From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?UTF-8?B?5p2O5pil5aWHIDxBcnRodXIgQ2h1bnFpIExpPg==?= Subject: Re: [PATCH] Test case of emulating multibyte NOP Date: Thu, 6 Jun 2013 00:28:16 +0800 Message-ID: References: <1370448172-22960-1-git-send-email-yzt356@gmail.com> <20130605161352.GI4725@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Cc: kvm , Paolo Bonzini To: Gleb Natapov Return-path: Received: from mail-lb0-f172.google.com ([209.85.217.172]:51728 "EHLO mail-lb0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756451Ab3FEQ2U (ORCPT ); Wed, 5 Jun 2013 12:28:20 -0400 Received: by mail-lb0-f172.google.com with SMTP id p10so2121578lbi.31 for ; Wed, 05 Jun 2013 09:28:16 -0700 (PDT) In-Reply-To: <20130605161352.GI4725@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On Thu, Jun 6, 2013 at 12:13 AM, Gleb Natapov 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 >> --- >> 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.