[PATCH v4 0/7] Make the rest of the VFIO driver interface use vfio_device

[PATCH v4 0/7] Make the rest of the VFIO driver interface use vfio_device

[Jason Gunthorpe]

Prior series have transformed other parts of VFIO from working on struct
device or struct vfio_group into working directly on struct
vfio_device. Based on that work we now have vfio_device's readily
available in all the drivers.

Update the rest of the driver facing API to use vfio_device as an input.

The following are switched from struct device to struct vfio_device:
  vfio_register_notifier()
  vfio_unregister_notifier()
  vfio_pin_pages()
  vfio_unpin_pages()
  vfio_dma_rw()

The following group APIs are obsoleted and removed by just using struct
vfio_device with the above:
  vfio_group_pin_pages()
  vfio_group_unpin_pages()
  vfio_group_iommu_domain()
  vfio_group_get_external_user_from_dev()

To retain the performance of the new device APIs relative to their group
versions optimize how vfio_group_add_container_user() is used to avoid
calling it when the driver must already guarantee the device is open and
the container_users incrd.

The remaining exported VFIO group interfaces are only used by kvm, and are
addressed by a parallel series.

This series is based on Christoph's gvt rework here:

 https://lore.kernel.org/all/5a8b9f48-2c32-8177-1c18-e3bd7bfde558@intel.com/

and so will need the PR merged first.

I have a followup series that needs this.

This is also part of the iommufd work - moving the driver facing interface
to vfio_device provides a much cleaner path to integrate with iommufd.

v4:
 - Use 'device' as the argument name for a struct vfio_device in vfio.c
v3: https://lore.kernel.org/r/0-v3-e131a9b6b467+14b6-vfio_mdev_no_group_jgg@nvidia.com
 - Based on VFIO's gvt/iommu merge
 - Remove mention of mdev_legacy_get_vfio_device() from commit message
 - Clarify commit message for vfio_dma_rw() conversion
 - Talk about the open_count change in the commit message
 - No code change
v2: https://lore.kernel.org/r/0-v2-6011bde8e0a1+5f-vfio_mdev_no_group_jgg@nvidia.com
 - Based on Christoph's series so mdev_legacy_get_vfio_device() is removed
 - Reflow indenting
 - Use vfio_assert_device_open() and WARN_ON_ONCE instead of open coding
   the assertion
v1: https://lore.kernel.org/r/0-v1-a8faf768d202+125dd-vfio_mdev_no_group_jgg@nvidia.com

Jason Gunthorpe (7):
  vfio: Make vfio_(un)register_notifier accept a vfio_device
  vfio/ccw: Remove mdev from struct channel_program
  vfio/mdev: Pass in a struct vfio_device * to vfio_pin/unpin_pages()
  vfio/mdev: Pass in a struct vfio_device * to vfio_dma_rw()
  drm/i915/gvt: Change from vfio_group_(un)pin_pages to
    vfio_(un)pin_pages
  vfio: Remove dead code
  vfio: Remove calls to vfio_group_add_container_user()

 .../driver-api/vfio-mediated-device.rst       |   4 +-
 drivers/gpu/drm/i915/gvt/gvt.h                |   5 +-
 drivers/gpu/drm/i915/gvt/kvmgt.c              |  51 ++-
 drivers/s390/cio/vfio_ccw_cp.c                |  47 +--
 drivers/s390/cio/vfio_ccw_cp.h                |   4 +-
 drivers/s390/cio/vfio_ccw_fsm.c               |   3 +-
 drivers/s390/cio/vfio_ccw_ops.c               |   7 +-
 drivers/s390/crypto/vfio_ap_ops.c             |  23 +-
 drivers/vfio/vfio.c                           | 299 +++---------------
 include/linux/vfio.h                          |  21 +-
 10 files changed, 109 insertions(+), 355 deletions(-)


base-commit: 676d7cda1a3c19872428a9bc818577a1aafafdd5
-- 
2.36.0

[PATCH v4 1/7] vfio: Make vfio_(un)register_notifier accept a vfio_device

[Jason Gunthorpe]

All callers have a struct vfio_device trivially available, pass it in
directly and avoid calling the expensive vfio_group_get_from_dev().

Acked-by: Eric Farman <farman@linux.ibm.com>
Reviewed-by: Jason J. Herne <jjherne@linux.ibm.com>
Reviewed-by: Tony Krowiak <akrowiak@linux.ibm.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
---
 drivers/gpu/drm/i915/gvt/kvmgt.c  | 24 ++++++++++++------------
 drivers/s390/cio/vfio_ccw_ops.c   |  7 +++----
 drivers/s390/crypto/vfio_ap_ops.c | 14 +++++++-------
 drivers/vfio/vfio.c               | 28 +++++++++-------------------
 include/linux/vfio.h              |  4 ++--
 5 files changed, 33 insertions(+), 44 deletions(-)

diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
index 0787ba5c301f5e..1cec4f1fdfaced 100644
--- a/drivers/gpu/drm/i915/gvt/kvmgt.c
+++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
@@ -810,8 +810,8 @@ static int intel_vgpu_open_device(struct vfio_device *vfio_dev)
 	vgpu->group_notifier.notifier_call = intel_vgpu_group_notifier;
 
 	events = VFIO_IOMMU_NOTIFY_DMA_UNMAP;
-	ret = vfio_register_notifier(vfio_dev->dev, VFIO_IOMMU_NOTIFY, &events,
-				&vgpu->iommu_notifier);
+	ret = vfio_register_notifier(vfio_dev, VFIO_IOMMU_NOTIFY, &events,
+				     &vgpu->iommu_notifier);
 	if (ret != 0) {
 		gvt_vgpu_err("vfio_register_notifier for iommu failed: %d\n",
 			ret);
@@ -819,8 +819,8 @@ static int intel_vgpu_open_device(struct vfio_device *vfio_dev)
 	}
 
 	events = VFIO_GROUP_NOTIFY_SET_KVM;
-	ret = vfio_register_notifier(vfio_dev->dev, VFIO_GROUP_NOTIFY, &events,
-				&vgpu->group_notifier);
+	ret = vfio_register_notifier(vfio_dev, VFIO_GROUP_NOTIFY, &events,
+				     &vgpu->group_notifier);
 	if (ret != 0) {
 		gvt_vgpu_err("vfio_register_notifier for group failed: %d\n",
 			ret);
@@ -873,12 +873,12 @@ static int intel_vgpu_open_device(struct vfio_device *vfio_dev)
 	vgpu->vfio_group = NULL;
 
 undo_register:
-	vfio_unregister_notifier(vfio_dev->dev, VFIO_GROUP_NOTIFY,
-					&vgpu->group_notifier);
+	vfio_unregister_notifier(vfio_dev, VFIO_GROUP_NOTIFY,
+				 &vgpu->group_notifier);
 
 undo_iommu:
-	vfio_unregister_notifier(vfio_dev->dev, VFIO_IOMMU_NOTIFY,
-					&vgpu->iommu_notifier);
+	vfio_unregister_notifier(vfio_dev, VFIO_IOMMU_NOTIFY,
+				 &vgpu->iommu_notifier);
 out:
 	return ret;
 }
@@ -907,13 +907,13 @@ static void __intel_vgpu_release(struct intel_vgpu *vgpu)
 
 	intel_gvt_release_vgpu(vgpu);
 
-	ret = vfio_unregister_notifier(vgpu->vfio_device.dev, VFIO_IOMMU_NOTIFY,
-					&vgpu->iommu_notifier);
+	ret = vfio_unregister_notifier(&vgpu->vfio_device, VFIO_IOMMU_NOTIFY,
+				       &vgpu->iommu_notifier);
 	drm_WARN(&i915->drm, ret,
 		 "vfio_unregister_notifier for iommu failed: %d\n", ret);
 
-	ret = vfio_unregister_notifier(vgpu->vfio_device.dev, VFIO_GROUP_NOTIFY,
-					&vgpu->group_notifier);
+	ret = vfio_unregister_notifier(&vgpu->vfio_device, VFIO_GROUP_NOTIFY,
+				       &vgpu->group_notifier);
 	drm_WARN(&i915->drm, ret,
 		 "vfio_unregister_notifier for group failed: %d\n", ret);
 
diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c
index c4d60cdbf247bf..b49e2e9db2dc6f 100644
--- a/drivers/s390/cio/vfio_ccw_ops.c
+++ b/drivers/s390/cio/vfio_ccw_ops.c
@@ -183,7 +183,7 @@ static int vfio_ccw_mdev_open_device(struct vfio_device *vdev)
 
 	private->nb.notifier_call = vfio_ccw_mdev_notifier;
 
-	ret = vfio_register_notifier(vdev->dev, VFIO_IOMMU_NOTIFY,
+	ret = vfio_register_notifier(vdev, VFIO_IOMMU_NOTIFY,
 				     &events, &private->nb);
 	if (ret)
 		return ret;
@@ -204,8 +204,7 @@ static int vfio_ccw_mdev_open_device(struct vfio_device *vdev)
 
 out_unregister:
 	vfio_ccw_unregister_dev_regions(private);
-	vfio_unregister_notifier(vdev->dev, VFIO_IOMMU_NOTIFY,
-				 &private->nb);
+	vfio_unregister_notifier(vdev, VFIO_IOMMU_NOTIFY, &private->nb);
 	return ret;
 }
 
