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Nadav Amit authored
The smsw instruction has an undocumented behavior, in which the high-order 16-bits of CR0 are also saved in a 32-bit destination register. This is similar to the way smsw behaves in long-mode. However, it is hard to test the long-mode case, since we need to cause an "invalid guest state" in long-mode. The test works as follows: it sets CR0.CD (bit 30), so any of the high 16-bits would be set. It then executes smsw to register destination and compares the register value with that of CR0. CR0 value is restored when the test is done. This test is expected to fail only when unrestricted mode is disabled or unsupported. Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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