draw: try to prevent overflows on index buffers

Pass in the size of the index buffer, when available, and use it
to handle out of bounds conditions. The behavior in the case of
an overflow needs to be the same as with other overflows in the
vertex processing pipeline meaning that a vertex should still
be generated but all attributes in it set to zero.

Signed-off-by: Zack Rusin <[email protected]>
Reviewed-by: José Fonseca <[email protected]>
Reviewed-by: Roland Scheidegger <[email protected]>

14 files changed, 137 insertions, 68 deletions

diff --git a/src/gallium/auxiliary/draw/draw_context.c b/src/gallium/auxiliary/draw/draw_context.c
index 4eb1919b871..78190388ef1 100644
--- a/src/gallium/auxiliary/draw/draw_context.c
+++ b/src/gallium/auxiliary/draw/draw_context.c
@@ -627,7 +627,8 @@ void draw_set_render( struct draw_context *draw,
  */
 void
 draw_set_indexes(struct draw_context *draw,
-                 const void *elements, unsigned elem_size)
+                 const void *elements, unsigned elem_size,
+                 unsigned elem_buffer_space)
 {
    assert(elem_size == 0 ||
           elem_size == 1 ||
@@ -635,6 +636,10 @@ draw_set_indexes(struct draw_context *draw,
           elem_size == 4);
    draw->pt.user.elts = elements;
    draw->pt.user.eltSizeIB = elem_size;
+   if (elem_size)
+      draw->pt.user.eltMax = elem_buffer_space / elem_size;
+   else
+      draw->pt.user.eltMax = 0;
 }
 
 
diff --git a/src/gallium/auxiliary/draw/draw_context.h b/src/gallium/auxiliary/draw/draw_context.h
index c7a40a1b1a2..47bad0d73d4 100644
--- a/src/gallium/auxiliary/draw/draw_context.h
+++ b/src/gallium/auxiliary/draw/draw_context.h
@@ -212,7 +212,8 @@ void draw_set_vertex_elements(struct draw_context *draw,
                               const struct pipe_vertex_element *elements);
 
 void draw_set_indexes(struct draw_context *draw,
-                      const void *elements, unsigned elem_size);
+                      const void *elements, unsigned elem_size,
+                      unsigned available_space);
 
 void draw_set_mapped_vertex_buffer(struct draw_context *draw,
                                    unsigned attr, const void *buffer,
diff --git a/src/gallium/auxiliary/draw/draw_llvm.c b/src/gallium/auxiliary/draw/draw_llvm.c
index 24b7be31362..017d7294100 100644
--- a/src/gallium/auxiliary/draw/draw_llvm.c
+++ b/src/gallium/auxiliary/draw/draw_llvm.c
@@ -1455,14 +1455,16 @@ draw_llvm_generate(struct draw_llvm *llvm, struct draw_llvm_variant *variant,
    struct gallivm_state *gallivm = variant->gallivm;
    LLVMContextRef context = gallivm->context;
    LLVMTypeRef int32_type = LLVMInt32TypeInContext(context);
-   LLVMTypeRef arg_types[8];
+   LLVMTypeRef arg_types[9];
+   unsigned num_arg_types =
+      elts ? Elements(arg_types) : Elements(arg_types) - 1;
    LLVMTypeRef func_type;
    LLVMValueRef context_ptr;
    LLVMBasicBlockRef block;
    LLVMBuilderRef builder;
    struct lp_type vs_type;
    LLVMValueRef end, start;
-   LLVMValueRef count, fetch_elts, fetch_count;
+   LLVMValueRef count, fetch_elts, fetch_elt_max, fetch_count;
    LLVMValueRef stride, step, io_itr;
    LLVMValueRef io_ptr, vbuffers_ptr, vb_ptr;
    LLVMValueRef zero = lp_build_const_int32(gallivm, 0);
@@ -1495,19 +1497,21 @@ draw_llvm_generate(struct draw_llvm *llvm, struct draw_llvm_variant *variant,
 
    memset(&system_values, 0, sizeof(system_values));
 
