path: root/drivers/video/fbdev/hyperv_fb.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2012, Microsoft Corporation.
 *
 * Author:
 *   Haiyang Zhang <haiyangz@microsoft.com>
 */

/*
 * Hyper-V Synthetic Video Frame Buffer Driver
 *
 * This is the driver for the Hyper-V Synthetic Video, which supports
 * screen resolution up to Full HD 1920x1080 with 32 bit color on Windows
 * Server 2012, and 1600x1200 with 16 bit color on Windows Server 2008 R2
 * or earlier.
 *
 * It also solves the double mouse cursor issue of the emulated video mode.
 *
 * The default screen resolution is 1152x864, which may be changed by a
 * kernel parameter:
 *     video=hyperv_fb:<width>x<height>
 *     For example: video=hyperv_fb:1280x1024
 *
 * Portrait orientation is also supported:
 *     For example: video=hyperv_fb:864x1152
 *
 * When a Windows 10 RS5+ host is used, the virtual machine screen
 * resolution is obtained from the host. The "video=hyperv_fb" option is
 * not needed, but still can be used to overwrite what the host specifies.
 * The VM resolution on the host could be set by executing the powershell
 * "set-vmvideo" command. For example
 *     set-vmvideo -vmname name -horizontalresolution:1920 \
 * -verticalresolution:1200 -resolutiontype single
 *
 * Gen 1 VMs also support direct using VM's physical memory for framebuffer.
 * It could improve the efficiency and performance for framebuffer and VM.
 * This requires to allocate contiguous physical memory from Linux kernel's
 * CMA memory allocator. To enable this, supply a kernel parameter to give
 * enough memory space to CMA allocator for framebuffer. For example:
 *    cma=130m
 * This gives 130MB memory to CMA allocator that can be allocated to
 * framebuffer. For reference, 8K resolution (7680x4320) takes about
 * 127MB memory.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/aperture.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/vmalloc.h>
#include <linux/init.h>
#include <linux/completion.h>
#include <linux/fb.h>
#include <linux/pci.h>
#include <linux/panic_notifier.h>
#include <linux/efi.h>
#include <linux/console.h>

#include <linux/hyperv.h>

/* Hyper-V Synthetic Video Protocol definitions and structures */
#define MAX_VMBUS_PKT_SIZE 0x4000

#define SYNTHVID_VERSION(major, minor) ((minor) << 16 | (major))
/* Support for VERSION_WIN7 is removed. #define is retained for reference. */
#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_VER_GET_MAJOR(ver) (ver & 0x0000ffff)
#define SYNTHVID_VER_GET_MINOR(ver) ((ver & 0xffff0000) >> 16)

#define SYNTHVID_DEPTH_WIN8 32
#define SYNTHVID_FB_SIZE_WIN8 (8 * 1024 * 1024)

enum pipe_msg_type {
	PIPE_MSG_INVALID,
	PIPE_MSG_DATA,
	PIPE_MSG_MAX
};

struct pipe_msg_hdr {
	u32 type;
	u32 size; /* size of message after this field */
} __packed;


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
};

#define		SYNTHVID_EDID_BLOCK_SIZE	128
#define		SYNTHVID_MAX_RESOLUTION_COUNT	64

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_supported_resolution_req {
	u8 maximum_resolution_count