From a08b594291c9c62a84ad5b820b77b7aff9079cb1 Mon Sep 17 00:00:00 2001
Message-Id: <a08b594291c9c62a84ad5b820b77b7aff9079cb1@dist-git>
From: Pavel Hrdina <phrdina@redhat.com>
Date: Wed, 13 Mar 2019 14:18:14 +0100
Subject: [PATCH] domcapabilities: fix detection if host-model is safe to use

According to libvirt documentation for host-model [1] it is safe to use
it only if 'fallback' attribute is set to 'forbid', this indicates that
the libvirt and QEMU are new enough and can safely filter list of cpu
features that will be guaranteed to be visible inside of the guest.

[1] <https://libvirt.org/formatdomain.html#elementsCPU>

Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
Reviewed-by: Cole Robinson <crobinso@redhat.com>
(cherry picked from commit 9fdbbca27fa820d58b1bff58d215e6847b848f0a)

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1525337

Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
Reviewed-by: Andrea Bolognani <abologna@redhat.com>
---
 virtinst/domcapabilities.py | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/virtinst/domcapabilities.py b/virtinst/domcapabilities.py
index ddc8b17c..822deda8 100644
--- a/virtinst/domcapabilities.py
+++ b/virtinst/domcapabilities.py
@@ -202,9 +202,10 @@ class DomainCapabilities(XMLBuilder):
         """
         Return True if domcaps reports support for cpu mode=host-model.
         host-model infact predates this support, however it wasn't
-        general purpose safe prior to domcaps advertisement
+        general purpose safe prior to domcaps advertisement.
         """
-        return [(m.name == "host-model" and m.supported)
+        return [(m.name == "host-model" and m.supported and
+                 m.models[0].fallback == "forbid")
                 for m in self.cpu.modes]
 
 
-- 
2.20.1