-   arg_types[0] = get_context_ptr_type(variant);       /* context */
-   arg_types[1] = get_vertex_header_ptr_type(variant); /* vertex_header */
-   arg_types[2] = get_buffer_ptr_type(variant);        /* vbuffers */
-   if (elts)
-      arg_types[3] = LLVMPointerType(int32_type, 0);/* fetch_elts * */
-   else
-      arg_types[3] = int32_type;                    /* start */
-   arg_types[4] = int32_type;                       /* fetch_count / count */
-   arg_types[5] = int32_type;                       /* stride */
-   arg_types[6] = get_vb_ptr_type(variant);            /* pipe_vertex_buffer's */
-   arg_types[7] = int32_type;                       /* instance_id */
+   i = 0;
+   arg_types[i++] = get_context_ptr_type(variant);       /* context */
+   arg_types[i++] = get_vertex_header_ptr_type(variant); /* vertex_header */
+   arg_types[i++] = get_buffer_ptr_type(variant);        /* vbuffers */
+   if (elts) {
+      arg_types[i++] = LLVMPointerType(int32_type, 0);/* fetch_elts  */
+      arg_types[i++] = int32_type;                  /* fetch_elt_max */
+   } else
+      arg_types[i++] = int32_type;                  /* start */
+   arg_types[i++] = int32_type;                     /* fetch_count / count */
+   arg_types[i++] = int32_type;                     /* stride */
+   arg_types[i++] = get_vb_ptr_type(variant);       /* pipe_vertex_buffer's */
+   arg_types[i++] = int32_type;                     /* instance_id */
 
-   func_type = LLVMFunctionType(int32_type, arg_types, Elements(arg_types), 0);
+   func_type = LLVMFunctionType(int32_type, arg_types, num_arg_types, 0);
 
    variant_func = LLVMAddFunction(gallivm->module,
                                   elts ? "draw_llvm_shader_elts" : "draw_llvm_shader",
@@ -1519,7 +1523,7 @@ draw_llvm_generate(struct draw_llvm *llvm, struct draw_llvm_variant *variant,
       variant->function = variant_func;
 
    LLVMSetFunctionCallConv(variant_func, LLVMCCallConv);
-   for (i = 0; i < Elements(arg_types); ++i)
+   for (i = 0; i < num_arg_types; ++i)
       if (LLVMGetTypeKind(arg_types[i]) == LLVMPointerTypeKind)
          LLVMAddAttribute(LLVMGetParam(variant_func, i),
                           LLVMNoAliasAttribute);
@@ -1527,9 +1531,9 @@ draw_llvm_generate(struct draw_llvm *llvm, struct draw_llvm_variant *variant,
    context_ptr               = LLVMGetParam(variant_func, 0);
    io_ptr                    = LLVMGetParam(variant_func, 1);
    vbuffers_ptr              = LLVMGetParam(variant_func, 2);
-   stride                    = LLVMGetParam(variant_func, 5);
-   vb_ptr                    = LLVMGetParam(variant_func, 6);
-   system_values.instance_id = LLVMGetParam(variant_func, 7);
+   stride                    = LLVMGetParam(variant_func, 5 + (elts ? 1 : 0));
+   vb_ptr                    = LLVMGetParam(variant_func, 6 + (elts ? 1 : 0));
+   system_values.instance_id = LLVMGetParam(variant_func, 7 + (elts ? 1 : 0));
 
    lp_build_name(context_ptr, "context");
    lp_build_name(io_ptr, "io");
@@ -1539,9 +1543,11 @@ draw_llvm_generate(struct draw_llvm *llvm, struct draw_llvm_variant *variant,
    lp_build_name(system_values.instance_id, "instance_id");
 
    if (elts) {
-      fetch_elts   = LLVMGetParam(variant_func, 3);
-      fetch_count  = LLVMGetParam(variant_func, 4);
+      fetch_elts    = LLVMGetParam(variant_func, 3);
+      fetch_elt_max = LLVMGetParam(variant_func, 4);
+      fetch_count   = LLVMGetParam(variant_func, 5);
       lp_build_name(fetch_elts, "fetch_elts");
+      lp_build_name(fetch_elt_max, "fetch_elt_max");
       lp_build_name(fetch_count, "fetch_count");
       start = count = NULL;
    }
@@ -1621,16 +1627,48 @@ draw_llvm_generate(struct draw_llvm *llvm, struct draw_llvm_variant *variant,
           * a few of the 4 vertex fetches will be out of bounds */
          true_index = lp_build_min(&bld, true_index, fetch_max);
 
