[Intel-gfx] [RFC 2/2] drm/i915/migrate: Evict and restore the ccs data

Hellstrom, Thomas thomas.hellstrom at intel.com
Mon Feb 7 14:55:42 UTC 2022


Hi, Ram,

A couple of quick questions before starting a more detailed review:

1) Does this also support migrating of compressed data LMEM->LMEM?
What-about inter-tile?

2) Do we need to block faulting of compressed data in the fault handler
as a follow-up patch?

/Thomas


On Mon, 2022-02-07 at 15:07 +0530, Ramalingam C wrote:
> When we are swapping out the local memory obj on flat-ccs capable
> platform,
> we need to capture the ccs data too along with main meory and we need
> to
> restore it when we are swapping in the content.
> 
> Extracting and restoring the CCS data is done through a special cmd
> called
> XY_CTRL_SURF_COPY_BLT
> 
> Signed-off-by: Ramalingam C <ramalingam.c at intel.com>
> ---
>  drivers/gpu/drm/i915/gt/intel_migrate.c | 283 +++++++++++++---------
> --
>  1 file changed, 155 insertions(+), 128 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/gt/intel_migrate.c
> b/drivers/gpu/drm/i915/gt/intel_migrate.c
> index 5bdab0b3c735..e60ae6ff1847 100644
> --- a/drivers/gpu/drm/i915/gt/intel_migrate.c
> +++ b/drivers/gpu/drm/i915/gt/intel_migrate.c
> @@ -449,14 +449,146 @@ static bool wa_1209644611_applies(int ver, u32
> size)
>         return height % 4 == 3 && height <= 8;
>  }
>  
> +/**
> + * DOC: Flat-CCS - Memory compression for Local memory
> + *
> + * On Xe-HP and later devices, we use dedicated compression control
> state (CCS)
> + * stored in local memory for each surface, to support the 3D and
> media
> + * compression formats.
> + *
> + * The memory required for the CCS of the entire local memory is
> 1/256 of the
> + * local memory size. So before the kernel boot, the required memory
> is reserved
> + * for the CCS data and a secure register will be programmed with
> the CCS base
> + * address.
> + *
> + * Flat CCS data needs to be cleared when a lmem object is
> allocated.
> + * And CCS data can be copied in and out of CCS region through
> + * XY_CTRL_SURF_COPY_BLT. CPU can't access the CCS data directly.
> + *
> + * When we exaust the lmem, if the object's placements support smem,
> then we can
> + * directly decompress the compressed lmem object into smem and
> start using it
> + * from smem itself.
> + *
> + * But when we need to swapout the compressed lmem object into a
> smem region
> + * though objects' placement doesn't support smem, then we copy the
> lmem content
> + * as it is into smem region along with ccs data (using
> XY_CTRL_SURF_COPY_BLT).
> + * When the object is referred, lmem content will be swaped in along
> with
> + * restoration of the CCS data (using XY_CTRL_SURF_COPY_BLT) at
> corresponding
> + * location.
> + *
> + *
> + * Flat-CCS Modifiers for different compression formats
> + * ----------------------------------------------------
> + *
> + * I915_FORMAT_MOD_F_TILED_DG2_RC_CCS - used to indicate the buffers
> of Flat CCS
> + * render compression formats. Though the general layout is same as
> + * I915_FORMAT_MOD_Y_TILED_GEN12_RC_CCS, new hashing/compression
> algorithm is
> + * used. Render compression uses 128 byte compression blocks
> + *
> + * I915_FORMAT_MOD_F_TILED_DG2_MC_CCS -used to indicate the buffers
> of Flat CCS
> + * media compression formats. Though the general layout is same as
> + * I915_FORMAT_MOD_Y_TILED_GEN12_MC_CCS, new hashing/compression
> algorithm is
> + * used. Media compression uses 256 byte compression blocks.
> + *
> + * I915_FORMAT_MOD_F_TILED_DG2_RC_CCS_CC - used to indicate the
> buffers of Flat
> + * CCS clear color render compression formats. Unified compression
> format for
> + * clear color render compression. The genral layout is a tiled
