Re: [PATCH v3 1/2] drm/hyperv: Add DRM driver for hyperv synthetic video device

[Thomas Zimmermann <tzimmermann@xxxxxxx>]

Hi,

fantastic. Thanks for sending an update. There's been a some bitrot 
meanwhile. Review below.

Am 16.02.21 um 01:39 schrieb Deepak Rawat:
> 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
>
> Signed-off-by: Deepak Rawat <drawat.floss@xxxxxxxxx>
> ---
>   drivers/gpu/drm/Kconfig                     |  12 +
>   drivers/gpu/drm/Makefile                    |   1 +
>   drivers/gpu/drm/hyperv/Makefile             |   8 +
>   drivers/gpu/drm/hyperv/hyperv_drm.h         |  51 ++
>   drivers/gpu/drm/hyperv/hyperv_drm_drv.c     | 313 +++++++++++++
>   drivers/gpu/drm/hyperv/hyperv_drm_modeset.c | 240 ++++++++++
>   drivers/gpu/drm/hyperv/hyperv_drm_proto.c   | 486 ++++++++++++++++++++
>   7 files changed, 1111 insertions(+)
>   create mode 100644 drivers/gpu/drm/hyperv/Makefile
>   create mode 100644 drivers/gpu/drm/hyperv/hyperv_drm.h
>   create mode 100644 drivers/gpu/drm/hyperv/hyperv_drm_drv.c
>   create mode 100644 drivers/gpu/drm/hyperv/hyperv_drm_modeset.c
>   create mode 100644 drivers/gpu/drm/hyperv/hyperv_drm_proto.c
>
> diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
> index 8bf103de1594..c17f4e9dcd82 100644
> --- a/drivers/gpu/drm/Kconfig
> +++ b/drivers/gpu/drm/Kconfig
> @@ -382,6 +382,18 @@ source "drivers/gpu/drm/tidss/Kconfig"
>   
>   source "drivers/gpu/drm/xlnx/Kconfig"
>   
> +config DRM_HYPERV
> +	tristate "DRM Support for hyperv 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 hyperv synthetic video device. Choose this
> +	 option if you would like to enable drm driver for Hyper-V virtual
> +	 machine.
> +
> +	 If M is selected the module will be called hyperv_drm.
> +
>   # Keep legacy drivers last
>   
>   menuconfig DRM_LEGACY
> diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
> index 926adef289db..294e321cd23f 100644
> --- a/drivers/gpu/drm/Makefile
> +++ b/drivers/gpu/drm/Makefile
> @@ -125,3 +125,4 @@ obj-$(CONFIG_DRM_ASPEED_GFX) += aspeed/
>   obj-$(CONFIG_DRM_MCDE) += mcde/
>   obj-$(CONFIG_DRM_TIDSS) += tidss/
>   obj-y			+= xlnx/
> +obj-$(CONFIG_DRM_HYPERV) += hyperv/
> diff --git a/drivers/gpu/drm/hyperv/Makefile b/drivers/gpu/drm/hyperv/Makefile
> new file mode 100644
> index 000000000000..0039b03db0be
> --- /dev/null
> +++ b/drivers/gpu/drm/hyperv/Makefile
> @@ -0,0 +1,8 @@
> +# SPDX-License-Identifier: GPL-2.0-only
> +
> +hyperv_drm-y := \
> +	hyperv_drm_proto.o \
> +	hyperv_drm_modeset.o \
> +	hyperv_drm_drv.o
> +
> +obj-$(CONFIG_DRM_HYPERV) += hyperv_drm.o
> diff --git a/drivers/gpu/drm/hyperv/hyperv_drm.h b/drivers/gpu/drm/hyperv/hyperv_drm.h
> new file mode 100644
> index 000000000000..4f8c627b303a
> --- /dev/null
> +++ b/drivers/gpu/drm/hyperv/hyperv_drm.h
> @@ -0,0 +1,51 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright 2012-2021 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
> diff --git a/drivers/gpu/drm/hyperv/hyperv_drm_drv.c b/drivers/gpu/drm/hyperv/hyperv_drm_drv.c
> new file mode 100644
> index 000000000000..b72c1a169125
> --- /dev/null
> +++ b/drivers/gpu/drm/hyperv/hyperv_drm_drv.c
> @@ -0,0 +1,313 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright 2012-2021 Microsoft
> + */
> +
> +#include <linux/efi.h>
> +#include <linux/hyperv.h>
> +#include <linux/module.h>
> +#include <linux/pci.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 hyperv 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 */ }
> +};
> +
> +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_get_vram_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_fb_helper_remove_conflicting_pci_framebuffers(pdev, "hypervdrmfb");