@@ -223,7 +222,7 @@ static void vfio_ccw_mdev_close_device(struct vfio_device *vdev)
 
 	cp_free(&private->cp);
 	vfio_ccw_unregister_dev_regions(private);
-	vfio_unregister_notifier(vdev->dev, VFIO_IOMMU_NOTIFY, &private->nb);
+	vfio_unregister_notifier(vdev, VFIO_IOMMU_NOTIFY, &private->nb);
 }
 
 static ssize_t vfio_ccw_mdev_read_io_region(struct vfio_ccw_private *private,
diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index ee0a3bf8f476ca..bfa7ee6ef532d9 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -1406,21 +1406,21 @@ static int vfio_ap_mdev_open_device(struct vfio_device *vdev)
 	matrix_mdev->group_notifier.notifier_call = vfio_ap_mdev_group_notifier;
 	events = VFIO_GROUP_NOTIFY_SET_KVM;
 
-	ret = vfio_register_notifier(vdev->dev, VFIO_GROUP_NOTIFY,
-				     &events, &matrix_mdev->group_notifier);
+	ret = vfio_register_notifier(vdev, VFIO_GROUP_NOTIFY, &events,
+				     &matrix_mdev->group_notifier);
 	if (ret)
 		return ret;
 
 	matrix_mdev->iommu_notifier.notifier_call = vfio_ap_mdev_iommu_notifier;
 	events = VFIO_IOMMU_NOTIFY_DMA_UNMAP;
-	ret = vfio_register_notifier(vdev->dev, VFIO_IOMMU_NOTIFY,
-				     &events, &matrix_mdev->iommu_notifier);
+	ret = vfio_register_notifier(vdev, VFIO_IOMMU_NOTIFY, &events,
+				     &matrix_mdev->iommu_notifier);
 	if (ret)
 		goto out_unregister_group;
 	return 0;
 
 out_unregister_group:
-	vfio_unregister_notifier(vdev->dev, VFIO_GROUP_NOTIFY,
+	vfio_unregister_notifier(vdev, VFIO_GROUP_NOTIFY,
 				 &matrix_mdev->group_notifier);
 	return ret;
 }
@@ -1430,9 +1430,9 @@ static void vfio_ap_mdev_close_device(struct vfio_device *vdev)
 	struct ap_matrix_mdev *matrix_mdev =
 		container_of(vdev, struct ap_matrix_mdev, vdev);
 
-	vfio_unregister_notifier(vdev->dev, VFIO_IOMMU_NOTIFY,
+	vfio_unregister_notifier(vdev, VFIO_IOMMU_NOTIFY,
 				 &matrix_mdev->iommu_notifier);
-	vfio_unregister_notifier(vdev->dev, VFIO_GROUP_NOTIFY,
+	vfio_unregister_notifier(vdev, VFIO_GROUP_NOTIFY,
 				 &matrix_mdev->group_notifier);
 	vfio_ap_mdev_unset_kvm(matrix_mdev);
 }
diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
index 0c766384cee0f8..d70890ab9cea92 100644
--- a/drivers/vfio/vfio.c
+++ b/drivers/vfio/vfio.c
@@ -2269,19 +2269,16 @@ static int vfio_unregister_group_notifier(struct vfio_group *group,
 	return ret;
 }
 
-int vfio_register_notifier(struct device *dev, enum vfio_notify_type type,
-			   unsigned long *events, struct notifier_block *nb)
+int vfio_register_notifier(struct vfio_device *device,
+			   enum vfio_notify_type type, unsigned long *events,
+			   struct notifier_block *nb)
 {
-	struct vfio_group *group;
+	struct vfio_group *group = device->group;
 	int ret;
 
-	if (!dev || !nb || !events || (*events == 0))
+	if (!nb || !events || (*events == 0))
 		return -EINVAL;
 
-	group = vfio_group_get_from_dev(dev);
-	if (!group)
-		return -ENODEV;
-
 	switch (type) {
 	case VFIO_IOMMU_NOTIFY:
 		ret = vfio_register_iommu_notifier(group, events, nb);
@@ -2292,25 +2289,20 @@ int vfio_register_notifier(struct device *dev, enum vfio_notify_type type,
 	default:
 		ret = -EINVAL;
 	}
-
-	vfio_group_put(group);
 	return ret;
 }
 EXPORT_SYMBOL(vfio_register_notifier);
 
-int vfio_unregister_notifier(struct device *dev, enum vfio_notify_type type,
+int vfio_unregister_notifier(struct vfio_device *device,
+			     enum vfio_notify_type type,
 			     struct notifier_block *nb)
 {
-	struct vfio_group *group;
+	struct vfio_group *group = device->group;
 	int ret;
 
-	if (!dev || !nb)
+	if (!nb)
 		return -EINVAL;
 
-	group = vfio_group_get_from_dev(dev);
-	if (!group)
-		return -ENODEV;
-
 	switch (type) {
 	case VFIO_IOMMU_NOTIFY:
 		ret = vfio_unregister_iommu_notifier(group, nb);
@@ -2321,8 +2313,6 @@ int vfio_unregister_notifier(struct device *dev, enum vfio_notify_type type,
 	default:
 		ret = -EINVAL;
 	}
-
-	vfio_group_put(group);
 	return ret;
 }
 EXPORT_SYMBOL(vfio_unregister_notifier);
diff --git a/include/linux/vfio.h b/include/linux/vfio.h
index 66dda06ec42d1b..a00fd722f044b0 100644
--- a/include/linux/vfio.h
+++ b/include/linux/vfio.h
@@ -178,11 +178,11 @@ enum vfio_notify_type {
 /* events for VFIO_GROUP_NOTIFY */
 #define VFIO_GROUP_NOTIFY_SET_KVM	BIT(0)
 
-extern int vfio_register_notifier(struct device *dev,
+extern int vfio_register_notifier(struct vfio_device *device,
 				  enum vfio_notify_type type,
 				  unsigned long *required_events,
 				  struct notifier_block *nb);
-extern int vfio_unregister_notifier(struct device *dev,
+extern int vfio_unregister_notifier(struct vfio_device *device,
 				    enum vfio_notify_type type,
 				    struct notifier_block *nb);
 
-- 
2.36.0

[PATCH v4 2/7] vfio/ccw: Remove mdev from struct channel_program

[Jason Gunthorpe]

The next patch wants the vfio_device instead. There is no reason to store
a pointer here since we can container_of back to the vfio_device.

Reviewed-by: Eric Farman <farman@linux.ibm.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
---
 drivers/s390/cio/vfio_ccw_cp.c  | 47 ++++++++++++++++++++-------------
 drivers/s390/cio/vfio_ccw_cp.h  |  4 +--
 drivers/s390/cio/vfio_ccw_fsm.c |  3 +--
 3 files changed, 30 insertions(+), 24 deletions(-)

diff --git a/drivers/s390/cio/vfio_ccw_cp.c b/drivers/s390/cio/vfio_ccw_cp.c
index 8d1b2771c1aa02..7a1cf3091cd647 100644
--- a/drivers/s390/cio/vfio_ccw_cp.c
+++ b/drivers/s390/cio/vfio_ccw_cp.c
@@ -16,6 +16,7 @@
 #include <asm/idals.h>
 
 #include "vfio_ccw_cp.h"
+#include "vfio_ccw_private.h"
 
 struct pfn_array {
 	/* Starting guest physical I/O address. */
@@ -98,17 +99,17 @@ static int pfn_array_alloc(struct pfn_array *pa, u64 iova, unsigned int len)
  * If the pin request partially succeeds, or fails completely,
  * all pages are left unpinned and a negative error value is returned.
  */
-static int pfn_array_pin(struct pfn_array *pa, struct device *mdev)
+static int pfn_array_pin(struct pfn_array *pa, struct vfio_device *vdev)
 {
 	int ret = 0;
 
-	ret = vfio_pin_pages(mdev, pa->pa_iova_pfn, pa->pa_nr,
+	ret = vfio_pin_pages(vdev->dev, pa->pa_iova_pfn, pa->pa_nr,
 			     IOMMU_READ | IOMMU_WRITE, pa->pa_pfn);
 
 	if (ret < 0) {
 		goto err_out;
 	} else if (ret > 0 && ret != pa->pa_nr) {
-		vfio_unpin_pages(mdev, pa->pa_iova_pfn, ret);
+		vfio_unpin_pages(vdev->dev, pa->pa_iova_pfn, ret);
 		ret = -EINVAL;
 		goto err_out;
 	}
@@ -122,11 +123,11 @@ static int pfn_array_pin(struct pfn_array *pa, struct device *mdev)
 }
 
 /* Unpin the pages before releasing the memory. */
-static void pfn_array_unpin_free(struct pfn_array *pa, struct device *mdev)
+static void pfn_array_unpin_free(struct pfn_array *pa, struct vfio_device *vdev)
 {
 	/* Only unpin if any pages were pinned to begin with */
 	if (pa->pa_nr)
-		vfio_unpin_pages(mdev, pa->pa_iova_pfn, pa->pa_nr);
+		vfio_unpin_pages(vdev->dev, pa->pa_iova_pfn, pa->pa_nr);
 	pa->pa_nr = 0;
 	kfree(pa->pa_iova_pfn);
 }
@@ -190,8 +191,7 @@ static void convert_ccw0_to_ccw1(struct ccw1 *source, unsigned long len)
  * Within the domain (@mdev), copy @n bytes from a guest physical
  * address (@iova) to a host physical address (@to).
  */
-static long copy_from_iova(struct device *mdev,
-			   void *to, u64 iova,
+static long copy_from_iova(struct vfio_device *vdev, void *to, u64 iova,
 			   unsigned long n)
 {
 	struct pfn_array pa = {0};
@@ -203,9 +203,9 @@ static long copy_from_iova(struct device *mdev,
 	if (ret < 0)
 		return ret;
 
