On Wed, 17 Oct 2012 12:09:54 +0100
Chris Wilson <ch...@chris-wilson.co.uk> wrote:

> With the introduction of per-process GTT space, the hardware designers
> thought it wise to also limit the ability to write to MMIO space to only
> a "secure" batch buffer. The ability to rewrite registers is the only
> way to program the hardware to perform certain operations like scanline
> waits (required for tear-free windowed updates). So we either have a
> choice of adding an interface to perform those synchronized updates
> inside the kernel, or we permit certain processes the ability to write
> to the "safe" registers from within its command stream. This patch
> exposes the ability to submit a SECURE batch buffer to
> DRM_ROOT_ONLY|DRM_MASTER processes.
> 
> Signed-off-by: Chris Wilson <ch...@chris-wilson.co.uk>
> ---
>  drivers/gpu/drm/i915/i915_dma.c            |    3 +++
>  drivers/gpu/drm/i915/i915_gem_execbuffer.c |   21 ++++++++++++++++++---
>  drivers/gpu/drm/i915/i915_trace.h          |   10 ++++++----
>  drivers/gpu/drm/i915/intel_ringbuffer.c    |   23 +++++++++++++++--------
>  drivers/gpu/drm/i915/intel_ringbuffer.h    |    4 +++-
>  include/drm/i915_drm.h                     |    6 ++++++
>  6 files changed, 51 insertions(+), 16 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
> index 5779e8f..f92c849 100644
> --- a/drivers/gpu/drm/i915/i915_dma.c
> +++ b/drivers/gpu/drm/i915/i915_dma.c
> @@ -1015,6 +1015,9 @@ static int i915_getparam(struct drm_device *dev, void 
> *data,
>       case I915_PARAM_HAS_PRIME_VMAP_FLUSH:
>               value = 1;
>               break;
> +     case I915_PARAM_HAS_SECURE_BATCHES:
> +             value = capable(CAP_SYS_ADMIN);
> +             break;
>       default:
>               DRM_DEBUG_DRIVER("Unknown parameter %d\n",
>                                param->param);
> diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c 
> b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> index bcd5aa2..4bbd088 100644
> --- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> +++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> @@ -816,6 +816,7 @@ i915_gem_do_execbuffer(struct drm_device *dev, void *data,
>       u32 exec_start, exec_len;
>       u32 seqno;
>       u32 mask;
> +     u32 flags;
>       int ret, mode, i;
>  
>       if (!i915_gem_check_execbuffer(args)) {
> @@ -827,6 +828,14 @@ i915_gem_do_execbuffer(struct drm_device *dev, void 
> *data,
>       if (ret)
>               return ret;
>  
> +     flags = 0;
> +     if (args->flags & I915_EXEC_SECURE) {
> +             if (!file->is_master || !capable(CAP_SYS_ADMIN))
> +                 return -EPERM;
> +
> +             flags |= I915_DISPATCH_SECURE;
> +     }
> +
>       switch (args->flags & I915_EXEC_RING_MASK) {
>       case I915_EXEC_DEFAULT:
>       case I915_EXEC_RENDER:
> @@ -999,6 +1008,9 @@ i915_gem_do_execbuffer(struct drm_device *dev, void 
> *data,
>       }
>       batch_obj->base.pending_read_domains |= I915_GEM_DOMAIN_COMMAND;
>  
> +     if (flags & I915_DISPATCH_SECURE && !batch_obj->has_global_gtt_mapping)
> +             i915_gem_gtt_bind_object(batch_obj, batch_obj->cache_level);
> +
>       ret = i915_gem_execbuffer_move_to_gpu(ring, &objects);
>       if (ret)
>               goto err;
> @@ -1044,7 +1056,7 @@ i915_gem_do_execbuffer(struct drm_device *dev, void 
> *data,
>                       goto err;
>       }
>  
> -     trace_i915_gem_ring_dispatch(ring, seqno);
> +     trace_i915_gem_ring_dispatch(ring, seqno, flags);
>  
>       exec_start = batch_obj->gtt_offset + args->batch_start_offset;
>       exec_len = args->batch_len;
> @@ -1056,12 +1068,15 @@ i915_gem_do_execbuffer(struct drm_device *dev, void 
> *data,
>                               goto err;
>  
>                       ret = ring->dispatch_execbuffer(ring,
