diff mbox series

[3/5] drm/i915: Disable pread/pwrite ioctl's for future platforms (v3)

Message ID 20210317234014.2271006-4-jason@jlekstrand.net (mailing list archive)
State New, archived
Headers show
Series drm/i915: Clean up some of the i915 uAPI (v6) | expand

Commit Message

Jason Ekstrand March 17, 2021, 11:40 p.m. UTC
From: Ashutosh Dixit <ashutosh.dixit@intel.com>

The rationale for this change is roughly as follows:

 1. The functionality can be done entirely in userspace with a
    combination of mmap + memcpy

 2. The only reason anyone in userspace is still using it is because
    someone implemented bo_subdata that way in libdrm ages ago and
    they're all too lazy to write the 5 lines of code to do a map.

 3. This falls cleanly into the category of things which will only get
    more painful with local memory support.

These ioctls aren't used much anymore by "real" userspace drivers.
Vulkan has never used them and neither has the iris GL driver.  The old
i965 GL driver does use PWRITE for glBufferSubData but it only supports
up through Gen11; Gen12 was never enabled in i965.  The compute driver
has never used PREAD/PWRITE.  The only remaining user is the media
driver which uses it exactly twice and they're easily removed [1] so
expecting them to drop it going forward is reasonable.

IGT changes which handle this kernel change have also been submitted [2].

[1] https://github.com/intel/media-driver/pull/1160
[2] https://patchwork.freedesktop.org/series/81384/

v2 (Jason Ekstrand):
 - Improved commit message with the status of all usermode drivers
 - A more future-proof platform check

v3 (Jason Ekstrand):
 - Drop the HAS_LMEM checks as they're already covered by the version
   checks

Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Signed-off-by: Jason Ekstrand <jason@jlekstrand.net>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
---
 drivers/gpu/drm/i915/i915_gem.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

Comments

Daniel Vetter March 18, 2021, 1:27 p.m. UTC | #1
On Wed, Mar 17, 2021 at 06:40:12PM -0500, Jason Ekstrand wrote:
> From: Ashutosh Dixit <ashutosh.dixit@intel.com>
> 
> The rationale for this change is roughly as follows:
> 
>  1. The functionality can be done entirely in userspace with a
>     combination of mmap + memcpy
> 
>  2. The only reason anyone in userspace is still using it is because
>     someone implemented bo_subdata that way in libdrm ages ago and
>     they're all too lazy to write the 5 lines of code to do a map.
> 
>  3. This falls cleanly into the category of things which will only get
>     more painful with local memory support.
> 
> These ioctls aren't used much anymore by "real" userspace drivers.
> Vulkan has never used them and neither has the iris GL driver.  The old
> i965 GL driver does use PWRITE for glBufferSubData but it only supports
> up through Gen11; Gen12 was never enabled in i965.  The compute driver
> has never used PREAD/PWRITE.  The only remaining user is the media
> driver which uses it exactly twice and they're easily removed [1] so
> expecting them to drop it going forward is reasonable.
> 
> IGT changes which handle this kernel change have also been submitted [2].
> 
> [1] https://github.com/intel/media-driver/pull/1160
> [2] https://patchwork.freedesktop.org/series/81384/
> 
> v2 (Jason Ekstrand):
>  - Improved commit message with the status of all usermode drivers
>  - A more future-proof platform check
> 
> v3 (Jason Ekstrand):
>  - Drop the HAS_LMEM checks as they're already covered by the version
>    checks
> 
> Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
> Signed-off-by: Jason Ekstrand <jason@jlekstrand.net>
> Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>

Merged the first three here. For the scheduler/context stuff I think we
should go back to normal due process with kernel patch + igt patches
tested together, then land igt first, then kernel, just to avoid hiccups
in CI.

Thanks, Daniel

> ---
>  drivers/gpu/drm/i915/i915_gem.c | 14 ++++++++++++++
>  1 file changed, 14 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index b2e3b5cfccb4a..80915467e0d84 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -374,10 +374,17 @@ int
>  i915_gem_pread_ioctl(struct drm_device *dev, void *data,
>  		     struct drm_file *file)
>  {
> +	struct drm_i915_private *i915 = to_i915(dev);
>  	struct drm_i915_gem_pread *args = data;
>  	struct drm_i915_gem_object *obj;
>  	int ret;
>  
> +	/* PREAD is disallowed for all platforms after TGL-LP.  This also
> +	 * covers all platforms with local memory.
> +	 */
> +	if (INTEL_GEN(i915) >= 12 && !IS_TIGERLAKE(i915))
> +		return -EOPNOTSUPP;
> +
>  	if (args->size == 0)
>  		return 0;
>  
> @@ -675,10 +682,17 @@ int
>  i915_gem_pwrite_ioctl(struct drm_device *dev, void *data,
>  		      struct drm_file *file)
>  {
> +	struct drm_i915_private *i915 = to_i915(dev);
>  	struct drm_i915_gem_pwrite *args = data;
>  	struct drm_i915_gem_object *obj;
>  	int ret;
>  
> +	/* PWRITE is disallowed for all platforms after TGL-LP.  This also
> +	 * covers all platforms with local memory.
> +	 */
> +	if (INTEL_GEN(i915) >= 12 && !IS_TIGERLAKE(i915))
> +		return -EOPNOTSUPP;
> +
>  	if (args->size == 0)
>  		return 0;
>  
> -- 
> 2.29.2
> 
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/intel-gfx
diff mbox series

Patch

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index b2e3b5cfccb4a..80915467e0d84 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -374,10 +374,17 @@  int
 i915_gem_pread_ioctl(struct drm_device *dev, void *data,
 		     struct drm_file *file)
 {
+	struct drm_i915_private *i915 = to_i915(dev);
 	struct drm_i915_gem_pread *args = data;
 	struct drm_i915_gem_object *obj;
 	int ret;
 
+	/* PREAD is disallowed for all platforms after TGL-LP.  This also
+	 * covers all platforms with local memory.
+	 */
+	if (INTEL_GEN(i915) >= 12 && !IS_TIGERLAKE(i915))
+		return -EOPNOTSUPP;
+
 	if (args->size == 0)
 		return 0;
 
@@ -675,10 +682,17 @@  int
 i915_gem_pwrite_ioctl(struct drm_device *dev, void *data,
 		      struct drm_file *file)
 {
+	struct drm_i915_private *i915 = to_i915(dev);
 	struct drm_i915_gem_pwrite *args = data;
 	struct drm_i915_gem_object *obj;
 	int ret;
 
+	/* PWRITE is disallowed for all platforms after TGL-LP.  This also
+	 * covers all platforms with local memory.
+	 */
+	if (INTEL_GEN(i915) >= 12 && !IS_TIGERLAKE(i915))
+		return -EOPNOTSUPP;
+
 	if (args->size == 0)
 		return 0;