From: Prerna Saxena Date: Tue, 4 Nov 2014 23:00:36 +0530 Subject: [PATCH] docs: Add documentation for compat mode. Add documentation to explain how compat-mode can be invoked with libvirt running on PowerPC architecture. It also mentions that this change is available libvirt 1.2.11 onwards. Signed-off-by: Prerna Saxena Reviewed-by: Michal Privoznik (cherry picked from commit 9265fd19b68d787e478f5e490524da794965a5f1) --- docs/formatdomain.html.in | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in index 0099ce7..bdaf808 100644 --- a/docs/formatdomain.html.in +++ b/docs/formatdomain.html.in @@ -1047,7 +1047,20 @@ (such as CPUID level) that don't work. Until these issues are fixed, it's a good idea to avoid using host-model and use custom mode with just the CPU model from host - capabilities XML. + capabilities XML. + (Since 1.2.11). PowerISA allows + processors to run VMs in binary compatibility mode supporting an + older version of ISA. Libvirt on PowerPC architecture uses the + host-model to signify a guest mode CPU running in + binary compatibility mode. Example: + When a user needs a power7 VM to run in compatibility mode + on a Power8 host, this can be described in XML as follows : +
+  <cpu mode='host-model'>
+    <model>power7</model>
+  </cpu>
+  ...
+
host-passthrough
With this mode, the CPU visible to the guest should be exactly the same as the host CPU even in the aspects that libvirt does not