drm/i915/gvt: Dmabuf support for GVT-g

This patch introduces a guest's framebuffer sharing mechanism based on
dma-buf subsystem. With this sharing mechanism, guest's framebuffer can
be shared between guest VM and host.

v17:
- modify VFIO_DEVICE_GET_GFX_DMABUF interface. (Alex)

v16:
- add x_hot and y_hot. (Gerd)
- add flag validation for VFIO_DEVICE_GET_GFX_DMABUF. (Alex)
- rebase 4.14.0-rc6.

v15:
- add VFIO_DEVICE_GET_GFX_DMABUF ABI. (Gerd)
- add intel_vgpu_dmabuf_cleanup() to clean up the vGPU's dmabuf. (Gerd)

v14:
- add PROBE, DMABUF and REGION flags. (Alex)

v12:
- refine the lifecycle of dmabuf.

v9:
- remove dma-buf management. (Alex)
- track the dma-buf create and release in kernel mode. (Gerd) (Daniel)

v8:
- refine the dma-buf ioctl definition.(Alex)
- add a lock to protect the dmabuf list. (Alex)

v7:
- release dma-buf related allocations in dma-buf's associated release
  function. (Alex)
- refine ioctl interface for querying plane info or create dma-buf.
  (Alex)

v6:
- align the dma-buf life cycle with the vfio device. (Alex)
- add the dma-buf related operations in a separate patch. (Gerd)
- i915 related changes. (Chris)

v5:
- fix bug while checking whether the gem obj is gvt's dma-buf when user
  change caching mode or domains. Add a helper function to do it.
  (Xiaoguang)
- add definition for the query plane and create dma-buf. (Xiaoguang)

v4:
- fix bug while checking whether the gem obj is gvt's dma-buf when set
  caching mode or doamins. (Xiaoguang)

v3:
- declare a new flag I915_GEM_OBJECT_IS_GVT_DMABUF in drm_i915_gem_object
  to represent the gem obj for gvt's dma-buf. The tiling mode, caching
  mode and domains can not be changed for this kind of gem object. (Alex)
- change dma-buf related information to be more generic. So other vendor
  can use the same interface. (Alex)

v2:
- create a management fd for dma-buf operations. (Alex)
- alloc gem object's backing storage in gem obj's get_pages() callback.
  (Chris)

Signed-off-by: Tina Zhang <tina.zhang@intel.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>

drivers/gpu/drm/i915/gvt/Makefile

@@ -2,7 +2,7 @@ GVT_DIR := gvt
 GVT_SOURCE := gvt.o aperture_gm.o handlers.o vgpu.o trace_points.o firmware.o \
 	interrupt.o gtt.o cfg_space.o opregion.o mmio.o display.o edid.o \
 	execlist.o scheduler.o sched_policy.o render.o cmd_parser.o debugfs.o \
-	fb_decoder.o
+	fb_decoder.o dmabuf.o
 
 ccflags-y				+= -I$(src) -I$(src)/$(GVT_DIR)
 i915-y					+= $(addprefix $(GVT_DIR)/, $(GVT_SOURCE))

drivers/gpu/drm/i915/gvt/dmabuf.h

@@ -0,0 +1,67 @@
+/*
+ * Copyright(c) 2017 Intel Corporation. All rights reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ * Authors:
+ *    Zhiyuan Lv <zhiyuan.lv@intel.com>
+ *
+ * Contributors:
+ *    Xiaoguang Chen
+ *    Tina Zhang <tina.zhang@intel.com>
+ */
+
+#ifndef _GVT_DMABUF_H_
+#define _GVT_DMABUF_H_
+#include <linux/vfio.h>
+
+struct intel_vgpu_fb_info {
+	__u64 start;
+	__u64 start_gpa;
+	__u64 drm_format_mod;
+	__u32 drm_format;	/* drm format of plane */
+	__u32 width;	/* width of plane */
+	__u32 height;	/* height of plane */
+	__u32 stride;	/* stride of plane */
+	__u32 size;	/* size of plane in bytes, align on page */
+	__u32 x_pos;	/* horizontal position of cursor plane */
+	__u32 y_pos;	/* vertical position of cursor plane */
+	__u32 x_hot;    /* horizontal position of cursor hotspot */
+	__u32 y_hot;    /* vertical position of cursor hotspot */
+	struct intel_vgpu_dmabuf_obj *obj;
+};
+
+/**
+ * struct intel_vgpu_dmabuf_obj- Intel vGPU device buffer object
+ */
+struct intel_vgpu_dmabuf_obj {
+	struct intel_vgpu *vgpu;
+	struct intel_vgpu_fb_info *info;
+	__u32 dmabuf_id;
+	struct kref kref;
+	bool initref;
+	struct list_head list;
+};
+
+int intel_vgpu_query_plane(struct intel_vgpu *vgpu, void *args);
+int intel_vgpu_get_dmabuf(struct intel_vgpu *vgpu, unsigned int dmabuf_id);
+void intel_vgpu_dmabuf_cleanup(struct intel_vgpu *vgpu);
+
+#endif