-	ret = pfn_array_pin(&pa, mdev);
+	ret = pfn_array_pin(&pa, vdev);
 	if (ret < 0) {
-		pfn_array_unpin_free(&pa, mdev);
+		pfn_array_unpin_free(&pa, vdev);
 		return ret;
 	}
 
@@ -226,7 +226,7 @@ static long copy_from_iova(struct device *mdev,
 			break;
 	}
 
-	pfn_array_unpin_free(&pa, mdev);
+	pfn_array_unpin_free(&pa, vdev);
 
 	return l;
 }
@@ -423,11 +423,13 @@ static int ccwchain_loop_tic(struct ccwchain *chain,
 
 static int ccwchain_handle_ccw(u32 cda, struct channel_program *cp)
 {
+	struct vfio_device *vdev =
+		&container_of(cp, struct vfio_ccw_private, cp)->vdev;
 	struct ccwchain *chain;
 	int len, ret;
 
 	/* Copy 2K (the most we support today) of possible CCWs */
-	len = copy_from_iova(cp->mdev, cp->guest_cp, cda,
+	len = copy_from_iova(vdev, cp->guest_cp, cda,
 			     CCWCHAIN_LEN_MAX * sizeof(struct ccw1));
 	if (len)
 		return len;
@@ -508,6 +510,8 @@ static int ccwchain_fetch_direct(struct ccwchain *chain,
 				 int idx,
 				 struct channel_program *cp)
 {
+	struct vfio_device *vdev =
+		&container_of(cp, struct vfio_ccw_private, cp)->vdev;
 	struct ccw1 *ccw;
 	struct pfn_array *pa;
 	u64 iova;
@@ -526,7 +530,7 @@ static int ccwchain_fetch_direct(struct ccwchain *chain,
 	if (ccw_is_idal(ccw)) {
 		/* Read first IDAW to see if it's 4K-aligned or not. */
 		/* All subsequent IDAws will be 4K-aligned. */
-		ret = copy_from_iova(cp->mdev, &iova, ccw->cda, sizeof(iova));
+		ret = copy_from_iova(vdev, &iova, ccw->cda, sizeof(iova));
 		if (ret)
 			return ret;
 	} else {
@@ -555,7 +559,7 @@ static int ccwchain_fetch_direct(struct ccwchain *chain,
 
 	if (ccw_is_idal(ccw)) {
 		/* Copy guest IDAL into host IDAL */
-		ret = copy_from_iova(cp->mdev, idaws, ccw->cda, idal_len);
+		ret = copy_from_iova(vdev, idaws, ccw->cda, idal_len);
 		if (ret)
 			goto out_unpin;
 
@@ -574,7 +578,7 @@ static int ccwchain_fetch_direct(struct ccwchain *chain,
 	}
 
 	if (ccw_does_data_transfer(ccw)) {
-		ret = pfn_array_pin(pa, cp->mdev);
+		ret = pfn_array_pin(pa, vdev);
 		if (ret < 0)
 			goto out_unpin;
 	} else {
@@ -590,7 +594,7 @@ static int ccwchain_fetch_direct(struct ccwchain *chain,
 	return 0;
 
 out_unpin:
-	pfn_array_unpin_free(pa, cp->mdev);
+	pfn_array_unpin_free(pa, vdev);
 out_free_idaws:
 	kfree(idaws);
 out_init:
@@ -632,8 +636,10 @@ static int ccwchain_fetch_one(struct ccwchain *chain,
  * Returns:
  *   %0 on success and a negative error value on failure.
  */
-int cp_init(struct channel_program *cp, struct device *mdev, union orb *orb)
+int cp_init(struct channel_program *cp, union orb *orb)
 {
+	struct vfio_device *vdev =
+		&container_of(cp, struct vfio_ccw_private, cp)->vdev;
 	/* custom ratelimit used to avoid flood during guest IPL */
 	static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 1);
 	int ret;
@@ -650,11 +656,12 @@ int cp_init(struct channel_program *cp, struct device *mdev, union orb *orb)
 	 * the problem if something does break.
 	 */
 	if (!orb->cmd.pfch && __ratelimit(&ratelimit_state))
-		dev_warn(mdev, "Prefetching channel program even though prefetch not specified in ORB");
+		dev_warn(
+			vdev->dev,
+			"Prefetching channel program even though prefetch not specified in ORB");
 
 	INIT_LIST_HEAD(&cp->ccwchain_list);
 	memcpy(&cp->orb, orb, sizeof(*orb));
-	cp->mdev = mdev;
 
 	/* Build a ccwchain for the first CCW segment */
 	ret = ccwchain_handle_ccw(orb->cmd.cpa, cp);
@@ -682,6 +689,8 @@ int cp_init(struct channel_program *cp, struct device *mdev, union orb *orb)
  */
 void cp_free(struct channel_program *cp)
 {
+	struct vfio_device *vdev =
+		&container_of(cp, struct vfio_ccw_private, cp)->vdev;
 	struct ccwchain *chain, *temp;
 	int i;
 
@@ -691,7 +700,7 @@ void cp_free(struct channel_program *cp)
 	cp->initialized = false;
 	list_for_each_entry_safe(chain, temp, &cp->ccwchain_list, next) {
 		for (i = 0; i < chain->ch_len; i++) {
-			pfn_array_unpin_free(chain->ch_pa + i, cp->mdev);
+			pfn_array_unpin_free(chain->ch_pa + i, vdev);
 			ccwchain_cda_free(chain, i);
 		}
 		ccwchain_free(chain);
diff --git a/drivers/s390/cio/vfio_ccw_cp.h b/drivers/s390/cio/vfio_ccw_cp.h
index ba31240ce96594..e4c436199b4cda 100644
--- a/drivers/s390/cio/vfio_ccw_cp.h
+++ b/drivers/s390/cio/vfio_ccw_cp.h
@@ -37,13 +37,11 @@
 struct channel_program {
 	struct list_head ccwchain_list;
 	union orb orb;
-	struct device *mdev;
 	bool initialized;
 	struct ccw1 *guest_cp;
 };
 
-extern int cp_init(struct channel_program *cp, struct device *mdev,
-		   union orb *orb);
+extern int cp_init(struct channel_program *cp, union orb *orb);
 extern void cp_free(struct channel_program *cp);
 extern int cp_prefetch(struct channel_program *cp);
 extern union orb *cp_get_orb(struct channel_program *cp, u32 intparm, u8 lpm);
diff --git a/drivers/s390/cio/vfio_ccw_fsm.c b/drivers/s390/cio/vfio_ccw_fsm.c
index e435a9cd92dacf..8483a266051c21 100644
--- a/drivers/s390/cio/vfio_ccw_fsm.c
+++ b/drivers/s390/cio/vfio_ccw_fsm.c
@@ -262,8 +262,7 @@ static void fsm_io_request(struct vfio_ccw_private *private,
 			errstr = "transport mode";
 			goto err_out;
 		}
-		io_region->ret_code = cp_init(&private->cp, mdev_dev(mdev),
-					      orb);
+		io_region->ret_code = cp_init(&private->cp, orb);
 		if (io_region->ret_code) {
 			VFIO_CCW_MSG_EVENT(2,
 					   "%pUl (%x.%x.%04x): cp_init=%d\n",
-- 
2.36.0

[PATCH v4 3/7] vfio/mdev: Pass in a struct vfio_device * to vfio_pin/unpin_pages()

[Jason Gunthorpe]

Every caller has a readily available vfio_device pointer, use that instead
of passing in a generic struct device. The struct vfio_device already
contains the group we need so this avoids complexity, extra refcountings,
and a confusing lifecycle model.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Eric Farman <farman@linux.ibm.com>
Reviewed-by: Jason J. Herne <jjherne@linux.ibm.com>
Reviewed-by: Tony Krowiak <akrowiak@linux.ibm.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
---
 .../driver-api/vfio-mediated-device.rst       |  4 +-
 drivers/s390/cio/vfio_ccw_cp.c                |  6 +--
 drivers/s390/crypto/vfio_ap_ops.c             |  9 ++--
 drivers/vfio/vfio.c                           | 46 +++++++------------
 include/linux/vfio.h                          |  4 +-
 5 files changed, 27 insertions(+), 42 deletions(-)

diff --git a/Documentation/driver-api/vfio-mediated-device.rst b/Documentation/driver-api/vfio-mediated-device.rst
index 784bbeb22adcf5..eded8719180fba 100644
--- a/Documentation/driver-api/vfio-mediated-device.rst
+++ b/Documentation/driver-api/vfio-mediated-device.rst
@@ -262,10 +262,10 @@ Translation APIs for Mediated Devices
 The following APIs are provided for translating user pfn to host pfn in a VFIO
 driver::
 
-	extern int vfio_pin_pages(struct device *dev, unsigned long *user_pfn,
+	int vfio_pin_pages(struct vfio_device *device, unsigned long *user_pfn,
 				  int npage, int prot, unsigned long *phys_pfn);
 
