Re: VMWare Workstation 6 for debugging Linux Kernel (!)

[Nigel Cunningham <nigel@nigel.suspend2.net>]

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Hi.

On Fri, 2007-04-20 at 04:21 -0700, Petr Vandrovec wrote:
> Andi Kleen wrote:
> > Xavier Bestel <xavier.bestel@free.fr> writes:
> > 
> >> On Fri, 2007-04-20 at 00:46 +0200, roland wrote:
> >>
> >>> We just quietly added an exciting feature to Workstation 6.0. I believe it 
> >>> will make WS6 a great tool for Linux kernel development. You can now debug 
> >>> kernel of Linux VM with gdb running on the Host without changing anything in 
> >>> the Guest VM. No kdb, no recompiling and no need for second machine. All you 
> >>> need is a single line in VM's configuration file.
> >> I think qemu has the exact same feature.
> > 
> > It doesn't seem to work for x86-64 there though.
> 
> Hello,
> 
> Do you mean with qemu or with VMware?  Yes, we do not support replay 
> with 64bit guests, but debug interface should just work.  Only gotcha is 
> that for 64bit guest you need another option:
> 
> debugStub.listen.guest64 = "TRUE"

Ah. That might help :)

> and then you need to attach gdb to port 8864 (*).  Unfortunately it does 
> not seem possible to build gdb which would support 16bit/32bit code 
> while using 64bit gdb on-wire format, so there are two interfaces.  And 
> if you single-step switch from 64bit mode to 32bit mode or back, you 
> also have to switch gdbs.  Yes, it is a bit unintuitive, and 
> additionally one gdb silently ignores breakpoints set up by other gdb, 
> so you need to keep breakpoints in sync between two gdbs yourself :-(
> 
> (*) If you are using gdb which has both 32bit and 64bit support, be sure 
> to issue appropriate 'set architecture xxx' before 'target remote 
> localhost:88xx' (i386:x86-64 for port 8864, i386 or i8086 for port 
> 8832).  Otherwise gdb is going to die complaining it could not parse 
> remote reply.

That too.

Thanks!

Nigel

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