Merge tag 'gvt-fixes-2020-04-14' of https://github.com/intel/gvt-linux into drm-intel-fixes

gvt-fixes-2020-04-14

- Fix guest page access by using VFIO dma r/w interface (Yan)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
From: Zhenyu Wang <zhenyuw@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200414083626.GQ11247@zhen-hp.sh.intel.com

drivers/gpu/drm/i915/gvt/kvmgt.c

@@ -131,6 +131,7 @@ struct kvmgt_vdev {
 	struct work_struct release_work;
 	atomic_t released;
 	struct vfio_device *vfio_device;
+	struct vfio_group *vfio_group;
 };
 
 static inline struct kvmgt_vdev *kvmgt_vdev(struct intel_vgpu *vgpu)
@@ -151,6 +152,7 @@ static void gvt_unpin_guest_page(struct intel_vgpu *vgpu, unsigned long gfn,
 		unsigned long size)
 {
 	struct drm_i915_private *i915 = vgpu->gvt->gt->i915;
+	struct kvmgt_vdev *vdev = kvmgt_vdev(vgpu);
 	int total_pages;
 	int npage;
 	int ret;
@@ -160,7 +162,7 @@ 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_unpin_pages(mdev_dev(kvmgt_vdev(vgpu)->mdev), &cur_gfn, 1);
+		ret = vfio_group_unpin_pages(vdev->vfio_group, &cur_gfn, 1);
 		drm_WARN_ON(&i915->drm, ret != 1);
 	}
 }
@@ -169,6 +171,7 @@ static void gvt_unpin_guest_page(struct intel_vgpu *vgpu, unsigned long gfn,
 static int gvt_pin_guest_page(struct intel_vgpu *vgpu, unsigned long gfn,
 		unsigned long size, struct page **page)
 {
+	struct kvmgt_vdev *vdev = kvmgt_vdev(vgpu);
 	unsigned long base_pfn = 0;
 	int total_pages;
 	int npage;
@@ -183,7 +186,7 @@ static int gvt_pin_guest_page(struct intel_vgpu *vgpu, unsigned long gfn,
 		unsigned long cur_gfn = gfn + npage;
 		unsigned long pfn;
 
-		ret = vfio_pin_pages(mdev_dev(kvmgt_vdev(vgpu)->mdev), &cur_gfn, 1,
+		ret = vfio_group_pin_pages(vdev->vfio_group, &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",
@@ -792,6 +795,7 @@ static int intel_vgpu_open(struct mdev_device *mdev)
 	struct kvmgt_vdev *vdev = kvmgt_vdev(vgpu);
 	unsigned long events;
 	int ret;
+	struct vfio_group *vfio_group;
 
 	vdev->iommu_notifier.notifier_call = intel_vgpu_iommu_notifier;
 	vdev->group_notifier.notifier_call = intel_vgpu_group_notifier;
@@ -814,6 +818,14 @@ static int intel_vgpu_open(struct mdev_device *mdev)
 		goto undo_iommu;
 	}
 
+	vfio_group = vfio_group_get_external_user_from_dev(mdev_dev(mdev));
+	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;
+	}
+	vdev->vfio_group = vfio_group;
+
 	/* Take a module reference as mdev core doesn't take
 	 * a reference for vendor driver.
 	 */
@@ -830,6 +842,10 @@ static int intel_vgpu_open(struct mdev_device *mdev)
 	return ret;
 
 undo_group:
+	vfio_group_put_external_user(vdev->vfio_group);
+	vdev->vfio_group = NULL;
+
+undo_register:
 	vfio_unregister_notifier(mdev_dev(mdev), VFIO_GROUP_NOTIFY,
 					&vdev->group_notifier);
 
@@ -884,6 +900,7 @@ static void __intel_vgpu_release(struct intel_vgpu *vgpu)
 	kvmgt_guest_exit(info);
 
 	intel_vgpu_release_msi_eventfd_ctx(vgpu);
+	vfio_group_put_external_user(vdev->vfio_group);
 
 	vdev->kvm = NULL;
 	vgpu->handle = 0;
@@ -2035,33 +2052,14 @@ static int kvmgt_rw_gpa(unsigned long handle, unsigned long gpa,
 			void *buf, unsigned long len, bool write)
 {
 	struct kvmgt_guest_info *info;
-	struct kvm *kvm;
-	int idx, ret;
-	bool kthread = current->mm == NULL;
 
 	if (!handle_valid(handle))
 		return -ESRCH;
 
 	info = (struct kvmgt_guest_info *)handle;
-	kvm = info->kvm;
-
-	if (kthread) {
-		if (!mmget_not_zero(kvm->mm))
-			return -EFAULT;
-		use_mm(kvm->mm);
-	}
-
-	idx = srcu_read_lock(&kvm->srcu);
-	ret = write ? kvm_write_guest(kvm, gpa, buf, len) :
-		      kvm_read_guest(kvm, gpa, buf, len);
-	srcu_read_unlock(&kvm->srcu, idx);
-
-	if (kthread) {
-		unuse_mm(kvm->mm);
-		mmput(kvm->mm);
-	}
 
-	return ret;
+	return vfio_dma_rw(kvmgt_vdev(info->vgpu)->vfio_group,
+			   gpa, buf, len, write);
 }
 
 static int kvmgt_read_gpa(unsigned long handle, unsigned long gpa,