On Thu, Jun 6, 2013 at 12:13 AM, Gleb Natapov <gleb@xxxxxxxxxx> wrote:
> This time the email is perfect :)
>
> On Thu, Jun 06, 2013 at 12:02:52AM +0800, Arthur Chunqi Li wrote:
>> Add multibyte NOP test case to kvm-unit-tests. This version adds test cases into x86/realmode.c. This can test one of bugs when booting RHEL5.9 64-bit.
>>
>> Signed-off-by: Arthur Chunqi Li <yzt356@xxxxxxxxx>
>> ---
>> x86/realmode.c | 24 ++++++++++++++++++++++++
>> 1 file changed, 24 insertions(+)
>>
>> diff --git a/x86/realmode.c b/x86/realmode.c
>> index 981be08..e103ca6 100644
>> --- a/x86/realmode.c
>> +++ b/x86/realmode.c
>> @@ -1504,6 +1504,29 @@ static void test_fninit(void)
>> report("fninit", 0, fsw == 0 && (fcw & 0x103f) == 0x003f);
>> }
>>
>> +static void test_nopl(void)
>> +{
>> + MK_INSN(nopl1, ".byte 0x90\n\r"); // 1 byte nop
>> + MK_INSN(nopl2, ".byte 0x66, 0x90\n\r"); // 2 bytes nop
>> + MK_INSN(nopl3, ".byte 0x0f, 0x1f, 0x00\n\r"); // 3 bytes nop
>> + MK_INSN(nopl4, ".byte 0x0f, 0x1f, 0x40, 0x00\n\r"); // 4 bytes nop
> But all nops below that are not supported in 16 bit mode. You can
> disassemble realmode.elf in 16bit node (objdump -z -d -mi8086
> x86/realmode.elf) and check yourself. Lets not complicate things for now
> and test only those that are easy to test.
Yes. But what if a 7-bytes nop runs in 16bit mode? Just the same as
https://bugzilla.redhat.com/show_bug.cgi?id=967652
DR6=00000000ffff0ff0 DR7=0000000000000400
EFER=0000000000000500
Code=00 00 e9 50 ff ff ff 00 00 00 00 85 d2 74 20 45 31 c0 31 c9 <0f>
1f 80 00 00 00 00 0f b6 04 31 41 83 c0 01 88 04 39 48 83 c1 01 41 39
d0 75 ec 48 89 f8
The error code is "0f 1f 80 00 00 00 00", which is a 7-bytes nop. Will
the emulator runs well in that case when booting RHEL5.9 64-bit?
Arthur
>
>> + MK_INSN(nopl5, ".byte 0x0f, 0x1f, 0x44, 0x00, 0x00\n\r"); // 5 bytes nop
>> + MK_INSN(nopl6, ".byte 0x66, 0x0f, 0x1f, 0x44, 0x00, 0x00\n\r"); // 6 bytes nop
>> + MK_INSN(nopl7, ".byte 0x0f, 0x1f, 0x80, 0x00, 0x00, 0x00, 0x00\n\r"); // 7 bytes nop
>> + MK_INSN(nopl8, ".byte 0x0f, 0x1f, 0x84, 0x00, 0x00, 0x00, 0x00, 0x00\n\r"); // 8 bytes nop
>> + MK_INSN(nopl9, ".byte 0x66, 0x0f, 0x1f, 0x84, 0x00, 0x00, 0x00, 0x00, 0x00\n\r"); // 9 bytes nop
>> + exec_in_big_real_mode(&insn_nopl1);
>> + exec_in_big_real_mode(&insn_nopl2);
>> + exec_in_big_real_mode(&insn_nopl3);
>> + exec_in_big_real_mode(&insn_nopl4);
>> + exec_in_big_real_mode(&insn_nopl5);
>> + exec_in_big_real_mode(&insn_nopl6);
>> + exec_in_big_real_mode(&insn_nopl7);
>> + exec_in_big_real_mode(&insn_nopl8);
>> + exec_in_big_real_mode(&insn_nopl9);
>> + report("nopl", 0, 1);
>> +}
>> +
>> void realmode_start(void)
>> {
>> test_null();
>> @@ -1548,6 +1571,7 @@ void realmode_start(void)
>> test_xlat();
>> test_salc();
>> test_fninit();
>> + test_nopl();
>>
>> exit(0);
>> }
>> --
>> 1.7.9.5
>
> --
> Gleb.
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