq_entry->vector, irq_entry);
 				goto err_wq_irqs;
 			}
-			dev_dbg(dev, "int handle requested: %u\n", idxd->int_handles[i - 1]);
+			dev_dbg(dev, "int handle requested: %u\n", irq_entry->int_handle);
 		}
 	}
 
@@ -161,9 +165,15 @@ static int idxd_setup_interrupts(struct idxd_device *idxd)
 	while (--i >= 0) {
 		irq_entry = &idxd->irq_entries[i];
 		free_irq(irq_entry->vector, irq_entry);
-		if (i != 0)
-			idxd_device_release_int_handle(idxd,
-						       idxd->int_handles[i], IDXD_IRQ_MSIX);
+		if (irq_entry->int_handle != INVALID_INT_HANDLE) {
+			idxd_device_release_int_handle(idxd, irq_entry->int_handle,
+						       IDXD_IRQ_MSIX);
+			irq_entry->int_handle = INVALID_INT_HANDLE;
+			irq_entry->pasid = INVALID_IOASID;
+		}
+		irq_entry->vector = -1;
+		irq_entry->wq = NULL;
+		irq_entry->idxd = NULL;
 	}
  err_misc_irq:
 	/* Disable error interrupt generation */
@@ -179,21 +189,19 @@ static void idxd_cleanup_interrupts(struct idxd_device *idxd)
 {
 	struct pci_dev *pdev = idxd->pdev;
 	struct idxd_irq_entry *irq_entry;
-	int i, msixcnt;
-
-	msixcnt = pci_msix_vec_count(pdev);
-	if (msixcnt <= 0)
-		return;
-
-	irq_entry = &idxd->irq_entries[0];
-	free_irq(irq_entry->vector, irq_entry);
-
-	for (i = 1; i < msixcnt; i++) {
+	int i;
 
+	for (i = 0; i < idxd->irq_cnt; i++) {
 		irq_entry = &idxd->irq_entries[i];
-		if (idxd->hw.cmd_cap & BIT(IDXD_CMD_RELEASE_INT_HANDLE))
-			idxd_device_release_int_handle(idxd, idxd->int_handles[i],
+		if (irq_entry->int_handle != INVALID_INT_HANDLE) {
+			idxd_device_release_int_handle(idxd, irq_entry->int_handle,
 						       IDXD_IRQ_MSIX);
+			irq_entry->int_handle = INVALID_INT_HANDLE;
+			irq_entry->pasid = INVALID_IOASID;
+		}
+		irq_entry->vector = -1;
+		irq_entry->wq = NULL;
+		irq_entry->idxd = NULL;
 		free_irq(irq_entry->vector, irq_entry);
 	}
 
@@ -379,13 +387,6 @@ static int idxd_setup_internals(struct idxd_device *idxd)
 
 	init_waitqueue_head(&idxd->cmd_waitq);
 
-	if (idxd->hw.cmd_cap & BIT(IDXD_CMD_REQUEST_INT_HANDLE)) {
-		idxd->int_handles = kcalloc_node(idxd->max_wqs, sizeof(int), GFP_KERNEL,
-						 dev_to_node(dev));
-		if (!idxd->int_handles)
-			return -ENOMEM;
-	}
-
 	rc = idxd_setup_wqs(idxd);
 	if (rc < 0)
 		goto err_wqs;
@@ -416,7 +417,6 @@ static int idxd_setup_internals(struct idxd_device *idxd)
 	for (i = 0; i < idxd->max_wqs; i++)
 		put_device(wq_confdev(idxd->wqs[i]));
  err_wqs:
-	kfree(idxd->int_handles);
 	return rc;
 }
 
@@ -451,6 +451,10 @@ static void idxd_read_caps(struct idxd_device *idxd)
 		dev_dbg(dev, "cmd_cap: %#x\n", idxd->hw.cmd_cap);
 	}
 
+	/* reading command capabilities */
+	if (idxd->hw.cmd_cap & BIT(IDXD_CMD_REQUEST_INT_HANDLE))
+		idxd->request_int_handles = true;
+
 	idxd->max_xfer_bytes = 1ULL << idxd->hw.gen_cap.max_xfer_shift;
 	dev_dbg(dev, "max xfer size: %llu bytes\n", idxd->max_xfer_bytes);
 	idxd->max_batch_size = 1U << idxd->hw.gen_cap.max_batch_shift;
@@ -748,15 +752,15 @@ static void idxd_release_int_handles(struct idxd_device *idxd)
 	struct device *dev = &idxd->pdev->dev;
 	int i, rc;
 
-	for (i = 0; i < idxd->num_wq_irqs; i++) {
-		if (idxd->hw.cmd_cap & BIT(IDXD_CMD_RELEASE_INT_HANDLE)) {
-			rc = idxd_device_release_int_handle(idxd, idxd->int_handles[i],
-							    IDXD_IRQ_MSIX);
+	for (i = 1; i < idxd->irq_cnt; i++) {
+		struct idxd_irq_entry *ie = &idxd->irq_entries[i];
+
+		if (ie->int_handle != INVALID_INT_HANDLE) {
+			rc = idxd_device_release_int_handle(idxd, ie->int_handle, IDXD_IRQ_MSIX);
 			if (rc < 0)
-				dev_warn(dev, "irq handle %d release failed\n",
-					 idxd->int_handles[i]);
+				dev_warn(dev, "irq handle %d release failed\n", ie->int_handle);
 			else
-				dev_dbg(dev, "int handle requested: %u\n", idxd->int_handles[i]);
+				dev_dbg(dev, "int handle released: %u\n", ie->int_handle);
 		}
 	}
 }
diff --git a/drivers/dma/idxd/submit.c b/drivers/dma/idxd/submit.c
index ea11809dbb32..d4688f369bc2 100644
--- a/drivers/dma/idxd/submit.c
+++ b/drivers/dma/idxd/submit.c
@@ -25,10 +25,10 @@ static struct idxd_desc *__get_desc(struct idxd_wq *wq, int idx, int cpu)
 	 * On host, MSIX vecotr 0 is used for misc interrupt. Therefore when we match
 	 * vector 1:1 to the WQ id, we need to add 1
 	 */
-	if (!idxd->int_handles)
+	if (wq->ie->int_handle == INVALID_INT_HANDLE)
 		desc->hw->int_handle = wq->id + 1;
 	else
-		desc->hw->int_handle = idxd->int_handles[wq->id];
+		desc->hw->int_handle = wq->ie->int_handle;
 
 	return desc;
 }
@@ -159,7 +159,7 @@ int idxd_submit_desc(struct idxd_wq *wq, struct idxd_desc *desc)
 	 * that we designated the descriptor to.
 	 */
 	if (desc->hw->flags & IDXD_OP_FLAG_RCI) {
-		ie = &idxd->irq_entries[wq->id + 1];
+		ie = wq->ie;
 		llist_add(&desc->llnode, &ie->pending_llist);
 	}
 
diff --git a/drivers/dma/idxd/sysfs.c b/drivers/dma/idxd/sysfs.c
index a9025be940db..90857e776273 100644
--- a/drivers/dma/idxd/sysfs.c
+++ b/drivers/dma/idxd/sysfs.c
@@ -1269,7 +1269,6 @@ static void idxd_conf_device_release(struct device *dev)
 	kfree(idxd->wqs);
 	kfree(idxd->engines);
 	kfree(idxd->irq_entries);
-	kfree(idxd->int_handles);
 	ida_free(&idxd_ida, idxd->id);
 	kfree(idxd);
 }

[PATCH 3/7] dmaengine: idxd: move interrupt handle assignment

[Dave Jiang]

In preparation of supporting interrupt handle revoke event, move the
interrupt handle assignment to right before the descriptor to be submitted.
This allows the interrupt handle revoke logic to assign the latest
interrupt handle on submission.

Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
---
 drivers/dma/idxd/submit.c |   14 +++++---------
 1 file changed, 5 insertions(+), 9 deletions(-)

diff --git a/drivers/dma/idxd/submit.c b/drivers/dma/idxd/submit.c
index d4688f369bc2..df02c5c814e7 100644
--- a/drivers/dma/idxd/submit.c
+++ b/drivers/dma/idxd/submit.c
@@ -21,15 +21,6 @@ static struct idxd_desc *__get_desc(struct idxd_wq *wq, int idx, int cpu)
 	if (device_pasid_enabled(idxd))
 		desc->hw->pasid = idxd->pasid;
 
-	/*
-	 * On host, MSIX vecotr 0 is used for misc interrupt. Therefore when we match
-	 * vector 1:1 to the WQ id, we need to add 1
-	 */
-	if (wq->ie->int_handle == INVALID_INT_HANDLE)
-		desc->hw->int_handle = wq->id + 1;
-	else
-		desc->hw->int_handle = wq->ie->int_handle;
-
 	return desc;
 }
 
@@ -160,6 +151,11 @@ int idxd_submit_desc(struct idxd_wq *wq, struct idxd_desc *desc)
 	 */
 	if (desc->hw->flags & IDXD_OP_FLAG_RCI) {
 		ie = wq->ie;
+		if (ie->int_handle == INVALID_INT_HANDLE)
+			desc->hw->int_handle = ie->id;
+		else
+			desc->hw->int_handle = ie->int_handle;
+
 		llist_add(&desc->llnode, &ie->pending_llist);
 	}
 

[PATCH 4/7] dmaengine: idxd: add helper for per interrupt handle drain

[Dave Jiang]

The helper is called at the completion of the interrupt handle refresh
event. It issues drain descriptors to each of the wq with associated
interrupt handle. The drain descriptor will have interrupt request set but
without completion record. This will ensure all descriptors with incorrect
interrupt completion handle get drained and a completion interrupt is
triggered for the guest driver to process them.

Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
---
 drivers/dma/idxd/irq.c |   41 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)

diff --git a/drivers/dma/idxd/irq.c b/drivers/dma/idxd/irq.c
index 573a2f6d0f7f..8bca0ed2d23c 100644
--- a/drivers/dma/idxd/irq.c
+++ b/drivers/dma/idxd/irq.c
@@ -55,6 +55,47 @@ static void idxd_device_reinit(struct work_struct *work)
 	idxd_device_clear_state(idxd);
 }
 
+/*
+ * The function sends a drain descriptor for the interrupt handle. The drain ensures
+ * all descriptors with this interrupt handle is flushed and the interrupt
+ * will allow the cleanup of the outstanding descriptors.
+ */
+static void idxd_int_handle_revoke_drain(struct idxd_irq_entry *ie)
+{
+	struct idxd_wq *wq = ie->wq;
+	struct idxd_device *idxd = ie->idxd;
+	struct device *dev = &idxd->pdev->dev;
+	struct dsa_hw_desc desc;
+	void __iomem *portal;
+	int rc;
+
+	memset(&desc, 0, sizeof(desc));
+
+	/* Issue a simple drain operation with interrupt but no completion record */
+	desc.flags = IDXD_OP_FLAG_RCI;
+	desc.opcode = DSA_OPCODE_DRAIN;
+	desc.priv = 1;
+
+	if (ie->pasid != INVALID_IOASID)
+		desc.pasid = ie->pasid;
+	desc.int_handle = ie->int_handle;
+	portal = idxd_wq_portal_addr(wq);
+
+	/*
+	 * The wmb() makes sure that the descriptor is all there before we
+	 * issue.
+	 */
+	wmb();
+	if (wq_dedicated(wq)) {
+		iosubmit_cmds512(portal, &desc, 1);
+	} else {
+		rc = enqcmds(portal, &desc);
+		/* This should not fail unless hardware failed. */
+		if (rc < 0)
+			dev_warn(dev, "Failed to submit drain desc on wq %d\n", wq->id);
+	}
+}
+
 static int process_misc_interrupts(struct idxd_device *idxd, u32 cause)
 {
 	struct device *dev = &idxd->pdev->dev;

[PATCH 5/7] dmaengine: idxd: create locked version of idxd_quiesce() call

[Dave Jiang]

Add a locked version of idxd_quiesce() call so that the quiesce can be
called with a lock in situations where the lock is not held by the caller.

In the driver probe/remove path, the lock is already held, so the raw
version can be called w/o locking.

Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
---
 drivers/dma/idxd/device.c |   10 +++++++++-
 drivers/dma/idxd/dma.c    |    4 ++--
 drivers/dma/idxd/idxd.h   |    1 +
 3 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/drivers/dma/idxd/device.c b/drivers/dma/idxd/device.c
index f381319615fd..943e9967627b 100644
--- a/drivers/dma/idxd/device.c
+++ b/drivers/dma/idxd/device.c
@@ -411,12 +411,20 @@ int idxd_wq_init_percpu_ref(struct idxd_wq *wq)
 	return 0;
 }
 
-void idxd_wq_quiesce(struct idxd_wq *wq)
+void __idxd_wq_quiesce(struct idxd_wq *wq)
 {
+	lockdep_assert_held(&wq->wq_lock);
 	percpu_ref_kill(&wq->wq_active);
 	wait_for_completion(&wq->wq_dead);
 }
 
+void idxd_wq_quiesce(struct idxd_wq *wq)
+{
+	mutex_lock(&wq->wq_lock);
+	__idxd_wq_quiesce(wq);
+	mutex_unlock(&wq->wq_lock);
+}
+
 /* Device control bits */
 static inline bool idxd_is_enabled(struct idxd_device *idxd)
 {
diff --git a/drivers/dma/idxd/dma.c b/drivers/dma/idxd/dma.c
index 1ea663215909..375dbae18583 100644
--- a/drivers/dma/idxd/dma.c
+++ b/drivers/dma/idxd/dma.c
@@ -316,7 +316,7 @@ static int idxd_dmaengine_drv_probe(struct idxd_dev *idxd_dev)
 	return 0;
 
 err_dma:
-	idxd_wq_quiesce(wq);
+	__idxd_wq_quiesce(wq);
 	percpu_ref_exit(&wq->wq_active);
 err_ref:
 	idxd_wq_free_resources(wq);
@@ -333,7 +333,7 @@ static void idxd_dmaengine_drv_remove(struct idxd_dev *idxd_dev)
 	struct idxd_wq *wq = idxd_dev_to_wq(idxd_dev);
 
 	mutex_lock(&wq->wq_lock);
-	idxd_wq_quiesce(wq);
+	__idxd_wq_quiesce(wq);
 	idxd_unregister_dma_channel(wq);
 	idxd_wq_free_resources(wq);
 	__drv_disable_wq(wq);
diff --git a/drivers/dma/idxd/idxd.h b/drivers/dma/idxd/idxd.h
index 355159d4ee68..970701738c8a 100644
--- a/drivers/dma/idxd/idxd.h
+++ b/drivers/dma/idxd/idxd.h
@@ -570,6 +570,7 @@ int idxd_wq_map_portal(struct idxd_wq *wq);
 void idxd_wq_unmap_portal(struct idxd_wq *wq);
 int idxd_wq_set_pasid(struct idxd_wq *wq, int pasid);
 int idxd_wq_disable_pasid(struct idxd_wq *wq);
+void __idxd_wq_quiesce(struct idxd_wq *wq);
 void idxd_wq_quiesce(struct idxd_wq *wq);
 int idxd_wq_init_percpu_ref(struct idxd_wq *wq);
 

[PATCH 6/7] dmaengine: idxd: handle invalid interrupt handle descriptors

[Dave Jiang]

Handle a descriptor that has been marked with invalid interrupt handle
error in status. Create a work item that will resubmit the descriptor. This
typically happens when the driver has handled the revoke interrupt handle
event and has a new interrupt handle.

Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
---
 drivers/dma/idxd/dma.c  |   14 +++++++++----
 drivers/dma/idxd/idxd.h |    1 +
 drivers/dma/idxd/irq.c  |   50 +++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 61 insertions(+), 4 deletions(-)

diff --git a/drivers/dma/idxd/dma.c b/drivers/dma/idxd/dma.c
index 375dbae18583..2ce873994e33 100644
--- a/drivers/dma/idxd/dma.c
+++ b/drivers/dma/idxd/dma.c
@@ -24,18 +24,24 @@ void idxd_dma_complete_txd(struct idxd_desc *desc,
 			   enum idxd_complete_type comp_type,
 			   bool free_desc)
 {
+	struct idxd_device *idxd = desc->wq->idxd;
 	struct dma_async_tx_descriptor *tx;
 	struct dmaengine_result res;
 	int complete = 1;
 
-	if (desc->completion->status == DSA_COMP_SUCCESS)
+	if (desc->completion->status == DSA_COMP_SUCCESS) {
 		res.result = DMA_TRANS_NOERROR;
-	else if (desc->completion->status)
+	} else if (desc->completion->status) {
+		if (idxd->request_int_handles && comp_type != IDXD_COMPLETE_ABORT &&
+		    desc->completion->status == DSA_COMP_INT_HANDLE_INVAL &&
+		    idxd_queue_int_handle_resubmit(desc))
+			return;
 		res.result = DMA_TRANS_WRITE_FAILED;
-	else if (comp_type == IDXD_COMPLETE_ABORT)
+	} else if (comp_type == IDXD_COMPLETE_ABORT) {
 		res.result = DMA_TRANS_ABORTED;
-	else
+	} else {
 		complete = 0;
+	}
 
 	tx = &desc->txd;
 	if (complete && tx->cookie) {
diff --git a/drivers/dma/idxd/idxd.h b/drivers/dma/idxd/idxd.h
index 970701738c8a..82c4915f58a2 100644
--- a/drivers/dma/idxd/idxd.h
+++ b/drivers/dma/idxd/idxd.h
@@ -524,6 +524,7 @@ void idxd_unregister_devices(struct idxd_device *idxd);
 int idxd_register_driver(void);
 void idxd_unregister_driver(void);
 void idxd_wqs_quiesce(struct idxd_device *idxd);
+bool idxd_queue_int_handle_resubmit(struct idxd_desc *desc);
 
 /* device interrupt control */
 void idxd_msix_perm_setup(struct idxd_device *idxd);
diff --git a/drivers/dma/idxd/irq.c b/drivers/dma/idxd/irq.c
index 8bca0ed2d23c..26fa871934e6 100644
--- a/drivers/dma/idxd/irq.c
+++ b/drivers/dma/idxd/irq.c
@@ -22,6 +22,11 @@ struct idxd_fault {
 	struct idxd_device *idxd;
 };
 
+struct idxd_resubmit {
+	struct work_struct work;
+	struct idxd_desc *desc;
+};
+
 static void idxd_device_reinit(struct work_struct *work)
 {
 	struct idxd_device *idxd = container_of(work, struct idxd_device, work);
@@ -218,6 +223,51 @@ irqreturn_t idxd_misc_thread(int vec, void *data)
 	return IRQ_HANDLED;
 }
 
+static void idxd_int_handle_resubmit_work(struct work_struct *work)
+{
+	struct idxd_resubmit *irw = container_of(work, struct idxd_resubmit, work);
+	struct idxd_desc *desc = irw->desc;
+	struct idxd_wq *wq = desc->wq;
+	int rc;
+
+	desc->completion->status = 0;
+	rc = idxd_submit_desc(wq, desc);
+	if (rc < 0) {
+		dev_dbg(&wq->idxd->pdev->dev, "Failed to resubmit desc %d to wq %d.\n",
+			desc->id, wq->id);
+		/*
+		 * If the error is not -EAGAIN, it means the submission failed due to wq
+		 * has been killed instead of ENQCMDS failure. Here the driver needs to
+		 * notify the submitter of the failure by reporting abort status.
+		 *
+		 * -EAGAIN comes from ENQCMDS failure. idxd_submit_desc() will handle the
+		 * abort.
+		 */
+		if (rc != -EAGAIN) {
+			desc->completion->status = IDXD_COMP_DESC_ABORT;
+			idxd_dma_complete_txd(desc, IDXD_COMPLETE_ABORT, false);
+		}
+		idxd_free_desc(wq, desc);
+	}
+	kfree(irw);
+}
+
+bool idxd_queue_int_handle_resubmit(struct idxd_desc *desc)
+{
+	struct idxd_wq *wq = desc->wq;
+	struct idxd_device *idxd = wq->idxd;
+	struct idxd_resubmit *irw;
+
+	irw = kzalloc(sizeof(*irw), GFP_KERNEL);
+	if (!irw)
+		return false;
+
+	irw->desc = desc;
+	INIT_WORK(&irw->work, idxd_int_handle_resubmit_work);
+	queue_work(idxd->wq, &irw->work);
+	return true;
+}
+
 static void irq_process_pending_llist(struct idxd_irq_entry *irq_entry)
 {
 	struct idxd_desc *desc, *t;

[PATCH 7/7] dmaengine: idxd: handle interrupt handle revoked event

[Dave Jiang]

"Interrupt handle revoked" is an event that happens when the driver is
running on a guest kernel and the VM is migrated to a new machine.
The device will trigger an interrupt that signals to the guest driver
that the interrupt handles need to be replaced.

The misc irq thread function calls a helper function to handle the
event. The function uses the WQ percpu_ref to quiesce the kernel
submissions. It then replaces the interrupt handles by requesting
interrupt handle command for each I/O MSIX vector. Once the handle is
updated, the driver will unblock the submission path to allow new
submissions.

The submitter will attempt to acquire a percpu_ref before submission. When
the request fails, it will wait on the wq_resurrect 'completion'.

The driver does anticipate the possibility of descriptors being submitted
before the WQ percpu_ref is killed. If a descriptor has already been
submitted, it will return with incorrect interrupt handle status. The
descriptor will be re-submitted with the new interrupt handle on the
completion path. For descriptors with incorrect interrupt handles,
completion interrupt won't be triggered.

At the completion of the interrupt handle refresh, the handling function
will call idxd_int_handle_refresh_drain() to issue drain descriptors to
each of the wq with associated interrupt handle. The drain descriptor will have
interrupt request set but without completion record. This will ensure all
descriptors with incorrect interrupt completion handle get drained and
a completion interrupt is triggered for the guest driver to process them.

Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Co-Developed-by: Sanjay Kumar <sanjay.k.kumar@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
---
 drivers/dma/idxd/device.c    |    6 ++
 drivers/dma/idxd/idxd.h      |    1 
 drivers/dma/idxd/init.c      |    1 
 drivers/dma/idxd/irq.c       |  137 ++++++++++++++++++++++++++++++++++++++++++
 drivers/dma/idxd/registers.h |    1 
 drivers/dma/idxd/submit.c    |   10 ++-
 6 files changed, 152 insertions(+), 4 deletions(-)

diff --git a/drivers/dma/idxd/device.c b/drivers/dma/idxd/device.c
index 943e9967627b..1dc5245107df 100644
--- a/drivers/dma/idxd/device.c
+++ b/drivers/dma/idxd/device.c
@@ -404,17 +404,21 @@ int idxd_wq_init_percpu_ref(struct idxd_wq *wq)
 	int rc;
 
 	memset(&wq->wq_active, 0, sizeof(wq->wq_active));
-	rc = percpu_ref_init(&wq->wq_active, idxd_wq_ref_release, 0, GFP_KERNEL);
+	rc = percpu_ref_init(&wq->wq_active, idxd_wq_ref_release,
+			     PERCPU_REF_ALLOW_REINIT, GFP_KERNEL);
 	if (rc < 0)
 		return rc;
 	reinit_completion(&wq->wq_dead);
+	reinit_completion(&wq->wq_resurrect);
 	return 0;
 }
 
 void __idxd_wq_quiesce(struct idxd_wq *wq)
 {
 	lockdep_assert_held(&wq->wq_lock);
+	reinit_completion(&wq->wq_resurrect);
 	percpu_ref_kill(&wq->wq_active);
+	complete_all(&wq->wq_resurrect);
 	wait_for_completion(&wq->wq_dead);
 }
 
diff --git a/drivers/dma/idxd/idxd.h b/drivers/dma/idxd/idxd.h
index 82c4915f58a2..51e79201636c 100644
--- a/drivers/dma/idxd/idxd.h
+++ b/drivers/dma/idxd/idxd.h
@@ -171,6 +171,7 @@ struct idxd_wq {
 	u32 portal_offset;
 	struct percpu_ref wq_active;
 	struct completion wq_dead;
+	struct completion wq_resurrect;
 	struct idxd_dev idxd_dev;
 	struct idxd_cdev *idxd_cdev;
 	struct wait_queue_head err_queue;
diff --git a/drivers/dma/idxd/init.c b/drivers/dma/idxd/init.c
index bae32a30081d..4a34121472ab 100644
--- a/drivers/dma/idxd/init.c
+++ b/drivers/dma/idxd/init.c
@@ -245,6 +245,7 @@ static int idxd_setup_wqs(struct idxd_device *idxd)
 		mutex_init(&wq->wq_lock);
 		init_waitqueue_head(&wq->err_queue);
 		init_completion(&wq->wq_dead);
+		init_completion(&wq->wq_resurrect);
 		wq->max_xfer_bytes = idxd->max_xfer_bytes;
 		wq->max_batch_size = idxd->max_batch_size;
 		wq->wqcfg = kzalloc_node(idxd->wqcfg_size, GFP_KERNEL, dev_to_node(dev));
diff --git a/drivers/dma/idxd/irq.c b/drivers/dma/idxd/irq.c
index 26fa871934e6..76718e6a9c5c 100644
--- a/drivers/dma/idxd/irq.c
+++ b/drivers/dma/idxd/irq.c
@@ -6,6 +6,7 @@
 #include <linux/pci.h>
 #include <linux/io-64-nonatomic-lo-hi.h>
 #include <linux/dmaengine.h>
+#include <linux/delay.h>
 #include <uapi/linux/idxd.h>
 #include "../dmaengine.h"
 #include "idxd.h"
@@ -27,6 +28,11 @@ struct idxd_resubmit {
 	struct idxd_desc *desc;
 };
 
+struct idxd_int_handle_revoke {
+	struct work_struct work;
+	struct idxd_device *idxd;
+};
+
 static void idxd_device_reinit(struct work_struct *work)
 {
 	struct idxd_device *idxd = container_of(work, struct idxd_device, work);
@@ -101,6 +107,120 @@ static void idxd_int_handle_revoke_drain(struct idxd_irq_entry *ie)
 	}
 }
 
+static void idxd_abort_invalid_int_handle_descs(struct idxd_irq_entry *ie)
+{
+	LIST_HEAD(flist);
+	struct idxd_desc *d, *t;
+	struct llist_node *head;
+
+	spin_lock(&ie->list_lock);
+	head = llist_del_all(&ie->pending_llist);
+	if (head) {
+		llist_for_each_entry_safe(d, t, head, llnode)
+			list_add_tail(&d->list, &ie->work_list);
+	}
+
+	list_for_each_entry_safe(d, t, &ie->work_list, list) {
+		if (d->completion->status == DSA_COMP_INT_HANDLE_INVAL)
+			list_move_tail(&d->list, &flist);
+	}
+	spin_unlock(&ie->list_lock);
+
+	list_for_each_entry_safe(d, t, &flist, list) {
+		list_del(&d->list);
+		idxd_dma_complete_txd(d, IDXD_COMPLETE_ABORT, true);
+	}
+}
+
+static void idxd_int_handle_revoke(struct work_struct *work)
+{
+	struct idxd_int_handle_revoke *revoke =
+		container_of(work, struct idxd_int_handle_revoke, work);
+	struct idxd_device *idxd = revoke->idxd;
+	struct pci_dev *pdev = idxd->pdev;
+	struct device *dev = &pdev->dev;
+	int i, new_handle, rc;
+
+	if (!idxd->request_int_handles) {
+		kfree(revoke);
+		dev_warn(dev, "Unexpected int handle refresh interrupt.\n");
+		return;
+	}
+
+	/*
+	 * The loop attempts to acquire new interrupt handle for all interrupt
+	 * vectors that supports a handle. If a new interrupt handle is acquired and the
+	 * wq is kernel type, the driver will kill the percpu_ref to pause all
+	 * ongoing descriptor submissions. The interrupt handle is then changed.
+	 * After change, the percpu_ref is revived and all the pending submissions
+	 * are woken to try again. A drain is sent to for the interrupt handle
+	 * at the end to make sure all invalid int handle descriptors are processed.
+	 */
+	for (i = 1; i < idxd->irq_cnt; i++) {
+		struct idxd_irq_entry *ie = &idxd->irq_entries[i];
+		struct idxd_wq *wq = ie->wq;
+
+		rc = idxd_device_request_int_handle(idxd, i, &new_handle, IDXD_IRQ_MSIX);
+		if (rc < 0) {
+			dev_warn(dev, "get int handle %d failed: %d\n", i, rc);
+			/*
+			 * Failed to acquire new interrupt handle. Kill the WQ
+			 * and release all the pending submitters. The submitters will
+			 * get error return code and handle appropriately.
+			 */
+			ie->int_handle = INVALID_INT_HANDLE;
+			idxd_wq_quiesce(wq);
+			idxd_abort_invalid_int_handle_descs(ie);
+			continue;
+		}
+
+		/* No change in interrupt handle, nothing needs to be done */
+		if (ie->int_handle == new_handle)
+			continue;
+
+		if (wq->state != IDXD_WQ_ENABLED || wq->type != IDXD_WQT_KERNEL) {
+			/*
+			 * All the MSIX interrupts are allocated at once during probe.
+			 * Therefore we need to update all interrupts even if the WQ
+			 * isn't supporting interrupt operations.
+			 */
+			ie->int_handle = new_handle;
+			continue;
+		}
+
+		mutex_lock(&wq->wq_lock);
+		reinit_completion(&wq->wq_resurrect);
+
+		/* Kill percpu_ref to pause additional descriptor submissions */
+		percpu_ref_kill(&wq->wq_active);
+
+		/* Wait for all submitters quiesce before we change interrupt handle */
+		wait_for_completion(&wq->wq_dead);
+
+		ie->int_handle = new_handle;
+
+		/* Revive percpu ref and wake up all the waiting submitters */
+		percpu_ref_reinit(&wq->wq_active);
+		complete_all(&wq->wq_resurrect);
+		mutex_unlock(&wq->wq_lock);
+
+		/*
+		 * The delay here is to wait for all possible MOVDIR64B that
+		 * are issued before percpu_ref_kill() has happened to have
+		 * reached the PCIe domain before the drain is issued. The driver
+		 * needs to ensure that the drain descriptor issued does not pass
+		 * all the other issued descriptors that contain the invalid
+		 * interrupt handle in order to ensure that the drain descriptor
+		 * interrupt will allow the cleanup of all the descriptors with
+		 * invalid interrupt handle.
+		 */
+		if (wq_dedicated(wq))
+			udelay(100);
+		idxd_int_handle_revoke_drain(ie);
+	}
+	kfree(revoke);
+}
+
 static int process_misc_interrupts(struct idxd_device *idxd, u32 cause)
 {
 	struct device *dev = &idxd->pdev->dev;
@@ -147,6 +267,23 @@ static int process_misc_interrupts(struct idxd_device *idxd, u32 cause)
 		err = true;
 	}
 