-	extern int vfio_unpin_pages(struct device *dev, unsigned long *user_pfn,
+	int vfio_unpin_pages(struct vfio_device *device, unsigned long *user_pfn,
 				    int npage);
 
 These functions call back into the back-end IOMMU module by using the pin_pages
diff --git a/drivers/s390/cio/vfio_ccw_cp.c b/drivers/s390/cio/vfio_ccw_cp.c
index 7a1cf3091cd647..0c2be9421ab78f 100644
--- a/drivers/s390/cio/vfio_ccw_cp.c
+++ b/drivers/s390/cio/vfio_ccw_cp.c
@@ -103,13 +103,13 @@ static int pfn_array_pin(struct pfn_array *pa, struct vfio_device *vdev)
 {
 	int ret = 0;
 
-	ret = vfio_pin_pages(vdev->dev, pa->pa_iova_pfn, pa->pa_nr,
+	ret = vfio_pin_pages(vdev, pa->pa_iova_pfn, pa->pa_nr,
 			     IOMMU_READ | IOMMU_WRITE, pa->pa_pfn);
 
 	if (ret < 0) {
 		goto err_out;
 	} else if (ret > 0 && ret != pa->pa_nr) {
-		vfio_unpin_pages(vdev->dev, pa->pa_iova_pfn, ret);
+		vfio_unpin_pages(vdev, pa->pa_iova_pfn, ret);
 		ret = -EINVAL;
 		goto err_out;
 	}
@@ -127,7 +127,7 @@ static void pfn_array_unpin_free(struct pfn_array *pa, struct vfio_device *vdev)
 {
 	/* Only unpin if any pages were pinned to begin with */
 	if (pa->pa_nr)
-		vfio_unpin_pages(vdev->dev, pa->pa_iova_pfn, pa->pa_nr);
+		vfio_unpin_pages(vdev, pa->pa_iova_pfn, pa->pa_nr);
 	pa->pa_nr = 0;
 	kfree(pa->pa_iova_pfn);
 }
diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index bfa7ee6ef532d9..e8914024f5b1af 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -124,8 +124,7 @@ static void vfio_ap_free_aqic_resources(struct vfio_ap_queue *q)
 		q->saved_isc = VFIO_AP_ISC_INVALID;
 	}
 	if (q->saved_pfn && !WARN_ON(!q->matrix_mdev)) {
-		vfio_unpin_pages(mdev_dev(q->matrix_mdev->mdev),
-				 &q->saved_pfn, 1);
+		vfio_unpin_pages(&q->matrix_mdev->vdev, &q->saved_pfn, 1);
 		q->saved_pfn = 0;
 	}
 }
@@ -258,7 +257,7 @@ static struct ap_queue_status vfio_ap_irq_enable(struct vfio_ap_queue *q,
 		return status;
 	}
 
-	ret = vfio_pin_pages(mdev_dev(q->matrix_mdev->mdev), &g_pfn, 1,
+	ret = vfio_pin_pages(&q->matrix_mdev->vdev, &g_pfn, 1,
 			     IOMMU_READ | IOMMU_WRITE, &h_pfn);
 	switch (ret) {
 	case 1:
@@ -301,7 +300,7 @@ static struct ap_queue_status vfio_ap_irq_enable(struct vfio_ap_queue *q,
 		break;
 	case AP_RESPONSE_OTHERWISE_CHANGED:
 		/* We could not modify IRQ setings: clear new configuration */
-		vfio_unpin_pages(mdev_dev(q->matrix_mdev->mdev), &g_pfn, 1);
+		vfio_unpin_pages(&q->matrix_mdev->vdev, &g_pfn, 1);
 		kvm_s390_gisc_unregister(kvm, isc);
 		break;
 	default:
@@ -1250,7 +1249,7 @@ static int vfio_ap_mdev_iommu_notifier(struct notifier_block *nb,
 		struct vfio_iommu_type1_dma_unmap *unmap = data;
 		unsigned long g_pfn = unmap->iova >> PAGE_SHIFT;
 
-		vfio_unpin_pages(mdev_dev(matrix_mdev->mdev), &g_pfn, 1);
+		vfio_unpin_pages(&matrix_mdev->vdev, &g_pfn, 1);
 		return NOTIFY_OK;
 	}
 
diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
index d70890ab9cea92..93caab1f29dbd7 100644
--- a/drivers/vfio/vfio.c
+++ b/drivers/vfio/vfio.c
@@ -1919,7 +1919,7 @@ EXPORT_SYMBOL(vfio_set_irqs_validate_and_prepare);
 /*
  * Pin a set of guest PFNs and return their associated host PFNs for local
  * domain only.
- * @dev [in]     : device
+ * @device [in]  : device
  * @user_pfn [in]: array of user/guest PFNs to be pinned.
  * @npage [in]   : count of elements in user_pfn array.  This count should not
  *		   be greater VFIO_PIN_PAGES_MAX_ENTRIES.
@@ -1927,32 +1927,26 @@ EXPORT_SYMBOL(vfio_set_irqs_validate_and_prepare);
  * @phys_pfn[out]: array of host PFNs
  * Return error or number of pages pinned.
  */
-int vfio_pin_pages(struct device *dev, unsigned long *user_pfn, int npage,
-		   int prot, unsigned long *phys_pfn)
+int vfio_pin_pages(struct vfio_device *device, unsigned long *user_pfn,
+		   int npage, int prot, unsigned long *phys_pfn)
 {
 	struct vfio_container *container;
-	struct vfio_group *group;
+	struct vfio_group *group = device->group;
 	struct vfio_iommu_driver *driver;
 	int ret;
 
-	if (!dev || !user_pfn || !phys_pfn || !npage)
+	if (!user_pfn || !phys_pfn || !npage)
 		return -EINVAL;
 
 	if (npage > VFIO_PIN_PAGES_MAX_ENTRIES)
 		return -E2BIG;
 
-	group = vfio_group_get_from_dev(dev);
-	if (!group)
-		return -ENODEV;
-
-	if (group->dev_counter > 1) {
-		ret = -EINVAL;
-		goto err_pin_pages;
-	}
+	if (group->dev_counter > 1)
+		return -EINVAL;
 
 	ret = vfio_group_add_container_user(group);
 	if (ret)
-		goto err_pin_pages;
+		return ret;
 
 	container = group->container;
 	driver = container->iommu_driver;
@@ -1965,43 +1959,37 @@ int vfio_pin_pages(struct device *dev, unsigned long *user_pfn, int npage,
 
 	vfio_group_try_dissolve_container(group);
 
-err_pin_pages:
-	vfio_group_put(group);
 	return ret;
 }
 EXPORT_SYMBOL(vfio_pin_pages);
 
 /*
  * Unpin set of host PFNs for local domain only.
- * @dev [in]     : device
+ * @device [in]  : device
  * @user_pfn [in]: array of user/guest PFNs to be unpinned. Number of user/guest
  *		   PFNs should not be greater than VFIO_PIN_PAGES_MAX_ENTRIES.
  * @npage [in]   : count of elements in user_pfn array.  This count should not
  *                 be greater than VFIO_PIN_PAGES_MAX_ENTRIES.
  * Return error or number of pages unpinned.
  */
-int vfio_unpin_pages(struct device *dev, unsigned long *user_pfn, int npage)
+int vfio_unpin_pages(struct vfio_device *device, unsigned long *user_pfn,
+		     int npage)
 {
 	struct vfio_container *container;
-	struct vfio_group *group;
 	struct vfio_iommu_driver *driver;
 	int ret;
 
-	if (!dev || !user_pfn || !npage)
+	if (!user_pfn || !npage)
 		return -EINVAL;
 
 	if (npage > VFIO_PIN_PAGES_MAX_ENTRIES)
 		return -E2BIG;
 
-	group = vfio_group_get_from_dev(dev);
-	if (!group)
-		return -ENODEV;
-
-	ret = vfio_group_add_container_user(group);
+	ret = vfio_group_add_container_user(device->group);
 	if (ret)
-		goto err_unpin_pages;
+		return ret;
 
-	container = group->container;
+	container = device->group->container;
 	driver = container->iommu_driver;
 	if (likely(driver && driver->ops->unpin_pages))
 		ret = driver->ops->unpin_pages(container->iommu_data, user_pfn,
@@ -2009,10 +1997,8 @@ int vfio_unpin_pages(struct device *dev, unsigned long *user_pfn, int npage)
 	else
 		ret = -ENOTTY;
 
-	vfio_group_try_dissolve_container(group);
+	vfio_group_try_dissolve_container(device->group);
 
-err_unpin_pages:
-	vfio_group_put(group);
 	return ret;
 }
 EXPORT_SYMBOL(vfio_unpin_pages);
diff --git a/include/linux/vfio.h b/include/linux/vfio.h
index a00fd722f044b0..bddc70f88899c3 100644
--- a/include/linux/vfio.h
+++ b/include/linux/vfio.h
@@ -150,9 +150,9 @@ extern long vfio_external_check_extension(struct vfio_group *group,
 
 #define VFIO_PIN_PAGES_MAX_ENTRIES	(PAGE_SIZE/sizeof(unsigned long))
 
-extern int vfio_pin_pages(struct device *dev, unsigned long *user_pfn,
+extern int vfio_pin_pages(struct vfio_device *device, unsigned long *user_pfn,
 			  int npage, int prot, unsigned long *phys_pfn);
-extern int vfio_unpin_pages(struct device *dev, unsigned long *user_pfn,
+extern int vfio_unpin_pages(struct vfio_device *device, unsigned long *user_pfn,
 			    int npage);
 
 extern int vfio_group_pin_pages(struct vfio_group *group,
-- 
2.36.0

[PATCH v4 4/7] vfio/mdev: Pass in a struct vfio_device * to vfio_dma_rw()

[Jason Gunthorpe]

Every caller has a readily available vfio_device pointer, use that instead
of passing in a generic struct device. Change vfio_dma_rw() to take in the
struct vfio_device and move the container users that would have been held
by vfio_group_get_external_user_from_dev() to vfio_dma_rw() directly, like
vfio_pin/unpin_pages().

