Fix compilation on older compilers.

%d0 constrain is wrong, rely on variable length to choose correct
register instead.

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
realmode: test SAHF instruction

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
kvm-unit-test: fix cpuid test

If cpuid is called with function value greater than max supported one
max supported value is used instead and index parameter is honored. That
is why we need to initialize index to same value in the test to get
same result from both cpuid invocations.

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>