+	if (cause & IDXD_INTC_INT_HANDLE_REVOKED) {
+		struct idxd_int_handle_revoke *revoke;
+
+		val |= IDXD_INTC_INT_HANDLE_REVOKED;
+
+		revoke = kzalloc(sizeof(*revoke), GFP_ATOMIC);
+		if (revoke) {
+			revoke->idxd = idxd;
+			INIT_WORK(&revoke->work, idxd_int_handle_revoke);
+			queue_work(idxd->wq, &revoke->work);
+
+		} else {
+			dev_err(dev, "Failed to allocate work for int handle revoke\n");
+			idxd_wqs_quiesce(idxd);
+		}
+	}
+
 	if (cause & IDXD_INTC_CMD) {
 		val |= IDXD_INTC_CMD;
 		complete(idxd->cmd_done);
diff --git a/drivers/dma/idxd/registers.h b/drivers/dma/idxd/registers.h
index 262c8220adbd..8e396698c22b 100644
--- a/drivers/dma/idxd/registers.h
+++ b/drivers/dma/idxd/registers.h
@@ -158,6 +158,7 @@ enum idxd_device_reset_type {
 #define IDXD_INTC_OCCUPY			0x04
 #define IDXD_INTC_PERFMON_OVFL		0x08
 #define IDXD_INTC_HALT_STATE		0x10
+#define IDXD_INTC_INT_HANDLE_REVOKED	0x80000000
 
 #define IDXD_CMD_OFFSET			0xa0
 union idxd_command_reg {
diff --git a/drivers/dma/idxd/submit.c b/drivers/dma/idxd/submit.c
index df02c5c814e7..776fa81db61d 100644
--- a/drivers/dma/idxd/submit.c
+++ b/drivers/dma/idxd/submit.c
@@ -127,14 +127,18 @@ int idxd_submit_desc(struct idxd_wq *wq, struct idxd_desc *desc)
 {
 	struct idxd_device *idxd = wq->idxd;
 	struct idxd_irq_entry *ie = NULL;
+	u32 desc_flags = desc->hw->flags;
 	void __iomem *portal;
 	int rc;
 
 	if (idxd->state != IDXD_DEV_ENABLED)
 		return -EIO;
 
-	if (!percpu_ref_tryget_live(&wq->wq_active))
-		return -ENXIO;
+	if (!percpu_ref_tryget_live(&wq->wq_active)) {
+		wait_for_completion(&wq->wq_resurrect);
+		if (!percpu_ref_tryget_live(&wq->wq_active))
+			return -ENXIO;
+	}
 
 	portal = idxd_wq_portal_addr(wq);
 
@@ -149,7 +153,7 @@ int idxd_submit_desc(struct idxd_wq *wq, struct idxd_desc *desc)
 	 * Pending the descriptor to the lockless list for the irq_entry
 	 * that we designated the descriptor to.
 	 */
-	if (desc->hw->flags & IDXD_OP_FLAG_RCI) {
+	if (desc_flags & IDXD_OP_FLAG_RCI) {
 		ie = wq->ie;
 		if (ie->int_handle == INVALID_INT_HANDLE)
 			desc->hw->int_handle = ie->id;

Re: [PATCH 1/7] dmaengine: idxd: rework descriptor free path on failure

[Vinod Koul]

On 20-10-21, 09:53, Dave Jiang wrote:
> Refactor the completion function to allow skipping of descriptor freeing on
> the submission failiure path. This completely removes descriptor freeing

s/failiure/failure

> from the submit failure path and leave the responsibility to the caller.
> 
> Reviewed-by: Kevin Tian <kevin.tian@intel.com>
> Signed-off-by: Dave Jiang <dave.jiang@intel.com>
> ---
>  drivers/dma/idxd/dma.c    |   10 ++++++++--
>  drivers/dma/idxd/idxd.h   |    8 +-------
>  drivers/dma/idxd/init.c   |    9 +++------
>  drivers/dma/idxd/irq.c    |    8 ++++----
>  drivers/dma/idxd/submit.c |   12 +++---------
>  5 files changed, 19 insertions(+), 28 deletions(-)
> 
> diff --git a/drivers/dma/idxd/dma.c b/drivers/dma/idxd/dma.c
> index c39e9483206a..1ea663215909 100644
> --- a/drivers/dma/idxd/dma.c
> +++ b/drivers/dma/idxd/dma.c
> @@ -21,7 +21,8 @@ static inline struct idxd_wq *to_idxd_wq(struct dma_chan *c)
>  }
>  
>  void idxd_dma_complete_txd(struct idxd_desc *desc,
> -			   enum idxd_complete_type comp_type)
> +			   enum idxd_complete_type comp_type,
> +			   bool free_desc)
>  {
>  	struct dma_async_tx_descriptor *tx;
>  	struct dmaengine_result res;
> @@ -44,6 +45,9 @@ void idxd_dma_complete_txd(struct idxd_desc *desc,
>  		tx->callback = NULL;
>  		tx->callback_result = NULL;
>  	}
> +
> +	if (free_desc)
> +		idxd_free_desc(desc->wq, desc);
>  }
>  
>  static void op_flag_setup(unsigned long flags, u32 *desc_flags)
> @@ -153,8 +157,10 @@ static dma_cookie_t idxd_dma_tx_submit(struct dma_async_tx_descriptor *tx)
>  	cookie = dma_cookie_assign(tx);
>  
>  	rc = idxd_submit_desc(wq, desc);
> -	if (rc < 0)
> +	if (rc < 0) {
> +		idxd_free_desc(wq, desc);

if there is an error in submit, should the caller not invoke terminate()
and get the cleanup done?

