From mboxrd@z Thu Jan 1 00:00:00 1970 From: ravi kerur Subject: Re: Q on ioctl support in netfront/netback Date: Wed, 17 Feb 2010 07:44:02 -0800 Message-ID: References: <4B791671.4050902@citrix.com> <1266377170.15135.13710.camel@agari.van.xensource.com> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============0835151244==" Return-path: In-Reply-To: <1266377170.15135.13710.camel@agari.van.xensource.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Daniel Stodden Cc: Paul Durrant , "xen-devel@lists.xensource.com" List-Id: xen-devel@lists.xenproject.org --===============0835151244== Content-Type: multipart/alternative; boundary=00163630f44535a01a047fcdb85d --00163630f44535a01a047fcdb85d Content-Type: text/plain; charset=ISO-8859-1 Hi Daniel, These registers are(DMA, statistics, and other h/w related to NIC), I just want to read those registers and in very few cases write to them. Currently, I can run those applications in dom0 and access directly but I wanted to check if anything is possible from domU? Other thing I tried using sockets from domU to dom0(albeit I had clear firewall settings in dom0) but Citrix support forum mentioned it is not the recommended way. I am not sure whether I answered your question, let me know if you need additional info. Thanks -RK On Tue, Feb 16, 2010 at 7:26 PM, Daniel Stodden wrote: > On Mon, 2010-02-15 at 10:54 -0500, ravi kerur wrote: > > Paul, > > > > Registers are not in netback, they are h/w registers on NIC and the > > driver supports reads/writes via ioctl calls. Driver is in dom0 and > > application which reads/writes registers is run in domU. > > Why do you want to map or preserve some register interface? > > Is this some sort of hardware multiplex? As Konrad pointed out, in that > case a PV driver is probably the wrong approach altogether. > > If what you want is just a bunch of extended control plane attributes, > rather consider mapping them to xenstore. > > That's slightly more asynchronous and probably not a great option if you > need a synchronous interface. Especially if you need individual return > values, not just a bunch of fields to write into. > > If the latter case, next option would be some dedicated shared memory > structure. But it's hard to imagine something like that to make > sense. :} > > Daniel > > --00163630f44535a01a047fcdb85d Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Hi Daniel,

These registers are(DMA, statistics, and other h/w relate= d to NIC), I just want to read those registers and in very few cases write = to them. Currently, I can run those applications in dom0 and access directl= y but I wanted to check if anything is possible from domU? Other thing I tr= ied using sockets from domU to dom0(albeit I had clear firewall settings in= dom0) but Citrix support forum mentioned it is not the recommended way. I = am not sure whether I answered your question, let me know if you need addit= ional info.

Thanks
-RK

On Tue, Feb 16, 2010 at= 7:26 PM, Daniel Stodden <daniel.stodden@citrix.com> wrote:
On Mon, 2010-02-15 at 10:54 -0500, ravi kerur wrote:
> Paul,
>
> Registers are not in netback, they are h/w registers on NIC and the > driver supports reads/writes via ioctl calls. Driver is in dom0 and > application which reads/writes registers is run in domU.

Why do you want to map or preserve = some register interface?

Is this some sort of hardware multiplex? As Konrad pointed out, in that
case a PV driver is probably the wrong approach altogether.

If what you want is just a bunch of extended control plane attributes,
rather consider mapping them to xenstore.

That's slightly more asynchronous and probably not a great option if yo= u
need a synchronous interface. Especially if you need individual return
values, not just a bunch of fields to write into.

If the latter case, next option would be some dedicated shared memory
structure. But it's hard to imagine something like that to make
sense. :}

Daniel


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