2019-08-13 10:56:44

by Wei Hu

[permalink] [raw]
Subject: [PATCH] video: hyperv: hyperv_fb: Obtain screen resolution from Hyper-V host

Beginning from Windows 10 RS5+, VM screen resolution is obtained from host.
The "video=hyperv_fb" boot time option is not needed, but still can be
used to overwrite the VM resolution. The VM resolution on the host could be
set by executing the powershell "set-vmvideo" command.

Signed-off-by: Iouri Tarassov <[email protected]>
Signed-off-by: Wei Hu <[email protected]>
---
drivers/video/fbdev/hyperv_fb.c | 136 +++++++++++++++++++++++++++++---
1 file changed, 125 insertions(+), 11 deletions(-)

diff --git a/drivers/video/fbdev/hyperv_fb.c b/drivers/video/fbdev/hyperv_fb.c
index 00f5bdcc6c6f..1042f3311fa2 100644
--- a/drivers/video/fbdev/hyperv_fb.c
+++ b/drivers/video/fbdev/hyperv_fb.c
@@ -23,6 +23,14 @@
*
* 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 the VM resolution. 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
*/

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
@@ -44,6 +52,7 @@
#define SYNTHVID_VERSION(major, minor) ((minor) << 16 | (major))
#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
@@ -82,16 +91,25 @@ enum synthvid_msg_type {
SYNTHVID_POINTER_SHAPE = 8,
SYNTHVID_FEATURE_CHANGE = 9,
SYNTHVID_DIRT = 10,
+ SYNTHVID_RESOLUTION_REQUEST = 13,
+ SYNTHVID_RESOLUTION_RESPONSE = 14,

- SYNTHVID_MAX = 11
+ 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;
@@ -102,6 +120,18 @@ struct synthvid_version_resp {
u8 max_video_outputs;
} __packed;

+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[1];
+} __packed;
+
struct synthvid_vram_location {
u64 user_ctx;
u8 is_vram_gpa_specified;
@@ -187,6 +217,8 @@ struct synthvid_msg {
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;

@@ -224,6 +256,8 @@ struct hvfb_par {

static uint screen_width = HVFB_WIDTH;
static uint screen_height = HVFB_HEIGHT;
+static uint screen_width_max = HVFB_WIDTH;
+static uint screen_height_max = HVFB_HEIGHT;
static uint screen_depth;
static uint screen_fb_size;

@@ -354,6 +388,7 @@ static void synthvid_recv_sub(struct hv_device *hdev)

/* 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(par->init_buf, msg, MAX_VMBUS_PKT_SIZE);
complete(&par->wait);
@@ -428,6 +463,64 @@ static int synthvid_negotiate_ver(struct hv_device *hdev, u32 ver)
}

par->synthvid_version = ver;
+ pr_info("Synthvid Version major %d, minor %d\n",
+ ver & 0x0000ffff, (ver & 0xffff0000) >> 16);
+
+out:
+ return ret;
+}
+
+/* Get current resolution from the host */
+static int synthvid_get_supported_resolution(struct hv_device *hdev)
+{
+ struct fb_info *info = hv_get_drvdata(hdev);
+ struct hvfb_par *par = info->par;
+ struct synthvid_msg *msg = (struct synthvid_msg *)par->init_buf;
+ int ret = 0;
+ 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;
+ synthvid_send(hdev, msg);
+
+ t = wait_for_completion_timeout(&par->wait, VSP_TIMEOUT);
+ if (!t) {
+ pr_err("Time out on waiting resolution response\n");
+ ret = -ETIMEDOUT;
+ goto out;
+ }
+
+ if (msg->resolution_resp.resolution_count == 0) {
+ pr_err("No supported resolutions\n");
+ ret = -ENODEV;
+ goto out;
+ }
+
+ index = msg->resolution_resp.default_resolution_index;
+ if (index >= msg->resolution_resp.resolution_count) {
+ pr_err("Invalid resolution index: %d\n", index);
+ ret = -ENODEV;
+ goto out;
+ }
+
+ for (i = 0; i < msg->resolution_resp.resolution_count; i++) {
+ screen_width_max = max_t(unsigned int, screen_width_max,
+ msg->resolution_resp.supported_resolution[i].width);
+ screen_height_max = max_t(unsigned int, screen_height_max,
+ msg->resolution_resp.supported_resolution[i].height);
+ }
+
+ screen_width =
+ msg->resolution_resp.supported_resolution[index].width;
+ screen_height =
+ msg->resolution_resp.supported_resolution[index].height;

out:
return ret;
@@ -448,11 +541,21 @@ static int synthvid_connect_vsp(struct hv_device *hdev)
}