> layout using
> + * 4Kb tiles i.e Tile4 layout.
> + */
> +
> +static inline u32 *i915_flush_dw(u32 *cmd, u64 dst, u32 flags)
> +{
> +       /* Mask the 3 LSB to use the PPGTT address space */
> +       *cmd++ = MI_FLUSH_DW | flags;
> +       *cmd++ = lower_32_bits(dst);
> +       *cmd++ = upper_32_bits(dst);
> +
> +       return cmd;
> +}
> +
> +static u32 calc_ctrl_surf_instr_size(struct drm_i915_private *i915,
> int size)
> +{
> +       u32 num_cmds, num_blks, total_size;
> +
> +       if (!GET_CCS_SIZE(i915, size))
> +               return 0;
> +
> +       /*
> +        * XY_CTRL_SURF_COPY_BLT transfers CCS in 256 byte
> +        * blocks. one XY_CTRL_SURF_COPY_BLT command can
> +        * trnasfer upto 1024 blocks.
> +        */
> +       num_blks = GET_CCS_SIZE(i915, size);
> +       num_cmds = (num_blks + (NUM_CCS_BLKS_PER_XFER - 1)) >> 10;
> +       total_size = (XY_CTRL_SURF_INSTR_SIZE) * num_cmds;
> +
> +       /*
> +        * We need to add a flush before and after
> +        * XY_CTRL_SURF_COPY_BLT
> +        */
> +       total_size += 2 * MI_FLUSH_DW_SIZE;
> +       return total_size;
> +}
> +
> +static u32 *_i915_ctrl_surf_copy_blt(u32 *cmd, u64 src_addr, u64
> dst_addr,
> +                                    u8 src_mem_access, u8
> dst_mem_access,
> +                                    int src_mocs, int dst_mocs,
> +                                    u16 num_ccs_blocks)
> +{
> +       int i = num_ccs_blocks;
> +
> +       /*
> +        * The XY_CTRL_SURF_COPY_BLT instruction is used to copy the
> CCS
> +        * data in and out of the CCS region.
> +        *
> +        * We can copy at most 1024 blocks of 256 bytes using one
> +        * XY_CTRL_SURF_COPY_BLT instruction.
> +        *
> +        * In case we need to copy more than 1024 blocks, we need to
> add
> +        * another instruction to the same batch buffer.
> +        *
> +        * 1024 blocks of 256 bytes of CCS represent a total 256KB of
> CCS.
> +        *
> +        * 256 KB of CCS represents 256 * 256 KB = 64 MB of LMEM.
> +        */
> +       do {
> +               /*
> +                * We use logical AND with 1023 since the size field
> +                * takes values which is in the range of 0 - 1023
> +                */
> +               *cmd++ = ((XY_CTRL_SURF_COPY_BLT) |
> +                         (src_mem_access << SRC_ACCESS_TYPE_SHIFT) |
> +                         (dst_mem_access << DST_ACCESS_TYPE_SHIFT) |
> +                         (((i - 1) & 1023) << CCS_SIZE_SHIFT));
> +               *cmd++ = lower_32_bits(src_addr);
> +               *cmd++ = ((upper_32_bits(src_addr) & 0xFFFF) |
> +                         (src_mocs << XY_CTRL_SURF_MOCS_SHIFT));
> +               *cmd++ = lower_32_bits(dst_addr);
> +               *cmd++ = ((upper_32_bits(dst_addr) & 0xFFFF) |
> +                         (dst_mocs << XY_CTRL_SURF_MOCS_SHIFT));
> +               src_addr += SZ_64M;
> +               dst_addr += SZ_64M;
> +               i -= NUM_CCS_BLKS_PER_XFER;
> +       } while (i > 0);
> +
> +       return cmd;
> +}
> +
>  static int emit_copy(struct i915_request *rq,
> -                    u32 dst_offset, u32 src_offset, int size)
> +                    bool dst_is_lmem, u32 dst_offset,
> +                    bool src_is_lmem, u32 src_offset, int size)
>  {
> +       struct drm_i915_private *i915 = rq->engine->i915;
>         const int ver = GRAPHICS_VER(rq->engine->i915);
>         u32 instance = rq->engine->instance;
> +       u32 num_ccs_blks, ccs_ring_size;
> +       u8 src_access, dst_access;
>         u32 *cs;
>  
> -       cs = intel_ring_begin(rq, ver >= 8 ? 10 : 6);
> +       ccs_ring_size = ((src_is_lmem || dst_is_lmem) &&
