drm/hyperv: Add DRM driver for hyperv synthetic video device

DRM driver for hyperv synthetic video device, based on hyperv_fb
framebuffer driver. Also added config option "DRM_HYPERV" to enabled
this driver.

v2:
- Add support for gen2 VM
- Fixed review comments

v3:
- Split into multiple files as suggested by Thomas Zimmermann
- Fixed hibernation issue as suggested by Dexuan Cui
- Use ioremap_cache as suggested by Dexuan Cui
- Incorporated other review comments

v4:
- Fix bitrotted code
- Review comments
- Updated the copyright and license to match hyperv_fb

v5:
- Address review comments and rebased with drm-misc-next

v6:
- Minor code/comment improvement as suggested by Dexuan Cui
Signed-off-by: Deepak Rawat <drawat.floss@gmail.com>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20210527112230.1274-1-drawat.floss@gmail.com

drivers/gpu/drm/Kconfig

@@ -379,6 +379,19 @@ source "drivers/gpu/drm/xlnx/Kconfig"
 
 source "drivers/gpu/drm/gud/Kconfig"
 
+config DRM_HYPERV
+	tristate "DRM Support for Hyper-V synthetic video device"
+	depends on DRM && PCI && MMU && HYPERV
+	select DRM_KMS_HELPER
+	select DRM_GEM_SHMEM_HELPER
+	help
+	 This is a KMS driver for Hyper-V synthetic video device. Choose this
+	 option if you would like to enable drm driver for Hyper-V virtual
+	 machine. Unselect Hyper-V framebuffer driver (CONFIG_FB_HYPERV) so
+	 that DRM driver is used by default.
+
+	 If M is selected the module will be called hyperv_drm.
+
 # Keep legacy drivers last
 
 menuconfig DRM_LEGACY

drivers/gpu/drm/Makefile

@@ -126,3 +126,4 @@ obj-$(CONFIG_DRM_MCDE) += mcde/
 obj-$(CONFIG_DRM_TIDSS) += tidss/
 obj-y			+= xlnx/
 obj-y			+= gud/
+obj-$(CONFIG_DRM_HYPERV) += hyperv/

drivers/gpu/drm/hyperv/Makefile

+# SPDX-License-Identifier: GPL-2.0-only
+
+hyperv_drm-y := \
+	hyperv_drm_drv.o \
+	hyperv_drm_modeset.o \
+	hyperv_drm_proto.o
+
+obj-$(CONFIG_DRM_HYPERV) += hyperv_drm.o

drivers/gpu/drm/hyperv/hyperv_drm.h

+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright 2021 Microsoft
+ */
+
+#ifndef _HYPERV_DRM_H_
+#define _HYPERV_DRM_H_
+
+#define VMBUS_MAX_PACKET_SIZE 0x4000
+
+struct hyperv_drm_device {
+	/* drm */
+	struct drm_device dev;
+	struct drm_simple_display_pipe pipe;
+	struct drm_connector connector;
+
+	/* mode */
+	u32 screen_width_max;
+	u32 screen_height_max;
+	u32 preferred_width;
+	u32 preferred_height;
+	u32 screen_depth;
+
+	/* hw */
+	struct resource *mem;
+	void __iomem *vram;
+	unsigned long fb_base;
+	unsigned long fb_size;
+	struct completion wait;
+	u32 synthvid_version;
+	u32 mmio_megabytes;
+
+	u8 init_buf[VMBUS_MAX_PACKET_SIZE];
+	u8 recv_buf[VMBUS_MAX_PACKET_SIZE];
+
+	struct hv_device *hdev;
+};
+
+#define to_hv(_dev) container_of(_dev, struct hyperv_drm_device, dev)
+
+/* hyperv_drm_modeset */
+int hyperv_mode_config_init(struct hyperv_drm_device *hv);
+
+/* hyperv_drm_proto */
+int hyperv_update_vram_location(struct hv_device *hdev, phys_addr_t vram_pp);
+int hyperv_update_situation(struct hv_device *hdev, u8 active, u32 bpp,
+			    u32 w, u32 h, u32 pitch);
+int hyperv_update_dirt(struct hv_device *hdev, struct drm_rect *rect);
+int hyperv_connect_vsp(struct hv_device *hdev);
+
+#endif

