[v2] drm/vmwgfx: Treat zero SVGA_REG_CURSOR_MAX_DIMENSION as unset

[PATCH v2] drm/vmwgfx: Treat zero SVGA_REG_CURSOR_MAX_DIMENSION as unset

Posted by fausten 1 month ago

The cursor plane code validates cursor dimensions against
SVGA_REG_CURSOR_MAX_DIMENSION before every cursor update, and
rejects the update with -EINVAL if the cursor is larger than the
reported maximum.

However, some SVGA implementations do not implement this register
and return 0 for it. In that case every cursor update is rejected,
and the log is spammed with:

  [drm] Cursor dimensions (64, 64) exceed device max 0

The visible symptom is that the hardware cursor never appears at
all on VMware Fusion guests (SVGA version 2), making the mouse
pointer invisible even though the input devices work fine.

Treat a reported maximum of 0 as "not implemented" and skip the
dimension check in that case, restoring the pre-existing behaviour
of accepting the cursor.

Tested on VMware Fusion with an SVGA version 2 device where the
cursor previously did not show up.

Fixes: d5ed8749168a ("drm/vmwgfx: enforce cursor size limits for MOB cursors")
Signed-off-by: fausten <yunfeng.li.nb@gmail.com>
---
Changes in v2:
- Fix author name and email address (v1 was sent with a wrong From).

 drivers/gpu/drm/vmwgfx/vmwgfx_cursor_plane.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_cursor_plane.c b/drivers/gpu/drm/vmwgfx/vmwgfx_cursor_plane.c
index d1e7df500..fbdd23ecb 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_cursor_plane.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_cursor_plane.c
@@ -237,8 +237,10 @@ static int vmw_cursor_mob_get(struct vmw_cursor_plane *vcp,
 	mob_max_size = vmw_read(dev_priv, SVGA_REG_MOB_MAX_SIZE);
 	cursor_max_dim = vmw_read(dev_priv, SVGA_REG_CURSOR_MAX_DIMENSION);
 
-	if (size > mob_max_size || vps->base.crtc_w > cursor_max_dim ||
-	    vps->base.crtc_h > cursor_max_dim)
+	/* Some SVGA implementations (e.g. VMware Fusion) report 0 here. */
+	if (cursor_max_dim &&
+	    (size > mob_max_size || vps->base.crtc_w > cursor_max_dim ||
+	     vps->base.crtc_h > cursor_max_dim))
 		return -EINVAL;
 
 	if (vps->cursor.mob) {
@@ -748,8 +750,10 @@ int vmw_cursor_plane_atomic_check(struct drm_plane *plane,
 		u32 cursor_max_dim =
 			vmw_read(vmw, SVGA_REG_CURSOR_MAX_DIMENSION);
 
-		if (new_state->crtc_w > cursor_max_dim ||
-		    new_state->crtc_h > cursor_max_dim) {
+		/* Some SVGA implementations (e.g. VMware Fusion) report 0 here. */
+		if (cursor_max_dim &&
+		    (new_state->crtc_w > cursor_max_dim ||
+		    new_state->crtc_h > cursor_max_dim)) {
 			drm_warn(&vmw->drm,
 				 "Cursor dimensions (%d, %d) exceed device max %u\n",
 				 new_state->crtc_w, new_state->crtc_h,
-- 
2.33.0