> HAS_FLAT_CCS(i915)) ?
> +                        calc_ctrl_surf_instr_size(i915, size) : 0;
> +
> +       cs = intel_ring_begin(rq, ver >= 8 ? 10 + ccs_ring_size : 6);
>         if (IS_ERR(cs))
>                 return PTR_ERR(cs);
>  
> @@ -492,6 +624,25 @@ static int emit_copy(struct i915_request *rq,
>                 *cs++ = src_offset;
>         }
>  
> +       if (ccs_ring_size) {
> +               /* TODO: Migration needs to be handled with resolve
> of compressed data */
> +               num_ccs_blks = (GET_CCS_SIZE(i915, size) +
> +                               NUM_CCS_BYTES_PER_BLOCK - 1) >> 8;
> +
> +               src_access = !src_is_lmem && dst_is_lmem;
> +               dst_access = !src_access;
> +
> +               if (src_access) /* Swapin of compressed data */
> +                       src_offset += size;
> +               else
> +                       dst_offset += size;
> +
> +               cs = _i915_ctrl_surf_copy_blt(cs, src_offset,
> dst_offset,
> +                                             src_access, dst_access,
> +                                             1, 1, num_ccs_blks);
> +               cs = i915_flush_dw(cs, dst_offset, MI_FLUSH_LLC |
> MI_FLUSH_CCS);
> +       }
> +
>         intel_ring_advance(rq, cs);
>         return 0;
>  }
> @@ -578,7 +729,8 @@ intel_context_migrate_copy(struct intel_context
> *ce,
>                 if (err)
>                         goto out_rq;
>  
> -               err = emit_copy(rq, dst_offset, src_offset, len);
> +               err = emit_copy(rq, dst_is_lmem, dst_offset,
> +                               src_is_lmem, src_offset, len);
>  
>                 /* Arbitration is re-enabled between requests. */
>  out_rq:
> @@ -596,131 +748,6 @@ intel_context_migrate_copy(struct intel_context
> *ce,
>         return err;
>  }
>  
> -/**
> - * DOC: Flat-CCS - Memory compression for Local memory
> - *
> - * On Xe-HP and later devices, we use dedicated compression control
> state (CCS)
> - * stored in local memory for each surface, to support the 3D and
> media
> - * compression formats.
> - *
> - * The memory required for the CCS of the entire local memory is
> 1/256 of the
> - * local memory size. So before the kernel boot, the required memory
> is reserved
> - * for the CCS data and a secure register will be programmed with
> the CCS base
> - * address.
> - *
> - * Flat CCS data needs to be cleared when a lmem object is
> allocated.
> - * And CCS data can be copied in and out of CCS region through
> - * XY_CTRL_SURF_COPY_BLT. CPU can't access the CCS data directly.
> - *
> - * When we exaust the lmem, if the object's placements support smem,
> then we can
> - * directly decompress the compressed lmem object into smem and
> start using it
> - * from smem itself.
> - *
> - * But when we need to swapout the compressed lmem object into a
> smem region
> - * though objects' placement doesn't support smem, then we copy the
> lmem content
> - * as it is into smem region along with ccs data (using
> XY_CTRL_SURF_COPY_BLT).
> - * When the object is referred, lmem content will be swaped in along
> with
> - * restoration of the CCS data (using XY_CTRL_SURF_COPY_BLT) at
> corresponding
> - * location.
> - *
> - *
> - * Flat-CCS Modifiers for different compression formats
> - * ----------------------------------------------------
> - *
> - * I915_FORMAT_MOD_F_TILED_DG2_RC_CCS - used to indicate the buffers
> of Flat CCS
> - * render compression formats. Though the general layout is same as
> - * I915_FORMAT_MOD_Y_TILED_GEN12_RC_CCS, new hashing/compression
> algorithm is
> - * used. Render compression uses 128 byte compression blocks
> - *
> - * I915_FORMAT_MOD_F_TILED_DG2_MC_CCS -used to indicate the buffers