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
---
 drivers/gpu/drm/i915/gvt/gvt.h |  4 ++--
 drivers/vfio/vfio.c            | 24 +++++++++++-------------
 include/linux/vfio.h           |  2 +-
 3 files changed, 14 insertions(+), 16 deletions(-)

diff --git a/drivers/gpu/drm/i915/gvt/gvt.h b/drivers/gpu/drm/i915/gvt/gvt.h
index 03ecffc2ba56a9..5a28ee965b7f3e 100644
--- a/drivers/gpu/drm/i915/gvt/gvt.h
+++ b/drivers/gpu/drm/i915/gvt/gvt.h
@@ -732,7 +732,7 @@ static inline int intel_gvt_read_gpa(struct intel_vgpu *vgpu, unsigned long gpa,
 {
 	if (!vgpu->attached)
 		return -ESRCH;
-	return vfio_dma_rw(vgpu->vfio_group, gpa, buf, len, false);
+	return vfio_dma_rw(&vgpu->vfio_device, gpa, buf, len, false);
 }
 
 /**
@@ -750,7 +750,7 @@ static inline int intel_gvt_write_gpa(struct intel_vgpu *vgpu,
 {
 	if (!vgpu->attached)
 		return -ESRCH;
-	return vfio_dma_rw(vgpu->vfio_group, gpa, buf, len, true);
+	return vfio_dma_rw(&vgpu->vfio_device, gpa, buf, len, true);
 }
 
 void intel_gvt_debugfs_remove_vgpu(struct intel_vgpu *vgpu);
diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
index 93caab1f29dbd7..85e1304099b8a5 100644
--- a/drivers/vfio/vfio.c
+++ b/drivers/vfio/vfio.c
@@ -2108,32 +2108,28 @@ EXPORT_SYMBOL(vfio_group_unpin_pages);
  * As the read/write of user space memory is conducted via the CPUs and is
  * not a real device DMA, it is not necessary to pin the user space memory.
  *
- * The caller needs to call vfio_group_get_external_user() or
- * vfio_group_get_external_user_from_dev() prior to calling this interface,
- * so as to prevent the VFIO group from disposal in the middle of the call.
- * But it can keep the reference to the VFIO group for several calls into
- * this interface.
- * After finishing using of the VFIO group, the caller needs to release the
- * VFIO group by calling vfio_group_put_external_user().
- *
- * @group [in]		: VFIO group
+ * @device [in]		: VFIO device
  * @user_iova [in]	: base IOVA of a user space buffer
  * @data [in]		: pointer to kernel buffer
  * @len [in]		: kernel buffer length
  * @write		: indicate read or write
  * Return error code on failure or 0 on success.
  */
-int vfio_dma_rw(struct vfio_group *group, dma_addr_t user_iova,
-		void *data, size_t len, bool write)
+int vfio_dma_rw(struct vfio_device *device, dma_addr_t user_iova, void *data,
+		size_t len, bool write)
 {
 	struct vfio_container *container;
 	struct vfio_iommu_driver *driver;
 	int ret = 0;
 
-	if (!group || !data || len <= 0)
+	if (!data || len <= 0)
 		return -EINVAL;
 
-	container = group->container;
+	ret = vfio_group_add_container_user(device->group);
+	if (ret)
+		return ret;
+
+	container = device->group->container;
 	driver = container->iommu_driver;
 
 	if (likely(driver && driver->ops->dma_rw))
@@ -2142,6 +2138,8 @@ int vfio_dma_rw(struct vfio_group *group, dma_addr_t user_iova,
 	else
 		ret = -ENOTTY;
 
+	vfio_group_try_dissolve_container(device->group);
+
 	return ret;
 }
 EXPORT_SYMBOL(vfio_dma_rw);
diff --git a/include/linux/vfio.h b/include/linux/vfio.h
index bddc70f88899c3..8a151025871776 100644
--- a/include/linux/vfio.h
+++ b/include/linux/vfio.h
@@ -161,7 +161,7 @@ extern int vfio_group_pin_pages(struct vfio_group *group,
 extern int vfio_group_unpin_pages(struct vfio_group *group,
 				  unsigned long *user_iova_pfn, int npage);
 
-extern int vfio_dma_rw(struct vfio_group *group, dma_addr_t user_iova,
+extern int vfio_dma_rw(struct vfio_device *device, dma_addr_t user_iova,
 		       void *data, size_t len, bool write);
 
 extern struct iommu_domain *vfio_group_iommu_domain(struct vfio_group *group);
-- 
2.36.0

[PATCH v4 5/7] drm/i915/gvt: Change from vfio_group_(un)pin_pages to vfio_(un)pin_pages

[Jason Gunthorpe]

Use the existing vfio_device versions of vfio_(un)pin_pages(). There is no
reason to use a group interface here, kvmgt has easy access to a
vfio_device.

Delete kvmgt_vdev::vfio_group since these calls were the last users.

Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
---
 drivers/gpu/drm/i915/gvt/gvt.h   |  1 -
 drivers/gpu/drm/i915/gvt/kvmgt.c | 27 ++++++---------------------
 2 files changed, 6 insertions(+), 22 deletions(-)

diff --git a/drivers/gpu/drm/i915/gvt/gvt.h b/drivers/gpu/drm/i915/gvt/gvt.h
index 5a28ee965b7f3e..2af4c83e733c6c 100644
--- a/drivers/gpu/drm/i915/gvt/gvt.h
+++ b/drivers/gpu/drm/i915/gvt/gvt.h
@@ -231,7 +231,6 @@ struct intel_vgpu {
 	struct kvm *kvm;
 	struct work_struct release_work;
 	atomic_t released;
-	struct vfio_group *vfio_group;
 
 	struct kvm_page_track_notifier_node track_node;
 #define NR_BKT (1 << 18)
diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
index 1cec4f1fdfaced..7655ffa97d5116 100644
--- a/drivers/gpu/drm/i915/gvt/kvmgt.c
+++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
@@ -243,7 +243,7 @@ static void gvt_unpin_guest_page(struct intel_vgpu *vgpu, unsigned long gfn,
 	for (npage = 0; npage < total_pages; npage++) {
 		unsigned long cur_gfn = gfn + npage;
 
-		ret = vfio_group_unpin_pages(vgpu->vfio_group, &cur_gfn, 1);
+		ret = vfio_unpin_pages(&vgpu->vfio_device, &cur_gfn, 1);
 		drm_WARN_ON(&i915->drm, ret != 1);
 	}
 }
@@ -266,8 +266,8 @@ static int gvt_pin_guest_page(struct intel_vgpu *vgpu, unsigned long gfn,
 		unsigned long cur_gfn = gfn + npage;
 		unsigned long pfn;
 
-		ret = vfio_group_pin_pages(vgpu->vfio_group, &cur_gfn, 1,
-					   IOMMU_READ | IOMMU_WRITE, &pfn);
+		ret = vfio_pin_pages(&vgpu->vfio_device, &cur_gfn, 1,
+				     IOMMU_READ | IOMMU_WRITE, &pfn);
 		if (ret != 1) {
 			gvt_vgpu_err("vfio_pin_pages failed for gfn 0x%lx, ret %d\n",
 				     cur_gfn, ret);
@@ -804,7 +804,6 @@ static int intel_vgpu_open_device(struct vfio_device *vfio_dev)
 	struct intel_vgpu *vgpu = vfio_dev_to_vgpu(vfio_dev);
 	unsigned long events;
 	int ret;
-	struct vfio_group *vfio_group;
 
 	vgpu->iommu_notifier.notifier_call = intel_vgpu_iommu_notifier;
 	vgpu->group_notifier.notifier_call = intel_vgpu_group_notifier;
@@ -827,28 +826,19 @@ static int intel_vgpu_open_device(struct vfio_device *vfio_dev)
 		goto undo_iommu;
 	}
 
-	vfio_group =
-		vfio_group_get_external_user_from_dev(vgpu->vfio_device.dev);
-	if (IS_ERR_OR_NULL(vfio_group)) {
-		ret = !vfio_group ? -EFAULT : PTR_ERR(vfio_group);
-		gvt_vgpu_err("vfio_group_get_external_user_from_dev failed\n");
-		goto undo_register;
-	}
-	vgpu->vfio_group = vfio_group;
-
 	ret = -EEXIST;
 	if (vgpu->attached)
-		goto undo_group;
+		goto undo_register;
 
 	ret = -ESRCH;
 	if (!vgpu->kvm || vgpu->kvm->mm != current->mm) {
 		gvt_vgpu_err("KVM is required to use Intel vGPU\n");
-		goto undo_group;
+		goto undo_register;
 	}
 
 	ret = -EEXIST;
 	if (__kvmgt_vgpu_exist(vgpu))
-		goto undo_group;
+		goto undo_register;
 
 	vgpu->attached = true;
 	kvm_get_kvm(vgpu->kvm);
@@ -868,10 +858,6 @@ static int intel_vgpu_open_device(struct vfio_device *vfio_dev)
 	atomic_set(&vgpu->released, 0);
 	return 0;
 