drivers/gpu/drm/hyperv/hyperv_drm_drv.c

+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright 2021 Microsoft
+ */
+
+#include <linux/efi.h>
+#include <linux/hyperv.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+
+#include <drm/drm_aperture.h>
+#include <drm/drm_atomic_helper.h>
+#include <drm/drm_drv.h>
+#include <drm/drm_fb_helper.h>
+#include <drm/drm_gem_shmem_helper.h>
+#include <drm/drm_simple_kms_helper.h>
+
+#include "hyperv_drm.h"
+
+#define DRIVER_NAME "hyperv_drm"
+#define DRIVER_DESC "DRM driver for Hyper-V synthetic video device"
+#define DRIVER_DATE "2020"
+#define DRIVER_MAJOR 1
+#define DRIVER_MINOR 0
+
+#define PCI_VENDOR_ID_MICROSOFT 0x1414
+#define PCI_DEVICE_ID_HYPERV_VIDEO 0x5353
+
+DEFINE_DRM_GEM_FOPS(hv_fops);
+
+static struct drm_driver hyperv_driver = {
+	.driver_features = DRIVER_MODESET | DRIVER_GEM | DRIVER_ATOMIC,
+
+	.name		 = DRIVER_NAME,
+	.desc		 = DRIVER_DESC,
+	.date		 = DRIVER_DATE,
+	.major		 = DRIVER_MAJOR,
+	.minor		 = DRIVER_MINOR,
+
+	.fops		 = &hv_fops,
+	DRM_GEM_SHMEM_DRIVER_OPS,
+};
+
+static int hyperv_pci_probe(struct pci_dev *pdev,
+			    const struct pci_device_id *ent)
+{
+	return 0;
+}
+
+static void hyperv_pci_remove(struct pci_dev *pdev)
+{
+}
+
+static const struct pci_device_id hyperv_pci_tbl[] = {
+	{
+		.vendor = PCI_VENDOR_ID_MICROSOFT,
+		.device = PCI_DEVICE_ID_HYPERV_VIDEO,
+	},
+	{ /* end of list */ }
+};
+
+/*
+ * PCI stub to support gen1 VM.
+ */
+static struct pci_driver hyperv_pci_driver = {
+	.name =		KBUILD_MODNAME,
+	.id_table =	hyperv_pci_tbl,
+	.probe =	hyperv_pci_probe,
+	.remove =	hyperv_pci_remove,
+};
+
+static int hyperv_setup_gen1(struct hyperv_drm_device *hv)
+{
+	struct drm_device *dev = &hv->dev;
+	struct pci_dev *pdev;
+	int ret;
+
+	pdev = pci_get_device(PCI_VENDOR_ID_MICROSOFT,
+			      PCI_DEVICE_ID_HYPERV_VIDEO, NULL);
+	if (!pdev) {
+		drm_err(dev, "Unable to find PCI Hyper-V video\n");
+		return -ENODEV;
+	}
+
+	ret = drm_aperture_remove_conflicting_pci_framebuffers(pdev, "hypervdrmfb");
+	if (ret) {
+		drm_err(dev, "Not able to remove boot fb\n");
+		return ret;
+	}
+
+	if (pci_request_region(pdev, 0, DRIVER_NAME) != 0)
+		drm_warn(dev, "Cannot request framebuffer, boot fb still active?\n");
+
+	if ((pdev->resource[0].flags & IORESOURCE_MEM) == 0) {
+		drm_err(dev, "Resource at bar 0 is not IORESOURCE_MEM\n");
+		ret = -ENODEV;
+		goto error;
+	}
+
+	hv->fb_base = pci_resource_start(pdev, 0);
+	hv->fb_size = pci_resource_len(pdev, 0);
+	if (!hv->fb_base) {
+		drm_err(dev, "Resource not available\n");
+		ret = -ENODEV;
+		goto error;
+	}
+
+	hv->fb_size = min(hv->fb_size,
+			  (unsigned long)(hv->mmio_megabytes * 1024 * 1024));
+	hv->vram = devm_ioremap(&pdev->dev, hv->fb_base, hv->fb_size);
+	if (!hv->vram) {
+		drm_err(dev, "Failed to map vram\n");
+		ret = -ENOMEM;
+	}
+
+error:
+	pci_dev_put(pdev);
+	return ret;
+}
+
+static int hyperv_setup_gen2(struct hyperv_drm_device *hv,
+			     struct hv_device *hdev)
+{
+	struct drm_device *dev = &hv->dev;
+	int ret;
+
+	drm_aperture_remove_conflicting_framebuffers(screen_info.lfb_base,
+						     screen_info.lfb_size,
+						     false,
+						     "hypervdrmfb");
+
+	hv->fb_size = (unsigned long)hv->mmio_megabytes * 1024 * 1024;
+
+	ret = vmbus_allocate_mmio(&hv->mem, hdev, 0, -1, hv->fb_size, 0x100000,
+				  true);
+	if (ret) {
+		drm_err(dev, "Failed to allocate mmio\n");
+		return -ENOMEM;
+	}
+
+	/*
+	 * Map the VRAM cacheable for performance. This is also required for VM
+	 * connect to display properly for ARM64 Linux VM, as the host also maps
+	 * the VRAM cacheable.
+	 */
+	hv->vram = ioremap_cache(hv->mem->start, hv->fb_size);
