panvk: Round FillBuffer sizes down to a multiple of 4

Reviewed-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/16276>

src/panfrost/ci/deqp-panfrost-g52-vk.toml

@@ -11,6 +11,7 @@ include = [
     "dEQP-VK.api.command_buffers.render_pass_continue",
     "dEQP-VK.api.command_buffers.render_pass_continue_no_fb",
     "dEQP-VK.api.copy_and_blit.core.*",
+    "dEQP-VK.api.fill_and_update_buffer.suballocation.*",
     "dEQP-VK.binding_model.descriptor_copy.compute.*",
     "dEQP-VK.compute.builtin_var.*",
     "dEQP-VK.draw.renderpass.instanced.draw_indexed_vk_*",

src/panfrost/vulkan/panvk_vX_meta_copy.c

@@ -2000,6 +2000,16 @@ panvk_meta_fill_buf(struct panvk_cmd_buffer *cmdbuf,
    };
    size = panvk_buffer_range(dst, offset, size);
 
+   /* From the Vulkan spec:
+    *
+    *    "size is the number of bytes to fill, and must be either a multiple
+    *    of 4, or VK_WHOLE_SIZE to fill the range from offset to the end of
+    *    the buffer. If VK_WHOLE_SIZE is used and the remaining size of the
+    *    buffer is not a multiple of 4, then the nearest smaller multiple is
+    *    used."
+    */
+   size &= ~3ull;
+
    assert(!(offset & 3) && !(size & 3));
 
    unsigned nwords = size / sizeof(uint32_t);