-undo_group:
-	vfio_group_put_external_user(vgpu->vfio_group);
-	vgpu->vfio_group = NULL;
-
 undo_register:
 	vfio_unregister_notifier(vfio_dev, VFIO_GROUP_NOTIFY,
 				 &vgpu->group_notifier);
@@ -925,7 +911,6 @@ static void __intel_vgpu_release(struct intel_vgpu *vgpu)
 	gvt_cache_destroy(vgpu);
 
 	intel_vgpu_release_msi_eventfd_ctx(vgpu);
-	vfio_group_put_external_user(vgpu->vfio_group);
 
 	vgpu->kvm = NULL;
 	vgpu->attached = false;
-- 
2.36.0

Re: [PATCH v4 5/7] drm/i915/gvt: Change from vfio_group_(un)pin_pages to vfio_(un)pin_pages

[Wang, Zhi A]

On 5/6/22 12:08 AM, Jason Gunthorpe wrote:
> Use the existing vfio_device versions of vfio_(un)pin_pages(). There is no
> reason to use a group interface here, kvmgt has easy access to a
> vfio_device.
> 
> Delete kvmgt_vdev::vfio_group since these calls were the last users.
> 
> Reviewed-by: Kevin Tian <kevin.tian@intel.com>
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
> ---
>  drivers/gpu/drm/i915/gvt/gvt.h   |  1 -
>  drivers/gpu/drm/i915/gvt/kvmgt.c | 27 ++++++---------------------
>  2 files changed, 6 insertions(+), 22 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/gvt/gvt.h b/drivers/gpu/drm/i915/gvt/gvt.h
> index 5a28ee965b7f3e..2af4c83e733c6c 100644
> --- a/drivers/gpu/drm/i915/gvt/gvt.h
> +++ b/drivers/gpu/drm/i915/gvt/gvt.h
> @@ -231,7 +231,6 @@ struct intel_vgpu {
>  	struct kvm *kvm;
>  	struct work_struct release_work;
>  	atomic_t released;
> -	struct vfio_group *vfio_group;
>  
>  	struct kvm_page_track_notifier_node track_node;
>  #define NR_BKT (1 << 18)
> diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
> index 1cec4f1fdfaced..7655ffa97d5116 100644
> --- a/drivers/gpu/drm/i915/gvt/kvmgt.c
> +++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
> @@ -243,7 +243,7 @@ static void gvt_unpin_guest_page(struct intel_vgpu *vgpu, unsigned long gfn,
>  	for (npage = 0; npage < total_pages; npage++) {
>  		unsigned long cur_gfn = gfn + npage;
>  
> -		ret = vfio_group_unpin_pages(vgpu->vfio_group, &cur_gfn, 1);
> +		ret = vfio_unpin_pages(&vgpu->vfio_device, &cur_gfn, 1);
>  		drm_WARN_ON(&i915->drm, ret != 1);
>  	}
>  }
> @@ -266,8 +266,8 @@ static int gvt_pin_guest_page(struct intel_vgpu *vgpu, unsigned long gfn,
>  		unsigned long cur_gfn = gfn + npage;
>  		unsigned long pfn;
>  
> -		ret = vfio_group_pin_pages(vgpu->vfio_group, &cur_gfn, 1,
> -					   IOMMU_READ | IOMMU_WRITE, &pfn);
> +		ret = vfio_pin_pages(&vgpu->vfio_device, &cur_gfn, 1,
> +				     IOMMU_READ | IOMMU_WRITE, &pfn);
>  		if (ret != 1) {
>  			gvt_vgpu_err("vfio_pin_pages failed for gfn 0x%lx, ret %d\n",
>  				     cur_gfn, ret);
> @@ -804,7 +804,6 @@ static int intel_vgpu_open_device(struct vfio_device *vfio_dev)
>  	struct intel_vgpu *vgpu = vfio_dev_to_vgpu(vfio_dev);
>  	unsigned long events;
>  	int ret;
> -	struct vfio_group *vfio_group;
>  
>  	vgpu->iommu_notifier.notifier_call = intel_vgpu_iommu_notifier;
>  	vgpu->group_notifier.notifier_call = intel_vgpu_group_notifier;
> @@ -827,28 +826,19 @@ static int intel_vgpu_open_device(struct vfio_device *vfio_dev)
>  		goto undo_iommu;
>  	}
>  
> -	vfio_group =
> -		vfio_group_get_external_user_from_dev(vgpu->vfio_device.dev);
> -	if (IS_ERR_OR_NULL(vfio_group)) {
> -		ret = !vfio_group ? -EFAULT : PTR_ERR(vfio_group);
> -		gvt_vgpu_err("vfio_group_get_external_user_from_dev failed\n");
> -		goto undo_register;
> -	}
> -	vgpu->vfio_group = vfio_group;
> -
>  	ret = -EEXIST;
>  	if (vgpu->attached)
> -		goto undo_group;
> +		goto undo_register;
>  
>  	ret = -ESRCH;
>  	if (!vgpu->kvm || vgpu->kvm->mm != current->mm) {
>  		gvt_vgpu_err("KVM is required to use Intel vGPU\n");
> -		goto undo_group;
> +		goto undo_register;
>  	}
>  
>  	ret = -EEXIST;
>  	if (__kvmgt_vgpu_exist(vgpu))
> -		goto undo_group;
> +		goto undo_register;
>  
>  	vgpu->attached = true;
>  	kvm_get_kvm(vgpu->kvm);
> @@ -868,10 +858,6 @@ static int intel_vgpu_open_device(struct vfio_device *vfio_dev)
>  	atomic_set(&vgpu->released, 0);
>  	return 0;
>  
> -undo_group:
> -	vfio_group_put_external_user(vgpu->vfio_group);
> -	vgpu->vfio_group = NULL;
> -
>  undo_register:
>  	vfio_unregister_notifier(vfio_dev, VFIO_GROUP_NOTIFY,
>  				 &vgpu->group_notifier);
> @@ -925,7 +911,6 @@ static void __intel_vgpu_release(struct intel_vgpu *vgpu)
>  	gvt_cache_destroy(vgpu);
>  
>  	intel_vgpu_release_msi_eventfd_ctx(vgpu);
> -	vfio_group_put_external_user(vgpu->vfio_group);
>  
>  	vgpu->kvm = NULL;
>  	vgpu->attached = false;
> 
Acked-by: Zhi Wang <zhi.a.wang@intel.com>

[PATCH v4 6/7] vfio: Remove dead code

[Jason Gunthorpe]

Now that callers have been updated to use the vfio_device APIs the driver
facing group interface is no longer used, delete it:

- vfio_group_get_external_user_from_dev()
- vfio_group_pin_pages()
- vfio_group_unpin_pages()
- vfio_group_iommu_domain()

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
--
FIXME: vfio_group_put_external_user() is removable too when combined with the KVM series
---
 drivers/vfio/vfio.c  | 151 -------------------------------------------
 include/linux/vfio.h |  11 ----
 2 files changed, 162 deletions(-)

diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
index 85e1304099b8a5..c651c4805acd59 100644
--- a/drivers/vfio/vfio.c
+++ b/drivers/vfio/vfio.c
@@ -1732,44 +1732,6 @@ struct vfio_group *vfio_group_get_external_user(struct file *filep)
 }
 EXPORT_SYMBOL_GPL(vfio_group_get_external_user);
 
-/*
- * External user API, exported by symbols to be linked dynamically.
- * The external user passes in a device pointer
- * to verify that:
- *	- A VFIO group is assiciated with the device;
- *	- IOMMU is set for the group.
- * If both checks passed, vfio_group_get_external_user_from_dev()
- * increments the container user counter to prevent the VFIO group
- * from disposal before external user exits and returns the pointer
- * to the VFIO group.
- *
- * When the external user finishes using the VFIO group, it calls
- * vfio_group_put_external_user() to release the VFIO group and
- * decrement the container user counter.
- *
- * @dev [in]	: device
- * Return error PTR or pointer to VFIO group.
- */
-
-struct vfio_group *vfio_group_get_external_user_from_dev(struct device *dev)
-{
-	struct vfio_group *group;
-	int ret;
-
-	group = vfio_group_get_from_dev(dev);
-	if (!group)
-		return ERR_PTR(-ENODEV);
-
-	ret = vfio_group_add_container_user(group);
-	if (ret) {
-		vfio_group_put(group);
-		return ERR_PTR(ret);
-	}
-
-	return group;
-}
-EXPORT_SYMBOL_GPL(vfio_group_get_external_user_from_dev);
-
 void vfio_group_put_external_user(struct vfio_group *group)
 {
 	vfio_group_try_dissolve_container(group);
@@ -2003,101 +1965,6 @@ int vfio_unpin_pages(struct vfio_device *device, unsigned long *user_pfn,
 }
 EXPORT_SYMBOL(vfio_unpin_pages);
 
