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[Qemu-devel] Re: Resume Flag support on i386/x86_64?
From: |
Jan Kiszka |
Subject: |
[Qemu-devel] Re: Resume Flag support on i386/x86_64? |
Date: |
Tue, 17 Feb 2009 10:18:39 +0100 |
User-agent: |
Mozilla/5.0 (X11; U; Linux i686 (x86_64); de; rv:1.8.1.12) Gecko/20080226 SUSE/2.0.0.12-1.1 Thunderbird/2.0.0.12 Mnenhy/0.7.5.666 |
Alex Smith wrote:
> Hi,
>
> Recently support for hardware breakpoint support on i386/x86_64 was
> added (revision 5747 -
> http://lists.gnu.org/archive/html/qemu-devel/2008-11/msg01025.html).
> I've been using hardware breakpoints while writing a debugger for my
> hobby OS kernel, however I've discovered that despite support being
> added for them in QEMU, the Resume Flag (bit 16 in EFLAGS) is not
> supported. When this flag is set on return from an interrupt, the CPU
> should ignore instruction breakpoints for the next instruction, and
> then clear the flag after checking for breakpoints (there's a
> description on page 18-10 of the Intel Software Developer's Manual
> Volume 3B).
Mmh, guess I missed this...
>
> Would it be possible to implement support for this?
I think so. Will take some fiddling within the code generator, will see
what I can do, but you have to be patient (long to-do list...) -- or
look into this on your own. ;)
Well, in the meantime you may also find a correct behavior by running
qemu in kvm mode because then the real hardware is used, and that should
already work as expected.
Jan
--
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