On Mon, Jun 10, 2013 at 01:09:15AM +0800, 李春奇 <Arthur Chunqi Li> wrote:
> I have finished the infrastructure but after changing test_mmx_movq_mf
> test case, it return error:
> unhandled excecption 6
> Return value from qemu: 15
>
> If I don't change %rsp and %rbp, it runs OK.
> So I wonder if this test case is strictly reply on %rsp and %rbp?
>
I can't help without seeing the code.
> On Mon, Jun 10, 2013 at 12:00 AM, Gleb Natapov <g...@redhat.com> wrote:
> > On Sun, Jun 09, 2013 at 11:23:26PM +0800, 李春奇 <Arthur Chunqi Li> wrote:
> >> On Sun, Jun 9, 2013 at 10:09 PM, Gleb Natapov <g...@redhat.com> wrote:
> >> > On Sun, Jun 09, 2013 at 09:22:27PM +0800, 李春奇 <Arthur Chunqi Li> wrote:
> >> >> On Sun, Jun 9, 2013 at 8:49 PM, Gleb Natapov <g...@redhat.com> wrote:
> >> >> > On Sun, Jun 09, 2013 at 08:44:32PM +0800, 李春奇 <Arthur Chunqi Li>
> >> >> > wrote:
> >> >> >> On Sun, Jun 9, 2013 at 7:07 PM, Gleb Natapov <g...@redhat.com> wrote:
> >> >> >> > On Fri, Jun 07, 2013 at 10:31:38AM +0800, Arthur Chunqi Li wrote:
> >> >> >> >> Add a function trap_emulator to run an instruction in emulator.
> >> >> >> >> Set inregs first (%rax, %rsp, %rbp, %rflags have special usage and
> >> >> >> >> cannot set in inregs), put instruction codec in alt_insn and call
> >> >> >> >> func with alt_insn_length. Get results in outregs.
> >> >> >> >>
> >> >> >> > Why %rax, %rsp, %rbp, %rflags cannot be set in inregs?
> >> >> >> >
> >> >> >> > %rax because trapping instruction uses it? Use one that does not
> >> >> >> > use
> >> >> >> > register at all: MOV r/m32, imm32
> >> >> >> I don't know why set %rax before call alt_insn_page can cause error.
> >> >> >> I
> >> >> >> use "xchg %%rax, 0+%[save]" before "call *%1" and the %rcx is not set
> >> >> >> correctly.
> >> >> > We better find this out :)
> >> >> I found that before calling alt_insn_page, address of "mem" is saved
> >> >> to %rax, why?
> >> > Because instruction that we use to trigger vmexit is mov %eax, (%rax) so
> >> > MMOI address mem is loaded into %rax before jumping into it.
> >> I think this is why changing %rax will cause error. If we use mov
> >> %eax, (%rax) to trigger vmexit, and %rax is changed before calling
> >> alt_insn_page, codes in alt_insn_page will not be executed and return
> >> directly.
> >> I changed the codes which trigger vmexit to "mov %eax, (%r8)" and set
> >> "mem" to %r8 before calling alt_insn_page, it runs OK.
> >>
> > Just use an instruction that does not use registers at all. mov $1, addr
> > where addr is immediate and encoded from mem parameter.
> >
> >> Besides, I also don't know if changed %rflags may cause some
> >> unpredictable actions, so now we just treat it with no error :)
> > If test sets rflags to a value that causes crashes this is a test bug,
> > no need to prevent this from happening.
> >
> > --
> > Gleb.
>
>
>
> --
> Arthur Chunqi Li
> Department of Computer Science
> School of EECS
> Peking University
> Beijing, China
--
Gleb.
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