> of Flat CCS
> - * media compression formats. Though the general layout is same as
> - * I915_FORMAT_MOD_Y_TILED_GEN12_MC_CCS, new hashing/compression
> algorithm is
> - * used. Media compression uses 256 byte compression blocks.
> - *
> - * I915_FORMAT_MOD_F_TILED_DG2_RC_CCS_CC - used to indicate the
> buffers of Flat
> - * CCS clear color render compression formats. Unified compression
> format for
> - * clear color render compression. The genral layout is a tiled
> layout using
> - * 4Kb tiles i.e Tile4 layout.
> - */
> -
> -static inline u32 *i915_flush_dw(u32 *cmd, u64 dst, u32 flags)
> -{
> -       /* Mask the 3 LSB to use the PPGTT address space */
> -       *cmd++ = MI_FLUSH_DW | flags;
> -       *cmd++ = lower_32_bits(dst);
> -       *cmd++ = upper_32_bits(dst);
> -
> -       return cmd;
> -}
> -
> -static u32 calc_ctrl_surf_instr_size(struct drm_i915_private *i915,
> int size)
> -{
> -       u32 num_cmds, num_blks, total_size;
> -
> -       if (!GET_CCS_SIZE(i915, size))
> -               return 0;
> -
> -       /*
> -        * XY_CTRL_SURF_COPY_BLT transfers CCS in 256 byte
> -        * blocks. one XY_CTRL_SURF_COPY_BLT command can
> -        * trnasfer upto 1024 blocks.
> -        */
> -       num_blks = GET_CCS_SIZE(i915, size);
> -       num_cmds = (num_blks + (NUM_CCS_BLKS_PER_XFER - 1)) >> 10;
> -       total_size = (XY_CTRL_SURF_INSTR_SIZE) * num_cmds;
> -
> -       /*
> -        * We need to add a flush before and after
> -        * XY_CTRL_SURF_COPY_BLT
> -        */
> -       total_size += 2 * MI_FLUSH_DW_SIZE;
> -       return total_size;
> -}
> -
> -static u32 *_i915_ctrl_surf_copy_blt(u32 *cmd, u64 src_addr, u64
> dst_addr,
> -                                    u8 src_mem_access, u8
> dst_mem_access,
> -                                    int src_mocs, int dst_mocs,
> -                                    u16 num_ccs_blocks)
> -{
> -       int i = num_ccs_blocks;
> -
> -       /*
> -        * The XY_CTRL_SURF_COPY_BLT instruction is used to copy the
> CCS
> -        * data in and out of the CCS region.
> -        *
> -        * We can copy at most 1024 blocks of 256 bytes using one
> -        * XY_CTRL_SURF_COPY_BLT instruction.
> -        *
> -        * In case we need to copy more than 1024 blocks, we need to
> add
> -        * another instruction to the same batch buffer.
> -        *
> -        * 1024 blocks of 256 bytes of CCS represent a total 256KB of
> CCS.
> -        *
> -        * 256 KB of CCS represents 256 * 256 KB = 64 MB of LMEM.
> -        */
> -       do {
> -               /*
> -                * We use logical AND with 1023 since the size field
> -                * takes values which is in the range of 0 - 1023
> -                */
> -               *cmd++ = ((XY_CTRL_SURF_COPY_BLT) |
> -                         (src_mem_access << SRC_ACCESS_TYPE_SHIFT) |
> -                         (dst_mem_access << DST_ACCESS_TYPE_SHIFT) |
> -                         (((i - 1) & 1023) << CCS_SIZE_SHIFT));
> -               *cmd++ = lower_32_bits(src_addr);
> -               *cmd++ = ((upper_32_bits(src_addr) & 0xFFFF) |
> -                         (src_mocs << XY_CTRL_SURF_MOCS_SHIFT));
> -               *cmd++ = lower_32_bits(dst_addr);
> -               *cmd++ = ((upper_32_bits(dst_addr) & 0xFFFF) |
> -                         (dst_mocs << XY_CTRL_SURF_MOCS_SHIFT));
> -               src_addr += SZ_64M;
> -               dst_addr += SZ_64M;
> -               i -= NUM_CCS_BLKS_PER_XFER;
> -       } while (i > 0);
> -
> -       return cmd;
> -}
> -
>  static int emit_clear(struct i915_request *rq,
>                       u64 offset,
>                       int size,

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