+	if (!hv->vram) {
+		drm_err(dev, "Failed to map vram\n");
+		ret = -ENOMEM;
+		goto error;
+	}
+
+	hv->fb_base = hv->mem->start;
+	return 0;
+
+error:
+	vmbus_free_mmio(hv->mem->start, hv->fb_size);
+	return ret;
+}
+
+static int hyperv_vmbus_probe(struct hv_device *hdev,
+			      const struct hv_vmbus_device_id *dev_id)
+{
+	struct hyperv_drm_device *hv;
+	struct drm_device *dev;
+	int ret;
+
+	hv = devm_drm_dev_alloc(&hdev->device, &hyperv_driver,
+				struct hyperv_drm_device, dev);
+	if (IS_ERR(hv))
+		return PTR_ERR(hv);
+
+	dev = &hv->dev;
+	init_completion(&hv->wait);
+	hv_set_drvdata(hdev, hv);
+	hv->hdev = hdev;
+
+	ret = hyperv_connect_vsp(hdev);
+	if (ret) {
+		drm_err(dev, "Failed to connect to vmbus.\n");
+		goto err_hv_set_drv_data;
+	}
+
+	if (efi_enabled(EFI_BOOT))
+		ret = hyperv_setup_gen2(hv, hdev);
+	else
+		ret = hyperv_setup_gen1(hv);
+
+	if (ret)
+		goto err_vmbus_close;
+
+	/*
+	 * Should be done only once during init and resume. Failing to update
+	 * vram location is not fatal. Device will update dirty area till
+	 * preferred resolution only.
+	 */
+	ret = hyperv_update_vram_location(hdev, hv->fb_base);
+	if (ret)
+		drm_warn(dev, "Failed to update vram location.\n");
+
+	ret = hyperv_mode_config_init(hv);
+	if (ret)
+		goto err_vmbus_close;
+
+	ret = drm_dev_register(dev, 0);
+	if (ret) {
+		drm_err(dev, "Failed to register drm driver.\n");
+		goto err_vmbus_close;
+	}
+
+	drm_fbdev_generic_setup(dev, 0);
+
+	return 0;
+
+err_vmbus_close:
+	vmbus_close(hdev->channel);
+err_hv_set_drv_data:
+	hv_set_drvdata(hdev, NULL);
+	return ret;
+}
+
+static int hyperv_vmbus_remove(struct hv_device *hdev)
+{
+	struct drm_device *dev = hv_get_drvdata(hdev);
+	struct hyperv_drm_device *hv = to_hv(dev);
+
+	drm_dev_unplug(dev);
+	drm_atomic_helper_shutdown(dev);
+	vmbus_close(hdev->channel);
+	hv_set_drvdata(hdev, NULL);
+	vmbus_free_mmio(hv->mem->start, hv->fb_size);
+
+	return 0;
+}
+
+static int hyperv_vmbus_suspend(struct hv_device *hdev)
+{
+	struct drm_device *dev = hv_get_drvdata(hdev);
+	int ret;
+
+	ret = drm_mode_config_helper_suspend(dev);
+	if (ret)
+		return ret;
+
+	vmbus_close(hdev->channel);
+
+	return 0;
+}
+
+static int hyperv_vmbus_resume(struct hv_device *hdev)
+{
+	struct drm_device *dev = hv_get_drvdata(hdev);
+	struct hyperv_drm_device *hv = to_hv(dev);
+	int ret;
+
+	ret = hyperv_connect_vsp(hdev);
+	if (ret)
+		return ret;
+
+	ret = hyperv_update_vram_location(hdev, hv->fb_base);
+	if (ret)
+		return ret;
+
+	return drm_mode_config_helper_resume(dev);
+}
+
+static const struct hv_vmbus_device_id hyperv_vmbus_tbl[] = {
+	/* Synthetic Video Device GUID */
+	{HV_SYNTHVID_GUID},
+	{}
+};
+
+static struct hv_driver hyperv_hv_driver = {
+	.name = KBUILD_MODNAME,
+	.id_table = hyperv_vmbus_tbl,
+	.probe = hyperv_vmbus_probe,
+	.remove = hyperv_vmbus_remove,
+	.suspend = hyperv_vmbus_suspend,
+	.resume = hyperv_vmbus_resume,
+	.driver = {
+		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
+	},
+};
+
+static int __init hyperv_init(void)
+{
+	int ret;
+
+	ret = pci_register_driver(&hyperv_pci_driver);
+	if (ret != 0)
+		return ret;
+
+	return vmbus_driver_register(&hyperv_hv_driver);
+}
+
+static void __exit hyperv_exit(void)
+{
+	vmbus_driver_unregister(&hyperv_hv_driver);
+	pci_unregister_driver(&hyperv_pci_driver);
+}
+
+module_init(hyperv_init);
+module_exit(hyperv_exit);
+
+MODULE_DEVICE_TABLE(pci, hyperv_pci_tbl);
+MODULE_DEVICE_TABLE(vmbus, hyperv_vmbus_tbl);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Deepak Rawat <drawat.floss@gmail.com>");
+MODULE_DESCRIPTION("DRM driver for Hyper-V synthetic video device");

