Re: [RFC PATCH 7/9] cxl/test: Add generic mock events

From: Jonathan Cameron <Jonathan.Cameron@huawei.com>
To: Ira Weiny <ira.weiny@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>,
	Alison Schofield <alison.schofield@intel.com>,
	Vishal Verma <vishal.l.verma@intel.com>,
	"Ben Widawsky" <bwidawsk@kernel.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	Davidlohr Bueso <dave@stgolabs.net>,
	<linux-kernel@vger.kernel.org>, <linux-cxl@vger.kernel.org>
Subject: Re: [RFC PATCH 7/9] cxl/test: Add generic mock events
Date: Tue, 20 Sep 2022 17:17:48 +0100	[thread overview]
Message-ID: <20220920171748.00001260@huawei.com> (raw)
In-Reply-To: <YyN0qY5yaXwTwLDF@iweiny-desk3>

On Thu, 15 Sep 2022 11:53:29 -0700
Ira Weiny <ira.weiny@intel.com> wrote:

> On Thu, Aug 25, 2022 at 12:31:19PM +0100, Jonathan Cameron wrote:
> > On Fri, 12 Aug 2022 22:32:41 -0700
> > ira.weiny@intel.com wrote:
> >   
> > > From: Ira Weiny <ira.weiny@intel.com>
> > > 
> > > Facilitate testing basic Get/Clear Event functionality by creating
> > > multiple logs and generic events with made up UUID's.
> > > 
> > > Data is completely made up with data patterns which should be easy to
> > > spot in trace output.  
> > Hi Ira,
> > 
> > I'm tempted to hack the QEMU emulation for this in with appropriately
> > complex interface to inject all the record types...  
> 
> Every time I look at the QEMU code it makes my head spin.  :-(

You get used to it ;)`

> 
> I really thought about adding some support there.  And I think for irq's it may
> work better?  But after your talk today I did a quick search to see what it
> would take to do irqs in QEMU and got even more confused.  :-(

Copy an example - though we haven't upstreamed any yet...

Either...

https://gitlab.com/jic23/qemu/-/commit/958fec58582b5cc910d2da4e2b855e134bb2c0c3#3dfd54f69a5f2382ddf5a6c00a52546d8b57316e_0_169

Or the CPMU one. 

https://lore.kernel.org/all/20220831153336.16165-2-Jonathan.Cameron@huawei.com/
to setup then look for msix_notify in 

https://lore.kernel.org/all/20220831153336.16165-4-Jonathan.Cameron@huawei.com/

> 
> > Lots to do there though, so not sure where this fits in my priority list!  
> 
> I bet it is higher on mine!  ;-)

:)

> 
> >   
> > > 
> > > Test traces are easy to obtain with a small script such as this:
> > > 
> > > 	#!/bin/bash -x
> > > 
> > > 	devices=`find /sys/devices/platform -name cxl_mem*`
> > > 
> > > 	# Generate fake events if reset is passed in  
> > 
> > reset is rather unintuitive naming.
> > 
> > fill_event_queue maybe or something more in that direction?  
> 
> Fair enough...  Naming is hard and I'm one of the worst.
> 
> I've changed to
> 
> <sysfs>/.../event_fill_queue
> <sysfs>/.../event_trigger
> 
> Thoughts?

Works for me.

..

J