> -                                                     exec_start, exec_len);
> +                                                     exec_start, exec_len,
> +                                                     flags);
>                       if (ret)
>                               goto err;
>               }
>       } else {
> -             ret = ring->dispatch_execbuffer(ring, exec_start, exec_len);
> +             ret = ring->dispatch_execbuffer(ring,
> +                                             exec_start, exec_len,
> +                                             flags);
>               if (ret)
>                       goto err;
>       }
> diff --git a/drivers/gpu/drm/i915/i915_trace.h 
> b/drivers/gpu/drm/i915/i915_trace.h
> index 8134421..3db4a68 100644
> --- a/drivers/gpu/drm/i915/i915_trace.h
> +++ b/drivers/gpu/drm/i915/i915_trace.h
> @@ -229,24 +229,26 @@ TRACE_EVENT(i915_gem_evict_everything,
>  );
>  
>  TRACE_EVENT(i915_gem_ring_dispatch,
> -         TP_PROTO(struct intel_ring_buffer *ring, u32 seqno),
> -         TP_ARGS(ring, seqno),
> +         TP_PROTO(struct intel_ring_buffer *ring, u32 seqno, u32 flags),
> +         TP_ARGS(ring, seqno, flags),
>  
>           TP_STRUCT__entry(
>                            __field(u32, dev)
>                            __field(u32, ring)
>                            __field(u32, seqno)
> +                          __field(u32, flags)
>                            ),
>  
>           TP_fast_assign(
>                          __entry->dev = ring->dev->primary->index;
>                          __entry->ring = ring->id;
>                          __entry->seqno = seqno;
> +                        __entry->flags = flags;
>                          i915_trace_irq_get(ring, seqno);
>                          ),
>  
> -         TP_printk("dev=%u, ring=%u, seqno=%u",
> -                   __entry->dev, __entry->ring, __entry->seqno)
> +         TP_printk("dev=%u, ring=%u, seqno=%u, flags=%x",
> +                   __entry->dev, __entry->ring, __entry->seqno, 
> __entry->flags)
>  );
>  
>  TRACE_EVENT(i915_gem_ring_flush,
> diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c 
> b/drivers/gpu/drm/i915/intel_ringbuffer.c
> index 133beb6..6a4b8fa 100644
> --- a/drivers/gpu/drm/i915/intel_ringbuffer.c
> +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
> @@ -964,7 +964,9 @@ gen6_ring_put_irq(struct intel_ring_buffer *ring)
>  }
>  
>  static int
> -i965_dispatch_execbuffer(struct intel_ring_buffer *ring, u32 offset, u32 
> length)
> +i965_dispatch_execbuffer(struct intel_ring_buffer *ring,
> +                      u32 offset, u32 length,
> +                      unsigned flags)
>  {
>       int ret;
>  
> @@ -975,7 +977,7 @@ i965_dispatch_execbuffer(struct intel_ring_buffer *ring, 
> u32 offset, u32 length)
>       intel_ring_emit(ring,
>                       MI_BATCH_BUFFER_START |
>                       MI_BATCH_GTT |
> -                     MI_BATCH_NON_SECURE_I965);
> +                     (flags & I915_DISPATCH_SECURE ? 0 : 
> MI_BATCH_NON_SECURE_I965));
>       intel_ring_emit(ring, offset);
>       intel_ring_advance(ring);
>  
> @@ -984,7 +986,8 @@ i965_dispatch_execbuffer(struct intel_ring_buffer *ring, 
> u32 offset, u32 length)
>  
>  static int
>  i830_dispatch_execbuffer(struct intel_ring_buffer *ring,
> -                             u32 offset, u32 len)
> +                             u32 offset, u32 len,
> +                             unsigned flags)
>  {
>       int ret;
>  
> @@ -993,7 +996,7 @@ i830_dispatch_execbuffer(struct intel_ring_buffer *ring,
>               return ret;
>  
>       intel_ring_emit(ring, MI_BATCH_BUFFER);
> -     intel_ring_emit(ring, offset | MI_BATCH_NON_SECURE);
> +     intel_ring_emit(ring, offset | (flags & I915_DISPATCH_SECURE ? 0 : 
> MI_BATCH_NON_SECURE));
