From 38658eb75dfabc579543a337f31efd65826a7eec Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marek=20Marczykowski-G=C3=B3recki?=
 <marmarek@invisiblethingslab.com>
Date: Mon, 14 Jul 2025 18:59:33 +0200
Subject: [PATCH 1/4] Extract common qemu options to a variable

---
 templates/libvirt/xen.xml | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/templates/libvirt/xen.xml b/templates/libvirt/xen.xml
index ec56214c3..f839a2b30 100644
--- a/templates/libvirt/xen.xml
+++ b/templates/libvirt/xen.xml
@@ -182,6 +182,8 @@
 
             {% if vm.virt_mode == 'hvm' %}
                 <!-- server_ip is the address of stubdomain. It hosts it's own DNS server. -->
+                {% set qemu_opts_common = "-qubes-audio:audiovm_xid=" ~
+                    audiovm_xid -%}
                 <emulator
                     {% if vm.features.check_with_template('linux-stubdom', True) %}
                         type="stubdom-linux"
@@ -190,20 +192,20 @@
                     {% endif %}
                     {% if vm.netvm %}
                       {% if vm.features.check_with_template('linux-stubdom', True) %}
-                        cmdline="-qubes-audio:audiovm_xid={{ audiovm_xid }} -qubes-net:client_ip={{ vm.ip -}}
+                        cmdline="{{ qemu_opts_common }} -qubes-net:client_ip={{ vm.ip -}}
                             ,dns_0={{ vm.dns[0] -}}
                             ,dns_1={{ vm.dns[1] -}}
                             ,gw={{ vm.netvm.gateway -}}
                             ,netmask={{ vm.netmask }}"
                       {% else %}
-                        cmdline="-qubes-audio:audiovm_xid={{ audiovm_xid }} -net lwip,client_ip={{ vm.ip -}}
+                        cmdline="{{ qemu_opts_common }} -net lwip,client_ip={{ vm.ip -}}
                             ,server_ip={{ vm.dns[1] -}}
                             ,dns={{ vm.dns[0] -}}
                             ,gw={{ vm.netvm.gateway -}}
                             ,netmask={{ vm.netmask }}"
                       {% endif %}
                     {% else %}
-                      cmdline="-qubes-audio:audiovm_xid={{ audiovm_xid }}"
+                      cmdline="{{ qemu_opts_common }}"
                     {% endif %}
                     {% if vm.stubdom_mem %}
                         memory="{{ vm.stubdom_mem * 1024 -}}"

From 5a752a8d8168bbef48643a7bedec6ae3a4d41ce5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marek=20Marczykowski-G=C3=B3recki?=
 <marmarek@invisiblethingslab.com>
Date: Mon, 14 Jul 2025 20:06:57 +0200
Subject: [PATCH 2/4] New feature to add custom qemu arguments

Implement qemu-extra-args feature that allows adding extra qemu options.
This is useful mostly for debugging.
---
 qubes/tests/vm/qubesvm.py | 62 +++++++++++++++++++++++++++++++++++++++
 templates/libvirt/xen.xml |  4 ++-
 2 files changed, 65 insertions(+), 1 deletion(-)

diff --git a/qubes/tests/vm/qubesvm.py b/qubes/tests/vm/qubesvm.py
index 11e6fa2e0..d1633a4f6 100644
--- a/qubes/tests/vm/qubesvm.py
+++ b/qubes/tests/vm/qubesvm.py
@@ -1172,6 +1172,68 @@ def test_600_libvirt_xml_hvm_with_guivm(self):
             lxml.etree.XML(libvirt_xml), lxml.etree.XML(expected)
         )
 
+    def test_600_libvirt_xml_hvm_with_qemu_args(self):
+        my_uuid = "7db78950-c467-4863-94d1-af59806384ea"
+        expected = """<domain type="xen">
+        <name>test-inst-test</name>
+        <uuid>7db78950-c467-4863-94d1-af59806384ea</uuid>
+        <memory unit="MiB">400</memory>
+        <currentMemory unit="MiB">400</currentMemory>
+        <vcpu placement="static">2</vcpu>
+        <cpu mode='host-passthrough'>
+            <!-- disable nested HVM -->
+            <feature name='vmx' policy='disable'/>
+            <feature name='svm' policy='disable'/>
+            <!-- let the guest know the TSC is safe to use (no migration) -->
+            <feature name='invtsc' policy='require'/>
+        </cpu>
+        <os>
+            <type arch="x86_64" machine="xenfv">hvm</type>
+                <!--
+                     For the libxl backend libvirt switches between OVMF (UEFI)
+                     and SeaBIOS based on the loader type. This has nothing to
+                     do with the hvmloader binary.
+                -->
+            <loader type="rom">hvmloader</loader>
+            <boot dev="cdrom" />
+            <boot dev="hd" />
+        </os>
+        <features>
+            <pae/>
+            <acpi/>
+            <apic/>
+            <viridian/>
+        </features>
+        <clock offset="variable" adjustment="0" basis="utc" />
+        <on_poweroff>destroy</on_poweroff>
+        <on_reboot>destroy</on_reboot>
+        <on_crash>destroy</on_crash>
+        <devices>
+            <!-- server_ip is the address of stubdomain. It hosts it's own DNS server. -->
+            <emulator type="stubdom-linux" cmdline="-qubes-audio:audiovm_xid=-1 -some-option"/>
+            <input type="tablet" bus="usb"/>
+            <video>
+                <model type="vga"/>
+            </video>
+            <graphics type="qubes"
+            log_level="2"
+            />
+            <console type="pty">
+                <target type="xen" port="0"/>
+            </console>
+        </devices>
+        </domain>
+        """
+        vm = self.get_vm(uuid=my_uuid)
+        vm.netvm = None
+        vm.virt_mode = "hvm"
+        vm.debug = True
+        vm.features['qemu-extra-args'] = '-some-option'
+        libvirt_xml = vm.create_config_file()
+        self.assertXMLEqual(
+            lxml.etree.XML(libvirt_xml), lxml.etree.XML(expected)
+        )
+
     def test_600_libvirt_xml_hvm_dom0_kernel(self):
         my_uuid = "7db78950-c467-4863-94d1-af59806384ea"
         expected = f"""<domain type="xen">
diff --git a/templates/libvirt/xen.xml b/templates/libvirt/xen.xml
index f839a2b30..9a82ca690 100644
--- a/templates/libvirt/xen.xml
+++ b/templates/libvirt/xen.xml
@@ -183,7 +183,9 @@
             {% if vm.virt_mode == 'hvm' %}
                 <!-- server_ip is the address of stubdomain. It hosts it's own DNS server. -->
                 {% set qemu_opts_common = "-qubes-audio:audiovm_xid=" ~
-                    audiovm_xid -%}
+                    audiovm_xid ~ " " ~
+                    vm.features.check_with_template('qemu-extra-args', '') -%}
+                {% set qemu_opts_common = qemu_opts_common | trim -%}
                 <emulator
                     {% if vm.features.check_with_template('linux-stubdom', True) %}
                         type="stubdom-linux"

