cpu: define the 'ssbd' CPUID feature bit (CVE-2018-3639)

New microcode introduces the "Speculative Store Bypass Disable"
CPUID feature bit. This needs to be exposed to guest OS to allow
them to protect against CVE-2018-3639.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Jiri Denemark <jdenemar@redhat.com>
(cherry picked from commit 1dbca2eccad58d91a5fd33962854f1a653638182)

diff --git a/src/cpu/cpu_map.xml b/src/cpu/cpu_map.xml
index 00a43b172c4711d25570107580055fa8950aadb3..245aec3309a45f348efb11533fc6ceea536cb661 100644 (file)
--- a/src/cpu/cpu_map.xml
+++ b/src/cpu/cpu_map.xml
@@ -298,6 +298,9 @@
     <feature name='spec-ctrl'>
       <cpuid eax_in='0x07' ecx_in='0x00' edx='0x04000000'/>
     </feature>
+    <feature name='ssbd'>
+      <cpuid eax_in='0x07' ecx_in='0x00' edx='0x80000000'/>
+    </feature>
 
     <!-- Processor Extended State Enumeration sub leaf 1 -->
     <feature name='xsaveopt'>