drivers/gpu/drm/hyperv/hyperv_drm_modeset.c

+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright 2021 Microsoft
+ */
+
+#include <linux/hyperv.h>
+
+#include <drm/drm_damage_helper.h>
+#include <drm/drm_drv.h>
+#include <drm/drm_fb_helper.h>
+#include <drm/drm_format_helper.h>
+#include <drm/drm_fourcc.h>
+#include <drm/drm_gem_atomic_helper.h>
+#include <drm/drm_gem_framebuffer_helper.h>
+#include <drm/drm_gem_shmem_helper.h>
+#include <drm/drm_probe_helper.h>
+#include <drm/drm_simple_kms_helper.h>
+
+#include "hyperv_drm.h"
+
+static int hyperv_blit_to_vram_rect(struct drm_framebuffer *fb,
+				    const struct dma_buf_map *map,
+				    struct drm_rect *rect)
+{
+	struct hyperv_drm_device *hv = to_hv(fb->dev);
+	void *vmap = map->vaddr; /* TODO: Use mapping abstraction properly */
+	int idx;
+
+	if (!drm_dev_enter(&hv->dev, &idx))
+		return -ENODEV;
+
+	drm_fb_memcpy_dstclip(hv->vram, fb->pitches[0], vmap, fb, rect);
+	drm_dev_exit(idx);
+
+	return 0;
+}
+
+static int hyperv_blit_to_vram_fullscreen(struct drm_framebuffer *fb, const struct dma_buf_map *map)
+{
+	struct drm_rect fullscreen = {
+		.x1 = 0,
+		.x2 = fb->width,
+		.y1 = 0,
+		.y2 = fb->height,
+	};
+	return hyperv_blit_to_vram_rect(fb, map, &fullscreen);
+}
+
+static int hyperv_connector_get_modes(struct drm_connector *connector)
+{
+	struct hyperv_drm_device *hv = to_hv(connector->dev);
+	int count;
+
+	count = drm_add_modes_noedid(connector,
+				     connector->dev->mode_config.max_width,
+				     connector->dev->mode_config.max_height);
+	drm_set_preferred_mode(connector, hv->preferred_width,
+			       hv->preferred_height);
+
+	return count;
+}
+
+static const struct drm_connector_helper_funcs hyperv_connector_helper_funcs = {
+	.get_modes = hyperv_connector_get_modes,
+};
+
+static const struct drm_connector_funcs hyperv_connector_funcs = {
+	.fill_modes = drm_helper_probe_single_connector_modes,
+	.destroy = drm_connector_cleanup,
+	.reset = drm_atomic_helper_connector_reset,
+	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
+	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
+};
+
+static inline int hyperv_conn_init(struct hyperv_drm_device *hv)
+{
+	drm_connector_helper_add(&hv->connector, &hyperv_connector_helper_funcs);
+	return drm_connector_init(&hv->dev, &hv->connector,
+				  &hyperv_connector_funcs,
+				  DRM_MODE_CONNECTOR_VIRTUAL);
+}
+
+static int hyperv_check_size(struct hyperv_drm_device *hv, int w, int h,
+			     struct drm_framebuffer *fb)
+{
+	u32 pitch = w * (hv->screen_depth / 8);
+
+	if (fb)
+		pitch = fb->pitches[0];
+
+	if (pitch * h > hv->fb_size)
+		return -EINVAL;
+
+	return 0;
+}
+
+static void hyperv_pipe_enable(struct drm_simple_display_pipe *pipe,
+			       struct drm_crtc_state *crtc_state,
+			       struct drm_plane_state *plane_state)
+{
+	struct hyperv_drm_device *hv = to_hv(pipe->crtc.dev);
+	struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(plane_state);
+
+	hyperv_update_situation(hv->hdev, 1,  hv->screen_depth,
+				crtc_state->mode.hdisplay,
+				crtc_state->mode.vdisplay,
+				plane_state->fb->pitches[0]);
+	hyperv_blit_to_vram_fullscreen(plane_state->fb, &shadow_plane_state->map[0]);
+}
+
+static int hyperv_pipe_check(struct drm_simple_display_pipe *pipe,
+			     struct drm_plane_state *plane_state,
+			     struct drm_crtc_state *crtc_state)
+{
+	struct hyperv_drm_device *hv = to_hv(pipe->crtc.dev);
+	struct drm_framebuffer *fb = plane_state->fb;
+
+	if (fb->format->format != DRM_FORMAT_XRGB8888)
+		return -EINVAL;
+
+	if (fb->pitches[0] * fb->height > hv->fb_size)
+		return -EINVAL;
+
+	return 0;
+}
+
+static void hyperv_pipe_update(struct drm_simple_display_pipe *pipe,
+			       struct drm_plane_state *old_state)
+{
+	struct hyperv_drm_device *hv = to_hv(pipe->crtc.dev);
+	struct drm_plane_state *state = pipe->plane.state;
+	struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(state);
+	struct drm_rect rect;
+
+	if (drm_atomic_helper_damage_merged(old_state, state, &rect)) {
+		hyperv_blit_to_vram_rect(state->fb, &shadow_plane_state->map[0], &rect);
+		hyperv_update_dirt(hv->hdev, &rect);
+	}
+}
+
+static const struct drm_simple_display_pipe_funcs hyperv_pipe_funcs = {
+	.enable	= hyperv_pipe_enable,
+	.check = hyperv_pipe_check,
+	.update	= hyperv_pipe_update,
+	DRM_GEM_SIMPLE_DISPLAY_PIPE_SHADOW_PLANE_FUNCS,
+};
+
+static const uint32_t hyperv_formats[] = {
+	DRM_FORMAT_XRGB8888,
+};
+
+static const uint64_t hyperv_modifiers[] = {
+	DRM_FORMAT_MOD_LINEAR,
+	DRM_FORMAT_MOD_INVALID
+};
+
+static inline int hyperv_pipe_init(struct hyperv_drm_device *hv)
+{
+	int ret;
+
+	ret = drm_simple_display_pipe_init(&hv->dev,
+					   &hv->pipe,
+					   &hyperv_pipe_funcs,
+					   hyperv_formats,
+					   ARRAY_SIZE(hyperv_formats),
+					   NULL,
+					   &hv->connector);
+	if (ret)
+		return ret;
+
+	drm_plane_enable_fb_damage_clips(&hv->pipe.plane);
+
+	return 0;
+}
+
+static enum drm_mode_status
+hyperv_mode_valid(struct drm_device *dev,
+		  const struct drm_display_mode *mode)
+{
+	struct hyperv_drm_device *hv = to_hv(dev);
+
+	if (hyperv_check_size(hv, mode->hdisplay, mode->vdisplay, NULL))
+		return MODE_BAD;
+
+	return MODE_OK;
+}
+
+static const struct drm_mode_config_funcs hyperv_mode_config_funcs = {
+	.fb_create = drm_gem_fb_create_with_dirty,
+	.mode_valid = hyperv_mode_valid,
+	.atomic_check = drm_atomic_helper_check,
+	.atomic_commit = drm_atomic_helper_commit,
+};
+
+int hyperv_mode_config_init(struct hyperv_drm_device *hv)
+{
+	struct drm_device *dev = &hv->dev;
+	int ret;
+
+	ret = drmm_mode_config_init(dev);
+	if (ret) {
+		drm_err(dev, "Failed to initialized mode setting.\n");
+		return ret;
+	}
+
+	dev->mode_config.min_width = 0;
+	dev->mode_config.min_height = 0;
+	dev->mode_config.max_width = hv->screen_width_max;
+	dev->mode_config.max_height = hv->screen_height_max;
+
+	dev->mode_config.preferred_depth = hv->screen_depth;
+	dev->mode_config.prefer_shadow = 0;
+
+	dev->mode_config.funcs = &hyperv_mode_config_funcs;
+
+	ret = hyperv_conn_init(hv);
+	if (ret) {
+		drm_err(dev, "Failed to initialized connector.\n");
+		return ret;
+	}
+
+	ret = hyperv_pipe_init(hv);
+	if (ret) {
+		drm_err(dev, "Failed to initialized pipe.\n");
+		return ret;
+	}
+
+	drm_mode_config_reset(dev);
+
+	return 0;
+}

