Re: Debugging 32 bit ARM guests running under QEMU KVM on 64 bit ARM hos
Re: Debugging 32 bit ARM guests running under QEMU KVM on 64 bit ARM hosts with gdb
Wed, 13 Jan 2021 11:02:52 -0500
<firstname.lastname@example.org> wrote on 01/12/2021 06:26:50 AM:
> From: "Alex Bennée" <email@example.com> > To: firstname.lastname@example.org > Cc: "Berto
Furth" <email@example.com>, firstname.lastname@example.org > Date: 01/12/2021
06:29 AM > Subject:
Re: Debugging 32 bit ARM guests running under QEMU KVM on
> 64 bit ARM hosts with gdb >
> email@example.com writes:
> >> From: "Berto Furth" <firstname.lastname@example.org>
> >> To: email@example.com
> >> Date: 01/08/2021 05:48 AM
> >> Subject: Debugging 32 bit ARM guests running under QEMU KVM
> >> bit ARM hosts with gdb
> >> I have noticed that when debugging a 32 bit arm (AA32) kvm
> >> running in a 64 bit ARM (aarch64 / AA64) host with "qemu-system-
> >> aarch64" and the "aarch64=off" flag set that
a remote gdb debugger
> >> still thinks that it's debugging ARM64. ...
> > Just FYI, my group has been maintaining a similar patch so we
> > 32-bit guests. I don't have qemu commit privileges (and
> > but I would be willing to support this activity in terms of testing
> > patches, which I can do on arm, ppc, and x86 guests. We
> > to recent QEMU versions recently, but for this I would.
> Re-reading the old thread I think this stalled because it wasn't
> entirely clear moving the gdbstub initialisation in the second patch
> the cleanest way to deal with things.
> Does you patch take a similar approach?
Sadly our patch
is pretty brutal. It hard wires the GDB stub to 32-bit. We ran into several
problems with the Eclipse version (at the time) stepping between 32 and
64-bit code. Since most of our code was 32-bit we just forced 32-bit access
always. More recently we have more 64-bit code, hence the interest in looking
for something that handles both more gracefully. I'm hoping the issues
with Eclipse have been resolved in the mean time.