+         system_values.vertex_id = LLVMBuildInsertElement(
+            gallivm->builder,
+            system_values.vertex_id, true_index,
+            lp_build_const_int32(gallivm, i), "");
+
          if (elts) {
             LLVMValueRef fetch_ptr;
-            fetch_ptr = LLVMBuildGEP(builder, fetch_elts,
-                                     &true_index, 1, "");
-            true_index = LLVMBuildLoad(builder, fetch_ptr, "fetch_elt");
+            LLVMValueRef index_overflowed;
+            LLVMValueRef index_ptr =
+               lp_build_alloca(
+                  gallivm,
+                  lp_build_vec_type(gallivm, lp_type_int(32)), "");
+            struct lp_build_if_state if_ctx;
+            index_overflowed = LLVMBuildICmp(builder, LLVMIntUGE,
+                                             true_index, fetch_elt_max,
+                                             "index_overflowed");
+            
+            lp_build_if(&if_ctx, gallivm, index_overflowed);
+            {
+               /* Generate maximum possible index so that
+                * generate_fetch can treat it just like
+                * any other overflow and return zeros.
+                * We don't have to worry about the restart
+                * primitive index because it has already been 
+                * handled
+                */
+               LLVMValueRef val =
+                  lp_build_const_int32(gallivm, 0xffffffff);
+               LLVMBuildStore(builder, val, index_ptr);
+            }
+            lp_build_else(&if_ctx);
+            {
+               LLVMValueRef val;
+               fetch_ptr = LLVMBuildGEP(builder, fetch_elts,
+                                        &true_index, 1, "");
+               val = LLVMBuildLoad(builder, fetch_ptr, "");
+               LLVMBuildStore(builder, val, index_ptr);
+            }
+            lp_build_endif(&if_ctx);
+            true_index = LLVMBuildLoad(builder, index_ptr, "true_index");
          }
 
-         system_values.vertex_id = LLVMBuildInsertElement(gallivm->builder,
-                                                          system_values.vertex_id, true_index,
-                                                          lp_build_const_int32(gallivm, i), "");
          for (j = 0; j < draw->pt.nr_vertex_elements; ++j) {
             struct pipe_vertex_element *velem = &draw->pt.vertex_element[j];
             LLVMValueRef vb_index =
diff --git a/src/gallium/auxiliary/draw/draw_llvm.h b/src/gallium/auxiliary/draw/draw_llvm.h
index d517b290666..347fde2b55f 100644
--- a/src/gallium/auxiliary/draw/draw_llvm.h
+++ b/src/gallium/auxiliary/draw/draw_llvm.h
@@ -271,6 +271,7 @@ typedef int
                            struct vertex_header *io,
                            const struct draw_vertex_buffer vbuffers[PIPE_MAX_ATTRIBS],
                            const unsigned *fetch_elts,
+                           unsigned fetch_max_elt,
                            unsigned fetch_count,
                            unsigned stride,
                            struct pipe_vertex_buffer *vertex_buffers,
diff --git a/src/gallium/auxiliary/draw/draw_private.h b/src/gallium/auxiliary/draw/draw_private.h
index 84344c36773..44698db93d0 100644
--- a/src/gallium/auxiliary/draw/draw_private.h
+++ b/src/gallium/auxiliary/draw/draw_private.h
@@ -186,7 +186,8 @@ struct draw_context
          /** bytes per index (0, 1, 2 or 4) */
          unsigned eltSizeIB;
          unsigned eltSize;
-         int eltBias;
+         unsigned eltMax;
+         int eltBias;         
          unsigned min_index;
          unsigned max_index;
          
