Differences

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--- fuss:libvirt [2018/01/19 23:37] – [Passing Plan 9 Permissions] office
+++ fuss:libvirt [2020/08/31 20:08] – [Setting Custom Interface Name for Bridge Networking Mode] office
@@ Line 11: / Line 11: @@
 Next, to start the install, run:
 <code bash>
-virt-install --name live --network bridge:br0 --ram 1024 --boot cdrom --cdrom live.iso --graphics vnc,listen=192.168.1.1,port=5901 --disk /var/lib/libvirt/images/live.img
+virt-install --name live \
+    --network bridge:br0 --ram 1024 \
+    --boot cdrom --cdrom live.iso \
+    --graphics vnc,listen=192.168.1.1,port=5901 \
+    --disk /var/lib/libvirt/images/live.img
 </code>
@@ Line 62: / Line 66: @@
 ...
       <model type='virtio'/>
-...
+      <driver>
+        <host gso='off' tso4='off' tso6='off' ecn='off' ufo='off'/>
+        <guest tso4='off' tso6='off' ecn='off'/>
+      </driver>
     </interface>
 </code>
+The ''driver'' block ensures that various offload parameters are turned off for the host and guest which is deemed to be good practice for virtio interfaces on a bridge. Additionally, the bridge can be configured to turn off most of the offloading:
+<code bash>
+ethtool -K br0 tso off sg off ufo off gro off gso off
+</code>
+where:
+  * ''br0'' is the bridge interface to which the virtio interfaces are added.
 ====== Speed-Up Virtualization using Multi-Queue VirtIO Networking ======
@@ Line 602: / Line 618: @@
 ====== Passing Plan 9 Permissions ======
-Given a passed-through folder defined in the domain configuration file:
+===== Access Mode Mapped =====
+The following configuration changes for the domain have to be made:
+<code xml>
+    <filesystem type='mount' accessmode='mapped'>
+      <source dir='/mnt/cdrom'/>
+      <target dir='cd'/>
+    </filesystem>
+</code>
+===== Access Mode Passthrough =====
+For passthrough access mode, the following configuration change has to be made for the domain:
 <code xml>
     <filesystem type='mount' accessmode='passthrough'>
@@ Line 610: / Line 639: @@
 </code>
-virtual machines running under ''qemu'' / ''kvm'' have to be started as root. To accomplish that, edit ''/etc/default/libvirt/qemu.conf'' and set:
+Virtual machines running under ''qemu'' / ''kvm'' have to be started as root. To accomplish that, edit ''/etc/default/libvirt/qemu.conf'' and set:
 <code>
 user = "root"
@@ Line 621: / Line 650: @@
 </code>
 has to be added to ''/etc/default/libvirt/qemu.conf''.
+===== Mounting the Share =====
 Once the virtual machine boots, the share can then be automatically mounted by adding the following line:
@@ Line 632: / Line 663: @@
   * ''posixacl'' turns on passing POSIX ACLs (very convenient for using ''getfacl'' and ''setfacl'' to fine tune permissions).
+====== Setting Custom Interface Name for Bridge Networking Mode ======
+libvirt allows using:
+<code>
+<target dev='...'/>
+</code>
+to set the custom name for bridge interfaces such as ''vnet0'', ''vnet1'', etc...
+However, if the name of the interface contains the substring ''vnet'', libvirt will ignore the entry and will not save it, for instance, setting the interface name with:
+<code>
+<target dev='vnet888'/>
+</code>
+will just be ignored by libvirt.
+To resolve this issue, use a more custom-tailored interface name, for instance:
+<code>
+<target dev='mynet0'/>
+</code>
+without containing the ''vnet'' substring.
+====== Strange Windows Install Errors ======
+One easy workaround for a BSoD on a fresh Windows install complaining about ''IRQL_NOT_LESS_OR_EQUAL'' or reaching a fatal error is to increase the RAM available above $3GiB$.