/* Negotiate the protocol version with host */
- if (vmbus_proto_version == VERSION_WS2008 ||
- vmbus_proto_version == VERSION_WIN7)
+ switch (vmbus_proto_version) {
+ case VERSION_WS2008:
+ case VERSION_WIN7:
ret = synthvid_negotiate_ver(hdev, SYNTHVID_VERSION_WIN7);
- else
+ break;
+ case VERSION_WIN8:
+ case VERSION_WIN8_1:
ret = synthvid_negotiate_ver(hdev, SYNTHVID_VERSION_WIN8);
+ break;
+ case VERSION_WIN10:
+ case VERSION_WIN10_V5:
+ default:
+ ret = synthvid_negotiate_ver(hdev, SYNTHVID_VERSION_WIN10);
+ break;
+ }

if (ret) {
pr_err("Synthetic video device version not accepted\n");
@@ -464,6 +567,12 @@ static int synthvid_connect_vsp(struct hv_device *hdev)
else
screen_depth = SYNTHVID_DEPTH_WIN8;

+ if (par->synthvid_version >= SYNTHVID_VERSION_WIN10) {
+ ret = synthvid_get_supported_resolution(hdev);
+ if (ret)
+ pr_info("Failed to get supported resolution from host, use default\n");
+ }
+
screen_fb_size = hdev->channel->offermsg.offer.
mmio_megabytes * 1024 * 1024;

@@ -653,6 +762,8 @@ static void hvfb_get_option(struct fb_info *info)
}

if (x < HVFB_WIDTH_MIN || y < HVFB_HEIGHT_MIN ||
+ (par->synthvid_version >= SYNTHVID_VERSION_WIN10 &&
+ (x > screen_width_max || y > screen_height_max)) ||
(par->synthvid_version == SYNTHVID_VERSION_WIN8 &&
x * y * screen_depth / 8 > SYNTHVID_FB_SIZE_WIN8) ||
(par->synthvid_version == SYNTHVID_VERSION_WIN7 &&
@@ -689,8 +800,12 @@ static int hvfb_getmem(struct hv_device *hdev, struct fb_info *info)
}

if (!(pci_resource_flags(pdev, 0) & IORESOURCE_MEM) ||
- pci_resource_len(pdev, 0) < screen_fb_size)
+ pci_resource_len(pdev, 0) < screen_fb_size) {
+ pr_err("Resource not available or (0x%lx < 0x%lx)\n",
+ (unsigned long) pci_resource_len(pdev, 0),
+ (unsigned long) screen_fb_size);
goto err1;
+ }

pot_end = pci_resource_end(pdev, 0);
pot_start = pot_end - screen_fb_size + 1;
@@ -781,17 +896,16 @@ static int hvfb_probe(struct hv_device *hdev,
goto error1;
}

+ hvfb_get_option(info);
+ pr_info("Screen resolution: %dx%d, Color depth: %d\n",
+ screen_width, screen_height, screen_depth);
+
ret = hvfb_getmem(hdev, info);
if (ret) {
pr_err("No memory for framebuffer\n");
goto error2;
}

- hvfb_get_option(info);
- pr_info("Screen resolution: %dx%d, Color depth: %d\n",
- screen_width, screen_height, screen_depth);
-
-
/* Set up fb_info */
info->flags = FBINFO_DEFAULT;

--
2.20.1


2019-08-18 20:08:21

by Michael Kelley (LINUX)

[permalink] [raw]
Subject: RE: [PATCH] video: hyperv: hyperv_fb: Obtain screen resolution from Hyper-V host

From: Wei Hu <[email protected]> Sent: Tuesday, August 13, 2019 2:55 AM
>
> Beginning from Windows 10 RS5+, VM screen resolution is obtained from host.
> The "video=hyperv_fb" boot time option is not needed, but still can be
> used to overwrite the VM resolution. The VM resolution on the host could be

I would word this as "used to override what the host specifies."

> set by executing the powershell "set-vmvideo" command.
>
> Signed-off-by: Iouri Tarassov <[email protected]>
> Signed-off-by: Wei Hu <[email protected]>
> ---
> drivers/video/fbdev/hyperv_fb.c | 136 +++++++++++++++++++++++++++++---
> 1 file changed, 125 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/video/fbdev/hyperv_fb.c b/drivers/video/fbdev/hyperv_fb.c
> index 00f5bdcc6c6f..1042f3311fa2 100644
> --- a/drivers/video/fbdev/hyperv_fb.c
> +++ b/drivers/video/fbdev/hyperv_fb.c
> @@ -23,6 +23,14 @@
> *
> * 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 the VM resolution. The

As above, "but still can be used to override what the host specifies."