This functon is not actually related to vram, but kicks out any drivers 
that might currently use the hardware. I'd try to do this outside  of 
the vram mapping code. Anyway, your choice.

> +	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 == 0) {

The prefered style is

  if (!hw->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_get_vram_gen2(struct hyperv_drm_device *hv,
> +				struct hv_device *hdev)
> +{
> +	struct drm_device *dev = &hv->dev;
> +	struct apertures_struct *ap;
> +	int ret;
> +
> +	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;
> +
> +	ap = alloc_apertures(1);
> +	if (!ap) {
> +		drm_err(dev, "Failed to get apertures\n");
> +		ret = -ENOMEM;
> +		goto error;
> +	}
> +
> +	ap->ranges[0].base = screen_info.lfb_base;
> +	ap->ranges[0].size = screen_info.lfb_size;
> +	remove_conflicting_framebuffers(ap, KBUILD_MODNAME, false);

You have to use drm_fb_helper_remove_conflicting_framebuffers() here. 
remove_conflicting framebuffers() requires frambuffer support 
(CONFIG_FB). Not setting this option would break your driver's build.

Also, I'd call this as early as possible. As I said, this removes other 
drivers. And you want to get rid of them as soon as possible to avoid 
interference.

> +	kfree(ap);
> +
> +	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;
> +
> +	/* Get the actual VRAM size from the device */
> +	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_get_vram_gen2(hv, hdev);
> +	else
> +		ret = hyperv_get_vram_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);
> +
> +	vmbus_close(hdev->channel);
> +
> +	return ret;
> +}
> +
> +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@xxxxxxxxx>");
> +MODULE_DESCRIPTION("DRM driver for hyperv synthetic video device");
> diff --git a/drivers/gpu/drm/hyperv/hyperv_drm_modeset.c b/drivers/gpu/drm/hyperv/hyperv_drm_modeset.c
> new file mode 100644
> index 000000000000..40ec0cff0e59
> --- /dev/null
> +++ b/drivers/gpu/drm/hyperv/hyperv_drm_modeset.c
> @@ -0,0 +1,240 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright 2012-2021 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_shmem_helper.h>
> +#include <drm/drm_gem_framebuffer_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,
> +				    struct drm_rect *rect)
> +{
> +	struct hyperv_drm_device *hv = to_hv(fb->dev);
> +	struct dma_buf_map map;
> +	void *vmap;
> +	int idx, ret;
> +
> +	if (!drm_dev_enter(&hv->dev, &idx))
> +		return -ENODEV;
> +
> +	ret = drm_gem_shmem_vmap(fb->obj[0], &map);
> +	if (ret) {
> +		drm_dev_exit(idx);
> +		return ret;
> +	}

This code bitrotted. Calling vmap during the atomic scren update could 
lead to a deadlock. So it's not actually allowed. We got away with it so 
far, but I recently cleaned this up. Vmappings have to be 
established/removed in prepare_fb and cleanup_fb.

But there's a helper to do that. drm_gem_atomic_helper.h contains 
plane-state functionality for shadow-buffered planes. It provies the 
mapping for your code. You won't have to do aynthing.

It looks like you based your code on the cirrus driver? If so, have a 
look at


https://lore.kernel.org/dri-devel/20210204200308.24216-5-tzimmermann@xxxxxxx/

so see hwo to convert to shadow-buffer helpers.