Re: [PATCH v2] drm/vmwgfx: Treat zero SVGA_REG_CURSOR_MAX_DIMENSION as unset

Posted by Maaz Mombasawala 1 month ago

On 8/23/26 1:59 AM, fausten wrote:
> The cursor plane code validates cursor dimensions against
> SVGA_REG_CURSOR_MAX_DIMENSION before every cursor update, and
> rejects the update with -EINVAL if the cursor is larger than the
> reported maximum.
> 
> However, some SVGA implementations do not implement this register
> and return 0 for it. In that case every cursor update is rejected,
> and the log is spammed with:
> 
>   [drm] Cursor dimensions (64, 64) exceed device max 0
> 
> The visible symptom is that the hardware cursor never appears at
> all on VMware Fusion guests (SVGA version 2), making the mouse
> pointer invisible even though the input devices work fine.
> 
> Treat a reported maximum of 0 as "not implemented" and skip the
> dimension check in that case, restoring the pre-existing behaviour
> of accepting the cursor.
> 
> Tested on VMware Fusion with an SVGA version 2 device where the
> cursor previously did not show up.
> 
> Fixes: d5ed8749168a ("drm/vmwgfx: enforce cursor size limits for MOB cursors")
> Signed-off-by: fausten <yunfeng.li.nb@gmail.com>
> ---
> Changes in v2:
> - Fix author name and email address (v1 was sent with a wrong From).
> 
>  drivers/gpu/drm/vmwgfx/vmwgfx_cursor_plane.c | 12 ++++++++----
>  1 file changed, 8 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_cursor_plane.c b/drivers/gpu/drm/vmwgfx/vmwgfx_cursor_plane.c
> index d1e7df500..fbdd23ecb 100644
> --- a/drivers/gpu/drm/vmwgfx/vmwgfx_cursor_plane.c
> +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_cursor_plane.c
> @@ -237,8 +237,10 @@ static int vmw_cursor_mob_get(struct vmw_cursor_plane *vcp,
>  	mob_max_size = vmw_read(dev_priv, SVGA_REG_MOB_MAX_SIZE);
>  	cursor_max_dim = vmw_read(dev_priv, SVGA_REG_CURSOR_MAX_DIMENSION);
>  
> -	if (size > mob_max_size || vps->base.crtc_w > cursor_max_dim ||
> -	    vps->base.crtc_h > cursor_max_dim)
> +	/* Some SVGA implementations (e.g. VMware Fusion) report 0 here. */

The issue here is not with vmware fusion but the hw version, SVGA_REG_CURSOR_MAX_DIMENSION requires cursor mobs,
which are available only on hw versions 18 and above. Please correct the comment here and below to reflect that.

> +	if (cursor_max_dim &&

Could you instead do cursor_max_dim > 0 here and below.

> +	    (size > mob_max_size || vps->base.crtc_w > cursor_max_dim ||
> +	     vps->base.crtc_h > cursor_max_dim))
>  		return -EINVAL;
>  
>  	if (vps->cursor.mob) {
> @@ -748,8 +750,10 @@ int vmw_cursor_plane_atomic_check(struct drm_plane *plane,
>  		u32 cursor_max_dim =
>  			vmw_read(vmw, SVGA_REG_CURSOR_MAX_DIMENSION);
>  
> -		if (new_state->crtc_w > cursor_max_dim ||
> -		    new_state->crtc_h > cursor_max_dim) {
> +		/* Some SVGA implementations (e.g. VMware Fusion) report 0 here. */
> +		if (cursor_max_dim &&
> +		    (new_state->crtc_w > cursor_max_dim ||
> +		    new_state->crtc_h > cursor_max_dim)) {
>  			drm_warn(&vmw->drm,
>  				 "Cursor dimensions (%d, %d) exceed device max %u\n",
>  				 new_state->crtc_w, new_state->crtc_h,


-- 
Maaz Mombasawala <maaz.mombasawala@broadcom.com>

[PATCH v4] drm/vmwgfx: Treat zero SVGA_REG_CURSOR_MAX_DIMENSION as unset

Posted by fausten 4 weeks ago

The cursor plane code validates cursor dimensions against
SVGA_REG_CURSOR_MAX_DIMENSION before every cursor update, and
rejects the update with -EINVAL if the cursor is larger than the
reported maximum.

However, this register is only available on hardware versions 18
and above, which introduced cursor MOBs. Older hardware (e.g. a
VMware Fusion guest with SVGA version 2) returns 0 for it.
In that case every cursor update is rejected,
and the log is spammed with:

  [drm] Cursor dimensions (64, 64) exceed device max 0

The visible symptom is that the hardware cursor never appears at
all on VMware Fusion guests (SVGA version 2), making the mouse
pointer invisible even though the input devices work fine.

Treat a reported maximum of 0 as "not implemented" and skip the
dimension check in that case, restoring the pre-existing behaviour
of accepting the cursor.

Tested on VMware Fusion with an SVGA version 2 device where the
cursor previously did not show up.

Fixes: d5ed8749168a ("drm/vmwgfx: enforce cursor size limits for MOB cursors")
Signed-off-by: Yunfeng Li <yunfeng.li.nb@gmail.com>
---
 drivers/gpu/drm/vmwgfx/vmwgfx_cursor_plane.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

---
Changes in v3:
- Use an explicit cursor_max_dim > 0 comparison (Maaz).
- Fix the comments: the register requires cursor MOBs which exist
  only on hw version 18 and above; it is not Fusion-specific
  (Maaz).