-- 
~Vinod

Re: [PATCH 4/7] dmaengine: idxd: add helper for per interrupt handle drain

[Vinod Koul]

On 20-10-21, 09:53, Dave Jiang wrote:
> The helper is called at the completion of the interrupt handle refresh
> event. It issues drain descriptors to each of the wq with associated
> interrupt handle. The drain descriptor will have interrupt request set but
> without completion record. This will ensure all descriptors with incorrect
> interrupt completion handle get drained and a completion interrupt is
> triggered for the guest driver to process them.
> 
> Reviewed-by: Kevin Tian <kevin.tian@intel.com>
> Signed-off-by: Dave Jiang <dave.jiang@intel.com>
> ---
>  drivers/dma/idxd/irq.c |   41 +++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 41 insertions(+)
> 
> diff --git a/drivers/dma/idxd/irq.c b/drivers/dma/idxd/irq.c
> index 573a2f6d0f7f..8bca0ed2d23c 100644
> --- a/drivers/dma/idxd/irq.c
> +++ b/drivers/dma/idxd/irq.c
> @@ -55,6 +55,47 @@ static void idxd_device_reinit(struct work_struct *work)
>  	idxd_device_clear_state(idxd);
>  }
>  
> +/*
> + * The function sends a drain descriptor for the interrupt handle. The drain ensures
> + * all descriptors with this interrupt handle is flushed and the interrupt
> + * will allow the cleanup of the outstanding descriptors.
> + */
> +static void idxd_int_handle_revoke_drain(struct idxd_irq_entry *ie)
> +{
> +	struct idxd_wq *wq = ie->wq;
> +	struct idxd_device *idxd = ie->idxd;
> +	struct device *dev = &idxd->pdev->dev;
> +	struct dsa_hw_desc desc;
> +	void __iomem *portal;
> +	int rc;
> +
> +	memset(&desc, 0, sizeof(desc));

declare and init it and avoid the memset:
        struct dsa_hw_desc desc = {};

> +
> +	/* Issue a simple drain operation with interrupt but no completion record */
> +	desc.flags = IDXD_OP_FLAG_RCI;
> +	desc.opcode = DSA_OPCODE_DRAIN;
> +	desc.priv = 1;
> +
> +	if (ie->pasid != INVALID_IOASID)
> +		desc.pasid = ie->pasid;
> +	desc.int_handle = ie->int_handle;
> +	portal = idxd_wq_portal_addr(wq);
> +
> +	/*
> +	 * The wmb() makes sure that the descriptor is all there before we
> +	 * issue.
> +	 */
> +	wmb();
> +	if (wq_dedicated(wq)) {
> +		iosubmit_cmds512(portal, &desc, 1);
> +	} else {
> +		rc = enqcmds(portal, &desc);
> +		/* This should not fail unless hardware failed. */
> +		if (rc < 0)
> +			dev_warn(dev, "Failed to submit drain desc on wq %d\n", wq->id);
> +	}
> +}
> +
>  static int process_misc_interrupts(struct idxd_device *idxd, u32 cause)
>  {
>  	struct device *dev = &idxd->pdev->dev;
> 

-- 
~Vinod

Re: [PATCH 6/7] dmaengine: idxd: handle invalid interrupt handle descriptors

[Vinod Koul]

On 20-10-21, 09:54, Dave Jiang wrote:
> Handle a descriptor that has been marked with invalid interrupt handle
> error in status. Create a work item that will resubmit the descriptor. This
> typically happens when the driver has handled the revoke interrupt handle
> event and has a new interrupt handle.
> 
> Reviewed-by: Kevin Tian <kevin.tian@intel.com>
> Signed-off-by: Dave Jiang <dave.jiang@intel.com>
> ---
>  drivers/dma/idxd/dma.c  |   14 +++++++++----
>  drivers/dma/idxd/idxd.h |    1 +
>  drivers/dma/idxd/irq.c  |   50 +++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 61 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/dma/idxd/dma.c b/drivers/dma/idxd/dma.c
> index 375dbae18583..2ce873994e33 100644
> --- a/drivers/dma/idxd/dma.c
> +++ b/drivers/dma/idxd/dma.c
> @@ -24,18 +24,24 @@ void idxd_dma_complete_txd(struct idxd_desc *desc,
>  			   enum idxd_complete_type comp_type,
>  			   bool free_desc)
>  {
> +	struct idxd_device *idxd = desc->wq->idxd;
>  	struct dma_async_tx_descriptor *tx;
>  	struct dmaengine_result res;
>  	int complete = 1;
>  
> -	if (desc->completion->status == DSA_COMP_SUCCESS)
> +	if (desc->completion->status == DSA_COMP_SUCCESS) {
>  		res.result = DMA_TRANS_NOERROR;
> -	else if (desc->completion->status)
> +	} else if (desc->completion->status) {
> +		if (idxd->request_int_handles && comp_type != IDXD_COMPLETE_ABORT &&
> +		    desc->completion->status == DSA_COMP_INT_HANDLE_INVAL &&
> +		    idxd_queue_int_handle_resubmit(desc))
> +			return;
>  		res.result = DMA_TRANS_WRITE_FAILED;
> -	else if (comp_type == IDXD_COMPLETE_ABORT)
> +	} else if (comp_type == IDXD_COMPLETE_ABORT) {
>  		res.result = DMA_TRANS_ABORTED;
> -	else
> +	} else {
>  		complete = 0;
> +	}
>  
>  	tx = &desc->txd;
>  	if (complete && tx->cookie) {
> diff --git a/drivers/dma/idxd/idxd.h b/drivers/dma/idxd/idxd.h
> index 970701738c8a..82c4915f58a2 100644
> --- a/drivers/dma/idxd/idxd.h
> +++ b/drivers/dma/idxd/idxd.h
> @@ -524,6 +524,7 @@ void idxd_unregister_devices(struct idxd_device *idxd);
>  int idxd_register_driver(void);
>  void idxd_unregister_driver(void);
>  void idxd_wqs_quiesce(struct idxd_device *idxd);
> +bool idxd_queue_int_handle_resubmit(struct idxd_desc *desc);
>  
>  /* device interrupt control */
>  void idxd_msix_perm_setup(struct idxd_device *idxd);
> diff --git a/drivers/dma/idxd/irq.c b/drivers/dma/idxd/irq.c
> index 8bca0ed2d23c..26fa871934e6 100644
> --- a/drivers/dma/idxd/irq.c
> +++ b/drivers/dma/idxd/irq.c
> @@ -22,6 +22,11 @@ struct idxd_fault {
>  	struct idxd_device *idxd;
>  };
>  
> +struct idxd_resubmit {
> +	struct work_struct work;
> +	struct idxd_desc *desc;
> +};
> +
>  static void idxd_device_reinit(struct work_struct *work)
>  {
>  	struct idxd_device *idxd = container_of(work, struct idxd_device, work);
> @@ -218,6 +223,51 @@ irqreturn_t idxd_misc_thread(int vec, void *data)
>  	return IRQ_HANDLED;
>  }
>  
> +static void idxd_int_handle_resubmit_work(struct work_struct *work)
> +{
> +	struct idxd_resubmit *irw = container_of(work, struct idxd_resubmit, work);
> +	struct idxd_desc *desc = irw->desc;
> +	struct idxd_wq *wq = desc->wq;
> +	int rc;
> +
> +	desc->completion->status = 0;
> +	rc = idxd_submit_desc(wq, desc);
> +	if (rc < 0) {
> +		dev_dbg(&wq->idxd->pdev->dev, "Failed to resubmit desc %d to wq %d.\n",
> +			desc->id, wq->id);
> +		/*
> +		 * If the error is not -EAGAIN, it means the submission failed due to wq
> +		 * has been killed instead of ENQCMDS failure. Here the driver needs to
> +		 * notify the submitter of the failure by reporting abort status.
> +		 *
> +		 * -EAGAIN comes from ENQCMDS failure. idxd_submit_desc() will handle the
> +		 * abort.
> +		 */
> +		if (rc != -EAGAIN) {
> +			desc->completion->status = IDXD_COMP_DESC_ABORT;
> +			idxd_dma_complete_txd(desc, IDXD_COMPLETE_ABORT, false);
> +		}
> +		idxd_free_desc(wq, desc);
> +	}
> +	kfree(irw);
> +}
> +
> +bool idxd_queue_int_handle_resubmit(struct idxd_desc *desc)
> +{
> +	struct idxd_wq *wq = desc->wq;
> +	struct idxd_device *idxd = wq->idxd;
> +	struct idxd_resubmit *irw;
> +
> +	irw = kzalloc(sizeof(*irw), GFP_KERNEL);