drivers/gpu/drm/hyperv/hyperv_drm_proto.c

+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright 2021 Microsoft
+ *
+ * Portions of this code is derived from hyperv_fb.c
+ */
+
+#include <linux/hyperv.h>
+
+#include <drm/drm_print.h>
+#include <drm/drm_simple_kms_helper.h>
+
+#include "hyperv_drm.h"
+
+#define VMBUS_RING_BUFSIZE (256 * 1024)
+#define VMBUS_VSP_TIMEOUT (10 * HZ)
+
+#define SYNTHVID_VERSION(major, minor) ((minor) << 16 | (major))
+#define SYNTHVID_VER_GET_MAJOR(ver) (ver & 0x0000ffff)
+#define SYNTHVID_VER_GET_MINOR(ver) ((ver & 0xffff0000) >> 16)
+#define SYNTHVID_VERSION_WIN7 SYNTHVID_VERSION(3, 0)
+#define SYNTHVID_VERSION_WIN8 SYNTHVID_VERSION(3, 2)
+#define SYNTHVID_VERSION_WIN10 SYNTHVID_VERSION(3, 5)
+
+#define SYNTHVID_DEPTH_WIN7 16
+#define SYNTHVID_DEPTH_WIN8 32
+#define SYNTHVID_FB_SIZE_WIN7 (4 * 1024 * 1024)
+#define SYNTHVID_FB_SIZE_WIN8 (8 * 1024 * 1024)
+#define SYNTHVID_WIDTH_MAX_WIN7 1600
+#define SYNTHVID_HEIGHT_MAX_WIN7 1200
+
+enum pipe_msg_type {
+	PIPE_MSG_INVALID,
+	PIPE_MSG_DATA,
+	PIPE_MSG_MAX
+};
+
+enum synthvid_msg_type {
+	SYNTHVID_ERROR			= 0,
+	SYNTHVID_VERSION_REQUEST	= 1,
+	SYNTHVID_VERSION_RESPONSE	= 2,
+	SYNTHVID_VRAM_LOCATION		= 3,
+	SYNTHVID_VRAM_LOCATION_ACK	= 4,
+	SYNTHVID_SITUATION_UPDATE	= 5,
+	SYNTHVID_SITUATION_UPDATE_ACK	= 6,
+	SYNTHVID_POINTER_POSITION	= 7,
+	SYNTHVID_POINTER_SHAPE		= 8,
+	SYNTHVID_FEATURE_CHANGE		= 9,
+	SYNTHVID_DIRT			= 10,
+	SYNTHVID_RESOLUTION_REQUEST	= 13,
+	SYNTHVID_RESOLUTION_RESPONSE	= 14,
+
+	SYNTHVID_MAX			= 15
+};
+
+struct pipe_msg_hdr {
+	u32 type;
+	u32 size; /* size of message after this field */
+} __packed;
+
+struct hvd_screen_info {
+	u16 width;
+	u16 height;
+} __packed;
+
+struct synthvid_msg_hdr {
+	u32 type;
+	u32 size;  /* size of this header + payload after this field */
+} __packed;
+
+struct synthvid_version_req {
+	u32 version;
+} __packed;
+
+struct synthvid_version_resp {
+	u32 version;
+	u8 is_accepted;
+	u8 max_video_outputs;
+} __packed;
+
+struct synthvid_vram_location {
+	u64 user_ctx;
+	u8 is_vram_gpa_specified;
+	u64 vram_gpa;
+} __packed;
+
+struct synthvid_vram_location_ack {
+	u64 user_ctx;
+} __packed;
+
+struct video_output_situation {
+	u8 active;
+	u32 vram_offset;
+	u8 depth_bits;
+	u32 width_pixels;
+	u32 height_pixels;
+	u32 pitch_bytes;
+} __packed;
+
+struct synthvid_situation_update {
+	u64 user_ctx;
+	u8 video_output_count;
+	struct video_output_situation video_output[1];
+} __packed;
+
+struct synthvid_situation_update_ack {
+	u64 user_ctx;
+} __packed;
+
+struct synthvid_pointer_position {
+	u8 is_visible;
+	u8 video_output;
+	s32 image_x;
+	s32 image_y;
+} __packed;
+
+#define SYNTHVID_CURSOR_MAX_X 96
+#define SYNTHVID_CURSOR_MAX_Y 96
+#define SYNTHVID_CURSOR_ARGB_PIXEL_SIZE 4
+#define SYNTHVID_CURSOR_MAX_SIZE (SYNTHVID_CURSOR_MAX_X * \
+	SYNTHVID_CURSOR_MAX_Y * SYNTHVID_CURSOR_ARGB_PIXEL_SIZE)
+#define SYNTHVID_CURSOR_COMPLETE (-1)
+
+struct synthvid_pointer_shape {
+	u8 part_idx;
+	u8 is_argb;
+	u32 width; /* SYNTHVID_CURSOR_MAX_X at most */
+	u32 height; /* SYNTHVID_CURSOR_MAX_Y at most */
+	u32 hot_x; /* hotspot relative to upper-left of pointer image */
+	u32 hot_y;
+	u8 data[4];
+} __packed;
+
+struct synthvid_feature_change {
+	u8 is_dirt_needed;
