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;
+}