Re: [PATCH kvm-unit-tests] x86: Test illegal movbe

[Paolo Bonzini <pbonzini@redhat.com>]

On 26/11/2014 14:48, Nadav Amit wrote:
> Previously KVM ignored the mod field of MOVBE instruction, so MOVBE from
> register to register succeeds, although it should fail (cause a #UD exception).
> This test check that a #UD is indeed delivered upon such MOVBE.
> 
> The test would not work if MOVBE is unsupported.
> 
> Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
> ---
>  x86/emulator.c | 22 ++++++++++++++++++++++
>  1 file changed, 22 insertions(+)
> 
> diff --git a/x86/emulator.c b/x86/emulator.c
> index 5aa4dbf..709978b 100644
> --- a/x86/emulator.c
> +++ b/x86/emulator.c
> @@ -1051,6 +1051,27 @@ static void test_simplealu(u32 *mem)
>      report("test", *mem == 0x8400);
>  }
>  
> +static void illegal_movbe_handler(struct ex_regs *regs)
> +{
> +	extern char bad_movbe_cont;
> +
> +	++exceptions;
> +	regs->rip = (ulong)&bad_movbe_cont;
> +}
> +
> +static void test_illegal_movbe(void)
> +{
> +	if (!(cpuid(1).c & (1 << 22)))
> +		printf("SKIP: illegal movbe\n");
> +
> +	exceptions = 0;
> +	handle_exception(UD_VECTOR, illegal_movbe_handler);
> +	asm volatile(".byte 0x0f; .byte 0x38; .byte 0xf0; .byte 0xc0;\n\t"
> +		     " bad_movbe_cont:" : : : "rax");
> +	report("illegal movbe", exceptions == 1);
> +	handle_exception(UD_VECTOR, 0);
> +}
> +
>  int main()
>  {
>  	void *mem;
> @@ -1119,6 +1140,7 @@ int main()
>  	test_string_io_mmio(mem);
>  
>  	test_jmp_noncanonical(mem);
> +	test_illegal_movbe();
>  
>  	return report_summary();
>  }
> 

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>

Thanks,

Paolo