>       intel_ring_emit(ring, offset + len - 8);
>       intel_ring_emit(ring, 0);
>       intel_ring_advance(ring);
> @@ -1003,7 +1006,8 @@ i830_dispatch_execbuffer(struct intel_ring_buffer *ring,
>  
>  static int
>  i915_dispatch_execbuffer(struct intel_ring_buffer *ring,
> -                             u32 offset, u32 len)
> +                      u32 offset, u32 len,
> +                      unsigned flags)
>  {
>       int ret;
>  
> @@ -1012,7 +1016,7 @@ i915_dispatch_execbuffer(struct intel_ring_buffer *ring,
>               return ret;
>  
>       intel_ring_emit(ring, MI_BATCH_BUFFER_START | MI_BATCH_GTT);
> -     intel_ring_emit(ring, offset | MI_BATCH_NON_SECURE);
> +     intel_ring_emit(ring, offset | (flags & I915_DISPATCH_SECURE ? 0 : 
> MI_BATCH_NON_SECURE));
>       intel_ring_advance(ring);
>  
>       return 0;
> @@ -1410,7 +1414,8 @@ static int gen6_ring_flush(struct intel_ring_buffer 
> *ring,
>  
>  static int
>  gen6_ring_dispatch_execbuffer(struct intel_ring_buffer *ring,
> -                           u32 offset, u32 len)
> +                           u32 offset, u32 len,
> +                           unsigned flags)
>  {
>       int ret;
>  
> @@ -1418,7 +1423,9 @@ gen6_ring_dispatch_execbuffer(struct intel_ring_buffer 
> *ring,
>       if (ret)
>               return ret;
>  
> -     intel_ring_emit(ring, MI_BATCH_BUFFER_START | MI_BATCH_NON_SECURE_I965);
> +     intel_ring_emit(ring,
> +                     MI_BATCH_BUFFER_START |
> +                     (flags & I915_DISPATCH_SECURE ? 0 : 
> MI_BATCH_NON_SECURE_I965));
>       /* bit0-7 is the length on GEN6+ */
>       intel_ring_emit(ring, offset);
>       intel_ring_advance(ring);
> diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h 
> b/drivers/gpu/drm/i915/intel_ringbuffer.h
> index 40b252e..2667f33 100644
> --- a/drivers/gpu/drm/i915/intel_ringbuffer.h
> +++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
> @@ -81,7 +81,9 @@ struct  intel_ring_buffer {
>       u32             (*get_seqno)(struct intel_ring_buffer *ring,
>                                    bool lazy_coherency);
>       int             (*dispatch_execbuffer)(struct intel_ring_buffer *ring,
> -                                            u32 offset, u32 length);
> +                                            u32 offset, u32 length,
> +                                            unsigned flags);
> +#define I915_DISPATCH_SECURE 0x1
>       void            (*cleanup)(struct intel_ring_buffer *ring);
>       int             (*sync_to)(struct intel_ring_buffer *ring,
>                                  struct intel_ring_buffer *to,
> diff --git a/include/drm/i915_drm.h b/include/drm/i915_drm.h
> index acfb377..4f41f8d 100644
> --- a/include/drm/i915_drm.h
> +++ b/include/drm/i915_drm.h
> @@ -316,6 +316,7 @@ typedef struct drm_i915_irq_wait {
>  #define I915_PARAM_HAS_SEMAPHORES     20
>  #define I915_PARAM_HAS_PRIME_VMAP_FLUSH       21
>  #define I915_PARAM_RSVD_FOR_FUTURE_USE        22
> +#define I915_PARAM_HAS_SECURE_BATCHES         23
>  
>  typedef struct drm_i915_getparam {
>       int param;
> @@ -694,6 +695,11 @@ struct drm_i915_gem_execbuffer2 {
>  /** Resets the SO write offset registers for transform feedback on gen7. */
>  #define I915_EXEC_GEN7_SOL_RESET     (1<<8)
>  
> +/** Request a privileged ("secure") batch buffer. Note only available for
> + * DRM_ROOT_ONLY | DRM_MASTER processes.
> + */
> +#define I915_EXEC_SECURE             (1<<9)
> +
>  #define I915_EXEC_CONTEXT_ID_MASK    (0xffffffff)
>  #define i915_execbuffer2_set_context_id(eb2, context) \
>       (eb2).rsvd1 = context & I915_EXEC_CONTEXT_ID_MASK

Yeah looks good.

Reviewed-by: Jesse Barnes <jbar...@virtuousgeek.org>

-- 
Jesse Barnes, Intel Open Source Technology Center
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