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From b46a1a6517874144f0cdf918f8148503bb5771e1 Mon Sep 17 00:00:00 2001
Message-Id: <b46a1a6517874144f0cdf918f8148503bb5771e1.1382534061.git.jdenemar@redhat.com>
From: Jiri Denemark <jdenemar@redhat.com>
Date: Tue, 22 Oct 2013 16:09:06 +0100
Subject: [PATCH] docs: Expand description of host-model CPU mode

https://bugzilla.redhat.com/show_bug.cgi?id=1014682

host-model is a nice idea but it's current implementation make it
useless on some hosts so it should be used with care.

(cherry picked from commit 34adf622a352cbb80a98162a0f9ac3f9de3f95cb)

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
---
 docs/formatdomain.html.in | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in
index 512e0df..132c16c 100644
--- a/docs/formatdomain.html.in
+++ b/docs/formatdomain.html.in
@@ -922,7 +922,16 @@
           model even if the destination host contains more capable CPUs for
           the running instance of the guest; but shutting down and restarting
           the guest may present different hardware to the guest according to
-          the capabilities of the new host.</dd>
+          the capabilities of the new host. <strong>Beware</strong>, due to the
+          way libvirt detects host CPU and due to the fact libvirt does not
+          talk to QEMU/KVM when creating the CPU model, CPU configuration
+          created using <code>host-model</code> may not work as expected. The
+          guest CPU may differ from the configuration and it may also confuse
+          guest OS by using a combination of CPU features and other parameters
+          (such as CPUID level) that don't work. Until these issues are fixed,
+          it's a good idea to avoid using <code>host-model</code> and use
+          <code>custom</code> mode with just the CPU model from host
+          capabilities XML.</dd>
           <dt><code>host-passthrough</code></dt>
           <dd>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
-- 
1.8.4