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Re: [Qemu-devel] [PATCH 00/43] Windbg supporting
From: |
Ladi Prosek |
Subject: |
Re: [Qemu-devel] [PATCH 00/43] Windbg supporting |
Date: |
Tue, 3 Oct 2017 16:16:01 +0200 |
Hi,
On Tue, Sep 26, 2017 at 1:04 PM, Mihail Abakumov
<address@hidden> wrote:
> We made the debugger module WinDbg (like GDB) for QEMU. This is the
> replacement of the remote stub in Windows kernel. Used for remote Windows
> kernel debugging without debugging mode.
>
> WinDbg is a multipurpose debugger for the Microsoft Windows computer
> operating system, distributed by Microsoft. Recent versions of WinDbg have
> been and are being distributed as part of the free Debugging Tools for
> Windows suite.
>
> How to start debugging QEMU using WinDbg:
> Run QEMU with next option:
> -windbg pipe:<name>
> QEMU will start and pause for waiting WinDbg connection.
> Run WinDbg with next options:
> -b -k com:pipe,baud=115200,port=\\.\pipe\<name>,resets=0
> Wait for debugger connect to kernel.
>
> Note: You can add Symbol Search Path in WinDbg such as
> srv*c:\tmp*http://msdl.microsoft.com/download/symbols.
>
> How it works:
> The WinDbg debugger has the possibility of connecting to a remote debug
> service (Kdsrv.exe) in the Windows kernel. Therefore, it is possible to
> connect to the guest system running in the QEMU emulator. Kernel debugging is
> possible only with the enabled debugging mode, may change at the same time.
> Our module of WinDbg debugger for QEMU is an alternative of the remote
> debugging service in the kernel. Thus, the debugger connects to the debugging
> module, not to the kernel of the operating system. The module obtains all the
> necessary information answering debugger requests from the QEMU emulator. At
> the same time for debugging there is no need to enable debugging mode in the
> kernel. This leads to hidden debugging. Our module supports all features of
> WinDbg regarding remote debugging, besides interception of events and
> exceptions. Only i386 is supported now.
I wanted to try this to debug a WinXP VM running on Linux from another
VM on the same host. I used my usual windbg setup only instead of
-serial tcp:localhost:8888
I had
-windbg tcp:localhost:8888
in the QEMU command line of the debugging target and
-serial tcp:localhost:8888,server,nowait
for the VM running windbg, but I didn't succeed even after disabling
KVM which seems to be one of the limitations.
I understand that you run QEMU on Windows. Before I dig deeper, have
you tried any other backend for -windbg or maybe running on a Linux
host? Is it expected to work?
Thank you!
Ladi
> ---
>
> Mihail Abakumov (43):
> windbg: added empty windbgstub files
> windbg: added windbg's KD header file
> windbg: modified windbgkd.h
> windbg: added '-windbg' option
> windbg: added helper features
> windbg: added WindbgState
> windbg: added chardev
> windbg: hook to wrmsr operation
> windbg: handler of fs/gs register
> windbg: structures for parsing data stream
> windbg: parsing data stream
> windbg: send data and control packets
> windbg: handler of parsing context
> windbg: init DBGKD_ANY_WAIT_STATE_CHANGE
> windbg: sized data buffer
> windbg: generate ExceptionStateChange
> windbg: generate LoadSymbolsStateChange
> windbg: windbg_vm_stop
> windbg: implemented windbg_process_control_packet
> windbg: implemented windbg_process_data_packet
> windbg: implemented windbg_process_manipulate_packet
> windbg: implemented kd_api_read_virtual_memory and
> kd_api_read_virtual_memory
> windbg: kernel's structures
> windbg: implemented kd_api_get_context and kd_api_set_context
> windbg: implemented kd_api_read_control_space and
> kd_api_write_control_space
> windbg: implemented windbg_read_context
> windbg: implemented windbg_write_context
> windbg: implemented windbg_read_ks_regs
> windbg: implemented windbg_write_ks_regs
> windbg: implemented windbg_set_sr
> windbg: implemented windbg_set_dr
> windbg: implemented windbg_set_dr7
> windbg: implemented windbg_hw_breakpoint_insert and
> windbg_hw_breakpoint_remove
> windbg: implemented kd_api_write_breakpoint and
> kd_api_restore_breakpoint
> windbg: debug exception subscribing
> windbg: implemented kd_api_continue
> windbg: implemented kd_api_read_io_space and kd_api_write_io_space
> windbg: implemented kd_api_read_physical_memory and
> kd_api_write_physical_memory
> windbg: implemented kd_api_get_version
> windbg: implemented kd_api_read_msr and kd_api_write_msr
> windbg: implemented kd_api_search_memory
> windbg: implemented kd_api_fill_memory
> windbg: implemented kd_api_query_memory
>
>
> Makefile.target | 5
> cpus.c | 18
> gdbstub.c | 4
> include/exec/windbgkd.h | 1030 ++++++++++++++++++++++
> include/exec/windbgstub-utils.h | 132 +++
> include/exec/windbgstub.h | 21
> include/sysemu/sysemu.h | 2
> qemu-options.hx | 8
> target/i386/misc_helper.c | 3
> vl.c | 8
> windbgstub-utils.c | 1788
> +++++++++++++++++++++++++++++++++++++++
> windbgstub.c | 464 ++++++++++
> 12 files changed, 3482 insertions(+), 1 deletion(-)
> create mode 100755 include/exec/windbgkd.h
> create mode 100755 include/exec/windbgstub-utils.h
> create mode 100755 include/exec/windbgstub.h
> create mode 100755 windbgstub-utils.c
> create mode 100755 windbgstub.c
>
> --
> Thanks,
> Mihail Abakumov