> + * 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
> */
>
> #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
> @@ -44,6 +52,7 @@
> #define SYNTHVID_VERSION(major, minor) ((minor) << 16 | (major))
> #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
> @@ -82,16 +91,25 @@ enum synthvid_msg_type {
> SYNTHVID_POINTER_SHAPE = 8,
> SYNTHVID_FEATURE_CHANGE = 9,
> SYNTHVID_DIRT = 10,
> + SYNTHVID_RESOLUTION_REQUEST = 13,
> + SYNTHVID_RESOLUTION_RESPONSE = 14,
>
> - SYNTHVID_MAX = 11
> + 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;
> @@ -102,6 +120,18 @@ struct synthvid_version_resp {
> u8 max_video_outputs;
> } __packed;
>
> +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[1];

It seems like the array size should be SYNTHVID_MAX_RESOLUTION_COUNT.
Otherwise code might not factor in the full size of the data structure, such
as in the memset() call in synthvid_get_supported_resolution().

> +} __packed;
> +
> struct synthvid_vram_location {
> u64 user_ctx;
> u8 is_vram_gpa_specified;
> @@ -187,6 +217,8 @@ struct synthvid_msg {
> 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;
>
> @@ -224,6 +256,8 @@ struct hvfb_par {
>
> static uint screen_width = HVFB_WIDTH;
> static uint screen_height = HVFB_HEIGHT;
> +static uint screen_width_max = HVFB_WIDTH;
> +static uint screen_height_max = HVFB_HEIGHT;
> static uint screen_depth;
> static uint screen_fb_size;
>
> @@ -354,6 +388,7 @@ static void synthvid_recv_sub(struct hv_device *hdev)
>
> /* 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(par->init_buf, msg, MAX_VMBUS_PKT_SIZE);
> complete(&par->wait);
> @@ -428,6 +463,64 @@ static int synthvid_negotiate_ver(struct hv_device *hdev, u32 ver)
> }
>
> par->synthvid_version = ver;
> + pr_info("Synthvid Version major %d, minor %d\n",
> + ver & 0x0000ffff, (ver & 0xffff0000) >> 16);
> +
> +out:
> + return ret;
> +}
> +
> +/* Get current resolution from the host */
> +static int synthvid_get_supported_resolution(struct hv_device *hdev)
> +{
> + struct fb_info *info = hv_get_drvdata(hdev);
> + struct hvfb_par *par = info->par;
> + struct synthvid_msg *msg = (struct synthvid_msg *)par->init_buf;
> + int ret = 0;
> + 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;
> + synthvid_send(hdev, msg);
> +
> + t = wait_for_completion_timeout(&par->wait, VSP_TIMEOUT);
> + if (!t) {
> + pr_err("Time out on waiting resolution response\n");
> + ret = -ETIMEDOUT;
> + goto out;
> + }
> +
> + if (msg->resolution_resp.resolution_count == 0) {
> + pr_err("No supported resolutions\n");
> + ret = -ENODEV;
> + goto out;
> + }
> +
> + index = msg->resolution_resp.default_resolution_index;
> + if (index >= msg->resolution_resp.resolution_count) {
> + pr_err("Invalid resolution index: %d\n", index);
> + ret = -ENODEV;
> + goto out;
> + }
> +
> + for (i = 0; i < msg->resolution_resp.resolution_count; i++) {
> + screen_width_max = max_t(unsigned int, screen_width_max,
> + msg->resolution_resp.supported_resolution[i].width);
> + screen_height_max = max_t(unsigned int, screen_height_max,
> + msg->resolution_resp.supported_resolution[i].height);
> + }
> +
> + screen_width =
> + msg->resolution_resp.supported_resolution[index].width;
> + screen_height =
> + msg->resolution_resp.supported_resolution[index].height;
>
> out:
> return ret;
> @@ -448,11 +541,21 @@ static int synthvid_connect_vsp(struct hv_device *hdev)
> }
>
> /* Negotiate the protocol version with host */
> - if (vmbus_proto_version == VERSION_WS2008 ||
> - vmbus_proto_version == VERSION_WIN7)
> + switch (vmbus_proto_version) {
> + case VERSION_WS2008:
> + case VERSION_WIN7:
> ret = synthvid_negotiate_ver(hdev, SYNTHVID_VERSION_WIN7);
> - else
> + break;
> + case VERSION_WIN8:
> + case VERSION_WIN8_1:
> ret = synthvid_negotiate_ver(hdev, SYNTHVID_VERSION_WIN8);
> + break;
> + case VERSION_WIN10:

I wonder if this does the right thing on a system with VERSION_WIN10. The existing
code would treat this like VERSION_WIN8. Your commit message says that the new
functionality of getting the resolution from the host came as part of RS5, and I suspect
there are host versions that report VERSION_WIN10 but that aren't RS5. You may have
already clarified this with the Hyper-V people, but if not, we should do so. The
version negotiation here doesn't fallback to an earlier version if Hyper-V doesn't accept
what this code requests. However, the more robust approach might be to implement
fallback on the SYNTHVID_VERSION setting.

> + case VERSION_WIN10_V5:
> + default:
> + ret = synthvid_negotiate_ver(hdev, SYNTHVID_VERSION_WIN10);
> + break;
> + }
>

Michael