+	u8 is_ptr_pos_needed;
+	u8 is_ptr_shape_needed;
+	u8 is_situ_needed;
+} __packed;
+
+struct rect {
+	s32 x1, y1; /* top left corner */
+	s32 x2, y2; /* bottom right corner, exclusive */
+} __packed;
+
+struct synthvid_dirt {
+	u8 video_output;
+	u8 dirt_count;
+	struct rect rect[1];
+} __packed;
+
+#define SYNTHVID_EDID_BLOCK_SIZE	128
+#define	SYNTHVID_MAX_RESOLUTION_COUNT	64
+
+struct synthvid_supported_resolution_req {
+	u8 maximum_resolution_count;
+} __packed;
+
+struct synthvid_supported_resolution_resp {
+	u8 edid_block[SYNTHVID_EDID_BLOCK_SIZE];
+	u8 resolution_count;
+	u8 default_resolution_index;
+	u8 is_standard;
+	struct hvd_screen_info supported_resolution[SYNTHVID_MAX_RESOLUTION_COUNT];
+} __packed;
+
+struct synthvid_msg {
+	struct pipe_msg_hdr pipe_hdr;
+	struct synthvid_msg_hdr vid_hdr;
+	union {
+		struct synthvid_version_req ver_req;
+		struct synthvid_version_resp ver_resp;
+		struct synthvid_vram_location vram;
+		struct synthvid_vram_location_ack vram_ack;
+		struct synthvid_situation_update situ;
+		struct synthvid_situation_update_ack situ_ack;
+		struct synthvid_pointer_position ptr_pos;
+		struct synthvid_pointer_shape ptr_shape;
+		struct synthvid_feature_change feature_chg;
+		struct synthvid_dirt dirt;
+		struct synthvid_supported_resolution_req resolution_req;
+		struct synthvid_supported_resolution_resp resolution_resp;
+	};
+} __packed;
+
+static inline bool hyperv_version_ge(u32 ver1, u32 ver2)
+{
+	if (SYNTHVID_VER_GET_MAJOR(ver1) > SYNTHVID_VER_GET_MAJOR(ver2) ||
+	    (SYNTHVID_VER_GET_MAJOR(ver1) == SYNTHVID_VER_GET_MAJOR(ver2) &&
+	     SYNTHVID_VER_GET_MINOR(ver1) >= SYNTHVID_VER_GET_MINOR(ver2)))
+		return true;
+
+	return false;
+}
+
+static inline int hyperv_sendpacket(struct hv_device *hdev, struct synthvid_msg *msg)
+{
+	static atomic64_t request_id = ATOMIC64_INIT(0);
+	struct hyperv_drm_device *hv = hv_get_drvdata(hdev);
+	int ret;
+
+	msg->pipe_hdr.type = PIPE_MSG_DATA;
+	msg->pipe_hdr.size = msg->vid_hdr.size;
+
+	ret = vmbus_sendpacket(hdev->channel, msg,
+			       msg->vid_hdr.size + sizeof(struct pipe_msg_hdr),
+			       atomic64_inc_return(&request_id),
+			       VM_PKT_DATA_INBAND, 0);
+
+	if (ret)
+		drm_err(&hv->dev, "Unable to send packet via vmbus\n");
+
+	return ret;
+}
+
+static int hyperv_negotiate_version(struct hv_device *hdev, u32 ver)
+{
+	struct hyperv_drm_device *hv = hv_get_drvdata(hdev);
+	struct synthvid_msg *msg = (struct synthvid_msg *)hv->init_buf;
+	struct drm_device *dev = &hv->dev;
+	unsigned long t;
+
+	memset(msg, 0, sizeof(struct synthvid_msg));
+	msg->vid_hdr.type = SYNTHVID_VERSION_REQUEST;
+	msg->vid_hdr.size = sizeof(struct synthvid_msg_hdr) +
+		sizeof(struct synthvid_version_req);
+	msg->ver_req.version = ver;
+	hyperv_sendpacket(hdev, msg);
+
+	t = wait_for_completion_timeout(&hv->wait, VMBUS_VSP_TIMEOUT);
+	if (!t) {
+		drm_err(dev, "Time out on waiting version response\n");
+		return -ETIMEDOUT;
+	}
+
+	if (!msg->ver_resp.is_accepted) {
+		drm_err(dev, "Version request not accepted\n");
+		return -ENODEV;
+	}
+
+	hv->synthvid_version = ver;
+	drm_info(dev, "Synthvid Version major %d, minor %d\n",
+		 SYNTHVID_VER_GET_MAJOR(ver), SYNTHVID_VER_GET_MINOR(ver));
+
+	return 0;
+}
+
