[Qemu-devel] [PATCH] don't expose lm bit if kernel is not 64-bit capable.

[Glauber Costa <glommer@redhat.com>]

If the kernel is not 64-bit capable (even if the host
machine is) do not expose the lm bit in guest cpuid.

Signed-off-by: Glauber Costa <glommer@redhat.com>
---
 target-i386/helper.c |    6 +++++-
 1 files changed, 5 insertions(+), 1 deletions(-)

diff --git a/target-i386/helper.c b/target-i386/helper.c
index a28ab93..997e4e1 100644
--- a/target-i386/helper.c
+++ b/target-i386/helper.c
@@ -24,6 +24,7 @@
 #include <inttypes.h>
 #include <signal.h>
 #include <assert.h>
+#include <sys/utsname.h>
 
 #include "cpu.h"
 #include "exec-all.h"
@@ -1520,13 +1521,16 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index,
 
         if (kvm_enabled()) {
             uint32_t h_eax, h_edx;
+            struct utsname utsname;
+
+            uname(&utsname);
 
             host_cpuid(0x80000001, &h_eax, NULL, NULL, &h_edx);
 
             /* disable CPU features that the host does not support */
 
             /* long mode */
-            if ((h_edx & 0x20000000) == 0 /* || !lm_capable_kernel */)
+            if ((h_edx & 0x20000000) == 0  || strcmp(utsname.machine, "x86_64"))
                 *edx &= ~0x20000000;
             /* syscall */
             if ((h_edx & 0x00000800) == 0)
-- 
1.5.6.5