From: Paul Brook <paul@codesourcery.com>
To: qemu-devel@nongnu.org
Cc: Marcel Kilgus <qemu@mail.kilgus.net>
Subject: Re: [Qemu-devel] Re: Debugging with paging enabled
Date: Fri, 10 Nov 2006 15:56:01 +0000 [thread overview]
Message-ID: <200611101556.02645.paul@codesourcery.com> (raw)
In-Reply-To: <1315607799.20061110153151@kilgus.net>
> Assuming that breakpoint locations are indeed meant to be virtual
> addresses, GDB would have to evaluate the CS descriptor, add the CS
> base to the EIP address and THEN check whether it knows the address.
> But as it seems to be segment-agnostic it doesn't do that and things
> break as a result.
As Dan said, gdb knows nothing about x86 segmentation. As soon as you have
nonzero segment bases you're pretty much on your own.
If you care about fixing this I suggest you get GDB folks to agree (and
document) how segmented memory models should work, then implement that model
in qemu. Hacking qemu to work for your particular case with unmodified gdb
probably "breaks" something else, so doesn't seem to improve the overall
usefulness.
I believe all common x86 OS use zero segment bases, and in long mode the CS/DS
segment bases are ignored.
Paul
next prev parent reply other threads:[~2006-11-10 15:56 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-11-08 2:30 [Qemu-devel] Debugging with paging enabled Marcel Kilgus
2006-11-08 21:13 ` [Qemu-devel] " Marcel Kilgus
2006-11-08 22:15 ` Fabrice Bellard
2006-11-08 23:33 ` Marcel Kilgus
2006-11-08 23:42 ` Daniel Jacobowitz
2006-11-08 23:57 ` Marcel Kilgus
2006-11-09 2:24 ` Daniel Jacobowitz
2006-11-10 13:14 ` andrzej zaborowski
2006-11-10 14:31 ` Marcel Kilgus
2006-11-10 15:56 ` Paul Brook [this message]
2006-11-10 16:14 ` Marcel Kilgus
2006-11-10 17:10 ` Daniel Jacobowitz
2006-11-10 19:01 ` Marcel Kilgus
2006-11-10 19:07 ` Daniel Jacobowitz
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