@@ -460,4 +461,12 @@ draw_get_rasterizer_no_cull( struct draw_context *draw,
                              boolean flatshade );
 
 
+/** 
+ * Return index i from the index buffer.
+ * If the index buffer would overflow we return the
+ * index of the first element in the vb.
+ */
+#define DRAW_GET_IDX(elts, i)                   \
+   ((i) >= draw->pt.user.eltMax) ? 0 : elts[i]
+
 #endif /* DRAW_PRIVATE_H */
diff --git a/src/gallium/auxiliary/draw/draw_pt.c b/src/gallium/auxiliary/draw/draw_pt.c
index a797d65de8c..14dde67b24c 100644
--- a/src/gallium/auxiliary/draw/draw_pt.c
+++ b/src/gallium/auxiliary/draw/draw_pt.c
@@ -339,7 +339,7 @@ draw_print_arrays(struct draw_context *draw, uint prim, int start, uint count)
 #define PRIM_RESTART_LOOP(elements) \
    do { \
       for (i = start; i < end; i++) { \
-         if (elements[i] == info->restart_index) { \
+         if (i < elt_max && elements[i] == info->restart_index) { \
             if (cur_count > 0) { \
                /* draw elts up to prev pos */ \
                draw_pt_arrays(draw, prim, cur_start, cur_count); \
@@ -371,6 +371,7 @@ draw_pt_arrays_restart(struct draw_context *draw,
    const unsigned start = info->start;
    const unsigned count = info->count;
    const unsigned end = start + count;
+   const unsigned elt_max = draw->pt.user.eltMax;
    unsigned i, cur_start, cur_count;
 
    assert(info->primitive_restart);
@@ -496,7 +497,7 @@ draw_vbo(struct draw_context *draw,
    assert(info->instance_count > 0);
    if (info->indexed)
       assert(draw->pt.user.elts);
-   
+
    count = info->count;
 
    draw->pt.user.eltBias = info->index_bias;
@@ -506,7 +507,7 @@ draw_vbo(struct draw_context *draw,
 
    if (0)
       debug_printf("draw_vbo(mode=%u start=%u count=%u):\n",
-                   info->mode, info->start, info->count);
+                   info->mode, info->start, count);
 
    if (0)
       tgsi_dump(draw->vs.vertex_shader->state.tokens, 0);
@@ -534,7 +535,7 @@ draw_vbo(struct draw_context *draw,
    }
 
    if (0)
-      draw_print_arrays(draw, info->mode, info->start, MIN2(info->count, 20));
+      draw_print_arrays(draw, info->mode, info->start, MIN2(count, 20));
 
    index_limit = util_draw_max_index(draw->pt.vertex_buffer,
                                      draw->pt.vertex_element,
diff --git a/src/gallium/auxiliary/draw/draw_pt_fetch_shade_pipeline_llvm.c b/src/gallium/auxiliary/draw/draw_pt_fetch_shade_pipeline_llvm.c
index fa8baf38889..f734311e73c 100644
--- a/src/gallium/auxiliary/draw/draw_pt_fetch_shade_pipeline_llvm.c
+++ b/src/gallium/auxiliary/draw/draw_pt_fetch_shade_pipeline_llvm.c
@@ -359,6 +359,7 @@ llvm_pipeline_generic( struct draw_pt_middle_end *middle,
                                             llvm_vert_info.verts,
                                             draw->pt.user.vbuffer,
                                             fetch_info->elts,
+                                            draw->pt.user.eltMax,
                                             fetch_info->count,
                                             fpme->vertex_size,
                                             draw->pt.vertex_buffer,
diff --git a/src/gallium/auxiliary/draw/draw_pt_vsplit_tmp.h b/src/gallium/auxiliary/draw/draw_pt_vsplit_tmp.h
index 2e94705609f..2d8957e91e7 100644
--- a/src/gallium/auxiliary/draw/draw_pt_vsplit_tmp.h
+++ b/src/gallium/auxiliary/draw/draw_pt_vsplit_tmp.h
@@ -45,16 +45,16 @@ CONCAT(vsplit_primitive_, ELT_TYPE)(struct vsplit_frontend *vsplit,
    unsigned fetch_start, fetch_count;
    const ushort *draw_elts = NULL;
    unsigned i;
-
-   ib += istart;
+   const unsigned start = istart;
+   const unsigned end = istart + icount;
 
