Re: [PATCH v2] drm/i915: don't whitelist oacontrol in cmd parser

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 





On Tue, Nov 22, 2016 at 1:34 PM, Daniel Vetter <daniel@xxxxxxxx> wrote:
On Tue, Nov 08, 2016 at 12:51:48PM +0000, Robert Bragg wrote:
> This v2 patch bumps the command parser version so it can be referenced in
> corresponding i-g-t gem_exec_parse changes.
>
> --- >8 ---

Scissors cut everything below, not everything above, hence next time
around pls switch around your comment and the commit message, as-is not
much left ;-)

Hmm, they cut away what's above and keep what's below in my experience - what command are you seeing the opposite with?

I just double checked this with git am --scissors

- Robert

 

Fixed up while applying.
-Daniel

>
> Being able to program OACONTROL from a non-privileged batch buffer is
> not sufficient to be able to configure the OA unit. This was originally
> allowed to help enable Mesa to expose OA counters via the
> INTEL_performance_query extension, but the current implementation based
> on programming OACONTROL via a batch buffer isn't able to report useable
> data without a more complete OA unit configuration. Mesa handles the
> possibility that writes to OACONTROL may not be allowed and so only
> advertises the extension after explicitly testing that a write to
> OACONTROL succeeds. Based on this; removing OACONTROL from the whitelist
> should be ok for userspace.
>
> Removing this simplifies adding a new kernel api for configuring the OA
> unit without needing to consider the possibility that userspace might
> trample on OACONTROL state which we'd like to start managing within
> the kernel instead. In particular running any Mesa based GL application
> currently results in clearing OACONTROL when initializing which would
> disable the capturing of metrics.
>
> v2:
>     This bumps the command parser version from 8 to 9, as the change is
>     visible to userspace.
>
> Signed-off-by: Robert Bragg <robert@xxxxxxxxxxxxx>
> Reviewed-by: Matthew Auld <matthew.auld@xxxxxxxxx>
> Reviewed-by: Sourab Gupta <sourab.gupta@xxxxxxxxx>
> ---
>  drivers/gpu/drm/i915/i915_cmd_parser.c | 42 ++++------------------------------
>  1 file changed, 5 insertions(+), 37 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_cmd_parser.c b/drivers/gpu/drm/i915/i915_cmd_parser.c
> index c9d2ecd..f5762cd 100644
> --- a/drivers/gpu/drm/i915/i915_cmd_parser.c
> +++ b/drivers/gpu/drm/i915/i915_cmd_parser.c
> @@ -450,7 +450,6 @@ static const struct drm_i915_reg_descriptor gen7_render_regs[] = {
>       REG64(PS_INVOCATION_COUNT),
>       REG64(PS_DEPTH_COUNT),
>       REG64_IDX(RING_TIMESTAMP, RENDER_RING_BASE),
> -     REG32(GEN7_OACONTROL), /* Only allowed for LRI and SRM. See below. */
>       REG64(MI_PREDICATE_SRC0),
>       REG64(MI_PREDICATE_SRC1),
>       REG32(GEN7_3DPRIM_END_OFFSET),
> @@ -1060,8 +1059,7 @@ bool intel_engine_needs_cmd_parser(struct intel_engine_cs *engine)
>  static bool check_cmd(const struct intel_engine_cs *engine,
>                     const struct drm_i915_cmd_descriptor *desc,
>                     const u32 *cmd, u32 length,
> -                   const bool is_master,
> -                   bool *oacontrol_set)
> +                   const bool is_master)
>  {
>       if (desc->flags & CMD_DESC_SKIP)
>               return true;
> @@ -1099,31 +1097,6 @@ static bool check_cmd(const struct intel_engine_cs *engine,
>                       }
>
>                       /*
> -                      * OACONTROL requires some special handling for
> -                      * writes. We want to make sure that any batch which
> -                      * enables OA also disables it before the end of the
> -                      * batch. The goal is to prevent one process from
> -                      * snooping on the perf data from another process. To do
> -                      * that, we need to check the value that will be written
> -                      * to the register. Hence, limit OACONTROL writes to
> -                      * only MI_LOAD_REGISTER_IMM commands.
> -                      */
> -                     if (reg_addr == i915_mmio_reg_offset(GEN7_OACONTROL)) {
> -                             if (desc->cmd.value == MI_LOAD_REGISTER_MEM) {
> -                                     DRM_DEBUG_DRIVER("CMD: Rejected LRM to OACONTROL\n");
> -                                     return false;
> -                             }
> -
> -                             if (desc->cmd.value == MI_LOAD_REGISTER_REG) {
> -                                     DRM_DEBUG_DRIVER("CMD: Rejected LRR to OACONTROL\n");
> -                                     return false;
> -                             }
> -
> -                             if (desc->cmd.value == MI_LOAD_REGISTER_IMM(1))
> -                                     *oacontrol_set = (cmd[offset + 1] != 0);
> -                     }
> -
> -                     /*
>                        * Check the value written to the register against the
>                        * allowed mask/value pair given in the whitelist entry.
>                        */
> @@ -1214,7 +1187,6 @@ int intel_engine_cmd_parser(struct intel_engine_cs *engine,
>       u32 *cmd, *batch_end;
>       struct drm_i915_cmd_descriptor default_desc = noop_desc;
>       const struct drm_i915_cmd_descriptor *desc = &default_desc;
> -     bool oacontrol_set = false; /* OACONTROL tracking. See check_cmd() */
>       bool needs_clflush_after = false;
>       int ret = 0;
>
> @@ -1270,8 +1242,7 @@ int intel_engine_cmd_parser(struct intel_engine_cs *engine,
>                       break;
>               }
>
> -             if (!check_cmd(engine, desc, cmd, length, is_master,
> -                            &oacontrol_set)) {
> +             if (!check_cmd(engine, desc, cmd, length, is_master)) {
>                       ret = -EACCES;
>                       break;
>               }
> @@ -1279,11 +1250,6 @@ int intel_engine_cmd_parser(struct intel_engine_cs *engine,
>               cmd += length;
>       }
>
> -     if (oacontrol_set) {
> -             DRM_DEBUG_DRIVER("CMD: batch set OACONTROL but did not clear it\n");
> -             ret = -EINVAL;
> -     }
> -
>       if (cmd >= batch_end) {
>               DRM_DEBUG_DRIVER("CMD: Got to the end of the buffer w/o a BBE cmd!\n");
>               ret = -EINVAL;
> @@ -1336,6 +1302,8 @@ int i915_cmd_parser_get_version(struct drm_i915_private *dev_priv)
>        * 8. Don't report cmd_check() failures as EINVAL errors to userspace;
>        *    rely on the HW to NOOP disallowed commands as it would without
>        *    the parser enabled.
> +      * 9. Don't whitelist or handle oacontrol specially, as ownership
> +      *    for oacontrol state is moving to i915-perf.
>        */
> -     return 8;
> +     return 9;
>  }
> --
> 2.10.1
>
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/intel-gfx

--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

_______________________________________________
Intel-gfx mailing list
Intel-gfx@xxxxxxxxxxxxxxxxxxxxx
https://lists.freedesktop.org/mailman/listinfo/intel-gfx

[Index of Archives]     [Linux USB Devel]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]
  Powered by Linux