From 9f5152f4c8f7b3712a9dfea0a94eb8be399473b2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marek=20Marczykowski-G=C3=B3recki?=
 <marmarek@invisiblethingslab.com>
Date: Mon, 14 Jul 2025 20:10:12 +0200
Subject: [PATCH 3/4] Enable Windows PV drivers logging when debug is set to
 True

Will (hopefully) help debugging issues like QubesOS/qubes-issues#9976
---
 qubes/tests/vm/qubesvm.py | 6 ++++--
 templates/libvirt/xen.xml | 2 ++
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/qubes/tests/vm/qubesvm.py b/qubes/tests/vm/qubesvm.py
index d1633a4f6..0993eb8d2 100644
--- a/qubes/tests/vm/qubesvm.py
+++ b/qubes/tests/vm/qubesvm.py
@@ -1143,7 +1143,8 @@ def test_600_libvirt_xml_hvm_with_guivm(self):
         <on_crash>destroy</on_crash>
         <devices>
             <!-- server_ip is the address of stubdomain. It hosts it's own DNS server. -->
-            <emulator type="stubdom-linux" cmdline="-qubes-audio:audiovm_xid=-1"/>
+            <emulator type="stubdom-linux"
+            cmdline="-qubes-audio:audiovm_xid=-1 -trace xen_platform_log"/>
             <input type="tablet" bus="usb"/>
             <video>
                 <model type="vga"/>
@@ -1210,7 +1211,8 @@ def test_600_libvirt_xml_hvm_with_qemu_args(self):
         <on_crash>destroy</on_crash>
         <devices>
             <!-- server_ip is the address of stubdomain. It hosts it's own DNS server. -->
-            <emulator type="stubdom-linux" cmdline="-qubes-audio:audiovm_xid=-1 -some-option"/>
+            <emulator type="stubdom-linux"
+            cmdline="-qubes-audio:audiovm_xid=-1 -some-option -trace xen_platform_log"/>
             <input type="tablet" bus="usb"/>
             <video>
                 <model type="vga"/>
diff --git a/templates/libvirt/xen.xml b/templates/libvirt/xen.xml
index 9a82ca690..40e009855 100644
--- a/templates/libvirt/xen.xml
+++ b/templates/libvirt/xen.xml
@@ -186,6 +186,8 @@
                     audiovm_xid ~ " " ~
                     vm.features.check_with_template('qemu-extra-args', '') -%}
                 {% set qemu_opts_common = qemu_opts_common | trim -%}
+                {% set qemu_opts_common = qemu_opts_common ~
+                    (" -trace xen_platform_log" if vm.debug else "") -%}
                 <emulator
                     {% if vm.features.check_with_template('linux-stubdom', True) %}
                         type="stubdom-linux"

From c531bb157401914b2178105657c8425cf36fea83 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marek=20Marczykowski-G=C3=B3recki?=
 <marmarek@invisiblethingslab.com>
Date: Sat, 19 Jul 2025 23:54:54 +0200
Subject: [PATCH 4/4] Add "network" block in default libvirt config template

Ease implementing https://www.qubes-os.org/doc/windows-debugging/
---
 templates/libvirt/xen.xml | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/templates/libvirt/xen.xml b/templates/libvirt/xen.xml
index 40e009855..307438933 100644
--- a/templates/libvirt/xen.xml
+++ b/templates/libvirt/xen.xml
@@ -167,9 +167,11 @@
                 {% endfor %}
             {% endfor %}
 
-            {% if vm.netvm %}
-                {% include 'libvirt/devices/net.xml' with context %}
-            {% endif %}
+            {% block network %}
+                {% if vm.netvm %}
+                    {% include 'libvirt/devices/net.xml' with context %}
+                {% endif %}
+            {% endblock %}
 
             {% for assignment in vm.devices.pci.get_assigned_devices(True) %}
                 {% for device in assignment.devices %}