From 012f9b19ef3812884e207dc431571502de4cebce Mon Sep 17 00:00:00 2001
From: Peter Krempa <pkrempa@redhat.com>
Date: Wed, 24 Oct 2012 15:10:51 +0200
Subject: [PATCH] cpu: Add recently added cpu feature flags.

Qemu has added some new feature flags. This patch adds them to libvirt.

The new features are for the cpuid function 0x7 that takes an argument
in the ecx register. Currently only 0x0 is used as the argument so I was
lazy and I just clear the registers to 0 before calling cpuid. In future
when there maybe will be some other possible arguments, we will need to
improve the cpu detection code to take this into account.
---
 src/cpu/cpu_map.xml | 12 ++++++++++++
 src/cpu/cpu_x86.c   |  8 +++++++-
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/src/cpu/cpu_map.xml b/src/cpu/cpu_map.xml
index affcce35ef..d059e2036b 100644
--- a/src/cpu/cpu_map.xml
+++ b/src/cpu/cpu_map.xml
@@ -142,6 +142,9 @@
     <feature name='pdcm'>
       <cpuid function='0x00000001' ecx='0x00008000'/>
     </feature>
+    <feature name='pcid'>
+      <cpuid function='0x00000001' ecx='0x00020000'/>
+    </feature>
     <feature name='dca'> <!-- CPUID_EXT_DCA -->
       <cpuid function='0x00000001' ecx='0x00040000'/>
     </feature>
@@ -261,6 +264,15 @@
       <cpuid function='0x80000001' ecx='0x00080000'/>
     </feature>
 
+    <!-- cpuid function 0x7 ecx 0x0 features -->
+    <!-- We support only ecx 0x0 now as it's done by a workaround -->
+    <feature name='smep'>
+      <cpuid function='0x00000007' ebx='0x00000080'/>
+    </feature>
+    <feature name='smap'>
+      <cpuid function='0x00000007' ebx='0x00080000'/>
+    </feature>
+
     <!-- models -->
     <model name='486'>
       <feature name='fpu'/>
diff --git a/src/cpu/cpu_x86.c b/src/cpu/cpu_x86.c
index 7cd67b8f77..e691c04a27 100644
--- a/src/cpu/cpu_x86.c
+++ b/src/cpu/cpu_x86.c
@@ -1539,7 +1539,10 @@ static inline void
 cpuidCall(struct cpuX86cpuid *cpuid)
 {
 # if __x86_64__
-    asm("cpuid"
+    asm("xor %%ebx, %%ebx;" /* clear the other registers as some cpuid */
+        "xor %%ecx, %%ecx;" /* functions may use them as additional */
+        "xor %%edx, %%edx;" /* arguments */
+        "cpuid;"
         : "=a" (cpuid->eax),
           "=b" (cpuid->ebx),
           "=c" (cpuid->ecx),
@@ -1550,6 +1553,9 @@ cpuidCall(struct cpuX86cpuid *cpuid)
      * for global offset table on i386 with -fPIC
      */
     asm("push %%ebx;"
+        "xor %%ebx, %%ebx;" /* clear the other registers as some cpuid */
+        "xor %%ecx, %%ecx;" /* functions may use them as additional */
+        "xor %%edx, %%edx;" /* arguments */
         "cpuid;"
         "mov %%ebx, %1;"
         "pop %%ebx;"
-- 
2.39.5