target-i386: check/enforce: Check SVM flag support as well

When nested SVM is supported, the kernel returns the SVM flag on
GET_SUPPORTED_CPUID[1], so we can check the SVM flag safely in
kvm_check_features_against_host().

I don't know why the original code ignored the SVM flag. Maybe it was
because kvm_cpu_fill_host() used the CPUID instruction directly instead
of GET_SUPPORTED_CPUID

[1] Older kernels (before v2.6.37) returned the SVM flag even if nested
    SVM was _not_ supported. So the only cases where this patch should
    change behavior is when SVM is being requested by the user or the
    CPU model, but not supported by the host. And on these cases we
    really want QEMU to abort if the "enforce" option is set.

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>

diff --git a/target-i386/cpu.c b/target-i386/cpu.c
index a2971d27eb8b90b4a3ecc192f641ca52383842ae..535cd52d176922de969f50338b182e285f50fde7 100644 (file)
--- a/target-i386/cpu.c
+++ b/target-i386/cpu.c
@@ -963,7 +963,7 @@ static int kvm_check_features_against_host(x86_def_t *guest_def)
         {&guest_def->ext2_features, &host_def.ext2_features,
             ~0, ext2_feature_name, 0x80000001, R_EDX},
         {&guest_def->ext3_features, &host_def.ext3_features,
-            ~CPUID_EXT3_SVM, ext3_feature_name, 0x80000001, R_ECX}
+            ~0, ext3_feature_name, 0x80000001, R_ECX}
     };
 
     assert(kvm_enabled());