12 files changed, 283 insertions, 59 deletions
diff --git a/docs/_templates/editpage.html b/docs/_templates/editpage.html
deleted file mode 100644
index 4319b0f5ac..0000000000
--- a/docs/_templates/editpage.html
+++ /dev/null
@@ -1,5 +0,0 @@
-<div id="editpage">
-  <ul>
-    <li><a href="https://gitlab.com/qemu-project/qemu/-/blob/master/docs/{{pagename}}.rst">Page source</a></li>
-  </ul>
-</div>
diff --git a/docs/conf.py b/docs/conf.py
index 2ee6111872..00cf66ab54 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -29,6 +29,7 @@
 import os
 import sys
 import sphinx
+from distutils.version import LooseVersion
 from sphinx.errors import ConfigError
 
 # Make Sphinx fail cleanly if using an old Python, rather than obscurely
@@ -150,38 +151,47 @@ with open(os.path.join(qemu_docdir, 'defs.rst.inc')) as f:
 # The theme to use for HTML and HTML Help pages.  See the documentation for
 # a list of builtin themes.
 #
-html_theme = 'alabaster'
+try:
+    import sphinx_rtd_theme
+except ImportError:
+    raise ConfigError(
+        'The Sphinx \'sphinx_rtd_theme\' HTML theme was not found.\n'
+    )
+
+html_theme = 'sphinx_rtd_theme'
 
 # Theme options are theme-specific and customize the look and feel of a theme
 # further.  For a list of options available for each theme, see the
 # documentation.
-# We initialize this to empty here, so the per-manual conf.py can just
-# add individual key/value entries.
-html_theme_options = {
-}
+if LooseVersion(sphinx_rtd_theme.__version__) >= LooseVersion("0.4.3"):
+    html_theme_options = {
+        "style_nav_header_background": "#802400",
+    }
+
+html_logo = os.path.join(qemu_docdir, "../ui/icons/qemu_128x128.png")
+
+html_favicon = os.path.join(qemu_docdir, "../ui/icons/qemu_32x32.png")
 
 # Add any paths that contain custom static files (such as style sheets) here,
 # relative to this directory. They are copied after the builtin static files,
 # so a file named "default.css" will overwrite the builtin "default.css".
-# QEMU doesn't yet have any static files, so comment this out so we don't
-# get a warning about a missing directory.
-# If we do ever add this then it would probably be better to call the
-# subdirectory sphinx_static, as the Linux kernel does.
-# html_static_path = ['_static']
+html_static_path = [os.path.join(qemu_docdir, "sphinx-static")]
+
+html_css_files = [
+    'theme_overrides.css',
+]
+
+html_context = {
+    "display_gitlab": True,
+    "gitlab_user": "qemu-project",
+    "gitlab_repo": "qemu",
+    "gitlab_version": "master",
+    "conf_py_path": "/docs/", # Path in the checkout to the docs root
+}
 
 # Custom sidebar templates, must be a dictionary that maps document names
 # to template names.
-#
-# This is required for the alabaster theme
-# refs: http://alabaster.readthedocs.io/en/latest/installation.html#sidebars
-html_sidebars = {
-    '**': [
-        'about.html',
-        'editpage.html',
-        'navigation.html',
-        'searchbox.html',
-    ]
-}
+#html_sidebars = {}
 
 # Don't copy the rST source files to the HTML output directory,
 # and don't put links to the sources into the output HTML.
diff --git a/docs/devel/_templates/editpage.html b/docs/devel/_templates/editpage.html
deleted file mode 100644
index a86d22bca8..0000000000
--- a/docs/devel/_templates/editpage.html
+++ /dev/null
@@ -1,5 +0,0 @@
-<div id="editpage">
-  <ul>
-    <li><a href="https://gitlab.com/qemu-project/qemu/-/blob/master/docs/devel/{{pagename}}.rst">Page source</a></li>
-  </ul>
-</div>
diff --git a/docs/devel/qgraph.rst b/docs/devel/qgraph.rst
index a9aff167ad..318534d4b0 100644
--- a/docs/devel/qgraph.rst
+++ b/docs/devel/qgraph.rst
@@ -92,6 +92,64 @@ The basic framework steps are the following:
 Depending on the QEMU binary used, only some drivers/machines will be
 available and only test that are reached by them will be executed.
 
