From: malc <av1474@comtv.ru>
To: Jun Koi <junkoi2004@gmail.com>
Cc: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] Which functions writes to memory?
Date: Fri, 16 Apr 2010 10:50:20 +0400 (MSD) [thread overview]
Message-ID: <alpine.LNX.2.00.1004161049280.15076@linmac> (raw)
In-Reply-To: <y2ufdaac4d51004152338r1aeb2dd5t42b2c47cce6e2dea@mail.gmail.com>
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On Fri, 16 Apr 2010, Jun Koi wrote:
> On Fri, Apr 16, 2010 at 3:17 PM, malc <av1474@comtv.ru> 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.
--
mailto:av1474@comtv.ru
next prev parent reply other threads:[~2010-04-16 8:48 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-04-16 5:56 [Qemu-devel] Which functions writes to memory? Jun Koi
2010-04-16 6:17 ` malc
2010-04-16 6:38 ` Jun Koi
2010-04-16 6:50 ` malc [this message]
2010-04-16 6:59 ` Jun Koi
2010-04-16 8:15 ` malc
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