What is the context of this function, should this be GFP_ATOMIC?

> +	if (!irw)
> +		return false;
> +
> +	irw->desc = desc;
> +	INIT_WORK(&irw->work, idxd_int_handle_resubmit_work);
> +	queue_work(idxd->wq, &irw->work);
> +	return true;
> +}
> +
>  static void irq_process_pending_llist(struct idxd_irq_entry *irq_entry)
>  {
>  	struct idxd_desc *desc, *t;
> 

-- 
~Vinod

Re: [PATCH 1/7] dmaengine: idxd: rework descriptor free path on failure

[Dave Jiang]

On 10/24/2021 9:56 PM, Vinod Koul wrote:
> On 20-10-21, 09:53, Dave Jiang wrote:
>> Refactor the completion function to allow skipping of descriptor freeing on
>> the submission failiure path. This completely removes descriptor freeing
> s/failiure/failure
>
>> from the submit failure path and leave the responsibility to the caller.
>>
>> Reviewed-by: Kevin Tian <kevin.tian@intel.com>
>> Signed-off-by: Dave Jiang <dave.jiang@intel.com>
>> ---
>>   drivers/dma/idxd/dma.c    |   10 ++++++++--
>>   drivers/dma/idxd/idxd.h   |    8 +-------
>>   drivers/dma/idxd/init.c   |    9 +++------
>>   drivers/dma/idxd/irq.c    |    8 ++++----
>>   drivers/dma/idxd/submit.c |   12 +++---------
>>   5 files changed, 19 insertions(+), 28 deletions(-)
>>
>> diff --git a/drivers/dma/idxd/dma.c b/drivers/dma/idxd/dma.c
>> index c39e9483206a..1ea663215909 100644
>> --- a/drivers/dma/idxd/dma.c
>> +++ b/drivers/dma/idxd/dma.c
>> @@ -21,7 +21,8 @@ static inline struct idxd_wq *to_idxd_wq(struct dma_chan *c)
>>   }
>>   
>>   void idxd_dma_complete_txd(struct idxd_desc *desc,
>> -			   enum idxd_complete_type comp_type)
>> +			   enum idxd_complete_type comp_type,
>> +			   bool free_desc)
>>   {
>>   	struct dma_async_tx_descriptor *tx;
>>   	struct dmaengine_result res;
>> @@ -44,6 +45,9 @@ void idxd_dma_complete_txd(struct idxd_desc *desc,
>>   		tx->callback = NULL;
>>   		tx->callback_result = NULL;
>>   	}
>> +
>> +	if (free_desc)
>> +		idxd_free_desc(desc->wq, desc);
>>   }
>>   
>>   static void op_flag_setup(unsigned long flags, u32 *desc_flags)
>> @@ -153,8 +157,10 @@ static dma_cookie_t idxd_dma_tx_submit(struct dma_async_tx_descriptor *tx)
>>   	cookie = dma_cookie_assign(tx);
>>   
>>   	rc = idxd_submit_desc(wq, desc);
>> -	if (rc < 0)
>> +	if (rc < 0) {
>> +		idxd_free_desc(wq, desc);
> if there is an error in submit, should the caller not invoke terminate()
> and get the cleanup done?
The driver doesn't have a terminate() implemented. This is the only 
place we can free the descriptor that has been allocated in prep() if 
the submission has failed. Also terminate takes chan as the parameter. 
The chan would not have any access to this failed descriptor. The 
submission failed and the descriptor is not in the submission list or 
has been aborted and removed from the submission list. So calling 
terminate would not actually free the said descriptor. Also there's no 
reason to stop the channel due to a failed descriptor. In this 
particular condition, simplest thing would be to just return the 
allocated descriptor back to the driver.

Re: [PATCH 4/7] dmaengine: idxd: add helper for per interrupt handle drain

[Dave Jiang]

On 10/24/2021 10:06 PM, Vinod Koul wrote:
> On 20-10-21, 09:53, Dave Jiang wrote:
>> The helper is called at the completion of the interrupt handle refresh
>> event. It issues drain descriptors to each of the wq with associated
>> interrupt handle. The drain descriptor will have interrupt request set but
>> without completion record. This will ensure all descriptors with incorrect
>> interrupt completion handle get drained and a completion interrupt is
>> triggered for the guest driver to process them.
>>
>> Reviewed-by: Kevin Tian <kevin.tian@intel.com>
>> Signed-off-by: Dave Jiang <dave.jiang@intel.com>
>> ---
>>   drivers/dma/idxd/irq.c |   41 +++++++++++++++++++++++++++++++++++++++++
>>   1 file changed, 41 insertions(+)
>>
>> diff --git a/drivers/dma/idxd/irq.c b/drivers/dma/idxd/irq.c
>> index 573a2f6d0f7f..8bca0ed2d23c 100644
>> --- a/drivers/dma/idxd/irq.c
>> +++ b/drivers/dma/idxd/irq.c
>> @@ -55,6 +55,47 @@ static void idxd_device_reinit(struct work_struct *work)
>>   	idxd_device_clear_state(idxd);
>>   }
>>   
>> +/*
>> + * The function sends a drain descriptor for the interrupt handle. The drain ensures
>> + * all descriptors with this interrupt handle is flushed and the interrupt
>> + * will allow the cleanup of the outstanding descriptors.
>> + */
>> +static void idxd_int_handle_revoke_drain(struct idxd_irq_entry *ie)
>> +{
>> +	struct idxd_wq *wq = ie->wq;
>> +	struct idxd_device *idxd = ie->idxd;
>> +	struct device *dev = &idxd->pdev->dev;
>> +	struct dsa_hw_desc desc;
>> +	void __iomem *portal;
>> +	int rc;
>> +
>> +	memset(&desc, 0, sizeof(desc));
> declare and init it and avoid the memset:
>          struct dsa_hw_desc desc = {};

Thanks. Will fix.


