From: Andrew Cooper <andrew.cooper3@citrix.com>
Date: Wed, 18 Jan 2017 08:52:19 +0000 (+0100)
Subject: x86/cpu: Don't update this_cpu for get_cpu_vendor(, gcv_guest)
X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=daf491dc1e87fe32b35f2ae75b4add0fa96c0d7f;p=people%2Fiwj%2Fxen.git

x86/cpu: Don't update this_cpu for get_cpu_vendor(, gcv_guest)

Otherwise booting a cross-vendor guest would cause PCPU hotplug to
malfunction, because of trying to use the wrong CPU driver.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
master commit: 291dcb4dd0140fac0e439760b4d51b2892ff9264
master date: 2017-01-03 13:33:16 +0000
---

diff --git a/xen/arch/x86/cpu/common.c b/xen/arch/x86/cpu/common.c
index 1d78ab4d84..b5da94a3e5 100644
--- a/xen/arch/x86/cpu/common.c
+++ b/xen/arch/x86/cpu/common.c
@@ -166,7 +166,8 @@ int get_cpu_vendor(const char v[], enum get_cpu_vendor mode)
 			if (!strcmp(v,cpu_devs[i]->c_ident[0]) ||
 			    (cpu_devs[i]->c_ident[1] && 
 			     !strcmp(v,cpu_devs[i]->c_ident[1]))) {
-				this_cpu = cpu_devs[i];
+				if (mode == gcv_host)
+					this_cpu = cpu_devs[i];
 				return i;
 			}
 		}