The patchset LGTM and works well with beignet. The 80%+ performance regression 
issue in darktable also has been fixed
after this patchset applied and enable the atomic in L3 at beignet side. So,

Reviewed-by: Zhigang Gong <[email protected]>

Thanks,
Zhigang Gong.

> -----Original Message-----
> From: Francisco Jerez [mailto:[email protected]]
> Sent: Friday, May 29, 2015 9:44 PM
> To: [email protected]
> Cc: Ville Syrjälä; Zhigang Gong; Brad Volkin
> Subject: [PATCH 1/3] drm/i915: Fix command parser to validate multiple
> register access with the same command.
> 
> Until now the software command checker assumed that commands could read
> or write at most a single register per packet.  This is not necessarily the 
> case,
> MI_LOAD_REGISTER_IMM expects a variable-length list of offset/value pairs
> and writes them in sequence.  The previous code would only check whether
> the first entry was valid, effectively allowing userspace to write 
> unrestricted
> registers of the MMIO space by sending a multi-register write with a legal 
> first
> register, with potential security implications on Gen6 and 7 hardware.
> 
> Fix it by extending the drm_i915_cmd_descriptor table to represent
> multi-register access and making validate_cmd() iterate for all register 
> offsets
> present in the command packet.
> 
> Signed-off-by: Francisco Jerez <[email protected]>
> ---
>  drivers/gpu/drm/i915/i915_cmd_parser.c | 74
> ++++++++++++++++++++--------------
>  drivers/gpu/drm/i915/i915_drv.h        |  5 +++
>  2 files changed, 48 insertions(+), 31 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_cmd_parser.c
> b/drivers/gpu/drm/i915/i915_cmd_parser.c
> index 61ae8ff..c4a5f73 100644
> --- a/drivers/gpu/drm/i915/i915_cmd_parser.c
> +++ b/drivers/gpu/drm/i915/i915_cmd_parser.c
> @@ -123,7 +123,7 @@ static const struct drm_i915_cmd_descriptor
> common_cmds[] = {
>       CMD(  MI_SEMAPHORE_MBOX,                SMI,   !F,  0xFF,
> R  ),
>       CMD(  MI_STORE_DWORD_INDEX,             SMI,   !F,  0xFF,
> R  ),
>       CMD(  MI_LOAD_REGISTER_IMM(1),          SMI,   !F,  0xFF,
> W,
> -           .reg = { .offset = 1, .mask = 0x007FFFFC }               ),
> +           .reg = { .offset = 1, .mask = 0x007FFFFC, .step = 2 }    ),
>       CMD(  MI_STORE_REGISTER_MEM(1),         SMI,   !F,  0xFF,
> W | B,
>             .reg = { .offset = 1, .mask = 0x007FFFFC },
>             .bits = {{
> @@ -939,7 +939,7 @@ bool i915_needs_cmd_parser(struct intel_engine_cs
> *ring)
> 
>  static bool check_cmd(const struct intel_engine_cs *ring,
>                     const struct drm_i915_cmd_descriptor *desc,
> -                   const u32 *cmd,
> +                   const u32 *cmd, u32 length,
>                     const bool is_master,
>                     bool *oacontrol_set)
>  {
> @@ -955,38 +955,49 @@ static bool check_cmd(const struct intel_engine_cs
> *ring,
>       }
> 
>       if (desc->flags & CMD_DESC_REGISTER) {
> -             u32 reg_addr = cmd[desc->reg.offset] & desc->reg.mask;
> -
>               /*
> -              * 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.
> +              * Get the distance between individual register offset
> +              * fields if the command can perform more than one
> +              * access at a time.
>                */
> -             if (reg_addr == OACONTROL) {
> -                     if (desc->cmd.value == MI_LOAD_REGISTER_MEM) {
> -                             DRM_DEBUG_DRIVER("CMD: Rejected LRM to
> OACONTROL\n");
> -                             return false;
> +             const u32 step = desc->reg.step ? desc->reg.step : length;
> +             u32 offset;
> +
> +             for (offset = desc->reg.offset; offset < length;
> +                  offset += step) {
> +                     const u32 reg_addr = cmd[offset] & desc->reg.mask;
> +
> +                     /*
> +                      * 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 == 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_IMM(1))
> +                                     *oacontrol_set = (cmd[offset + 1] != 0);
>                       }
> 
> -                     if (desc->cmd.value == MI_LOAD_REGISTER_IMM(1))
> -                             *oacontrol_set = (cmd[2] != 0);
> -             }
> -
> -             if (!valid_reg(ring->reg_table,
> -                            ring->reg_count, reg_addr)) {
> -                     if (!is_master ||
> -                         !valid_reg(ring->master_reg_table,
> -                                    ring->master_reg_count,
> -                                    reg_addr)) {
> -                             DRM_DEBUG_DRIVER("CMD: Rejected register 0x%08X 
> in
> command: 0x%08X (ring=%d)\n",
> -                                              reg_addr,
> -                                              *cmd,
> -                                              ring->id);
> -                             return false;
> +                     if (!valid_reg(ring->reg_table,
> +                                    ring->reg_count, reg_addr)) {
> +                             if (!is_master ||
> +                                 !valid_reg(ring->master_reg_table,
> +                                            ring->master_reg_count,
> +                                            reg_addr)) {
> +                                     DRM_DEBUG_DRIVER("CMD: Rejected register
> 0x%08X in command: 0x%08X (ring=%d)\n",
> +                                                      reg_addr, *cmd,
> +                                                      ring->id);
> +                                     return false;
> +                             }
>                       }
>               }
>       }
> @@ -1110,7 +1121,8 @@ int i915_parse_cmds(struct intel_engine_cs *ring,
>                       break;
>               }
> 
> -             if (!check_cmd(ring, desc, cmd, is_master, &oacontrol_set)) {
> +             if (!check_cmd(ring, desc, cmd, length, is_master,
> +                            &oacontrol_set)) {
>                       ret = -EINVAL;
>                       break;
>               }
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 8ae6f7f..3850288 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -2228,10 +2228,15 @@ struct drm_i915_cmd_descriptor {
>        * Describes where to find a register address in the command to check
>        * against the ring's register whitelist. Only valid if flags has the
>        * CMD_DESC_REGISTER bit set.
> +      *
> +      * A non-zero step value implies that the command may access multiple
> +      * registers in sequence (e.g. LRI), in that case step gives the
> +      * distance in dwords between individual offset fields.
>        */
>       struct {
>               u32 offset;
>               u32 mask;
> +             u32 step;
>       } reg;
> 
>  #define MAX_CMD_DESC_BITMASKS 3
> --
> 2.3.5

_______________________________________________
Intel-gfx mailing list
[email protected]
http://lists.freedesktop.org/mailman/listinfo/intel-gfx

Reply via email to