[Qemu-devel] gdbstub breakpoints not working across virtual address spaces

[Qemu-devel] gdbstub breakpoints not working across virtual address spaces

[Bradley Schatz]

I have breakpoints failing in the case where a breakpoint is set on a
virtual address in another virtual address space. The virtual address
is mapped to nothing in the current virtual address space.

I would like breakpoints to arbitrarily apply across all virtual
address spaces.

My initial investigations suggest that a call to breakpoint_invalidate
after cr3 has been set to the new virtual address space, somewhere in
the softmmu, would be the place to start.

Any suggestions to point me on the right path?

Thanks,

Bradley

Re: [Qemu-devel] gdbstub breakpoints not working across virtual address spaces

[Daniel Jacobowitz]

On Wed, Sep 19, 2007 at 10:28:00PM +1000, Bradley Schatz wrote:
> I have breakpoints failing in the case where a breakpoint is set on a
> virtual address in another virtual address space. The virtual address
> is mapped to nothing in the current virtual address space.
> 
> I would like breakpoints to arbitrarily apply across all virtual
> address spaces.

I think they already do.  Specific example, please.

-- 
Daniel Jacobowitz
CodeSourcery

Re: [Qemu-devel] gdbstub breakpoints not working across virtual address spaces

[Bradley Schatz]

I am running a windows2k guest, which in turn is running coLinux. I
wish to set a breakpoint in the linux instance.

A windows driver loads, and builds the page tables of two independent
virtual address spaces, and backs them with page frames allocated
using the windows driver API. The two addreess spaces are a trampoline
address space, and then the coLinux address space. The driver then
switches to the linux virtual address space via the trampoline space.

I am currently setting a breakpoint on an address in the linux address
space before the driver is even loaded. On running, the breakpoint is
ignored, but colinux runs.

Thanks,

Bradley



On 9/19/07, Daniel Jacobowitz <drow@false.org> wrote:
> On Wed, Sep 19, 2007 at 10:28:00PM +1000, Bradley Schatz wrote:
> > I have breakpoints failing in the case where a breakpoint is set on a
> > virtual address in another virtual address space. The virtual address
> > is mapped to nothing in the current virtual address space.
> >
> > I would like breakpoints to arbitrarily apply across all virtual
> > address spaces.
>
> I think they already do.  Specific example, please.
>
> --
> Daniel Jacobowitz
> CodeSourcery
>
>
>

Re: [Qemu-devel] gdbstub breakpoints not working across virtual address spaces

[Bradley Schatz]

Trying things a different way, I find that issuing a:
  breakpoint *0xc...

will break properly.


On 9/20/07, Bradley Schatz <blschatz@gmail.com> wrote:
> I am running a windows2k guest, which in turn is running coLinux. I
> wish to set a breakpoint in the linux instance.
>
> A windows driver loads, and builds the page tables of two independent
> virtual address spaces, and backs them with page frames allocated
> using the windows driver API. The two addreess spaces are a trampoline
> address space, and then the coLinux address space. The driver then
> switches to the linux virtual address space via the trampoline space.
>
> I am currently setting a breakpoint on an address in the linux address
> space before the driver is even loaded. On running, the breakpoint is
> ignored, but colinux runs.
>
> Thanks,
>
> Bradley
>
>
>
> On 9/19/07, Daniel Jacobowitz <drow@false.org> wrote:
> > On Wed, Sep 19, 2007 at 10:28:00PM +1000, Bradley Schatz wrote:
> > > I have breakpoints failing in the case where a breakpoint is set on a
> > > virtual address in another virtual address space. The virtual address
> > > is mapped to nothing in the current virtual address space.
> > >
> > > I would like breakpoints to arbitrarily apply across all virtual
> > > address spaces.
> >
> > I think they already do.  Specific example, please.
> >
> > --
> > Daniel Jacobowitz
> > CodeSourcery
> >
> >
> >
>