+Troubleshooting unavailable tests
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+If there is no path from an available machine to a test then that test will be
+unavailable and won't execute. This can happen if a test or driver did not set
+up its qgraph node correctly. It can also happen if the necessary machine type
+or device is missing from the QEMU binary because it was compiled out or
+otherwise.
+
+It is possible to troubleshoot unavailable tests by running::
+
+  $ QTEST_QEMU_BINARY=build/qemu-system-x86_64 build/tests/qtest/qos-test --verbose
+  # ALL QGRAPH EDGES: {
+  #   src='virtio-net'
+  #      |-> dest='virtio-net-tests/vhost-user/multiqueue' type=2 (node=0x559142109e30)
+  #      |-> dest='virtio-net-tests/vhost-user/migrate' type=2 (node=0x559142109d00)
+  #   src='virtio-net-pci'
+  #      |-> dest='virtio-net' type=1 (node=0x55914210d740)
+  #   src='pci-bus'
+  #      |-> dest='virtio-net-pci' type=2 (node=0x55914210d880)
+  #   src='pci-bus-pc'
+  #      |-> dest='pci-bus' type=1 (node=0x559142103f40)
+  #   src='i440FX-pcihost'
+  #      |-> dest='pci-bus-pc' type=0 (node=0x55914210ac70)
+  #   src='x86_64/pc'
+  #      |-> dest='i440FX-pcihost' type=0 (node=0x5591421117f0)
+  #   src=''
+  #      |-> dest='x86_64/pc' type=0 (node=0x559142111600)
+  #      |-> dest='arm/raspi2' type=0 (node=0x559142110740)
+  ...
+  # }
+  # ALL QGRAPH NODES: {
+  #   name='virtio-net-tests/announce-self' type=3 cmd_line='(null)' [available]
+  #   name='arm/raspi2' type=0 cmd_line='-M raspi2 ' [UNAVAILABLE]
+  ...
+  # }
+
+The ``virtio-net-tests/announce-self`` test is listed as "available" in the
+"ALL QGRAPH NODES" output. This means the test will execute. We can follow the
+qgraph path in the "ALL QGRAPH EDGES" output as follows: '' -> 'x86_64/pc' ->
+'i440FX-pcihost' -> 'pci-bus-pc' -> 'pci-bus' -> 'virtio-net-pci' ->
+'virtio-net'. The root of the qgraph is '' and the depth first search begins
+there.
+
+The ``arm/raspi`` machine node is listed as "UNAVAILABLE". Although it is
+reachable from the root via '' -> 'arm/raspi2' the node is unavailable because
+the QEMU binary did not list it when queried by the framework. This is expected
+because we used the ``qemu-system-x86_64`` binary which does not support ARM
+machine types.
+
+If a test is unexpectedly listed as "UNAVAILABLE", first check that the "ALL
+QGRAPH EDGES" output reports edge connectivity from the root ('') to the test.
+If there is no connectivity then the qgraph nodes were not set up correctly and
+the driver or test code is incorrect. If there is connectivity, check the
+availability of each node in the path in the "ALL QGRAPH NODES" output. The
+first unavailable node in the path is the reason why the test is unavailable.
+Typically this is because the QEMU binary lacks support for the necessary
+machine type or device.
+
 Creating a new driver and its interface
 """""""""""""""""""""""""""""""""""""""""
 
diff --git a/docs/interop/_templates/editpage.html b/docs/interop/_templates/editpage.html
deleted file mode 100644
index 215e562681..0000000000
--- a/docs/interop/_templates/editpage.html
+++ /dev/null
@@ -1,5 +0,0 @@
-<div id="editpage">
-  <ul>
-    <li><a href="https://gitlab.com/qemu-project/qemu/-/blob/master/docs/interop/{{pagename}}.rst">Page source</a></li>
-  </ul>
-</div>
diff --git a/docs/meson.build b/docs/meson.build
index f84306ba7e..855e3916e9 100644
--- a/docs/meson.build
+++ b/docs/meson.build
@@ -27,10 +27,9 @@ if sphinx_build.found()
   build_docs = (sphinx_build_test_out.returncode() == 0)
 
