wiki:Xen_Lab7

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Version 13 (modified by rider, 15 years ago) (diff)
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【前言】
【Step 0: 流程】
【Step 1: 首先查看主機上的顯卡資訊】
【Step 2: 產生一台實驗用虛擬機器】
【Step 3: PCI Frontend Configuration 設定你的 DomU 】
【Step 4: PCI Backend Configuration 設定你的 Dom0 】
【Step 5: 硬體定址存取設定】
1. 1. 1. Permissive Flag
    2. User-space Quirks
【Step 6: 啟動並登入你的虛擬機器 DomU 】
【Step 7: 設定你的 DomU 基本環境】

實作七：Xen PCI Passthrough 操作

【前言】

小叮嚀

為了使 Xen patched Kerenl 能支援 PCI Passthrough, 請務必確認以下Xen 相關的核心配置.

CONFIG_XEN_PCIDEV_FRONTEND=y
CONFIG_XEN_PCIDEV_BACKEND=y
CONFIG_XEN_PCIDEV_BACKEND_PASS is not set
CONFIG_XEN_PCIDEV_BACKEND_VPCI=y
CONFIG_XEN_PCIDEV_BACKEND_SLOT is not set

小技巧
- Binding at Boot-Time.
- 直接將顯示卡所佔的 PCI_Address 在開機時就隱藏起來,使得一開始便能直接 bind 到該 PCI_Address.
- 透過 lspci 指令來查詢顯示卡所佔的實體 PCI Address.
```
/boot/vmlinuz-2.6.22.9 root=UUID=d3fa560e-7071-46d8-a168-036f40960c7b ro console=tty0 pciback.hide=(0000:01:00.0)
```
- 如果透過 lspci 指令查出顯示卡為 unknown 或是其他不明資訊, 請先更新 PCI ID database 試看看.
```
$ update-pciids
```

【Step 0: 流程】

本範例將說明如何使用及設定 Xen PCI Passthrough

【Step 1: 首先查看主機上的顯卡資訊】

$ lspci -vv | more

01:00.0 VGA compatible controller: nVidia Corporation G92 [GeForce 9800 GT] (rev a2)
        Subsystem: ASUSTeK Computer Inc. Device 82a0
        Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx-
        Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
        Latency: 0
        Interrupt: pin A routed to IRQ 16
        Region 0: Memory at fd000000 (32-bit, non-prefetchable) [size=16M]
        Region 1: Memory at d0000000 (64-bit, prefetchable) [size=256M]
        Region 3: Memory at fa000000 (64-bit, non-prefetchable) [size=32M]
        Region 5: I/O ports at dc80 [size=128]
        [virtual] Expansion ROM at fea00000 [disabled] [size=128K]
        Capabilities: <access denied>
        Kernel driver in use: nvidia
        Kernel modules: nvidia, nvidiafb

【Step 2: 產生一台實驗用虛擬機器】

設定你想要怎樣規格的虛擬機器.

$ sudo vim /etc/xen-tools/xen-tools.conf

dir = /home
install-method = debootstrap
size   = 4Gb      # Disk image size.
memory = 256Mb    # Memory size
swap   = 128Mb    # Swap size
fs     = ext3     # use the EXT3 filesystem for the disk image.
dist   = hardy    # Default distribution to install. ---> For CUDA Support (Ubuntu 8.0.4)
image  = sparse   # Specify sparse vs. full disk images.
gateway   = 192.168.100.254
netmask   = 255.255.255.0
broadcast = 192.168.100.255
kernel      = /boot/vmlinuz-`uname -r`
initrd      = /boot/initrd.img-`uname -r`
mirror = http://gb.archive.ubuntu.com/ubuntu/
ext3_options   = noatime,nodiratime,errors=remount-ro
ext2_options   = noatime,nodiratime,errors=remount-ro
xfs_options    = defaults
reiser_options = defaults

$ sudo xen-create-image --hostname=xg01 --ip=192.168.100.X --mac=00:16:XX:XX:XX:XX --force