>
>> +
>> +	/* Issue a simple drain operation with interrupt but no completion record */
>> +	desc.flags = IDXD_OP_FLAG_RCI;
>> +	desc.opcode = DSA_OPCODE_DRAIN;
>> +	desc.priv = 1;
>> +
>> +	if (ie->pasid != INVALID_IOASID)
>> +		desc.pasid = ie->pasid;
>> +	desc.int_handle = ie->int_handle;
>> +	portal = idxd_wq_portal_addr(wq);
>> +
>> +	/*
>> +	 * The wmb() makes sure that the descriptor is all there before we
>> +	 * issue.
>> +	 */
>> +	wmb();
>> +	if (wq_dedicated(wq)) {
>> +		iosubmit_cmds512(portal, &desc, 1);
>> +	} else {
>> +		rc = enqcmds(portal, &desc);
>> +		/* This should not fail unless hardware failed. */
>> +		if (rc < 0)
>> +			dev_warn(dev, "Failed to submit drain desc on wq %d\n", wq->id);
>> +	}
>> +}
>> +
>>   static int process_misc_interrupts(struct idxd_device *idxd, u32 cause)
>>   {
>>   	struct device *dev = &idxd->pdev->dev;
>>

Re: [PATCH 6/7] dmaengine: idxd: handle invalid interrupt handle descriptors

[Dave Jiang]

On 10/24/2021 10:08 PM, Vinod Koul wrote:
> On 20-10-21, 09:54, Dave Jiang wrote:
>> Handle a descriptor that has been marked with invalid interrupt handle
>> error in status. Create a work item that will resubmit the descriptor. This
>> typically happens when the driver has handled the revoke interrupt handle
>> event and has a new interrupt handle.
>>
>> Reviewed-by: Kevin Tian <kevin.tian@intel.com>
>> Signed-off-by: Dave Jiang <dave.jiang@intel.com>
>> ---
>>   drivers/dma/idxd/dma.c  |   14 +++++++++----
>>   drivers/dma/idxd/idxd.h |    1 +
>>   drivers/dma/idxd/irq.c  |   50 +++++++++++++++++++++++++++++++++++++++++++++++
>>   3 files changed, 61 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/dma/idxd/dma.c b/drivers/dma/idxd/dma.c
>> index 375dbae18583..2ce873994e33 100644
>> --- a/drivers/dma/idxd/dma.c
>> +++ b/drivers/dma/idxd/dma.c
>> @@ -24,18 +24,24 @@ void idxd_dma_complete_txd(struct idxd_desc *desc,
>>   			   enum idxd_complete_type comp_type,
>>   			   bool free_desc)
>>   {
>> +	struct idxd_device *idxd = desc->wq->idxd;
>>   	struct dma_async_tx_descriptor *tx;
>>   	struct dmaengine_result res;
>>   	int complete = 1;
>>   
>> -	if (desc->completion->status == DSA_COMP_SUCCESS)
>> +	if (desc->completion->status == DSA_COMP_SUCCESS) {
>>   		res.result = DMA_TRANS_NOERROR;
>> -	else if (desc->completion->status)
>> +	} else if (desc->completion->status) {
>> +		if (idxd->request_int_handles && comp_type != IDXD_COMPLETE_ABORT &&
>> +		    desc->completion->status == DSA_COMP_INT_HANDLE_INVAL &&
>> +		    idxd_queue_int_handle_resubmit(desc))
>> +			return;
>>   		res.result = DMA_TRANS_WRITE_FAILED;
>> -	else if (comp_type == IDXD_COMPLETE_ABORT)
>> +	} else if (comp_type == IDXD_COMPLETE_ABORT) {
>>   		res.result = DMA_TRANS_ABORTED;
>> -	else
>> +	} else {
>>   		complete = 0;
>> +	}
>>   
>>   	tx = &desc->txd;
>>   	if (complete && tx->cookie) {
>> diff --git a/drivers/dma/idxd/idxd.h b/drivers/dma/idxd/idxd.h
>> index 970701738c8a..82c4915f58a2 100644
>> --- a/drivers/dma/idxd/idxd.h
>> +++ b/drivers/dma/idxd/idxd.h
>> @@ -524,6 +524,7 @@ void idxd_unregister_devices(struct idxd_device *idxd);
>>   int idxd_register_driver(void);
>>   void idxd_unregister_driver(void);
>>   void idxd_wqs_quiesce(struct idxd_device *idxd);
>> +bool idxd_queue_int_handle_resubmit(struct idxd_desc *desc);
>>   
>>   /* device interrupt control */
>>   void idxd_msix_perm_setup(struct idxd_device *idxd);
>> diff --git a/drivers/dma/idxd/irq.c b/drivers/dma/idxd/irq.c
>> index 8bca0ed2d23c..26fa871934e6 100644
>> --- a/drivers/dma/idxd/irq.c
>> +++ b/drivers/dma/idxd/irq.c
>> @@ -22,6 +22,11 @@ struct idxd_fault {
>>   	struct idxd_device *idxd;
>>   };
>>   
>> +struct idxd_resubmit {
>> +	struct work_struct work;
>> +	struct idxd_desc *desc;
>> +};
>> +
>>   static void idxd_device_reinit(struct work_struct *work)
>>   {
>>   	struct idxd_device *idxd = container_of(work, struct idxd_device, work);
>> @@ -218,6 +223,51 @@ irqreturn_t idxd_misc_thread(int vec, void *data)
>>   	return IRQ_HANDLED;
>>   }
>>   
>> +static void idxd_int_handle_resubmit_work(struct work_struct *work)
>> +{
>> +	struct idxd_resubmit *irw = container_of(work, struct idxd_resubmit, work);
>> +	struct idxd_desc *desc = irw->desc;
>> +	struct idxd_wq *wq = desc->wq;
>> +	int rc;
>> +
>> +	desc->completion->status = 0;
>> +	rc = idxd_submit_desc(wq, desc);
>> +	if (rc < 0) {
>> +		dev_dbg(&wq->idxd->pdev->dev, "Failed to resubmit desc %d to wq %d.\n",
>> +			desc->id, wq->id);
>> +		/*
>> +		 * If the error is not -EAGAIN, it means the submission failed due to wq
>> +		 * has been killed instead of ENQCMDS failure. Here the driver needs to
>> +		 * notify the submitter of the failure by reporting abort status.
>> +		 *
>> +		 * -EAGAIN comes from ENQCMDS failure. idxd_submit_desc() will handle the
>> +		 * abort.
>> +		 */
>> +		if (rc != -EAGAIN) {
>> +			desc->completion->status = IDXD_COMP_DESC_ABORT;
>> +			idxd_dma_complete_txd(desc, IDXD_COMPLETE_ABORT, false);
>> +		}
>> +		idxd_free_desc(wq, desc);
>> +	}
>> +	kfree(irw);
>> +}
>> +
>> +bool idxd_queue_int_handle_resubmit(struct idxd_desc *desc)
>> +{
>> +	struct idxd_wq *wq = desc->wq;
>> +	struct idxd_device *idxd = wq->idxd;
>> +	struct idxd_resubmit *irw;
>> +
>> +	irw = kzalloc(sizeof(*irw), GFP_KERNEL);
> What is the context of this function, should this be GFP_ATOMIC?

This is done out of a worker thread. So no need for ATOMIC.


>
>> +	if (!irw)
>> +		return false;
>> +
>> +	irw->desc = desc;
>> +	INIT_WORK(&irw->work, idxd_int_handle_resubmit_work);
>> +	queue_work(idxd->wq, &irw->work);
>> +	return true;
>> +}
>> +
>>   static void irq_process_pending_llist(struct idxd_irq_entry *irq_entry)
>>   {
>>   	struct idxd_desc *desc, *t;
>>