====== Piotr Jaroszyński: Usermode debugging under Linux ======
===== Week 9 [ Jul 19 - Jul 25 2010 ] =====

==== drivers in userspace ====

I have just pushed my [[http://git.etherboot.org/?p=people/peper/gpxe.git;a=shortlog;h=refs/heads/drivers|drivers in userspace branch]]. It's still a bit rough but it gets the job done. See [[week10|next week's report]] for an issue that particularly bugs me. Before getting into details of the implementation let's see a quick HOWTO first:

  * Checkout my [[http://git.etherboot.org/?p=people/peper/gpxe.git;a=shortlog;h=refs/heads/drivers|drivers branch]]
  * You should be able to build a generic gpxe.linux binary with all the drivers:
<code>
make bin-$ARCH-linux/gpxe.linux
</code>
  * Checkout [[http://github.com/peper/uio-dma/tree/gpxe|the gpxe branch]] of my clone of the UIO-DMA repo
  * Build it. If you are building against kernel <2.6.33 revert 98b95f6 [build] Update the location of utsrelease.h
<code>
$ ./configure --with-kernel=... && make
</code>
  * Load modules
<code>
# insmod kmod/uio-dma.ko
# insmod kmod/uio-dma-pci.ko
</code>
  * Get a spare nic or run under kvm with multiple nics
  * If the device is bound to a driver (lspci -k shows that) unbind it first:
<code>
# echo -n "0000:00:04.0" > /sys/bus/pci/drivers/$driver/unbind
</code>
  * Add the vendor and device number to the uio-dma-pci driver
<code>
# echo "8086 100e" > /sys/bus/pci/drivers/uio-dma-pci/new_id
</code>
  * That should autobind the device, to do it manully
<code>
# echo -n "0000:00:04.0" > /sys/bus/pci/drivers/uio-dma-pci/bind
</code>
  * Expected ''dmesg'' output
<code>
UIO DMA kernel backend - version 2.0
Copyright (c) 2009 Qualcomm Inc. Written by Max Krasnyansky <maxk@qualcomm.com>
Driver enabling UIO-DMA for a device version: 0.0.0
ACPI: PCI Interrupt Link [LNKD] enabled at IRQ 10
uio-dma-pci 0000:00:04.0: PCI INT A -> Link[LNKD] -> GSI 10 (level, high) -> IRQ 10
uio-dma: added device. id 0 0000:00:04.0
</code>
  * Run gpxe with ''-net lpci,dev=$DEV''
<code>
# ./gpxe.linux --net lpci,dev=00:04.0
</code>
  * Expected results on a linux guest run in quemu-kvm with the e1000 nic emulated. And gpxe with a simple embedded script that just fetches a 100mb file.
<code>
# lspci -nn | grep 04
00:04.0 Ethernet controller [0200]: Intel Corporation 82540EM Gigabit Ethernet Controller [8086:100e] (rev 03)
# ./gpxe.linux --net lpci,dev=00:04.0
gPXE initialising devices...ok



gPXE 1.0.1+ -- Open Source Boot Firmware -- http://etherboot.org
Features: HTTP DNS TFTP
DHCP (net0 52:54:00:12:34:58).... ok
net0: 52:54:00:12:34:58 on PCI00:04.0 (open)
  [Link:up, TX:3 TXE:0 RX:10 RXE:0]
http://root.piotrj.org/files/gpxe/100mb................ ok
time: 15s
</code>