I tried that, but it seems like I'm getting an interrupt storm on the
debugger VM (CPU spends all its time in the kernel) when I try to attach
the debugger. This observation furthers my suspicion that there is
communication, but there is something wrong with the protocol...

On Tue, Jun 22, 2021 at 12:43 PM Tamas K Lengyel <tamas.k.lengyel@gmail.com>
wrote:

> I used Xen 4.15 and a pretty new version of Windows 10. It is a bit
> finicky, you have to run the debug commands on the debugee and then
> reboot. When the VM is rebooting the domain ID changes so you have to
> start the serial bridge then. Windbg will attach afterwards. Just make
> sure both VMs have serial='pty' set in their config file.
>
> Tamas
>
> On Tue, Jun 22, 2021 at 12:33 PM Neil Sikka <neilsikka@gmail.com> wrote:
> >
> > Thanks for the quick response, Tamas. I tried what you said and windbg
> waits and the debugee hangs when I click the break button in windbg, but I
> don't see any output in windbg. This means that there is SOME communication
> over the serial port that causes the debugee to hang when I click break.
> Could it be a debugger protocol issue? I also tried the guidance here by
> running the crlf program:
> > https://www.qubes-os.org/doc/windows-debugging/
> > But windbg waits and the debugee hangs in a similar manner.
> >
> > What versions of WIndows and Xen are you using?
> >
> > On Tue, Jun 22, 2021 at 12:10 PM Tamas K Lengyel <
> tamas.k.lengyel@gmail.com> wrote:
> >>
> >> I have managed to get windbg working with a serial bridge between two
> >> Win10 VMs using the following script:
> >>
> https://github.com/intel/kernel-fuzzer-for-xen-project/blob/master/scripts/serial-bridge.sh
> .
> >> The debugee has to enable a couple options so that windbg can attach:
> >>
> https://github.com/intel/kernel-fuzzer-for-xen-project/blob/master/scripts/debug.cmd
> .
> >>
> >> Tamas
> >>
> >> On Tue, Jun 22, 2021 at 12:01 PM Neil Sikka <neilsikka@gmail.com>
> wrote:
> >> >
> >> > Hello,
> >> > Has anyone gotten a Windows10 (Version 1709 of later) kernel debugger
> attached when running the Windows10 debugger VM and the Windows10 debugee
> VM on Xen 4.13.0 hypervisor? I am getting a "NIC hardware initialization
> failed" error. I tried the suggestions in the discussion here (
> https://bugzilla.redhat.com/show_bug.cgi?id=1947015):
> >> > -cpu
> Skylake-Server-IBRS,ss=on,vmx=on,hypervisor=on,tsc-adjust=on,clflushopt=on,umip=on,pku=on,md-clear=on,stibp=on,arch-capabilities=on,ssbd=on,xsaves=on,ibpb=on,amd-ssbd=on,
> \
> >> >
> skip-l1dfl-vmentry=on,mpx=off,hv-time,hv-relaxed,hv-vapic,hv-spinlocks=0x1fff,hv-vendor-id=KVMKVMKVM
> >> >
> >> > note: i had to remove the following 2 arguments due to errors from
> QEMU:
> >> > pschange-mc-no=on
> >> > hv_vpindex
> >> >
> >> > Here was the error:
> >> > C:\Users\user\Desktop\oldDebuggers\x64>kdnet.exe
> >> >
> >> > Network debugging is supported on the following NICs:
> >> > busparams=0.4.0, Intel(R) PRO/1000 MT Network Connection, Plugged in.
> >> > The Microsoft hypervisor running this VM does not support KDNET.
> >> > Please upgrade to the hypervisor shipped in Windows 8 or WS2012 or
> later.
> >> >
> >> > KDNET initialization failed.  Status = 0xC0000182.
> >> > NIC hardware initialization failed.
> >> >
> >> > I am using an Intel e1000 NIC emulated through QEMU because its
> supposedly a supported NIC for Windows kernel NET debugging.
> >> >
> >> > Thanks in Advance!
> >> >
> >> > --
> >> > My Blog: http://www.neilscomputerblog.blogspot.com/
> >> > Twitter: @neilsikka
> >
> >
> >
> > --
> > My Blog: http://www.neilscomputerblog.blogspot.com/
> > Twitter: @neilsikka
>


-- 
My Blog: http://www.neilscomputerblog.blogspot.com/
Twitter: @neilsikka