Re: [PATCH kvm-unit-tests] emulator: test 64-bit mov with immediate operand

Marcelo Tosatti
2012-12-13T21:47:54Z

On Thu, Dec 13, 2012 at 01:11:55PM +0100, Paolo Bonzini wrote:
> MOV immediate instruction (opcodes 0xB8-0xBF) may take 64-bit operand.
> Some hypervisor implementations assumed the operand is 32-bit. This
> should never happen because the instruction has no memory operand, but
> (like the existing test_mmx_movq_mf) the testcase tricks the emulator
> into executing one by mismatching the page tables and the corresponding
> TLB entry.
>
> Cc: Nadav Amit <nadav.amit@gmail.com>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
> x86/emulator.c | 33 +++++++++++++++++++++++++++++++++
> 1 file changed, 33 insertions(+)

Wicked, missed that. If you're unlucky, though, TLB entry can
be gone by then (unlikely, though).

Applied, thanks.