Commit 396d2cfc authored by Eduardo Habkost's avatar Eduardo Habkost Committed by Andreas Färber
Browse files

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: default avatarEduardo Habkost <ehabkost@redhat.com>
Reviewed-by: default avatarGleb Natapov <gleb@redhat.com>
Signed-off-by: default avatarAndreas Färber <afaerber@suse.de>
parent 22714625

target-i386/cpu.c

+1 −1
Original line number Diff line number Diff line
@@ -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());