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From: John Baldwin <jhb@freebsd.org>
To: freebsd-current@freebsd.org
Cc: Jim Harris <jim.harris@gmail.com>, Luigi Rizzo <rizzo@iet.unipi.it>
Subject: Re: accessing a PCIe register from userspace through kmem or other
 ways ?
Date: Thu, 31 Mar 2016 13:39:25 -0700
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On Wednesday, March 30, 2016 11:20:51 AM Jim Harris wrote:
> On Wed, Mar 30, 2016 at 10:47 AM, Luigi Rizzo <rizzo@iet.unipi.it> wrote:
> 
> > Hi,
> > I'd like to test the rate at which I can access device registers
> > on a PCIe card, and was wondering whether I need to patch a device
> > driver, or perhaps I can use /dev/kmem once I figure out where
> > the registers are mapped ?
> >
> 
> You do not need to patch a device driver.  Have you looked at
> libpciaccess?  This should give you everything you need.

You can also look at what pciconf uses.  (It has a read_config() method
that uses an ioctl on an fd of /dev/pci).

-- 
John Baldwin