On Wed, Jun 05, 2013 at 05:46:31PM +0800, 李春奇 <Arthur Chunqi Li> wrote:
> I mean after adding unrestricted_guest=0, the error is reproduced.
Ah, OK. unrestricted_guest=0 works then :)
> 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
--
Gleb.
--
To unsubscribe from this list: send the line "unsubscribe kvm" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
