| Message ID | 20220502142618.2704-2-ramalingam.c@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Flat-CCS eviction enhancements | expand |
On Mon, 02 May 2022, Ramalingam C <ramalingam.c@intel.com> wrote: > While locating the start of ccs scatterlist in smem scatterlist, that has > to be the size of lmem obj size + corresponding ccs data size, report bug > if scatterlist terminate before that length. > > v2: > s/GEM_BUG_ON/BUG_ON with more commenting [Matt] > v3: > Converted GEM_BUG_ON into BUG_ON with more documentation [Matt] > > Signed-off-by: Ramalingam C <ramalingam.c@intel.com> > Reviewed-by: Matthew Auld <matthew.auld@intel.com> (v1) > --- > drivers/gpu/drm/i915/gt/intel_migrate.c | 14 +++++++++++++- > 1 file changed, 13 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/i915/gt/intel_migrate.c b/drivers/gpu/drm/i915/gt/intel_migrate.c > index 9d552f30b627..168d17b6f48a 100644 > --- a/drivers/gpu/drm/i915/gt/intel_migrate.c > +++ b/drivers/gpu/drm/i915/gt/intel_migrate.c > @@ -687,6 +687,16 @@ static void get_ccs_sg_sgt(struct sgt_dma *it, u32 bytes_to_cpy) > bytes_to_cpy -= len; > > it->sg = __sg_next(it->sg); > + > + /* > + * On Flat-CCS capable platform when we back the lmem pages with > + * smem pages we add extra pages at the end of the smem > + * scatterlist, to store the ccs data corresponding to the lmem > + * pages. get_ccs_sg_sgt() is called to get the pointer for the > + * start of the extra pages added at the end of smem scatterlist. > + * So scatterlist can't end at or before bytes_to_cpy. > + */ > + BUG_ON(!it->sg); Why would you have to bring the entire kernel down in this case? Why not just let it oops on the NULL pointer dereference? I'd prefer nuking *all* of the current BUG/BUG_ON in the driver, and not add any single one back. BR, Jani. > it->dma = sg_dma_address(it->sg); > it->max = it->dma + sg_dma_len(it->sg); > } while (bytes_to_cpy); > @@ -748,8 +758,10 @@ intel_context_migrate_copy(struct intel_context *ce, > * Need to fix it. > */ > ccs_bytes_to_cpy = src_sz != dst_sz ? GET_CCS_BYTES(i915, bytes_to_cpy) : 0; > - if (ccs_bytes_to_cpy) > + if (ccs_bytes_to_cpy) { > + WARN_ON(abs(src_sz - dst_sz) < ccs_bytes_to_cpy); > get_ccs_sg_sgt(&it_ccs, bytes_to_cpy); > + } > } > > src_offset = 0;
diff --git a/drivers/gpu/drm/i915/gt/intel_migrate.c b/drivers/gpu/drm/i915/gt/intel_migrate.c index 9d552f30b627..168d17b6f48a 100644 --- a/drivers/gpu/drm/i915/gt/intel_migrate.c +++ b/drivers/gpu/drm/i915/gt/intel_migrate.c @@ -687,6 +687,16 @@ static void get_ccs_sg_sgt(struct sgt_dma *it, u32 bytes_to_cpy) bytes_to_cpy -= len; it->sg = __sg_next(it->sg); + + /* + * On Flat-CCS capable platform when we back the lmem pages with + * smem pages we add extra pages at the end of the smem + * scatterlist, to store the ccs data corresponding to the lmem + * pages. get_ccs_sg_sgt() is called to get the pointer for the + * start of the extra pages added at the end of smem scatterlist. + * So scatterlist can't end at or before bytes_to_cpy. + */ + BUG_ON(!it->sg); it->dma = sg_dma_address(it->sg); it->max = it->dma + sg_dma_len(it->sg); } while (bytes_to_cpy); @@ -748,8 +758,10 @@ intel_context_migrate_copy(struct intel_context *ce, * Need to fix it. */ ccs_bytes_to_cpy = src_sz != dst_sz ? GET_CCS_BYTES(i915, bytes_to_cpy) : 0; - if (ccs_bytes_to_cpy) + if (ccs_bytes_to_cpy) { + WARN_ON(abs(src_sz - dst_sz) < ccs_bytes_to_cpy); get_ccs_sg_sgt(&it_ccs, bytes_to_cpy); + } } src_offset = 0;