[virglrenderer-devel] [PATCH 2/2] protect gl{BeginEnd}ConditionalRendering calls

[Po-Hsien Wang]

Shouldn't have_gl_conditional_render deps on !gles?

On Wed, Jul 18, 2018 at 1:04 AM Erik Faye-Lund <erik.faye-lund at collabora.com>
wrote:

> Otherwise, it'd be possible to generate evil commands from a rouge
> guest-driver that can crash the VM.
>
> This is a bit trickier than the previous one, because we were already
> mixing calls to the OpenGL 3.0 version and the GL_NV_conditional_render
> version, which indicates that this was previously only safe if *both*
> were supported, that is OpenGL 3.0 *with* GL_NV_conditional_render. Now
> this code should match the caps we generate, which shouldn't give any
> percieved feature-regressions or gl-versions supported.
>
> Signed-off-by: Erik Faye-Lund <erik.faye-lund at collabora.com>
> ---
> So this is a little bit tric
>
>  src/vrend_renderer.c | 30 ++++++++++++++++++++++++------
>  1 file changed, 24 insertions(+), 6 deletions(-)
>
> diff --git a/src/vrend_renderer.c b/src/vrend_renderer.c
> index 564807a..f34a58f 100644
> --- a/src/vrend_renderer.c
> +++ b/src/vrend_renderer.c
> @@ -109,6 +109,8 @@ struct global_renderer_state {
>     bool have_ms_scaled_blit;
>     bool have_nv_prim_restart;
>     bool have_gl_prim_restart;
> +   bool have_gl_conditional_render;
> +   bool have_nv_conditional_render;
>     bool have_bit_encoding;
>     bool have_gles31_vertex_attrib_binding;
>     bool have_tf2;
> @@ -4523,6 +4525,10 @@ int vrend_renderer_init(struct vrend_if_cbs *cbs,
> uint32_t flags)
>        vrend_state.have_gl_prim_restart = true;
>     else if (epoxy_has_gl_extension("GL_NV_primitive_restart"))
>        vrend_state.have_nv_prim_restart = true;
> +   if (gl_ver >= 30)
> +      vrend_state.have_gl_conditional_render = true;
> +   else if (epoxy_has_gl_extension("GL_NV_conditional_render"))
> +      vrend_state.have_nv_conditional_render = true;
>     if (gl_ver >= 40 || (gles && gl_ver >= 30) ||
>         epoxy_has_gl_extension("GL_ARB_transform_feedback2")) {
>        vrend_state.have_tf2 = true;
> @@ -7008,11 +7014,18 @@ static void vrend_pause_render_condition(struct
> vrend_context *ctx, bool pause)
>  {
>     if (pause) {
>        if (ctx->sub->cond_render_q_id)
> -         glEndConditionalRenderNV();
> +         if (vrend_state.have_gl_conditional_render)
> +            glEndConditionalRender();
> +         else if (vrend_state.have_nv_conditional_render)
> +            glEndConditionalRenderNV();
>     } else {
>        if (ctx->sub->cond_render_q_id)
> -         glBeginConditionalRender(ctx->sub->cond_render_q_id,
> -                                  ctx->sub->cond_render_gl_mode);
> +         if (vrend_state.have_gl_conditional_render)
> +            glBeginConditionalRender(ctx->sub->cond_render_q_id,
> +                                     ctx->sub->cond_render_gl_mode);
> +         else if (vrend_state.have_nv_conditional_render)
> +            glBeginConditionalRenderNV(ctx->sub->cond_render_q_id,
> +                                       ctx->sub->cond_render_gl_mode);
>     }
>  }
>
> @@ -7025,7 +7038,10 @@ void vrend_render_condition(struct vrend_context
> *ctx,
>     GLenum glmode = 0;
>
>     if (handle == 0) {
> -      glEndConditionalRenderNV();
> +      if (vrend_state.have_gl_conditional_render)
> +         glEndConditionalRender();
> +      else if (vrend_state.have_nv_conditional_render)
> +         glEndConditionalRenderNV();
>        ctx->sub->cond_render_q_id = 0;
>        ctx->sub->cond_render_gl_mode = 0;
>        return;
> @@ -7054,8 +7070,10 @@ void vrend_render_condition(struct vrend_context
> *ctx,
>
>     ctx->sub->cond_render_q_id = q->id;
>     ctx->sub->cond_render_gl_mode = glmode;
> -   glBeginConditionalRender(q->id, glmode);
> -
> +   if (vrend_state.have_gl_conditional_render)
> +      glBeginConditionalRender(q->id, glmode);
> +   if (vrend_state.have_nv_conditional_render)
> +      glBeginConditionalRenderNV(q->id, glmode);
>  }
>
>  int vrend_create_so_target(struct vrend_context *ctx,
> --
> 2.18.0.rc2
>
>
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