-/*
- * Pin a set of guest IOVA PFNs and return their associated host PFNs for a
- * VFIO group.
- *
- * The caller needs to call vfio_group_get_external_user() or
- * vfio_group_get_external_user_from_dev() prior to calling this interface,
- * so as to prevent the VFIO group from disposal in the middle of the call.
- * But it can keep the reference to the VFIO group for several calls into
- * this interface.
- * After finishing using of the VFIO group, the caller needs to release the
- * VFIO group by calling vfio_group_put_external_user().
- *
- * @group [in]		: VFIO group
- * @user_iova_pfn [in]	: array of user/guest IOVA PFNs to be pinned.
- * @npage [in]		: count of elements in user_iova_pfn array.
- *			  This count should not be greater
- *			  VFIO_PIN_PAGES_MAX_ENTRIES.
- * @prot [in]		: protection flags
- * @phys_pfn [out]	: array of host PFNs
- * Return error or number of pages pinned.
- */
-int vfio_group_pin_pages(struct vfio_group *group,
-			 unsigned long *user_iova_pfn, int npage,
-			 int prot, unsigned long *phys_pfn)
-{
-	struct vfio_container *container;
-	struct vfio_iommu_driver *driver;
-	int ret;
-
-	if (!group || !user_iova_pfn || !phys_pfn || !npage)
-		return -EINVAL;
-
-	if (group->dev_counter > 1)
-		return -EINVAL;
-
-	if (npage > VFIO_PIN_PAGES_MAX_ENTRIES)
-		return -E2BIG;
-
-	container = group->container;
-	driver = container->iommu_driver;
-	if (likely(driver && driver->ops->pin_pages))
-		ret = driver->ops->pin_pages(container->iommu_data,
-					     group->iommu_group, user_iova_pfn,
-					     npage, prot, phys_pfn);
-	else
-		ret = -ENOTTY;
-
-	return ret;
-}
-EXPORT_SYMBOL(vfio_group_pin_pages);
-
-/*
- * Unpin a set of guest IOVA PFNs for a VFIO group.
- *
- * The caller needs to call vfio_group_get_external_user() or
- * vfio_group_get_external_user_from_dev() prior to calling this interface,
- * so as to prevent the VFIO group from disposal in the middle of the call.
- * But it can keep the reference to the VFIO group for several calls into
- * this interface.
- * After finishing using of the VFIO group, the caller needs to release the
- * VFIO group by calling vfio_group_put_external_user().
- *
- * @group [in]		: vfio group
- * @user_iova_pfn [in]	: array of user/guest IOVA PFNs to be unpinned.
- * @npage [in]		: count of elements in user_iova_pfn array.
- *			  This count should not be greater than
- *			  VFIO_PIN_PAGES_MAX_ENTRIES.
- * Return error or number of pages unpinned.
- */
-int vfio_group_unpin_pages(struct vfio_group *group,
-			   unsigned long *user_iova_pfn, int npage)
-{
-	struct vfio_container *container;
-	struct vfio_iommu_driver *driver;
-	int ret;
-
-	if (!group || !user_iova_pfn || !npage)
-		return -EINVAL;
-
-	if (npage > VFIO_PIN_PAGES_MAX_ENTRIES)
-		return -E2BIG;
-
-	container = group->container;
-	driver = container->iommu_driver;
-	if (likely(driver && driver->ops->unpin_pages))
-		ret = driver->ops->unpin_pages(container->iommu_data,
-					       user_iova_pfn, npage);
-	else
-		ret = -ENOTTY;
-
-	return ret;
-}
-EXPORT_SYMBOL(vfio_group_unpin_pages);
-
-
 /*
  * This interface allows the CPUs to perform some sort of virtual DMA on
  * behalf of the device.
@@ -2301,24 +2168,6 @@ int vfio_unregister_notifier(struct vfio_device *device,
 }
 EXPORT_SYMBOL(vfio_unregister_notifier);
 
-struct iommu_domain *vfio_group_iommu_domain(struct vfio_group *group)
-{
-	struct vfio_container *container;
-	struct vfio_iommu_driver *driver;
-
-	if (!group)
-		return ERR_PTR(-EINVAL);
-
-	container = group->container;
-	driver = container->iommu_driver;
-	if (likely(driver && driver->ops->group_iommu_domain))
-		return driver->ops->group_iommu_domain(container->iommu_data,
-						       group->iommu_group);
-
-	return ERR_PTR(-ENOTTY);
-}
-EXPORT_SYMBOL_GPL(vfio_group_iommu_domain);
-
 /*
  * Module/class support
  */
diff --git a/include/linux/vfio.h b/include/linux/vfio.h
index 8a151025871776..6195edd2edcd7b 100644
--- a/include/linux/vfio.h
+++ b/include/linux/vfio.h
@@ -140,8 +140,6 @@ int vfio_mig_get_next_state(struct vfio_device *device,
  */
 extern struct vfio_group *vfio_group_get_external_user(struct file *filep);
 extern void vfio_group_put_external_user(struct vfio_group *group);
-extern struct vfio_group *vfio_group_get_external_user_from_dev(struct device
-								*dev);
 extern bool vfio_external_group_match_file(struct vfio_group *group,
 					   struct file *filep);
 extern int vfio_external_user_iommu_id(struct vfio_group *group);
@@ -154,18 +152,9 @@ extern int vfio_pin_pages(struct vfio_device *device, unsigned long *user_pfn,
 			  int npage, int prot, unsigned long *phys_pfn);
 extern int vfio_unpin_pages(struct vfio_device *device, unsigned long *user_pfn,
 			    int npage);
-
-extern int vfio_group_pin_pages(struct vfio_group *group,
-				unsigned long *user_iova_pfn, int npage,
-				int prot, unsigned long *phys_pfn);
-extern int vfio_group_unpin_pages(struct vfio_group *group,
-				  unsigned long *user_iova_pfn, int npage);
-
 extern int vfio_dma_rw(struct vfio_device *device, dma_addr_t user_iova,
 		       void *data, size_t len, bool write);
 
-extern struct iommu_domain *vfio_group_iommu_domain(struct vfio_group *group);
-
 /* each type has independent events */
 enum vfio_notify_type {
 	VFIO_IOMMU_NOTIFY = 0,
-- 
2.36.0

[PATCH v4 7/7] vfio: Remove calls to vfio_group_add_container_user()

[Jason Gunthorpe]

When the open_device() op is called the container_users is incremented and
held incremented until close_device(). Thus, so long as drivers call
functions within their open_device()/close_device() region they do not
need to worry about the container_users.

These functions can all only be called between open_device() and
close_device():

  vfio_pin_pages()
  vfio_unpin_pages()
  vfio_dma_rw()
  vfio_register_notifier()
  vfio_unregister_notifier()

Eliminate the calls to vfio_group_add_container_user() and add
vfio_assert_device_open() to detect driver mis-use. This causes the
close_device() op to check device->open_count so always leave it elevated
while calling the op.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
---
 drivers/vfio/vfio.c | 80 ++++++++++-----------------------------------
 1 file changed, 17 insertions(+), 63 deletions(-)

diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
index c651c4805acd59..8bb38941c1dfd8 100644
--- a/drivers/vfio/vfio.c
+++ b/drivers/vfio/vfio.c
@@ -1115,6 +1115,12 @@ static int vfio_group_add_container_user(struct vfio_group *group)
 
 static const struct file_operations vfio_device_fops;
 
+/* true if the vfio_device has open_device() called but not close_device() */
+static bool vfio_assert_device_open(struct vfio_device *device)
+{
+	return !WARN_ON_ONCE(!READ_ONCE(device->open_count));
+}
+
 static int vfio_group_get_device_fd(struct vfio_group *group, char *buf)
 {
 	struct vfio_device *device;
@@ -1329,8 +1335,10 @@ static int vfio_device_fops_release(struct inode *inode, struct file *filep)
 	struct vfio_device *device = filep->private_data;
 
 	mutex_lock(&device->dev_set->lock);
-	if (!--device->open_count && device->ops->close_device)
+	vfio_assert_device_open(device);
+	if (device->open_count == 1 && device->ops->close_device)
 		device->ops->close_device(device);
+	device->open_count--;
 	mutex_unlock(&device->dev_set->lock);
 
 	module_put(device->dev->driver->owner);
@@ -1897,7 +1905,8 @@ int vfio_pin_pages(struct vfio_device *device, unsigned long *user_pfn,
 	struct vfio_iommu_driver *driver;
 	int ret;
 
-	if (!user_pfn || !phys_pfn || !npage)
+	if (!user_pfn || !phys_pfn || !npage ||
+	    !vfio_assert_device_open(device))
 		return -EINVAL;
 
 	if (npage > VFIO_PIN_PAGES_MAX_ENTRIES)
@@ -1906,10 +1915,6 @@ int vfio_pin_pages(struct vfio_device *device, unsigned long *user_pfn,
 	if (group->dev_counter > 1)
 		return -EINVAL;
 
-	ret = vfio_group_add_container_user(group);
-	if (ret)
-		return ret;
-
 	container = group->container;
 	driver = container->iommu_driver;
 	if (likely(driver && driver->ops->pin_pages))
@@ -1919,8 +1924,6 @@ int vfio_pin_pages(struct vfio_device *device, unsigned long *user_pfn,
 	else
 		ret = -ENOTTY;
 
-	vfio_group_try_dissolve_container(group);
-
 	return ret;
 }
 EXPORT_SYMBOL(vfio_pin_pages);
@@ -1941,16 +1944,12 @@ int vfio_unpin_pages(struct vfio_device *device, unsigned long *user_pfn,
 	struct vfio_iommu_driver *driver;
 	int ret;
 