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

@@ -181,6 +181,8 @@ static const struct intel_gvt_ops intel_gvt_ops = {
 	.vgpu_deactivate = intel_gvt_deactivate_vgpu,
 	.gvt_find_vgpu_type = intel_gvt_find_vgpu_type,
 	.get_gvt_attrs = intel_get_gvt_attrs,
+	.vgpu_query_plane = intel_vgpu_query_plane,
+	.vgpu_get_dmabuf = intel_vgpu_get_dmabuf,
 };
 
 /**

drivers/gpu/drm/i915/gvt/gvt.h

@@ -47,6 +47,7 @@
 #include "render.h"
 #include "cmd_parser.h"
 #include "fb_decoder.h"
+#include "dmabuf.h"
 
 #define GVT_MAX_VGPU 8
 
@@ -209,8 +210,16 @@ struct intel_vgpu {
 		struct kvm *kvm;
 		struct work_struct release_work;
 		atomic_t released;
+		struct vfio_device *vfio_device;
 	} vdev;
 #endif
+
+	struct list_head dmabuf_obj_list_head;
+	struct mutex dmabuf_lock;
+	struct idr object_idr;
+
+	struct completion vblank_done;
+
 };
 
 /* validating GM healthy status*/
@@ -536,6 +545,8 @@ struct intel_gvt_ops {
 			const char *name);
 	bool (*get_gvt_attrs)(struct attribute ***type_attrs,
 			struct attribute_group ***intel_vgpu_type_groups);
+	int (*vgpu_query_plane)(struct intel_vgpu *vgpu, void *);
+	int (*vgpu_get_dmabuf)(struct intel_vgpu *vgpu, unsigned int);
 };
 
 

drivers/gpu/drm/i915/gvt/hypercall.h

@@ -56,6 +56,8 @@ struct intel_gvt_mpt {
 	int (*set_trap_area)(unsigned long handle, u64 start, u64 end,
 			     bool map);
 	int (*set_opregion)(void *vgpu);
+	int (*get_vfio_device)(void *vgpu);
+	void (*put_vfio_device)(void *vgpu);
 };
 
 extern struct intel_gvt_mpt xengt_mpt;

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

@@ -377,10 +377,23 @@ static int intel_vgpu_register_reg(struct intel_vgpu *vgpu,
 	vgpu->vdev.region[vgpu->vdev.num_regions].flags = flags;
 	vgpu->vdev.region[vgpu->vdev.num_regions].data = data;
 	vgpu->vdev.num_regions++;
-
 	return 0;
 }
 
+static int kvmgt_get_vfio_device(void *p_vgpu)
+{
+	struct intel_vgpu *vgpu = (struct intel_vgpu *)p_vgpu;
+
+	vgpu->vdev.vfio_device = vfio_device_get_from_dev(
+		mdev_dev(vgpu->vdev.mdev));
+	if (!vgpu->vdev.vfio_device) {
+		gvt_vgpu_err("failed to get vfio device\n");
+		return -ENODEV;
+	}
+	return 0;
+}
+
+
 static int kvmgt_set_opregion(void *p_vgpu)
 {
 	struct intel_vgpu *vgpu = (struct intel_vgpu *)p_vgpu;
@@ -409,6 +422,14 @@ static int kvmgt_set_opregion(void *p_vgpu)
 	return ret;
 }
 
+static void kvmgt_put_vfio_device(void *vgpu)
+{
+	if (WARN_ON(!((struct intel_vgpu *)vgpu)->vdev.vfio_device))
+		return;
+
+	vfio_device_put(((struct intel_vgpu *)vgpu)->vdev.vfio_device);
+}
+
 static int intel_vgpu_create(struct kobject *kobj, struct mdev_device *mdev)
 {
 	struct intel_vgpu *vgpu = NULL;
@@ -1146,6 +1167,33 @@ static long intel_vgpu_ioctl(struct mdev_device *mdev, unsigned int cmd,
 	} else if (cmd == VFIO_DEVICE_RESET) {
 		intel_gvt_ops->vgpu_reset(vgpu);
 		return 0;
+	} else if (cmd == VFIO_DEVICE_QUERY_GFX_PLANE) {
+		struct vfio_device_gfx_plane_info dmabuf;
+		int ret = 0;
+
+		minsz = offsetofend(struct vfio_device_gfx_plane_info,
+				    dmabuf_id);
+		if (copy_from_user(&dmabuf, (void __user *)arg, minsz))
+			return -EFAULT;
+		if (dmabuf.argsz < minsz)
+			return -EINVAL;
+
+		ret = intel_gvt_ops->vgpu_query_plane(vgpu, &dmabuf);
+		if (ret != 0)
+			return ret;
+
+		return copy_to_user((void __user *)arg, &dmabuf, minsz) ?
+								-EFAULT : 0;
+	} else if (cmd == VFIO_DEVICE_GET_GFX_DMABUF) {
+		__u32 dmabuf_id;
+		__s32 dmabuf_fd;
+
+		if (get_user(dmabuf_id, (__u32 __user *)arg))
+			return -EFAULT;
+
+		dmabuf_fd = intel_gvt_ops->vgpu_get_dmabuf(vgpu, dmabuf_id);
+		return dmabuf_fd;
+
 	}
 
