Re: [Qemu-devel] Which functions writes to memory?

[malc]

On Fri, 16 Apr 2010, Jun Koi wrote:

> 2010/4/16 malc <address@hidden>:
> > On Fri, 16 Apr 2010, Jun Koi wrote:
> >
> >> On Fri, Apr 16, 2010 at 3:17 PM, malc <address@hidden> wrote:
> >> > On Fri, 16 Apr 2010, Jun Koi wrote:
> >> >
> >> >> Hi,
> >> >>
> >> >> I am writing a small tool to trace all the activities that write to an
> >> >> area of (virtual) memory in Qemu.
> >> >> I am currently doing that by putting my code at the top of the below
> >> >> macro in softmmu_header.h
> >> >>
> >> >> static inline void glue(glue(st, SUFFIX), MEMSUFFIX)....
> >> >>
> >> >> However, it seems I still miss some written events: in some occasions,
> >> >> I believe that Qemu has another code writing data to memory, which
> >> >> happens even before this macro.
> >> >> Is it true that elsewhere, Qemu also writes into memory besides using
> >> >> above function?
> >> >>
> >> >> The memory area I am tracking for written events belong to normal area
> >> >> in OS kernel, where usually only normal code (kernel, not something
> >> >> like SMM handler)  write to.
> >> >
> >> > Once the TLB is properly set up st helpers are bypassed entirely and
> >> > tcg generated code writes to it directly, it's quite easy to "workaround"
> >> > that at the expense of much slower execution.
> >> >
> >>
> >> This saves me a lot of frustrated time, thanks!
> >>
> >> Now I can see that tcg code calls to __stb*_mmu(), but cannot find any
> >> code call to st*_mmu().
> >> Do you have any hint?
> >
> > The tcg generated code fetches appropriate helper's address from the
> > qemu_st/ld_helpers array and calls it indirectly.
> 
> Sorry if that was not clear, but my question is: which code called
> st*mmu() macros (in softmmu_header.h)
> 
> I searched around everywhere, but dont see which calls these macros.
> 

It's being called by automatically generated code, code generators for
various platforms leave in tcg/platform/tcg-target.c

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