   if not build_docs
-    warning('@0@ is either too old or uses too old a Python version'
-            .format(sphinx_build.full_path()))
+    warning('@0@: @1@'.format(sphinx_build.full_path(), sphinx_build_test_out.stderr()))
     if get_option('docs').enabled()
-      error('Install a Python 3 version of python-sphinx')
+      error('Install a Python 3 version of python-sphinx and the readthedoc theme')
     endif
   endif
 endif
diff --git a/docs/specs/_templates/editpage.html b/docs/specs/_templates/editpage.html
deleted file mode 100644
index aaa468aa98..0000000000
--- a/docs/specs/_templates/editpage.html
+++ /dev/null
@@ -1,5 +0,0 @@
-<div id="editpage">
-  <ul>
-    <li><a href="https://gitlab.com/qemu-project/qemu/-/blob/master/docs/specs/{{pagename}}.rst">Page source</a></li>
-  </ul>
-</div>
diff --git a/docs/sphinx-static/theme_overrides.css b/docs/sphinx-static/theme_overrides.css
new file mode 100644
index 0000000000..c70ef95128
--- /dev/null
+++ b/docs/sphinx-static/theme_overrides.css
@@ -0,0 +1,161 @@
+/* -*- coding: utf-8; mode: css -*-
+ *
+ * Sphinx HTML theme customization: read the doc
+ * Based on Linux Documentation/sphinx-static/theme_overrides.css
+ */
+
+/* Improve contrast and increase size for easier reading. */
+
+body {
+    font-family: serif;
+    color: black;
+    font-size: 100%;
+}
+
+h1, h2, .rst-content .toctree-wrapper p.caption, h3, h4, h5, h6, legend {
+    font-family: sans-serif;
+}
+
+.rst-content dl:not(.docutils) dt {
+    border-top: none;
+    border-left: solid 3px #ccc;
+    background-color: #f0f0f0;
+    color: black;
+}
+
+.wy-nav-top {
+    background: #802400;
+}
+
+.wy-side-nav-search input[type="text"] {
+    border-color: #f60;
+}
+
+.wy-menu-vertical p.caption {
+    color: white;
+}
+
+.wy-menu-vertical li.current a {
+    color: #505050;
+}
+
+.wy-menu-vertical li.on a, .wy-menu-vertical li.current > a {
+    color: #303030;
+}
+
+.fa-gitlab {
+      box-shadow: 0 4px 8px 0 rgba(0,0,0,0.2), 0 3px 10px 0 rgba(0,0,0,0.19);
+      border-radius: 5px;
+}
+
+div[class^="highlight"] pre {
+    font-family: monospace;
+    color: black;
+    font-size: 100%;
+}
+
+.wy-menu-vertical {
+    font-family: sans-serif;
+}
+
+.c {
+    font-style: normal;
+}
+
+p {
+    font-size: 100%;
+}
+
+/* Interim: Code-blocks with line nos - lines and line numbers don't line up.
+ * see: https://github.com/rtfd/sphinx_rtd_theme/issues/419
+ */
+
+div[class^="highlight"] pre {
+    line-height: normal;
+}
+.rst-content .highlight > pre {
+    line-height: normal;
+}
+
+/* Keep fields from being strangely far apart due to inheirited table CSS. */
+.rst-content table.field-list th.field-name {
+    padding-top: 1px;
+    padding-bottom: 1px;
+}
+.rst-content table.field-list td.field-body {
+    padding-top: 1px;
+    padding-bottom: 1px;
+}
+
+@media screen {
+
+    /* content column
+     *
+     * RTD theme's default is 800px as max width for the content, but we have
+     * tables with tons of columns, which need the full width of the view-port.
+     */
+
+    .wy-nav-content{max-width: none; }
+
+    /* table:
+     *
+     *   - Sequences of whitespace should collapse into a single whitespace.
+     *   - make the overflow auto (scrollbar if needed)
+     *   - align caption "left" ("center" is unsuitable on vast tables)
+     */
+
+    .wy-table-responsive table td { white-space: normal; }
+    .wy-table-responsive { overflow: auto; }
+    .rst-content table.docutils caption { text-align: left; font-size: 100%; }
+
+    /* captions:
+     *
+     *   - captions should have 100% (not 85%) font size
+     *   - hide the permalink symbol as long as link is not hovered
+     */
+
+    .toc-title {
+        font-size: 150%;
+        font-weight: bold;
+    }
+
+    caption, .wy-table caption, .rst-content table.field-list caption {
+        font-size: 100%;
+    }
+    caption a.headerlink { opacity: 0; }
+    caption a.headerlink:hover { opacity: 1; }
+
+    /* Menu selection and keystrokes */
+
+    span.menuselection {
+        color: blue;
+        font-family: "Courier New", Courier, monospace
+    }
+
+    code.kbd, code.kbd span {
+        color: white;
+        background-color: darkblue;
+        font-weight: bold;
+        font-family: "Courier New", Courier, monospace
+    }
+
+    /* fix bottom margin of lists items */
+
+    .rst-content .section ul li:last-child, .rst-content .section ul li p:last-child {
+          margin-bottom: 12px;
+    }
+
+    /* inline literal: drop the borderbox, padding and red color */
+
+    code, .rst-content tt, .rst-content code {
+        color: inherit;
+        border: none;
+        padding: unset;
+        background: inherit;
+        font-size: 85%;
+    }
+
+    .rst-content tt.literal,.rst-content tt.literal,.rst-content code.literal {
+        color: inherit;
+    }
+}
diff --git a/docs/system/_templates/editpage.html b/docs/system/_templates/editpage.html
deleted file mode 100644
index 6586b2e257..0000000000
--- a/docs/system/_templates/editpage.html
+++ /dev/null
@@ -1,5 +0,0 @@
-<div id="editpage">
-  <ul>
-    <li><a href="https://gitlab.com/qemu-project/qemu/-/blob/master/docs/system/{{pagename}}.rst">Page source</a></li>
-  </ul>
-</div>
diff --git a/docs/tools/_templates/editpage.html b/docs/tools/_templates/editpage.html
deleted file mode 100644
index 2a9c8fc92b..0000000000
--- a/docs/tools/_templates/editpage.html
+++ /dev/null
@@ -1,5 +0,0 @@
-<div id="editpage">
-  <ul>
-    <li><a href="https://gitlab.com/qemu-project/qemu/-/blob/master/docs/tools/{{pagename}}.rst">Page source</a></li>
-  </ul>
-</div>
diff --git a/docs/tools/qemu-img.rst b/docs/tools/qemu-img.rst
index c9efcfaefc..cfe1147879 100644
--- a/docs/tools/qemu-img.rst
+++ b/docs/tools/qemu-img.rst
@@ -866,6 +866,37 @@ Supported image file formats:
     issue ``lsattr filename`` to check if the NOCOW flag is set or not
     (Capital 'C' is NOCOW flag).
 