 	return 0;
@@ -1387,6 +1435,9 @@ static int kvmgt_guest_init(struct mdev_device *mdev)
 	kvmgt_protect_table_init(info);
 	gvt_cache_init(vgpu);
 
+	mutex_init(&vgpu->dmabuf_lock);
+	init_completion(&vgpu->vblank_done);
+
 	info->track_node.track_write = kvmgt_page_track_write;
 	info->track_node.track_flush_slot = kvmgt_page_track_flush_slot;
 	kvm_page_track_register_notifier(kvm, &info->track_node);
@@ -1528,6 +1579,8 @@ struct intel_gvt_mpt kvmgt_mpt = {
 	.write_gpa = kvmgt_write_gpa,
 	.gfn_to_mfn = kvmgt_gfn_to_pfn,
 	.set_opregion = kvmgt_set_opregion,
+	.get_vfio_device = kvmgt_get_vfio_device,
+	.put_vfio_device = kvmgt_put_vfio_device,
 };
 EXPORT_SYMBOL_GPL(kvmgt_mpt);
 

drivers/gpu/drm/i915/gvt/mpt.h

@@ -309,4 +309,34 @@ static inline int intel_gvt_hypervisor_set_opregion(struct intel_vgpu *vgpu)
 	return intel_gvt_host.mpt->set_opregion(vgpu);
 }
 
+/**
+ * intel_gvt_hypervisor_get_vfio_device - increase vfio device ref count
+ * @vgpu: a vGPU
+ *
+ * Returns:
+ * Zero on success, negative error code if failed.
+ */
+static inline int intel_gvt_hypervisor_get_vfio_device(struct intel_vgpu *vgpu)
+{
+	if (!intel_gvt_host.mpt->get_vfio_device)
+		return 0;
+
+	return intel_gvt_host.mpt->get_vfio_device(vgpu);
+}
+
+/**
+ * intel_gvt_hypervisor_put_vfio_device - decrease vfio device ref count
+ * @vgpu: a vGPU
+ *
+ * Returns:
+ * Zero on success, negative error code if failed.
+ */
+static inline void intel_gvt_hypervisor_put_vfio_device(struct intel_vgpu *vgpu)
+{
+	if (!intel_gvt_host.mpt->put_vfio_device)
+		return;
+
+	intel_gvt_host.mpt->put_vfio_device(vgpu);
+}
+
 #endif /* _GVT_MPT_H_ */

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

@@ -236,6 +236,7 @@ void intel_gvt_deactivate_vgpu(struct intel_vgpu *vgpu)
 	}
 
 	intel_vgpu_stop_schedule(vgpu);
+	intel_vgpu_dmabuf_cleanup(vgpu);
 
 	mutex_unlock(&gvt->lock);
 }
@@ -265,6 +266,7 @@ void intel_gvt_destroy_vgpu(struct intel_vgpu *vgpu)
 	intel_gvt_hypervisor_detach_vgpu(vgpu);
 	intel_vgpu_free_resource(vgpu);
 	intel_vgpu_clean_mmio(vgpu);
+	intel_vgpu_dmabuf_cleanup(vgpu);
 	vfree(vgpu);
 
 	intel_gvt_update_vgpu_types(gvt);
@@ -349,7 +351,8 @@ static struct intel_vgpu *__intel_gvt_create_vgpu(struct intel_gvt *gvt,
 	vgpu->handle = param->handle;
 	vgpu->gvt = gvt;
 	vgpu->sched_ctl.weight = param->weight;
-
+	INIT_LIST_HEAD(&vgpu->dmabuf_obj_list_head);
+	idr_init(&vgpu->object_idr);
 	intel_vgpu_init_cfg_space(vgpu, param->primary);
 
 	ret = intel_vgpu_init_mmio(vgpu);

drivers/gpu/drm/i915/i915_gem_object.h

@@ -261,6 +261,8 @@ struct drm_i915_gem_object {
 		} userptr;
 
 		unsigned long scratch;
+
+		void *gvt_info;
 	};
 
 	/** for phys allocated objects */