+int hyperv_update_vram_location(struct hv_device *hdev, phys_addr_t vram_pp)
+{
+	struct hyperv_drm_device *hv = hv_get_drvdata(hdev);
+	struct synthvid_msg *msg = (struct synthvid_msg *)hv->init_buf;
+	struct drm_device *dev = &hv->dev;
+	unsigned long t;
+
+	memset(msg, 0, sizeof(struct synthvid_msg));
+	msg->vid_hdr.type = SYNTHVID_VRAM_LOCATION;
+	msg->vid_hdr.size = sizeof(struct synthvid_msg_hdr) +
+		sizeof(struct synthvid_vram_location);
+	msg->vram.user_ctx = vram_pp;
+	msg->vram.vram_gpa = vram_pp;
+	msg->vram.is_vram_gpa_specified = 1;
+	hyperv_sendpacket(hdev, msg);
+
+	t = wait_for_completion_timeout(&hv->wait, VMBUS_VSP_TIMEOUT);
+	if (!t) {
+		drm_err(dev, "Time out on waiting vram location ack\n");
+		return -ETIMEDOUT;
+	}
+	if (msg->vram_ack.user_ctx != vram_pp) {
+		drm_err(dev, "Unable to set VRAM location\n");
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+int hyperv_update_situation(struct hv_device *hdev, u8 active, u32 bpp,
+			    u32 w, u32 h, u32 pitch)
+{
+	struct synthvid_msg msg;
+
+	memset(&msg, 0, sizeof(struct synthvid_msg));
+
+	msg.vid_hdr.type = SYNTHVID_SITUATION_UPDATE;
+	msg.vid_hdr.size = sizeof(struct synthvid_msg_hdr) +
+		sizeof(struct synthvid_situation_update);
+	msg.situ.user_ctx = 0;
+	msg.situ.video_output_count = 1;
+	msg.situ.video_output[0].active = active;
+	/* vram_offset should always be 0 */
+	msg.situ.video_output[0].vram_offset = 0;
+	msg.situ.video_output[0].depth_bits = bpp;
+	msg.situ.video_output[0].width_pixels = w;
+	msg.situ.video_output[0].height_pixels = h;
+	msg.situ.video_output[0].pitch_bytes = pitch;
+
+	hyperv_sendpacket(hdev, &msg);
+
+	return 0;
+}
+
+int hyperv_update_dirt(struct hv_device *hdev, struct drm_rect *rect)
+{
+	struct synthvid_msg msg;
+
+	memset(&msg, 0, sizeof(struct synthvid_msg));
+
+	msg.vid_hdr.type = SYNTHVID_DIRT;
+	msg.vid_hdr.size = sizeof(struct synthvid_msg_hdr) +
+		sizeof(struct synthvid_dirt);
+	msg.dirt.video_output = 0;
+	msg.dirt.dirt_count = 1;
+	msg.dirt.rect[0].x1 = rect->x1;
+	msg.dirt.rect[0].y1 = rect->y1;
+	msg.dirt.rect[0].x2 = rect->x2;
+	msg.dirt.rect[0].y2 = rect->y2;
+
+	hyperv_sendpacket(hdev, &msg);
+
+	return 0;
+}
+
+static int hyperv_get_supported_resolution(struct hv_device *hdev)
+{
+	struct hyperv_drm_device *hv = hv_get_drvdata(hdev);
+	struct synthvid_msg *msg = (struct synthvid_msg *)hv->init_buf;
+	struct drm_device *dev = &hv->dev;
+	unsigned long t;
+	u8 index;
+	int i;
+
+	memset(msg, 0, sizeof(struct synthvid_msg));
+	msg->vid_hdr.type = SYNTHVID_RESOLUTION_REQUEST;
+	msg->vid_hdr.size = sizeof(struct synthvid_msg_hdr) +
+		sizeof(struct synthvid_supported_resolution_req);
+	msg->resolution_req.maximum_resolution_count =
+		SYNTHVID_MAX_RESOLUTION_COUNT;
+	hyperv_sendpacket(hdev, msg);
+
+	t = wait_for_completion_timeout(&hv->wait, VMBUS_VSP_TIMEOUT);
+	if (!t) {
+		drm_err(dev, "Time out on waiting resolution response\n");
+		return -ETIMEDOUT;
+	}
+
+	if (msg->resolution_resp.resolution_count == 0) {
+		drm_err(dev, "No supported resolutions\n");
+		return -ENODEV;
+	}
+
+	index = msg->resolution_resp.default_resolution_index;
+	if (index >= msg->resolution_resp.resolution_count) {
+		drm_err(dev, "Invalid resolution index: %d\n", index);
+		return -ENODEV;
+	}
+
