Re: [PATCH 2/2] Add xen-hyp-rw

[Don Slutz <don.slutz@gmail.com>]

On 06/18/15 13:05, Andrew Cooper wrote:
> On 18/06/15 16:55, Don Slutz wrote:
>> This allows reading and writing of variables in the hypervisor.
>>
>> for example (read case -- default 4 bytes):
>>
>>   xen-hyp-rw /boot/System.map-xen* opt_hvm_debug_level
>>   opt_hvm_debug_level @ 0xffff82d080285610 is 0x0(0)
>>
>> Write case:
>>
>>   xen-hyp-rw /boot/System.map-xen* opt_hvm_debug_level 4 -1
>>   opt_hvm_debug_level @ 0xffff82d080285610 is 0x0(0)
>>   opt_hvm_debug_level @ 0xffff82d080285610 set to 0xffffffff(4294967295)
>>
>> Signed-off-by: Don Slutz <dslutz@verizon.com>
>> CC: Don Slutz <don.slutz@gmail.com>
> 
> As a crazy thought...
> 
> Would it not be easier to modify gdbsx to allow gdb to connect remotely
> to the hypervisor context?

I tried this to start, but kept running into issues.  A lot of them were
about pausing and unpausing the target domain.

> 
> That way, any gdb-like tools could consume an appropriate xen-syms and
> make changes like this.
> 

Yes.  This code was a lot faster to get working.

I used a lot of the xg "library" of gdbsx to do the work.  Only 2 new
routines: hyp_attach() and hyp_detach() in that code.

   -Don Slutz

> ~Andrew
>