    /* use the ib directly */
    if (min_index == 0 && sizeof(ib[0]) == sizeof(draw_elts[0])) {
       if (icount > vsplit->max_vertices)
          return FALSE;
 
-      for (i = 0; i < icount; i++) {
-         ELT_TYPE idx = ib[i];
+      for (i = start; i < end; i++) {
+         ELT_TYPE idx = DRAW_GET_IDX(ib, i);
          if (idx < min_index || idx > max_index) {
             debug_printf("warning: index out of range\n");
          }
@@ -85,23 +85,23 @@ CONCAT(vsplit_primitive_, ELT_TYPE)(struct vsplit_frontend *vsplit,
 
    if (!draw_elts) {
       if (min_index == 0) {
-         for (i = 0; i < icount; i++) {
-            ELT_TYPE idx = ib[i];
+         for (i = start; i < end; i++) {
+            ELT_TYPE idx = DRAW_GET_IDX(ib, i);
 
             if (idx < min_index || idx > max_index) {
                debug_printf("warning: index out of range\n");
             }
-            vsplit->draw_elts[i] = (ushort) idx;
+            vsplit->draw_elts[i - start] = (ushort) idx;
          }
       }
       else {
-         for (i = 0; i < icount; i++) {
-            ELT_TYPE idx = ib[i];
+         for (i = start; i < end; i++) {
+            ELT_TYPE idx = DRAW_GET_IDX(ib, i);
 
             if (idx < min_index || idx > max_index) {
                debug_printf("warning: index out of range\n");
             }
-            vsplit->draw_elts[i] = (ushort) (idx - min_index);
+            vsplit->draw_elts[i - start] = (ushort) (idx - min_index);
          }
       }
 
@@ -138,41 +138,41 @@ CONCAT(vsplit_segment_cache_, ELT_TYPE)(struct vsplit_frontend *vsplit,
    spoken = !!spoken;
    if (ibias == 0) {
       if (spoken)
-         ADD_CACHE(vsplit, ib[ispoken]);
+         ADD_CACHE(vsplit, DRAW_GET_IDX(ib, ispoken));
 
       for (i = spoken; i < icount; i++)
-         ADD_CACHE(vsplit, ib[istart + i]);
+         ADD_CACHE(vsplit, DRAW_GET_IDX(ib, istart + i));
 
       if (close)
-         ADD_CACHE(vsplit, ib[iclose]);
+         ADD_CACHE(vsplit, DRAW_GET_IDX(ib, iclose));
    }
    else if (ibias > 0) {
       if (spoken)
-         ADD_CACHE(vsplit, (uint) ib[ispoken] + ibias);
+         ADD_CACHE(vsplit, (uint) DRAW_GET_IDX(ib, ispoken) + ibias);
 
       for (i = spoken; i < icount; i++)
-         ADD_CACHE(vsplit, (uint) ib[istart + i] + ibias);
+         ADD_CACHE(vsplit, (uint) DRAW_GET_IDX(ib, istart + i) + ibias);
 
       if (close)
-         ADD_CACHE(vsplit, (uint) ib[iclose] + ibias);
+         ADD_CACHE(vsplit, (uint) DRAW_GET_IDX(ib, iclose) + ibias);
    }
    else {
       if (spoken) {
          if ((int) ib[ispoken] < -ibias)
             return;
-         ADD_CACHE(vsplit, ib[ispoken] + ibias);
+         ADD_CACHE(vsplit, DRAW_GET_IDX(ib, ispoken) + ibias);
       }
 
