Thanks Eric, Does this also apply for PCI express? Daniel On Mon, Mar 5, 2012 at 4:56 PM, Eric Blake <eblake(a)redhat.com&gt; wrote:

Hi All , I have tried the same using dell R710 server and RHEL6.1 after enabled the VT-D option enabled . and checked it was not working with my enviromment .. any body tested below on Dell server ...If i have missed anything .. *PCI passthrough* This chapter covers using PCI passthrough with KVM. Certain hardware platforms allow virtualized guests to directly access various hardware devices and components. This process in virtualization is known as *passthrough*. Passthrough is known as *device* * assignment *in some of the KVM documentation and the KVM code. The KVM hypervisor supports attaching PCI devices on the host system to virtualized guests. PCI passthrough allows guests to have exclusive access to PCI devices for a range of tasks. PCI passthrough allows PCI devices to appear and behave as if they were physically attached to the guest operating system. PCI passthrough can improve the I/O performance of devices attached to virtualized guests. Almost all PCI and PCI Express devices that support passthrough, except for graphics cards, can be directly attached to virtualized guests with PCI passthrough. PCI passthrough is only available on hardware platforms supporting either Intel VT-d or AMD IOMMU. These Intel VT-d or AMD IOMMU extensions must be enabled in BIOS for PCI passthrough to function. Red Hat Enterprise Linux 6.0 and newer supports hot plugging PCI passthrough devices into virtualized guests. Out of the 32 available PCI devices for a guest 4 are not removable. This means there are only 28 PCI slots available for additional devices per guest. Every para-virtualized network or block device uses one slot. Each guest can use up to 28 additional devices made up of any combination of paravirtualized network, para-virtualized disk devices, or other PCI devices using VT-d. Procedure 12.1. Preparing an Intel system for PCI passthrough 1. *Enable the Intel VT-d extensions* The Intel VT-d extensions provides hardware support for directly assigning a physical devices to guest. The VT-d extensions are required for PCI passthrough with Red Hat Enterprise Linux. The extensions must be enabled in the BIOS. Some system manufacturers disable these extensions by default. These extensions are often called various terms in BIOS which differ from manufacturer to manufacturer. Consult your system manufacturer's documentation. 2. *Activate Intel VT-d in the kernel* Activate Intel VT-d in the kernel by appending the *intel_iommu=on *parameter to the kernel line of the kernel line in the */boot/grub/grub.conf *file. The example below is a modified *grub.conf *file with Intel VT-d activated. default=0 timeout=5 splashimage=(hd0,0)/grub/splash.xpm.gz hiddenmenu title Red Hat Enterprise Linux Server (2.6.32-36.x86-645) root (hd0,0) kernel /vmlinuz-2.6.32-36.x86-64 ro root=/dev/VolGroup00/LogVol00 rhgb quiet *intel_iommu=on* initrd /initrd-2.6.32-36.x86-64.img * Chapter 12. PCI passthrough* 108 3. *Ready to use* Reboot the system to enable the changes. Your system is now PCI passthrough capable. Procedure 12.2. Preparing an AMD system for PCI passthrough • *Enable AMD IOMMU extensions* The AMD IOMMU extensions are required for PCI passthrough with Red Hat Enterprise Linux. The extensions must be enabled in the BIOS. Some system manufacturers disable these extensions by default. AMD systems only require that the IOMMU is enabled in the BIOS. The system is ready for PCI passthrough once the IOMMU is enabled. * 12.1. Adding a PCI device with virsh* These steps cover adding a PCI device to a virtualized guest on a KVM hypervisor using hardwareassisted PCI passthrough. This example uses a USB controller device with the PCI identifier code, * pci_8086_3a6c*, and a fully virtualized guest named *win2k3*. 1. *Identify the device* Identify the PCI device designated for passthrough to the guest. The *virsh nodedev-list* command lists all devices attached to the system. The *--tree *option is useful for identifying devices attached to the PCI device (for example, disk controllers and USB controllers). # virsh nodedev-list --tree For a list of only PCI devices, run the following command: # virsh nodedev-list | grep pci In the output from this command, each PCI device is identified by a string, as shown in the following example output: pci_0000_00_00_0 pci_0000_00_02_0 pci_0000_00_02_1 pci_0000_00_03_0 pci_0000_00_03_2 pci_0000_00_03_3 pci_0000_00_19_0 pci_0000_00_1a_0 pci_0000_00_1a_1 pci_0000_00_1a_2 pci_0000_00_1a_7 pci_0000_00_1b_0 pci_0000_00_1c_0 * Tip: determining the PCI device* Comparing *lspci *output to *lspci -n *(which turns off name resolution) output can assist in deriving which device has which device identifier code. Adding a PCI device with virsh 109 Record the PCI device number; the number is needed in other steps. 2. Information on the domain, bus and function are available from output of the *virsh nodedevdumpxml* command: # virsh nodedev-dumpxml pci_8086_3a6c <device> <name>pci_8086_3a6c</name> <parent>computer</parent> <capability type='pci'> <domain>0</domain> <bus>0</bus> <slot>26</slot> <function>7</function> <id='0x3a6c'>82801JD/DO (ICH10 Family) USB2 EHCI Controller #2</product> <vendor id='0x8086'>Intel Corporation</vendor> </capability> </device> 3. Detach the device from the system. Attached devices cannot be used and may cause various errors if connected to a guest without detaching first. # virsh nodedev-dettach pci_8086_3a6c Device pci_8086_3a6c dettached 4. Convert slot and function values to hexadecimal values (from decimal) to get the PCI bus addresses. Append "0x" to the beginning of the output to tell the computer that the value is a hexadecimal number. For example, if bus = 0, slot = 26 and function = 7 run the following: $ printf %x 0 0 $ printf %x 26 1a $ printf %x 7 7 The values to use: bus='0x00' slot='0x1a' function='0x7' 5. Run *virsh edit *(or virsh attach device) and added a device entry in the *<devices> *section to attach the PCI device to the guest. # virsh edit *win2k3* <hostdev mode='subsystem' type='pci' managed='yes'> <source> <address domain='0x0000' bus='0x00' slot='0x1a' function='0x7'/> </source> </hostdev> 6. Once the guest system is configured to use the PCI address, the host system must be configured to stop using the device. The *ehci *driver is loaded by default for the USB PCI controller. * Chapter 12. PCI passthrough* 110 $ readlink /sys/bus/pci/devices/0000\:00\:1a.7/driver ../../../bus/pci/drivers/ehci_hcd 7. Detach the device: $ virsh nodedev-dettach pci_8086_3a6c 8. Verify it is now under the control of pci_stub: $ readlink /sys/bus/pci/devices/0000\:00\:1d.7/driver ../../../bus/pci/drivers/pci-stub 9. Set a sebool to allow the management of the PCI device from the guest: $ setsebool -P virt_manage_sysfs 1 10. Start the guest system : # virsh start *win2k3* The PCI device should now be successfully attached to the guest and accessible to the guest On Mon, Mar 5, 2012 at 9:47 PM, Eric Blake <eblake(a)redhat.com&gt; wrote: -- With Best Regards, Nitin Kumar Sr. System Engineer-Unix (CSC India Pvt. Ltd, Noida ) +91-9999706444