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_cursor_plane.c b/drivers/gpu/drm/vmwgfx/vmwgfx_cursor_plane.c
index d1e7df500..3d4660684 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_cursor_plane.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_cursor_plane.c
@@ -237,8 +237,10 @@ static int vmw_cursor_mob_get(struct vmw_cursor_plane *vcp,
 	mob_max_size = vmw_read(dev_priv, SVGA_REG_MOB_MAX_SIZE);
 	cursor_max_dim = vmw_read(dev_priv, SVGA_REG_CURSOR_MAX_DIMENSION);
 
-	if (size > mob_max_size || vps->base.crtc_w > cursor_max_dim ||
-	    vps->base.crtc_h > cursor_max_dim)
+	/* Cursor MOBs, and thus this register, exist only on hw version 18+. */
+	if (cursor_max_dim > 0 &&
+	    (size > mob_max_size || vps->base.crtc_w > cursor_max_dim ||
+	     vps->base.crtc_h > cursor_max_dim))
 		return -EINVAL;
 
 	if (vps->cursor.mob) {
@@ -748,8 +750,10 @@ int vmw_cursor_plane_atomic_check(struct drm_plane *plane,
 		u32 cursor_max_dim =
 			vmw_read(vmw, SVGA_REG_CURSOR_MAX_DIMENSION);
 
-		if (new_state->crtc_w > cursor_max_dim ||
-		    new_state->crtc_h > cursor_max_dim) {
+		/* Cursor MOBs, and thus this register, exist only on hw version 18+. */
+		if (cursor_max_dim > 0 &&
+		    (new_state->crtc_w > cursor_max_dim ||
+		     new_state->crtc_h > cursor_max_dim)) {
 			drm_warn(&vmw->drm,
 				 "Cursor dimensions (%d, %d) exceed device max %u\n",
 				 new_state->crtc_w, new_state->crtc_h,
-- 
2.33.0

Re: [PATCH v4] drm/vmwgfx: Treat zero SVGA_REG_CURSOR_MAX_DIMENSION as unset

Posted by Maaz Mombasawala 3 weeks, 4 days ago

On 8/30/26 8:16 AM, fausten wrote:
> The cursor plane code validates cursor dimensions against
> SVGA_REG_CURSOR_MAX_DIMENSION before every cursor update, and
> rejects the update with -EINVAL if the cursor is larger than the
> reported maximum.
> 
> However, this register is only available on hardware versions 18
> and above, which introduced cursor MOBs. Older hardware (e.g. a
> VMware Fusion guest with SVGA version 2) returns 0 for it.
> In that case every cursor update is rejected,
> and the log is spammed with:
> 
>   [drm] Cursor dimensions (64, 64) exceed device max 0
> 
> The visible symptom is that the hardware cursor never appears at
> all on VMware Fusion guests (SVGA version 2), making the mouse
> pointer invisible even though the input devices work fine.
> 
> Treat a reported maximum of 0 as "not implemented" and skip the
> dimension check in that case, restoring the pre-existing behaviour
> of accepting the cursor.
> 
> Tested on VMware Fusion with an SVGA version 2 device where the
> cursor previously did not show up.
> 
> Fixes: d5ed8749168a ("drm/vmwgfx: enforce cursor size limits for MOB cursors")
> Signed-off-by: Yunfeng Li <yunfeng.li.nb@gmail.com>
> ---
>  drivers/gpu/drm/vmwgfx/vmwgfx_cursor_plane.c | 12 ++++++++----
>  1 file changed, 8 insertions(+), 4 deletions(-)
> 
> ---
> Changes in v3:
> - Use an explicit cursor_max_dim > 0 comparison (Maaz).
> - Fix the comments: the register requires cursor MOBs which exist
>   only on hw version 18 and above; it is not Fusion-specific
>   (Maaz).
> 
> diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_cursor_plane.c b/drivers/gpu/drm/vmwgfx/vmwgfx_cursor_plane.c
> index d1e7df500..3d4660684 100644
> --- a/drivers/gpu/drm/vmwgfx/vmwgfx_cursor_plane.c
> +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_cursor_plane.c
> @@ -237,8 +237,10 @@ static int vmw_cursor_mob_get(struct vmw_cursor_plane *vcp,
>  	mob_max_size = vmw_read(dev_priv, SVGA_REG_MOB_MAX_SIZE);
>  	cursor_max_dim = vmw_read(dev_priv, SVGA_REG_CURSOR_MAX_DIMENSION);
>  
> -	if (size > mob_max_size || vps->base.crtc_w > cursor_max_dim ||
> -	    vps->base.crtc_h > cursor_max_dim)
> +	/* Cursor MOBs, and thus this register, exist only on hw version 18+. */
> +	if (cursor_max_dim > 0 &&
> +	    (size > mob_max_size || vps->base.crtc_w > cursor_max_dim ||
> +	     vps->base.crtc_h > cursor_max_dim))
>  		return -EINVAL;
>  
>  	if (vps->cursor.mob) {
> @@ -748,8 +750,10 @@ int vmw_cursor_plane_atomic_check(struct drm_plane *plane,
>  		u32 cursor_max_dim =
>  			vmw_read(vmw, SVGA_REG_CURSOR_MAX_DIMENSION);
>  
> -		if (new_state->crtc_w > cursor_max_dim ||
> -		    new_state->crtc_h > cursor_max_dim) {
> +		/* Cursor MOBs, and thus this register, exist only on hw version 18+. */
> +		if (cursor_max_dim > 0 &&
> +		    (new_state->crtc_w > cursor_max_dim ||
> +		     new_state->crtc_h > cursor_max_dim)) {
>  			drm_warn(&vmw->drm,
>  				 "Cursor dimensions (%d, %d) exceed device max %u\n",
>  				 new_state->crtc_w, new_state->crtc_h,

