Re: [Xen-users] pci passthrough how to that works?

[Brian Krusic <brian@xxxxxxxxxx>]

> On Jan 6, 2010, at 2:57 PM, Matthias Reif wrote:
>
>
>
> xen-users-bounces@xxxxxxxxxxxxxxxxxxx wrote on 07/01/2010 09:32:23 AM:
>
> > Hi,
> >
> > I'm running Centos 5.3 for dom0 and domUs and using Xen 3.4.1 (AMD V  
> > enabled Sun box).
> >
> > Using lspci, I see that my device I wished ignored by dom0 so that I  
> > can use it for 1 of my domUs is;
> >
> > 07:00.0
> >
> > In grub.conf, I added this to my module line;
> >
> > pciback.permissive pciback.hide (07:00.0)
> >
> > Upon reboot, lspci on dom0 still shows that pci device.
> >
> > I've also modded my modprob.conf;
> >
> > options pciback hide=(07:00.0)
> >
> > Any ideas how I can get pci passthrough to work?
> >
> > - Brian
> >
>
> The pciback module needs to be loaded into initrd, so it can seize
> the device at boot time.
> Your boot log should confirm this if it says something like "unknwon
> kernel option pciback.hide
> ignoring."
>
> Try something like this:
>
> mkinitrd -f --preload=pciback /boot/initrd-$(uname -r).img $(uname -r)
>
> Also, pciback has to be loaded before the driver for your device.
> This is not always the case.
> I tried to seize a SCSI controller to pass a tape drive to a domU,
> but its driver had to be loaded
> first to get access to the disks where the initrd etc is stored (I
> presume). When pciback was loaded
> the driver had already taken control of the device.
> If that's the case, late binding may be an option for you, where you
> unbind the driver from the
> device after the system has booted and then bind it to pciback prior
> to starting your domU.
>
> Eg.
> # echo -n 0000:07:00.0 > /sys/bus/pci/drivers/<your_driver_name>/unbind
> # echo -n 0000:07:00.0 > /sys/bus/pci/drivers/pciback/new_slot
> # echo -n 0000:07:00.0 > /sys/bus/pci/drivers/pciback/bind
>
>
> Matthias
>
>
>
>
Brian Krusic <brian@xxxxxxxxxx> wrote on 07/01/2010 12:26:27 PM:

> Hi Matthias,
>
> Heres what I did;
>
> mkinitrd -f –preload=pciback /boot/initrd-$(uname -r).img $(uname -r)
>
> Then added this line to modprob.conf
>
> options pciback hide=(07:00.0)
>
> After a reboot, I still see the device under lspci, is this normal?
>
> I went ahead and added this to the file xend-pci-permissive.sxp;
>
> (unconstrained_dev_ids
> #(’0123:4567:89AB:CDEF’)
> (’10de:042f’)
> )
>
> I got the 10de:042f from doing this;
>
> lspci -n
>
> Which gave;
>
> 07:00.00 0300: 10de:042f (rev a1)
>
> The next step is to assign this PCI device to domU.  In normal
> syntax I would simply edit domU config file and add;
>
> pci = [ "07:00.0"]
>
> But my domU configs are now using config.sxp which is this new
> bloody XML format.
>
> How do I put pci = [ "07:00.0"] in this XML format?
>
>  
> - Brian
>


First make sure that the new initrd that you built with pciback included is
also referred to in your /boot/grub/grub.conf

Secondly I would put the pciback module options also into grub.conf. I am not
sure whether modprobe.conf is actually used at boot time.

Eg.
title CentOS (2.6.18-128.4.1.el5xen) Hypervisor 3.4.1 CentOS dom0
        root (hd0,0)
        kernel /xen.gz-3.4.1
        module /vmlinuz-2.6.18-128.4.1.el5xen ro root=/dev/md1 pciback.hide=(07:00.0)
        module /initrd-2.6.18-128.4.1.el5xen.img


Then check dmesg to confirm that pciback is loaded and is trying to seize the device.

