From: Jan Beulich <JBeulich@suse.com>
Date: Tue, 22 May 2018 11:40:02 +0000 (-0600)
Subject: libxc/x86/PV: don't hand through CPUID leaf 0x80000008 as is
X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=849cc9ac56eff8a8d575ed9f484aad72f383862c;p=people%2Fiwj%2Fxen.git

libxc/x86/PV: don't hand through CPUID leaf 0x80000008 as is

Just like for HVM the feature set should be used for EBX output, while
EAX should be restricted to the low 16 bits and ECX/EDX should be zero.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
---

diff --git a/tools/libxc/xc_cpuid_x86.c b/tools/libxc/xc_cpuid_x86.c
index 9fa2f7c360..21537f06f1 100644
--- a/tools/libxc/xc_cpuid_x86.c
+++ b/tools/libxc/xc_cpuid_x86.c
@@ -575,6 +575,12 @@ static void xc_cpuid_pv_policy(xc_interface *xch,
         break;
     }
 
+    case 0x80000008:
+        regs[0] &= 0x0000ffffu;
+        regs[1] = info->featureset[featureword_of(X86_FEATURE_CLZERO)];
+        regs[2] = regs[3] = 0;
+        break;
+
     case 0x00000005: /* MONITOR/MWAIT */
     case 0x0000000b: /* Extended Topology Enumeration */
     case 0x8000000a: /* SVM revision and features */