【Step 3: PCI Frontend Configuration 設定你的 DomU 】

$ sudo vim /etc/xen/xg01.cfg

kernel      = '/boot/vmlinuz-2.6.22.9'
ramdisk     = '/boot/initrd.img-2.6.22.9'
 
memory      = '256'
vcpus       = '4'

# 配置你的 PCIE 顯示卡
pci         = ['01:00.0']

root        = '/dev/sda2 ro'
disk        = [
                  'file:/home/domains/xg01/disk.img,sda2,w',
                  'file:/home/domains/xg01/swap.img,sda1,w',
              ]
name        = 'xg01'
 
#
#  Networking
#
vif         = [ 'ip=192.168.100.X ,mac=00:16:XX:XX:XX:XX' ]
 
#
#  Behaviour
#
on_poweroff = 'destroy'
on_reboot   = 'restart'
on_crash    = 'restart'

【Step 4: PCI Backend Configuration 設定你的 Dom0 】

切換身份為 Super user.
```
$ sudo su -
```
隱藏 dom0 的PCI 匯流排的位址, 並交由 pciback 模組來控制該匯流排存取權.
```
$ echo -n "0000:01:00.0" > /sys/bus/pci/drivers/nvidia/unbind
```

將 dev_ids 轉到 pciback 成為新的 binding slot.

$ echo -n "0000:01:00.0" > /sys/bus/pci/drivers/pciback/new_slot
$ echo -n "0000:01:00.0" > /sys/bus/pci/drivers/pciback/bind

$ cat /sys/bus/pci/drivers/pciback/slots

0000:01:00.0

警告: 請確認您的顯示卡資源沒有被其 Kernel module 所佔有及控制: 您顯示卡的 symlink 不應該存在著.

PATH: /sys/bus/pci/devices/0000:01:00.0/
driver -> ../../../../bus/pci/drivers/nvidia ---> 此連結不應存在. NVIDIA module 已無該裝置控制權.
driver -> ../../../../bus/pci/drivers/pciback ---> 控制權應該已經交賦予 pciback module.

【Step 5: 硬體定址存取設定】

Permissive Flag

$ sudo vim /etc/xen/xend-pci-permissive.sxp

(unconstrained_dev_ids
     #('0123:4567:89AB:CDEF')
     ('0000:01:00.0')
)

User-space Quirks

$ sudo vim /etc/xen/xend-pci-quirks.sxp

(pci_ids
   # Entries are formated as follows:  
   #     <vendor>:<device>[:<subvendor>:<subdevice>]

   ('10de:0605'   # NVIDIA 9800GT
   )
)

【Step 6: 啟動並登入你的虛擬機器 DomU 】

說明: 用 root 免密碼先登入,然後建立自己的帳號. 改用自己的帳號登入(亦可用 root 登入 , 不新建帳號 )
@ Dom0
```
$ sudo xm create -c xg01.cfg
```

@ DomU

$ sudo adduser username
$ sudo vim /etc/sudoers

username    ALL=(ALL) ALL

【Step 7: 設定你的 DomU 基本環境】

設定 locales (系統語系),避免亂碼現象發生.

$ sudo vim /etc/profile

# Locale
export LANGUAGE="en_US.UTF-8"
export LC_ALL="en_US.UTF-8"
export LANG="en_US.UTF-8"

$ source /etc/profile
$ sudo dpkg-reconfigure locales

更新 PCI ID Database.(當您發現系統無法偵測到你的顯示卡時)
```
$ sudo apt-get update
$ sudo apt-get install wget
$ sudo update-pciids
```

查看顯卡資訊有無正常顯示.

$ lspci

00:00.0 VGA compatible controller: nVidia Corporation GeForce 9800 GT (rev a2)

查看顯卡資源有無順利分配到 DomU.

$ dmesg | grep pci

pcifront pci-0: Installing PCI frontend
pcifront pci-0: Creating PCI Frontend Bus 0000:00
pciback 0000:00:00.0: probing...
pciback: pcistub_init_devices_late

【討論 & 休息】

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