This patch bricked my testing VM, investigating..


-- 
Maaz Mombasawala <maaz.mombasawala@broadcom.com>

Re: [PATCH v2] drm/vmwgfx: Treat zero SVGA_REG_CURSOR_MAX_DIMENSION as unset

Posted by Maaz Mombasawala 1 month ago

On 8/23/26 1:59 AM, fausten wrote:
> The cursor plane code validates cursor dimensions against
> SVGA_REG_CURSOR_MAX_DIMENSION before every cursor update, and
> rejects the update with -EINVAL if the cursor is larger than the
> reported maximum.
> 
> However, some SVGA implementations do not implement this register
> and return 0 for it. In that case every cursor update is rejected,
> and the log is spammed with:
> 
>   [drm] Cursor dimensions (64, 64) exceed device max 0
> 
> The visible symptom is that the hardware cursor never appears at
> all on VMware Fusion guests (SVGA version 2), making the mouse
> pointer invisible even though the input devices work fine.
> 
> Treat a reported maximum of 0 as "not implemented" and skip the
> dimension check in that case, restoring the pre-existing behaviour
> of accepting the cursor.
> 
> Tested on VMware Fusion with an SVGA version 2 device where the
> cursor previously did not show up.

I take it this is an x86_64 mac? What version of fusion are you using?
Also what is the hwVersion of your VM?

> 
> Fixes: d5ed8749168a ("drm/vmwgfx: enforce cursor size limits for MOB cursors")
> Signed-off-by: fausten <yunfeng.li.nb@gmail.com>
> ---
> Changes in v2:
> - Fix author name and email address (v1 was sent with a wrong From).
> 
>  drivers/gpu/drm/vmwgfx/vmwgfx_cursor_plane.c | 12 ++++++++----
>  1 file changed, 8 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_cursor_plane.c b/drivers/gpu/drm/vmwgfx/vmwgfx_cursor_plane.c
> index d1e7df500..fbdd23ecb 100644
> --- a/drivers/gpu/drm/vmwgfx/vmwgfx_cursor_plane.c
> +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_cursor_plane.c
> @@ -237,8 +237,10 @@ static int vmw_cursor_mob_get(struct vmw_cursor_plane *vcp,
>  	mob_max_size = vmw_read(dev_priv, SVGA_REG_MOB_MAX_SIZE);
>  	cursor_max_dim = vmw_read(dev_priv, SVGA_REG_CURSOR_MAX_DIMENSION);
>  
> -	if (size > mob_max_size || vps->base.crtc_w > cursor_max_dim ||
> -	    vps->base.crtc_h > cursor_max_dim)
> +	/* Some SVGA implementations (e.g. VMware Fusion) report 0 here. */
> +	if (cursor_max_dim &&
> +	    (size > mob_max_size || vps->base.crtc_w > cursor_max_dim ||
> +	     vps->base.crtc_h > cursor_max_dim))
>  		return -EINVAL;
>  
>  	if (vps->cursor.mob) {
> @@ -748,8 +750,10 @@ int vmw_cursor_plane_atomic_check(struct drm_plane *plane,
>  		u32 cursor_max_dim =
>  			vmw_read(vmw, SVGA_REG_CURSOR_MAX_DIMENSION);
>  
> -		if (new_state->crtc_w > cursor_max_dim ||
> -		    new_state->crtc_h > cursor_max_dim) {
> +		/* Some SVGA implementations (e.g. VMware Fusion) report 0 here. */
> +		if (cursor_max_dim &&
> +		    (new_state->crtc_w > cursor_max_dim ||
> +		    new_state->crtc_h > cursor_max_dim)) {
>  			drm_warn(&vmw->drm,
>  				 "Cursor dimensions (%d, %d) exceed device max %u\n",
>  				 new_state->crtc_w, new_state->crtc_h,


