From mboxrd@z Thu Jan  1 00:00:00 1970
From: Don Slutz <don.slutz@gmail.com>
Subject: Re: [PATCH 2/2] Add xen-hyp-rw
Date: Thu, 18 Jun 2015 16:50:18 -0400
Message-ID: <55832F0A.9060901@Gmail.com>
References: <1434642932-24807-1-git-send-email-dslutz@verizon.com>
	<1434642932-24807-3-git-send-email-dslutz@verizon.com>
	<5582FA3F.4030108@citrix.com>
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
Return-path: <xen-devel-bounces@lists.xen.org>
In-Reply-To: <5582FA3F.4030108@citrix.com>
List-Unsubscribe: <http://lists.xen.org/cgi-bin/mailman/options/xen-devel>,
	<mailto:xen-devel-request@lists.xen.org?subject=unsubscribe>
List-Post: <mailto:xen-devel@lists.xen.org>
List-Help: <mailto:xen-devel-request@lists.xen.org?subject=help>
List-Subscribe: <http://lists.xen.org/cgi-bin/mailman/listinfo/xen-devel>,
	<mailto:xen-devel-request@lists.xen.org?subject=subscribe>
Sender: xen-devel-bounces@lists.xen.org
Errors-To: xen-devel-bounces@lists.xen.org
To: Andrew Cooper <andrew.cooper3@citrix.com>, Don Slutz <dslutz@verizon.com>, xen-devel@lists.xen.org
Cc: Keir Fraser <keir@xen.org>, Ian Campbell <ian.campbell@citrix.com>, Stefano Stabellini <stefano.stabellini@eu.citrix.com>, Tim Deegan <tim@xen.org>, Ian Jackson <ian.jackson@eu.citrix.com>, Jan Beulich <jbeulich@suse.com>, Wei Liu <wei.liu2@citrix.com>, Mukesh Rathor <mukesh.rathor@oracle.com>
List-Id: xen-devel@lists.xenproject.org

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
>