Re: [Xen-devel] [PATCH] tools/tests: Add EIP check to test_x86_emulator.c

[Razvan Cojocaru <rcojocaru@xxxxxxxxxxxxxxx>]

On 08/07/2014 11:32 AM, Jan Beulich wrote:
>>>> On 07.08.14 at 10:18, <andrew.cooper3@xxxxxxxxxx> wrote:
>> On 07/08/2014 09:16, Razvan Cojocaru wrote:
>>> The test now also checks that EIP was modified after emulating
>>> instructions after (and including) the "movq %mm3,(%ecx)..."
>>> code block.
>>>
>>> Signed-off-by: Razvan Cojocaru <rcojocaru@xxxxxxxxxxxxxxx>
>>
>> These checks do check that the instruction pointer has changed, which
>> catches your problem, but doesn't check that it has changed correctly. 
>> You need to work out exactly how long the instruction is a verify that
>> eip points to first byte of the next instruction.
> 
> And apart from that this should be done for all tests, not just the
> MMX/SSE/AVX ones.

The other tests already do this, but there it's simpler to check. For
example:

218     printf("%-40s", "Testing addl %%ecx,%%eax...");
219     instr[0] = 0x01; instr[1] = 0xc8;
220     regs.eflags = 0x200;
221     regs.eip    = (unsigned long)&instr[0];
222     regs.ecx    = 0x12345678;
223     regs.eax    = 0x7FFFFFFF;
224     rc = x86_emulate(&ctxt, &emulops);
225     if ( (rc != X86EMUL_OKAY) ||
226          (regs.ecx != 0x12345678) ||
227          (regs.eax != 0x92345677) ||
228          (regs.eflags != 0xa94) ||
229          (regs.eip != (unsigned long)&instr[2]) )
230         goto fail;
231     printf("okay\n");


Thanks,
Razvan Cojocaru

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