-- 
Maaz Mombasawala <maaz.mombasawala@broadcom.com>

[PATCH v3] drm/vmwgfx: Treat zero SVGA_REG_CURSOR_MAX_DIMENSION as unset

Posted by fausten 1 month ago

From: Yunfeng Li <yunfeng.li.nb@gmail.com>

The cursor plane code validates cursor dimensions against
SVGA_REG_CURSOR_MAX_DIMENSION before every cursor update, and
rejects the update with -EINVAL if the cursor is larger than the
reported maximum.

However, this register is only available on hardware versions 18
and above, which introduced cursor MOBs. Older hardware (e.g. a
VMware Fusion guest with SVGA version 2) returns 0 for it.
In that case every cursor update is rejected,
and the log is spammed with:

  [drm] Cursor dimensions (64, 64) exceed device max 0

The visible symptom is that the hardware cursor never appears at
all on VMware Fusion guests (SVGA version 2), making the mouse
pointer invisible even though the input devices work fine.

Treat a reported maximum of 0 as "not implemented" and skip the
dimension check in that case, restoring the pre-existing behaviour
of accepting the cursor.

Tested on VMware Fusion with an SVGA version 2 device where the
cursor previously did not show up.

Fixes: d5ed8749168a ("drm/vmwgfx: enforce cursor size limits for MOB cursors")
Signed-off-by: Yunfeng Li <yunfeng.li.nb@gmail.com>
---
Changes in v3:
- Use an explicit cursor_max_dim > 0 comparison (Zack Rusin).
- Fix the comments: the register requires cursor MOBs which exist
  only on hw version 18 and above; it is not Fusion-specific
  (Zack Rusin).

 drivers/gpu/drm/vmwgfx/vmwgfx_cursor_plane.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_cursor_plane.c b/drivers/gpu/drm/vmwgfx/vmwgfx_cursor_plane.c
index d1e7df500..3d4660684 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_cursor_plane.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_cursor_plane.c
@@ -237,8 +237,10 @@ static int vmw_cursor_mob_get(struct vmw_cursor_plane *vcp,
 	mob_max_size = vmw_read(dev_priv, SVGA_REG_MOB_MAX_SIZE);
 	cursor_max_dim = vmw_read(dev_priv, SVGA_REG_CURSOR_MAX_DIMENSION);
 
-	if (size > mob_max_size || vps->base.crtc_w > cursor_max_dim ||
-	    vps->base.crtc_h > cursor_max_dim)
+	/* Cursor MOBs, and thus this register, exist only on hw version 18+. */
+	if (cursor_max_dim > 0 &&
+	    (size > mob_max_size || vps->base.crtc_w > cursor_max_dim ||
+	     vps->base.crtc_h > cursor_max_dim))
 		return -EINVAL;
 
 	if (vps->cursor.mob) {
@@ -748,8 +750,10 @@ int vmw_cursor_plane_atomic_check(struct drm_plane *plane,
 		u32 cursor_max_dim =
 			vmw_read(vmw, SVGA_REG_CURSOR_MAX_DIMENSION);
 
-		if (new_state->crtc_w > cursor_max_dim ||
-		    new_state->crtc_h > cursor_max_dim) {
+		/* Cursor MOBs, and thus this register, exist only on hw version 18+. */
+		if (cursor_max_dim > 0 &&
+		    (new_state->crtc_w > cursor_max_dim ||
+		     new_state->crtc_h > cursor_max_dim)) {
 			drm_warn(&vmw->drm,
 				 "Cursor dimensions (%d, %d) exceed device max %u\n",
 				 new_state->crtc_w, new_state->crtc_h,
-- 
2.33.0