Re: [Qemu-devel] Re: PC traces from QEMU

["Shashidhar Mysore" <shashimc@gmail.com>]

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Hi Stuart,

Thanks for the patch. It works well for me, except that the log file grows
so huge and qemu slows down quite a lot. Did you have problems with this? I
was wondering if there was a way to actually begin the PC trace collection
after completely booting QEMU and also restrict it to a particular process
ID?

Just a clarification, does the log now have all retired PCs?

Thanks,
-Shashi.

On 3/30/07, Stuart Brady <sdbrady@ntlworld.com> wrote:
>
> On Thu, Mar 29, 2007 at 06:28:14PM -0700, Shashidhar Mysore wrote:
> > Hi Stuart,
> >
> > Thanks for the reply, but since I'm a little new to qemu, can you please
> > elaborate on how to insert the op_dump_pc function to extract the PC
> values?
>
> Well, here's a patch that does it:
>
> Index: target-i386/exec.h
> ===================================================================
> RCS file: /sources/qemu/qemu/target-i386/exec.h,v
> retrieving revision 1.31
> diff -u -r1.31 exec.h
> --- target-i386/exec.h  24 Sep 2006 18:40:46 -0000      1.31
> +++ target-i386/exec.h  30 Mar 2007 11:02:08 -0000
> @@ -146,6 +146,8 @@
>
> extern CCTable cc_table[];
>
> +void helper_dump_pc(target_ulong PC);
> +
> void load_seg(int seg_reg, int selector);
> void helper_ljmp_protected_T0_T1(int next_eip);
> void helper_lcall_real_T0_T1(int shift, int next_eip);
> Index: target-i386/helper.c
> ===================================================================
> RCS file: /sources/qemu/qemu/target-i386/helper.c,v
> retrieving revision 1.74
> diff -u -r1.74 helper.c
> --- target-i386/helper.c        1 Feb 2007 22:12:19 -0000       1.74
> +++ target-i386/helper.c        30 Mar 2007 11:02:09 -0000
> @@ -30,6 +30,16 @@
> } while (0)
> #endif
>
> +void helper_dump_pc(target_ulong pc)
> +{
> +    if (logfile)
> +#ifdef TARGET_X86_64
> +        fprintf(logfile, "PC = %016" PRIx64 "\n", pc);
> +#else
> +        fprintf(logfile, "PC = %08x\n", pc);
> +#endif
> +}
> +
> const uint8_t parity_table[256] = {
>      CC_P, 0, 0, CC_P, 0, CC_P, CC_P, 0,
>      0, CC_P, CC_P, 0, CC_P, 0, 0, CC_P,
> Index: target-i386/op.c
> ===================================================================
> RCS file: /sources/qemu/qemu/target-i386/op.c,v
> retrieving revision 1.47
> diff -u -r1.47 op.c
> --- target-i386/op.c    1 Feb 2007 22:11:07 -0000       1.47
> +++ target-i386/op.c    30 Mar 2007 11:02:09 -0000
> @@ -132,6 +132,11 @@
>
> #endif
>
> +void OPPROTO op_dump_pc(void)
> +{
> +    helper_dump_pc(PARAM1);
> +}
> +
> /* operations with flags */
>
> /* update flags with T0 and T1 (add/sub case) */
> Index: target-i386/translate.c
> ===================================================================
> RCS file: /sources/qemu/qemu/target-i386/translate.c,v
> retrieving revision 1.62
> diff -u -r1.62 translate.c
> --- target-i386/translate.c     16 Jan 2007 19:28:58 -0000      1.62
> +++ target-i386/translate.c     30 Mar 2007 11:02:10 -0000
> @@ -3155,6 +3155,7 @@
>      int rex_w, rex_r;
>
>      s->pc = pc_start;
> +    gen_op_dump_pc(s->pc);
>      prefixes = 0;
>      aflag = s->code32;
>      dflag = s->code32;
>
> It's probably not the best way to do this, but it worked well enough for
> my purposes.  (target-z80 -- where there is only one address space! :-)
> --
> Stuart Brady
>

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