+	for (i = 0; i < msg->resolution_resp.resolution_count; i++) {
+		hv->screen_width_max = max_t(u32, hv->screen_width_max,
+			msg->resolution_resp.supported_resolution[i].width);
+		hv->screen_height_max = max_t(u32, hv->screen_height_max,
+			msg->resolution_resp.supported_resolution[i].height);
+	}
+
+	hv->preferred_width =
+		msg->resolution_resp.supported_resolution[index].width;
+	hv->preferred_height =
+		msg->resolution_resp.supported_resolution[index].height;
+
+	return 0;
+}
+
+static void hyperv_receive_sub(struct hv_device *hdev)
+{
+	struct hyperv_drm_device *hv = hv_get_drvdata(hdev);
+	struct synthvid_msg *msg;
+
+	if (!hv)
+		return;
+
+	msg = (struct synthvid_msg *)hv->recv_buf;
+
+	/* Complete the wait event */
+	if (msg->vid_hdr.type == SYNTHVID_VERSION_RESPONSE ||
+	    msg->vid_hdr.type == SYNTHVID_RESOLUTION_RESPONSE ||
+	    msg->vid_hdr.type == SYNTHVID_VRAM_LOCATION_ACK) {
+		memcpy(hv->init_buf, msg, VMBUS_MAX_PACKET_SIZE);
+		complete(&hv->wait);
+		return;
+	}
+}
+
+static void hyperv_receive(void *ctx)
+{
+	struct hv_device *hdev = ctx;
+	struct hyperv_drm_device *hv = hv_get_drvdata(hdev);
+	struct synthvid_msg *recv_buf;
+	u32 bytes_recvd;
+	u64 req_id;
+	int ret;
+
+	if (!hv)
+		return;
+
+	recv_buf = (struct synthvid_msg *)hv->recv_buf;
+
+	do {
+		ret = vmbus_recvpacket(hdev->channel, recv_buf,
+				       VMBUS_MAX_PACKET_SIZE,
+				       &bytes_recvd, &req_id);
+		if (bytes_recvd > 0 &&
+		    recv_buf->pipe_hdr.type == PIPE_MSG_DATA)
+			hyperv_receive_sub(hdev);
+	} while (bytes_recvd > 0 && ret == 0);
+}
+
+int hyperv_connect_vsp(struct hv_device *hdev)
+{
+	struct hyperv_drm_device *hv = hv_get_drvdata(hdev);
+	struct drm_device *dev = &hv->dev;
+	int ret;
+
+	ret = vmbus_open(hdev->channel, VMBUS_RING_BUFSIZE, VMBUS_RING_BUFSIZE,
+			 NULL, 0, hyperv_receive, hdev);
+	if (ret) {
+		drm_err(dev, "Unable to open vmbus channel\n");
+		return ret;
+	}
+
+	/* Negotiate the protocol version with host */
+	switch (vmbus_proto_version) {
+	case VERSION_WIN10:
+	case VERSION_WIN10_V5:
+		ret = hyperv_negotiate_version(hdev, SYNTHVID_VERSION_WIN10);
+		if (!ret)
+			break;
+		fallthrough;
+	case VERSION_WIN8:
+	case VERSION_WIN8_1:
+		ret = hyperv_negotiate_version(hdev, SYNTHVID_VERSION_WIN8);
+		if (!ret)
+			break;
+		fallthrough;
+	case VERSION_WS2008:
+	case VERSION_WIN7:
+		ret = hyperv_negotiate_version(hdev, SYNTHVID_VERSION_WIN7);
+		break;
+	default:
+		ret = hyperv_negotiate_version(hdev, SYNTHVID_VERSION_WIN10);
+		break;
+	}
+
+	if (ret) {
+		drm_err(dev, "Synthetic video device version not accepted %d\n", ret);
+		goto error;
+	}
+
+	if (hv->synthvid_version == SYNTHVID_VERSION_WIN7)
+		hv->screen_depth = SYNTHVID_DEPTH_WIN7;
+	else
+		hv->screen_depth = SYNTHVID_DEPTH_WIN8;
+
+	if (hyperv_version_ge(hv->synthvid_version, SYNTHVID_VERSION_WIN10)) {
+		ret = hyperv_get_supported_resolution(hdev);
+		if (ret)
+			drm_err(dev, "Failed to get supported resolution from host, use default\n");
+	} else {
+		hv->screen_width_max = SYNTHVID_WIDTH_MAX_WIN7;
+		hv->screen_height_max = SYNTHVID_HEIGHT_MAX_WIN7;
+	}
+
+	hv->mmio_megabytes = hdev->channel->offermsg.offer.mmio_megabytes;
+
+	return 0;
+
+error:
+	vmbus_close(hdev->channel);
+	return ret;
+}