+  ``data_file``
+    Filename where all guest data will be stored. If this option is used,
+    the qcow2 file will only contain the image's metadata.
+
+    Note: Data loss will occur if the given filename already exists when
+    using this option with ``qemu-img create`` since ``qemu-img`` will create
+    the data file anew, overwriting the file's original contents. To simply
+    update the reference to point to the given pre-existing file, use
+    ``qemu-img amend``.
+
+  ``data_file_raw``
+    If this option is set to ``on``, QEMU will always keep the external data
+    file consistent as a standalone read-only raw image.
+
+    It does this by forwarding all write accesses to the qcow2 file through to
+    the raw data file, including their offsets. Therefore, data that is visible
+    on the qcow2 node (i.e., to the guest) at some offset is visible at the same
+    offset in the raw data file. This results in a read-only raw image. Writes
+    that bypass the qcow2 metadata may corrupt the qcow2 metadata because the
+    out-of-band writes may result in the metadata falling out of sync with the
+    raw image.
+
+    If this option is ``off``, QEMU will use the data file to store data in an
+    arbitrary manner. The file’s content will not make sense without the
+    accompanying qcow2 metadata. Where data is written will have no relation to
+    its offset as seen by the guest, and some writes (specifically zero writes)
+    may not be forwarded to the data file at all, but will only be handled by
+    modifying qcow2 metadata.
+
+    This option can only be enabled if ``data_file`` is set.
+
 ``Other``
 
   QEMU also supports various other image file formats for
diff --git a/docs/user/_templates/editpage.html b/docs/user/_templates/editpage.html
deleted file mode 100644
index 1f5ee01e60..0000000000
--- a/docs/user/_templates/editpage.html
+++ /dev/null
@@ -1,5 +0,0 @@
-<div id="editpage">
-  <ul>
-    <li><a href="https://gitlab.com/qemu-project/qemu/-/blob/master/docs/user/{{pagename}}.rst">Page source</a></li>
-  </ul>
-</div>