Yes, doing;

dmesg | grep pciback

yields;

pciback 0000:07:00.0: seizing device

How do I get it visible in domU?

Its a pci-e based add on graphics card, my primary being on the motherboard.

In xend-pci-permissive.sxp I have added;

(unconstrained_dev_ids 

(’10de:042f’) 

) 

Keep in mind my domU configs are in this XML format and look something like this;

domain

    (domid 2)

    (vcpus_params ((cap 0) (weight 256)))

    (PV_args )

    (PV_bootloader /usr/bin/pygrub)

    (cpus ((2) (3)))

    (pci '=')

    (VCPUs_live 2)

    (actions_after_crash restart)

    (uuid c58c75ca-b6ca-0888-37e1-4e43137c5e24)

    (PV_ramdisk )

    (name_label logantools)

    (VCPUs_at_startup 1)

    (HVM_boot_params ())

    (platform ((device_model /usr/lib64/xen/bin/qemu-dm) (pci '=')))

    (PV_kernel )

    (memory_static_min 0)

    (HVM_boot_policy )

    (VCPUs_max 2)

    (memory_static_max 1073741824)

    (actions_after_shutdown destroy)

    (memory_dynamic_max 1073741824)

    (is_a_template False)

    (memory_dynamic_min 1073741824)

    (target 0)

    (PV_bootloader_args )

    (other_config ())

    (auto_power_on False)

    (actions_after_reboot restart)

    (on_crash restart)

    (uuid c58c75ca-b6ca-0888-37e1-4e43137c5e24)

    (bootloader_args )

    (vcpus 2)

    (name logantools)

    (on_poweroff destroy)

    (on_reboot restart)

    (cpus ((2) (3)))

    (bootloader /usr/bin/pygrub)

    (maxmem 1024)

    (memory 1024)

    (shadow_memory 0)

    (vcpu_avail '3')

    (features )

    (on_xend_start ignore)

    (on_xend_stop ignore)

    (start_time 1262827803.79)

    (cpu_time 15.85152715)

    (image

        (linux

            (kernel )

            (pci '=')

            (device_model /usr/lib64/xen/bin/qemu-dm)

            (notes

                (FEATURES

                    'writable_page_tables|writable_descriptor_tables|auto_translated_physmap|pae_pgdir_above_4gb|supervisor_mode_kernel'

                )

                (VIRT_BASE 18446744071562067968)

                (GUEST_VERSION 2.6)

                (PADDR_OFFSET 18446744071562067968)

                (GUEST_OS linux)

                (HYPERCALL_PAGE 18446744071564189696)

                (LOADER generic)

                (ENTRY 18446744071564165120)

                (XEN_VERSION xen-3.0)

            )

        )

    )

    (status 1)

    (state ------)

    (store_mfn 1625844)

    (console_mfn 1625843)

    (device

        (vif

            (bridge bond0)

            (mac 00:16:36:60:3f:34)

            (script /etc/xen/scripts/vif-bridge)

            (uuid b088f989-4eb2-bd1e-a372-e8278e86bfa9)

            (backend 0)

        )

    )

    (device (vkbd (backend 0)))

    (device

        (vfb

            (vncunused 1)

            (keymap en-us)

            (vnc 1)

            (uuid 9394a20e-3ae2-29c1-17a8-7148e4b3df2d)

            (location 127.0.0.1:5901)

        )

    )

    (device

        (console

            (protocol vt100)

            (location 2)

            (uuid 0a7d47e5-d259-dbee-0f24-25c93c5bd0cc)

        )

    )

    (device

        (tap

            (protocol x86_64-abi)

            (uuid 4fa9e83c-9940-b9ff-94a1-526c26ced26c)

            (bootable 1)

            (dev xvda:disk)

            (uname tap:aio:/var/lib/libvirt/images/logantools.img)

            (mode w)

            (backend 0)

            (bootable 1)

            (VDI )

        )

    )

)

 

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