[Xen-changelog] [xen stable-4.9] libxc/x86/PV: don't hand through CPUID leaf 0x80000008 as is

[patchbot@xxxxxxx]

commit 46863c67f1f2cdf1eac4b818b1b1f90ea648b5d7
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Wed Jul 4 12:32:57 2018 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Wed Jul 4 12:32:57 2018 +0200

    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@xxxxxxxx>
    Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    master commit: 849cc9ac56eff8a8d575ed9f484aad72f383862c
    master date: 2018-05-29 10:51:02 +0100
---
 tools/libxc/xc_cpuid_x86.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/tools/libxc/xc_cpuid_x86.c b/tools/libxc/xc_cpuid_x86.c
index 9143864a63..f84ab37c49 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 */
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.9

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