[Mesa-dev] [PATCH v2] virgl: Add command and flags to initiate debugging on the host

[Gert Wollny]

From: Gert Wollny <gert.wollny at collabora.com>

On the host VREND_DEBUG=guestallow must be set to let the guest override
the debug flags.

v2: Send flag string instead of flags, this avoids the need to keep
    the flags in sync.

Signed-off-by: Gert Wollny <gert.wollny at collabora.com>
---
The corresponding virglrenderer patch series is in this MR: 
https://gitlab.freedesktop.org/virgl/virglrenderer/merge_requests/39

Thanks for reviewing

 src/gallium/drivers/virgl/virgl_context.c  |  6 ++++++
 src/gallium/drivers/virgl/virgl_encode.c   | 24 ++++++++++++++++++++++++
 src/gallium/drivers/virgl/virgl_encode.h   |  3 +++
 src/gallium/drivers/virgl/virgl_protocol.h |  1 +
 4 files changed, 34 insertions(+)

diff --git a/src/gallium/drivers/virgl/virgl_context.c b/src/gallium/drivers/virgl/virgl_context.c
index 4511bf3b2f..92547a8d57 100644
--- a/src/gallium/drivers/virgl/virgl_context.c
+++ b/src/gallium/drivers/virgl/virgl_context.c
@@ -1164,6 +1164,7 @@ struct pipe_context *virgl_context_create(struct pipe_screen *pscreen,
    struct virgl_context *vctx;
    struct virgl_screen *rs = virgl_screen(pscreen);
    vctx = CALLOC_STRUCT(virgl_context);
+   const char *host_debug_flagstring;
 
    vctx->cbuf = rs->vws->cmd_buf_create(rs->vws);
    if (!vctx->cbuf) {
@@ -1268,6 +1269,11 @@ struct pipe_context *virgl_context_create(struct pipe_screen *pscreen,
    virgl_encoder_create_sub_ctx(vctx, vctx->hw_sub_ctx_id);
 
    virgl_encoder_set_sub_ctx(vctx, vctx->hw_sub_ctx_id);
+
+   host_debug_flagstring = getenv("VIRGL_HOST_DEBUG");
+   if (host_debug_flagstring)
+      virgl_encode_host_debug_flagstring(vctx, host_debug_flagstring);
+
    return &vctx->base;
 fail:
    return NULL;
diff --git a/src/gallium/drivers/virgl/virgl_encode.c b/src/gallium/drivers/virgl/virgl_encode.c
index 29920b22be..9b3d8c8d99 100644
--- a/src/gallium/drivers/virgl/virgl_encode.c
+++ b/src/gallium/drivers/virgl/virgl_encode.c
@@ -1044,3 +1044,27 @@ int virgl_encode_texture_barrier(struct virgl_context *ctx,
    virgl_encoder_write_dword(ctx->cbuf, flags);
    return 0;
 }
+
+int virgl_encode_host_debug_flagstring(struct virgl_context *ctx,
+                                       char *flagstring)
+{
+   unsigned long slen = strlen(flagstring) + 1;
+   uint32_t sslen;
+   uint32_t string_length;
+
+   if (!slen)
+      return 0;
+
+   if (slen > 4 * 0xffff) {
+      debug_printf("VIRGL: host debug flag string too long, will be truncated\n");
+      slen = 4 * 0xffff;
+   }
+
+   sslen = (uint32_t )(slen + 3) / 4;
+   string_length = (uint32_t)MIN2(sslen * 4, slen);
+
+   virgl_encoder_write_cmd_dword(ctx, VIRGL_CMD0(VIRGL_CCMD_SET_DEBUG_FLAGS, 0, sslen));
+   virgl_encoder_write_block(ctx->cbuf, (uint8_t *)flagstring, string_length);
+
+   return 0;
+}
diff --git a/src/gallium/drivers/virgl/virgl_encode.h b/src/gallium/drivers/virgl/virgl_encode.h
index 40e62d453b..80b943a6b3 100644
--- a/src/gallium/drivers/virgl/virgl_encode.h
+++ b/src/gallium/drivers/virgl/virgl_encode.h
@@ -276,4 +276,7 @@ int virgl_encode_launch_grid(struct virgl_context *ctx,
                              const struct pipe_grid_info *grid_info);
 int virgl_encode_texture_barrier(struct virgl_context *ctx,
                                  unsigned flags);
+
+int virgl_encode_host_debug_flagstring(struct virgl_context *ctx,
+                                       char *envname);
 #endif
diff --git a/src/gallium/drivers/virgl/virgl_protocol.h b/src/gallium/drivers/virgl/virgl_protocol.h
index 8d99c5ed47..3373121bf7 100644
--- a/src/gallium/drivers/virgl/virgl_protocol.h
+++ b/src/gallium/drivers/virgl/virgl_protocol.h
@@ -92,6 +92,7 @@ enum virgl_context_cmd {
    VIRGL_CCMD_SET_FRAMEBUFFER_STATE_NO_ATTACH,
    VIRGL_CCMD_TEXTURE_BARRIER,
    VIRGL_CCMD_SET_ATOMIC_BUFFERS,
+   VIRGL_CCMD_SET_DEBUG_FLAGS,
 };
 
 /*
-- 
2.16.4