> +
> +	vmap = map.vaddr;
> +	drm_fb_memcpy_dstclip(hv->vram, vmap, fb, rect);
> +	drm_gem_shmem_vunmap(fb->obj[0], vmap);
> +	drm_dev_exit(idx);
> +
> +	return 0;
> +}
> +
> +static int hyperv_blit_to_vram_fullscreen(struct drm_framebuffer *fb)
> +{
> +	struct drm_rect fullscreen = {
> +		.x1 = 0,
> +		.x2 = fb->width,
> +		.y1 = 0,
> +		.y2 = fb->height,
> +	};
> +	return hyperv_blit_to_vram_rect(fb, &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 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_VGA);
> +}
> +
> +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);
> +
> +	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);
> +}
> +
> +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_rect rect;
> +
> +	if (drm_atomic_helper_damage_merged(old_state, state, &rect)) {
> +		hyperv_blit_to_vram_rect(state->fb, &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,
> +};
> +
> +static const uint32_t hyperv_formats[] = {
> +	DRM_FORMAT_XRGB8888,
> +};
> +
> +static const uint64_t hyperv_modifiers[] = {
> +	DRM_FORMAT_MOD_LINEAR,
> +	DRM_FORMAT_MOD_INVALID
> +};
> +
> +static 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);

Better return here if it fails.

> +
> +	drm_plane_enable_fb_damage_clips(&hv->pipe.plane);
> +
> +	return ret;
> +}
> +
> +static struct drm_framebuffer*
> +hyperv_fb_create(struct drm_device *dev, struct drm_file *file_priv,
> +		 const struct drm_mode_fb_cmd2 *mode_cmd)
> +{
> +	return drm_gem_fb_create_with_dirty(dev, file_priv, mode_cmd);
> +}
> +
> +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 = hyperv_fb_create,
> +	.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;
> +	}

Maybe just inline _conn_init() and _pipe_init(). These functions don't 
seem to provide much.

Best regards
Thomas

> +
> +	drm_mode_config_reset(dev);
> +
> +	return 0;
> +}
> diff --git a/drivers/gpu/drm/hyperv/hyperv_drm_proto.c b/drivers/gpu/drm/hyperv/hyperv_drm_proto.c
> new file mode 100644
> index 000000000000..4e61992be121
> --- /dev/null
> +++ b/drivers/gpu/drm/hyperv/hyperv_drm_proto.c
> @@ -0,0 +1,486 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright 2012-2021 Microsoft
> + */
> +
> +#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;
> +	int ret = 0;
> +
> +	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");
> +		ret = -ETIMEDOUT;
> +		goto out;
> +	}
> +	if (!msg->ver_resp.is_accepted) {
> +		ret = -ENODEV;
> +		goto out;
> +	}
> +
> +	hv->synthvid_version = ver;
> +	drm_info(dev, "Synthvid Version major %d, minor %d\n",
> +		 SYNTHVID_VER_GET_MAJOR(ver), SYNTHVID_VER_GET_MINOR(ver));
> +
> +out:
> +	return ret;
> +}
> +
> +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;
> +	int ret = 0;
> +
> +	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");
> +		ret = -ETIMEDOUT;
> +		goto out;
> +	}
> +	if (msg->vram_ack.user_ctx != vram_pp) {
> +		drm_err(dev, "Unable to set VRAM location\n");
> +		ret = -ENODEV;
> +	}
> +
> +out:
> +	return ret;
> +}
> +
> +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;
> +	int ret = 0;
> +	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");
> +		ret = -ETIMEDOUT;
> +		goto out;
> +	}
> +
> +	if (msg->resolution_resp.resolution_count == 0) {
> +		drm_err(dev, "No supported resolutions\n");
> +		ret = -ENODEV;
> +		goto out;
> +	}
> +
> +	index = msg->resolution_resp.default_resolution_index;
> +	if (index >= msg->resolution_resp.resolution_count) {
> +		drm_err(dev, "Invalid resolution index: %d\n", index);
> +		ret = -ENODEV;
> +		goto out;
> +	}
> +
> +	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;
> +
> +out:
> +	return ret;
> +}
> +
> +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;
> +}

--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Felix Imendörffer

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