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QEMU is my favorite emulator, but there are three things I badly wish it could do. Dump GDT entries, dump IDT entries, and allow me to view a specific page mapping. Those three features in Bochs saved me quite a few times.

iansjack wrote:

bzt wrote:Neither does qemu

That's just not true.
Use qemu in conjunction with gdb

Then you don't use qemu's built-in monitor, you're using GDB.

nexos wrote:QEMU is my favorite emulator, but there are three things I badly wish it could do. Dump GDT entries, dump IDT entries, and allow me to view a specific page mapping. Those three features in Bochs saved me quite a few times.

Use the qemu's built-in monitor, that can show you such info. Not sure about a specific page, but it can dump the active MMU tables (so all pages at once) with "info tbl". Sadly there's no formatted "info gdt", you are limited to "x /fmt" for dumping the GDT and the IDT. The "info registers" command will show you the start offsets and limits.

Cheers,
bzt

I did say I was talking about gdb. You use both gdb and the qemu monitor as they supply different information.

But the point is that gdb provides source-level debugging, whilst the Virtual box debugger doesn't.

iansjack wrote:I did say I was talking about gdb.

And I did say I wasn't.

iansjack wrote:But the point is that gdb provides source-level debugging, whilst the Virtual box debugger doesn't.

That ain't a fair comparition. As I said, a vm debugger will never be a source-level debugger, just as a source-level debugger never will be a vm debugger. You should compare VB debugger to bochs' and qemu's monitor in this regard. All I was saying, that now you can do things in VB debugger that you already could do in bochs and qemu monitor for ages (but VB lacked), and which never will be available to gdb. Sorry if I wasn't clear.

Cheers,
bzt

I'm not really concerned with comparing debuggers. I just want something that does the job.

It's not as if I'm constrained to using just one tool.