I mean after adding unrestricted_guest=0, the error is reproduced.
Sorry for confused expression. I have committed another patch in
x86/realmode.c.
On Wed, Jun 5, 2013 at 5:28 PM, Gleb Natapov <gleb@xxxxxxxxxx> wrote:
> On Wed, Jun 05, 2013 at 05:23:18PM +0800, 李春奇 <Arthur Chunqi Li> wrote:
>> Yes, I load kvm-intel with unrestricted_guest=0 and the emulator runs
>> well. I will give another test case in x86/realmode.c later.
>>
> The test fails for me on CPU without unrestricted guest support. This
> means you either test on fixed kernel or unrestricted_guest=0 is broken.
>
>> BTW, what is the action when a 64-bit instruction executes in
>> x86/realmode.c? Should I add 64-bit insn tests only in x86/emulator.c?
>>
> Yes, 64-bit or 32-bit instructions should be added to x86/emulator.c.
>
>> On Wed, Jun 5, 2013 at 4:27 PM, Gleb Natapov <gleb@xxxxxxxxxx> wrote:
>> > On Wed, Jun 05, 2013 at 03:00:33PM +0800, 李春奇 <Arthur Chunqi Li> wrote:
>> >> Yes, that should be the point. x86/realmode.c is always running in
>> >> emulation mode. I added the testing here there but no error occurred. I
>> >> cannot find the reason.
>> >>
>> >> The code is as follows added to x86/realmode.c
>> >> static void test_nopl(void)
>> >> {
>> >> MK_INSN(nopl, ".byte 0x0f, 0x1f, 0x00\n\r");
>> >> exec_in_big_real_mode(&insn_nopl);
>> >> report("nopl", 0, 1);
>> >> }
>> >>
>> >> and I objdump from realmode.flat is as follows:
>> >> 00006458 <insn_code_nopl>:
>> >> 6458: 0f 1f 00 nopl (%eax)
>> >>
>> >> But there cause no error when executing this insn. Why?
>> >>
>> > Because you probably use cpu that supports unrestricted mode or use AMD
>> > processor. Can you try loading kvm-intel with unrestricted_guest=0
>> > option?
>> >
>> >>
>> >> On Wed, Jun 5, 2013 at 2:42 PM, Gleb Natapov <gleb@xxxxxxxxxx> wrote:
>> >>
>> >> > On Wed, Jun 05, 2013 at 10:16:46AM +0800, 李春奇 <Arthur Chunqi Li> wrote:
>> >> > > Add multibyte NOP test case to kvm-unit-tests. This case can test one
>> >> > > of bugs when booting RHEL5.9 64-bit.
>> >> > >
>> >> > Adding the test to x86/realmode.c will be much easier.
>> >> >
>> >> > > Signed-off-by: Arthur Chunqi Li <yzt356@xxxxxxxxx>
>> >> > > ---
>> >> > > x86/emulator.c | 33 +++++++++++++++++++++++++++++++++
>> >> > > 1 file changed, 33 insertions(+)
>> >> > >
>> >> > > diff --git a/x86/emulator.c b/x86/emulator.c
>> >> > > index 96576e5..f26c70f 100644
>> >> > > --- a/x86/emulator.c
>> >> > > +++ b/x86/emulator.c
>> >> > > @@ -901,6 +901,37 @@ static void test_simplealu(u32 *mem)
>> >> > > report("test", *mem == 0x8400);
>> >> > > }
>> >> > >
>> >> > > +static void test_nopl(uint64_t *mem, uint8_t *insn_page,
>> >> > > + uint8_t *alt_insn_page, void *insn_ram)
>> >> > > +{
>> >> > > + ulong *cr3 = (ulong *)read_cr3();
>> >> > > +
>> >> > > + // Pad with RET instructions
>> >> > > + memset(insn_page, 0xc3, 4096);
>> >> > > + memset(alt_insn_page, 0xc3, 4096);
>> >> > > + // Place a trapping instruction in the page to trigger a VMEXIT
>> >> > > + insn_page[0] = 0x89; // mov %eax, (%rax)
>> >> > > + insn_page[1] = 0x00;
>> >> > > + insn_page[2] = 0x90; // nop
>> >> > > + // Place nopl 0x0(%eax) in alt_insn_page for emulator to execuate
>> >> > > + alt_insn_page[0] = 0x0f; // nop DWORD ptr[EAX]
>> >> > > + alt_insn_page[1] = 0x1f;
>> >> > > + alt_insn_page[2] = 0x00;
>> >> > > +
>> >> > > + // Load the code TLB with insn_page, but point the page tables at
>> >> > > + // alt_insn_page (and keep the data TLB clear, for AMD decode
>> >> > assist).
>> >> > > + // This will make the CPU trap on the insn_page instruction but the
>> >> > > + // hypervisor will see alt_insn_page.
>> >> > > + install_page(cr3, virt_to_phys(insn_page), insn_ram);
>> >> > > + // Load code TLB
>> >> > > + invlpg(insn_ram);
>> >> > > + asm volatile("call *%0" : : "r"(insn_ram + 3));
>> >> > > + // Trap, let hypervisor emulate at alt_insn_page
>> >> > > + install_page(cr3, virt_to_phys(alt_insn_page), insn_ram);
>> >> > > + asm volatile("call *%0" : : "r"(insn_ram), "a"(mem));
>> >> > > + report("nopl", 1);
>> >> > > +}
>> >> > > +
>> >> > > int main()
>> >> > > {
>> >> > > void *mem;
>> >> > > @@ -964,6 +995,8 @@ int main()
>> >> > >
>> >> > > test_string_io_mmio(mem);
>> >> > >
>> >> > > + test_nopl(mem, insn_page, alt_insn_page, insn_ram);
>> >> > > +
>> >> > > printf("\nSUMMARY: %d tests, %d failures\n", tests, fails);
>> >> > > return fails ? 1 : 0;
>> >> > > }
>> >> > > --
>> >> > > 1.7.9.5
>> >> >
>> >> > --
>> >> > Gleb.
>> >> >
>> >>
>> >>
>> >>
>> >> --
>> >> Arthur Chunqi Li
>> >> Department of Computer Science
>> >> School of EECS
>> >> Peking University
>> >> Beijing, China
>> >
>> > --
>> > Gleb.
>>
>>
>>
>> --
>> Arthur Chunqi Li
>> Department of Computer Science
>> School of EECS
>> Peking University
>> Beijing, China
>
> --
> Gleb.
--
Arthur Chunqi Li
Department of Computer Science
School of EECS
Peking University
Beijing, China
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