       for (i = spoken; i < icount; i++) {
-         if ((int) ib[istart + i] < -ibias)
+         if ((int) DRAW_GET_IDX(ib, istart + i) < -ibias)
             return;
-         ADD_CACHE(vsplit, ib[istart + i] + ibias);
+         ADD_CACHE(vsplit, DRAW_GET_IDX(ib, istart + i) + ibias);
       }
 
       if (close) {
-         if ((int) ib[iclose] < -ibias)
+         if ((int) DRAW_GET_IDX(ib, iclose) < -ibias)
             return;
-         ADD_CACHE(vsplit, ib[iclose] + ibias);
+         ADD_CACHE(vsplit, DRAW_GET_IDX(ib, iclose) + ibias);
       }
    }
 
diff --git a/src/gallium/drivers/i915/i915_context.c b/src/gallium/drivers/i915/i915_context.c
index 90427dca963..93599def2a5 100644
--- a/src/gallium/drivers/i915/i915_context.c
+++ b/src/gallium/drivers/i915/i915_context.c
@@ -83,7 +83,7 @@ i915_draw_vbo(struct pipe_context *pipe, const struct pipe_draw_info *info)
          mapped_indices = i915_buffer(i915->index_buffer.buffer)->data;
       draw_set_indexes(draw,
                        (ubyte *) mapped_indices + i915->index_buffer.offset,
-                       i915->index_buffer.index_size);
+                       i915->index_buffer.index_size, ~0);
    }
 
    if (i915->constants[PIPE_SHADER_VERTEX])
@@ -109,7 +109,7 @@ i915_draw_vbo(struct pipe_context *pipe, const struct pipe_draw_info *info)
       draw_set_mapped_vertex_buffer(i915->draw, i, NULL, 0);
    }
    if (mapped_indices)
-      draw_set_indexes(draw, NULL, 0);
+      draw_set_indexes(draw, NULL, 0, 0);
 
    if (i915->num_vertex_sampler_views > 0)
       i915_cleanup_vertex_sampling(i915);
diff --git a/src/gallium/drivers/llvmpipe/lp_draw_arrays.c b/src/gallium/drivers/llvmpipe/lp_draw_arrays.c
index 63c22c31304..4e239043ec4 100644
--- a/src/gallium/drivers/llvmpipe/lp_draw_arrays.c
+++ b/src/gallium/drivers/llvmpipe/lp_draw_arrays.c
@@ -81,13 +81,19 @@ llvmpipe_draw_vbo(struct pipe_context *pipe, const struct pipe_draw_info *info)
 
    /* Map index buffer, if present */
    if (info->indexed) {
+      unsigned available_space = ~0;
       mapped_indices = lp->index_buffer.user_buffer;
-      if (!mapped_indices)
+      if (!mapped_indices) {
          mapped_indices = llvmpipe_resource_data(lp->index_buffer.buffer);
-
+         if (lp->index_buffer.buffer->width0 > lp->index_buffer.offset)
+            available_space =
+               (lp->index_buffer.buffer->width0 - lp->index_buffer.offset);
+         else
+            available_space = 0;
+      }
       draw_set_indexes(draw,
                        (ubyte *) mapped_indices + lp->index_buffer.offset,
-                       lp->index_buffer.index_size);
+                       lp->index_buffer.index_size, available_space);
    }
 
    for (i = 0; i < lp->num_so_targets; i++) {
@@ -126,7 +132,7 @@ llvmpipe_draw_vbo(struct pipe_context *pipe, const struct pipe_draw_info *info)
       draw_set_mapped_vertex_buffer(draw, i, NULL, 0);
    }
    if (mapped_indices) {
-      draw_set_indexes(draw, NULL, 0);
+      draw_set_indexes(draw, NULL, 0, 0);
    }
    draw_set_mapped_so_targets(draw, 0, NULL);
 