-	if (!user_pfn || !npage)
+	if (!user_pfn || !npage || !vfio_assert_device_open(device))
 		return -EINVAL;
 
 	if (npage > VFIO_PIN_PAGES_MAX_ENTRIES)
 		return -E2BIG;
 
-	ret = vfio_group_add_container_user(device->group);
-	if (ret)
-		return ret;
-
 	container = device->group->container;
 	driver = container->iommu_driver;
 	if (likely(driver && driver->ops->unpin_pages))
@@ -1959,8 +1958,6 @@ int vfio_unpin_pages(struct vfio_device *device, unsigned long *user_pfn,
 	else
 		ret = -ENOTTY;
 
-	vfio_group_try_dissolve_container(device->group);
-
 	return ret;
 }
 EXPORT_SYMBOL(vfio_unpin_pages);
@@ -1989,13 +1986,9 @@ int vfio_dma_rw(struct vfio_device *device, dma_addr_t user_iova, void *data,
 	struct vfio_iommu_driver *driver;
 	int ret = 0;
 
-	if (!data || len <= 0)
+	if (!data || len <= 0 || !vfio_assert_device_open(device))
 		return -EINVAL;
 
-	ret = vfio_group_add_container_user(device->group);
-	if (ret)
-		return ret;
-
 	container = device->group->container;
 	driver = container->iommu_driver;
 
@@ -2004,9 +1997,6 @@ int vfio_dma_rw(struct vfio_device *device, dma_addr_t user_iova, void *data,
 					  user_iova, data, len, write);
 	else
 		ret = -ENOTTY;
-
-	vfio_group_try_dissolve_container(device->group);
-
 	return ret;
 }
 EXPORT_SYMBOL(vfio_dma_rw);
@@ -2019,10 +2009,6 @@ static int vfio_register_iommu_notifier(struct vfio_group *group,
 	struct vfio_iommu_driver *driver;
 	int ret;
 
-	ret = vfio_group_add_container_user(group);
-	if (ret)
-		return -EINVAL;
-
 	container = group->container;
 	driver = container->iommu_driver;
 	if (likely(driver && driver->ops->register_notifier))
@@ -2030,9 +2016,6 @@ static int vfio_register_iommu_notifier(struct vfio_group *group,
 						     events, nb);
 	else
 		ret = -ENOTTY;
-
-	vfio_group_try_dissolve_container(group);
-
 	return ret;
 }
 
@@ -2043,10 +2026,6 @@ static int vfio_unregister_iommu_notifier(struct vfio_group *group,
 	struct vfio_iommu_driver *driver;
 	int ret;
 
-	ret = vfio_group_add_container_user(group);
-	if (ret)
-		return -EINVAL;
-
 	container = group->container;
 	driver = container->iommu_driver;
 	if (likely(driver && driver->ops->unregister_notifier))
@@ -2054,9 +2033,6 @@ static int vfio_unregister_iommu_notifier(struct vfio_group *group,
 						       nb);
 	else
 		ret = -ENOTTY;
-
-	vfio_group_try_dissolve_container(group);
-
 	return ret;
 }
 
@@ -2085,10 +2061,6 @@ static int vfio_register_group_notifier(struct vfio_group *group,
 	if (*events)
 		return -EINVAL;
 
-	ret = vfio_group_add_container_user(group);
-	if (ret)
-		return -EINVAL;
-
 	ret = blocking_notifier_chain_register(&group->notifier, nb);
 
 	/*
@@ -2098,25 +2070,6 @@ static int vfio_register_group_notifier(struct vfio_group *group,
 	if (!ret && set_kvm && group->kvm)
 		blocking_notifier_call_chain(&group->notifier,
 					VFIO_GROUP_NOTIFY_SET_KVM, group->kvm);
-
-	vfio_group_try_dissolve_container(group);
-
-	return ret;
-}
-
-static int vfio_unregister_group_notifier(struct vfio_group *group,
-					 struct notifier_block *nb)
-{
-	int ret;
-
-	ret = vfio_group_add_container_user(group);
-	if (ret)
-		return -EINVAL;
-
-	ret = blocking_notifier_chain_unregister(&group->notifier, nb);
-
-	vfio_group_try_dissolve_container(group);
-
 	return ret;
 }
 
@@ -2127,7 +2080,8 @@ int vfio_register_notifier(struct vfio_device *device,
 	struct vfio_group *group = device->group;
 	int ret;
 
-	if (!nb || !events || (*events == 0))
+	if (!nb || !events || (*events == 0) ||
+	    !vfio_assert_device_open(device))
 		return -EINVAL;
 
 	switch (type) {
@@ -2151,7 +2105,7 @@ int vfio_unregister_notifier(struct vfio_device *device,
 	struct vfio_group *group = device->group;
 	int ret;
 
-	if (!nb)
+	if (!nb || !vfio_assert_device_open(device))
 		return -EINVAL;
 
 	switch (type) {
@@ -2159,7 +2113,7 @@ int vfio_unregister_notifier(struct vfio_device *device,
 		ret = vfio_unregister_iommu_notifier(group, nb);
 		break;
 	case VFIO_GROUP_NOTIFY:
-		ret = vfio_unregister_group_notifier(group, nb);
+		ret = blocking_notifier_chain_unregister(&group->notifier, nb);
 		break;
 	default:
 		ret = -EINVAL;
-- 
2.36.0

Re: [PATCH v4 0/7] Make the rest of the VFIO driver interface use vfio_device

[Alex Williamson]

On Thu,  5 May 2022 21:08:38 -0300
Jason Gunthorpe <jgg@nvidia.com> wrote:

> Prior series have transformed other parts of VFIO from working on struct
> device or struct vfio_group into working directly on struct
> vfio_device. Based on that work we now have vfio_device's readily
> available in all the drivers.
> 
> Update the rest of the driver facing API to use vfio_device as an input.
> 
> The following are switched from struct device to struct vfio_device:
>   vfio_register_notifier()
>   vfio_unregister_notifier()
>   vfio_pin_pages()
>   vfio_unpin_pages()
>   vfio_dma_rw()
> 
> The following group APIs are obsoleted and removed by just using struct
> vfio_device with the above:
>   vfio_group_pin_pages()
>   vfio_group_unpin_pages()
>   vfio_group_iommu_domain()
>   vfio_group_get_external_user_from_dev()
> 
> To retain the performance of the new device APIs relative to their group
> versions optimize how vfio_group_add_container_user() is used to avoid
> calling it when the driver must already guarantee the device is open and
> the container_users incrd.
> 
> The remaining exported VFIO group interfaces are only used by kvm, and are
> addressed by a parallel series.
> 
> This series is based on Christoph's gvt rework here:
> 
>  https://lore.kernel.org/all/5a8b9f48-2c32-8177-1c18-e3bd7bfde558@intel.com/
> 
> and so will need the PR merged first.
> 
> I have a followup series that needs this.
> 
> This is also part of the iommufd work - moving the driver facing interface
> to vfio_device provides a much cleaner path to integrate with iommufd.
> 
> v4:
>  - Use 'device' as the argument name for a struct vfio_device in vfio.c
> v3: https://lore.kernel.org/r/0-v3-e131a9b6b467+14b6-vfio_mdev_no_group_jgg@nvidia.com
>  - Based on VFIO's gvt/iommu merge
>  - Remove mention of mdev_legacy_get_vfio_device() from commit message
>  - Clarify commit message for vfio_dma_rw() conversion
>  - Talk about the open_count change in the commit message
>  - No code change
> v2: https://lore.kernel.org/r/0-v2-6011bde8e0a1+5f-vfio_mdev_no_group_jgg@nvidia.com
>  - Based on Christoph's series so mdev_legacy_get_vfio_device() is removed
>  - Reflow indenting
>  - Use vfio_assert_device_open() and WARN_ON_ONCE instead of open coding
>    the assertion
> v1: https://lore.kernel.org/r/0-v1-a8faf768d202+125dd-vfio_mdev_no_group_jgg@nvidia.com
> 
> Jason Gunthorpe (7):
>   vfio: Make vfio_(un)register_notifier accept a vfio_device
>   vfio/ccw: Remove mdev from struct channel_program
>   vfio/mdev: Pass in a struct vfio_device * to vfio_pin/unpin_pages()
>   vfio/mdev: Pass in a struct vfio_device * to vfio_dma_rw()
>   drm/i915/gvt: Change from vfio_group_(un)pin_pages to
>     vfio_(un)pin_pages
>   vfio: Remove dead code
>   vfio: Remove calls to vfio_group_add_container_user()
> 
>  .../driver-api/vfio-mediated-device.rst       |   4 +-
>  drivers/gpu/drm/i915/gvt/gvt.h                |   5 +-
>  drivers/gpu/drm/i915/gvt/kvmgt.c              |  51 ++-
>  drivers/s390/cio/vfio_ccw_cp.c                |  47 +--
>  drivers/s390/cio/vfio_ccw_cp.h                |   4 +-
>  drivers/s390/cio/vfio_ccw_fsm.c               |   3 +-
>  drivers/s390/cio/vfio_ccw_ops.c               |   7 +-
>  drivers/s390/crypto/vfio_ap_ops.c             |  23 +-
>  drivers/vfio/vfio.c                           | 299 +++---------------
>  include/linux/vfio.h                          |  21 +-
>  10 files changed, 109 insertions(+), 355 deletions(-)

Applied to vfio next branch for v5.19.  Thanks,

Alex