diff --git a/src/gallium/drivers/nv30/nv30_draw.c b/src/gallium/drivers/nv30/nv30_draw.c
index 92185c922c2..e0a1628eb91 100644
--- a/src/gallium/drivers/nv30/nv30_draw.c
+++ b/src/gallium/drivers/nv30/nv30_draw.c
@@ -423,9 +423,9 @@ nv30_render_vbo(struct pipe_context *pipe, const struct pipe_draw_info *info)
                                   PIPE_TRANSFER_READ, &transferi);
       draw_set_indexes(draw,
                        (ubyte *) map + nv30->idxbuf.offset,
-                       nv30->idxbuf.index_size);
+                       nv30->idxbuf.index_size, ~0);
    } else {
-      draw_set_indexes(draw, NULL, 0);
+      draw_set_indexes(draw, NULL, 0, 0);
    }
 
    draw_vbo(draw, info);
diff --git a/src/gallium/drivers/r300/r300_state.c b/src/gallium/drivers/r300/r300_state.c
index b3e25e1ad0f..36d510dc45e 100644
--- a/src/gallium/drivers/r300/r300_state.c
+++ b/src/gallium/drivers/r300/r300_state.c
@@ -1856,7 +1856,7 @@ static void r300_set_index_buffer_swtcl(struct pipe_context* pipe,
         }
         draw_set_indexes(r300->draw,
                          (const ubyte *) buf + ib->offset,
-                         ib->index_size);
+                         ib->index_size, ~0);
     }
 }
 
diff --git a/src/gallium/drivers/softpipe/sp_draw_arrays.c b/src/gallium/drivers/softpipe/sp_draw_arrays.c
index 839fd220500..45b1390de4d 100644
--- a/src/gallium/drivers/softpipe/sp_draw_arrays.c
+++ b/src/gallium/drivers/softpipe/sp_draw_arrays.c
@@ -89,13 +89,20 @@ softpipe_draw_vbo(struct pipe_context *pipe,
 
    /* Map index buffer, if present */
    if (info->indexed) {
+      unsigned available_space = ~0;
       mapped_indices = sp->index_buffer.user_buffer;
-      if (!mapped_indices)
+      if (!mapped_indices) {
          mapped_indices = softpipe_resource(sp->index_buffer.buffer)->data;
+         if (sp->index_buffer.buffer->width0 > sp->index_buffer.offset)
+            available_space =
+               (sp->index_buffer.buffer->width0 - sp->index_buffer.offset);
+         else
+            available_space = 0;
+      }
 
       draw_set_indexes(draw,
                        (ubyte *) mapped_indices + sp->index_buffer.offset,
-                       sp->index_buffer.index_size);
+                       sp->index_buffer.index_size, available_space);
    }
 
 
@@ -125,7 +132,7 @@ softpipe_draw_vbo(struct pipe_context *pipe,
       draw_set_mapped_vertex_buffer(draw, i, NULL, 0);
    }
    if (mapped_indices) {
-      draw_set_indexes(draw, NULL, 0);
+      draw_set_indexes(draw, NULL, 0, 0);
    }
 
    draw_set_mapped_so_targets(draw, 0, NULL);
diff --git a/src/gallium/drivers/svga/svga_swtnl_draw.c b/src/gallium/drivers/svga/svga_swtnl_draw.c
index 850575c14b9..0a049569ff7 100644
--- a/src/gallium/drivers/svga/svga_swtnl_draw.c
+++ b/src/gallium/drivers/svga/svga_swtnl_draw.c
@@ -84,7 +84,7 @@ svga_swtnl_draw_vbo(struct svga_context *svga,
                             &ib_transfer);
       draw_set_indexes(draw,
                        (const ubyte *) map + svga->curr.ib.offset,
-                       svga->curr.ib.index_size);
+                       svga->curr.ib.index_size, ~0);
    }
 
    if (svga->curr.cb[PIPE_SHADER_VERTEX]) {
@@ -118,7 +118,7 @@ svga_swtnl_draw_vbo(struct svga_context *svga,
 
    if (ib_transfer) {
       pipe_buffer_unmap(&svga->pipe, ib_transfer);
-      draw_set_indexes(draw, NULL, 0);
+      draw_set_indexes(draw, NULL, 0, 0);
    }
 
    if (svga->curr.cb[PIPE_SHADER_VERTEX]) {