From: kvm-owner@xxxxxxxxxxxxxxx [kvm-owner@xxxxxxxxxxxxxxx] on behalf of Chris Wright [chrisw@xxxxxxxxxxxx]
Sent: 21 December 2010 18:33
To: Prasad Joshi
Cc: Chris Wright; kvm@xxxxxxxxxxxxxxx
Subject: Re: Query on IOMMU
* Prasad Joshi (P.G.Joshi@xxxxxxxxxxxxxxxxxxxxx) wrote:
> > From: kvm-owner@xxxxxxxxxxxxxxx [kvm-owner@xxxxxxxxxxxxxxx] on behalf of Chris Wright [chrisw@xxxxxxxxxxxx]
> > Yes I am using AMD processor and ASUS motherboard. Both of them have the IOMMU support, atleast it is mentioned on the Xen VT-d
>
> > Looks like we need some additional info in the wiki. Care to create an
> > account and add the info?
>
> Sure I would love to.
> Thanks, you can use the VT-d portion as an example.
> The useful dmesg info will be AMD-Vi: messages, the important line
> is this one:
> AMD-Vi: Enabling IOMMU at ...
> (and if you boot with amd_iommu_dump you'll get extra debugging info)
I will add this information ASAP
> > Thanks a lot for your reply. Yes I am interested in working on GPU pass-through to Virtual Machine. But for now I am trying to pass-through a network card to VM.
> Great, GPU assignment has plenty of issues ;)
<snip>
> It still fails with the same error, here is the screen shot.
>
> root@prasad-kvm:/sys# uptime
> 17:29:11 up 2 min, 3 users, load average: 0.93, 0.52, 0.20
>
> root@prasad-kvm:/sys# ls -l /sys/bus/pci/devices/0000:01:05.0/driver
> lrwxrwxrwx 1 root root 0 2010-12-21 17:26 /sys/bus/pci/devices/0000:01:05.0/driver -> ../../../../bus/pci/drivers/e100
>
> root@prasad-kvm:/sys# lsmod | grep pci_stub
>
> root@prasad-kvm:/sys# modprobe pci_stub
>
> root@prasad-kvm:/sys# lsmod | grep pci_stub
> pci_stub 1590 0
>
> root@prasad-kvm:/sys# echo "8086 1229" > /sys/bus/pci/drivers/pci-stub/new_id
>
> root@prasad-kvm:/sys# echo "0000:01:05.0" > /sys/bus/pci/drivers/e100/unbind
>
> root@prasad-kvm:/sys# echo "0000:01:05.0" > /sys/bus/pci/drivers/pci-stub/bind
>
> root@prasad-kvm:/sys# echo "8086 1229" > /sys/bus/pci/drivers/pci-stub/remove_id
>
> root@prasad-kvm:/sys# ls -l /sys/bus/pci/devices/0000:01:05.0/driver
> lrwxrwxrwx 1 root root 0 2010-12-21 17:31 /sys/bus/pci/devices/0000:01:05.0/driver -> ../../../../bus/pci/drivers/pci-stub
>
> root@prasad-kvm:~/VMDisks# modprobe kvm_amd
>
> root@prasad-kvm:~/VMDisks# lsmod | grep -i kvm
> kvm_amd 56416 0
> kvm 348987 1 kvm_amd
>
> root@prasad-kvm:~/VMDisks# qemu-system-x86_64 -hda Ubuntu-10.10-amd64.img -m 1024M -device pci-assign,host=01:05.0
> Failed to assign device "(null)" : Device or resource busy
> *** The driver 'pci-stub' is occupying your device 0000:01:05.0.
> ***
> *** You can try the following commands to free it:
> ***
> *** $ echo "8086 1229" > /sys/bus/pci/drivers/pci-stub/new_id
> *** $ echo "0000:01:05.0" > /sys/bus/pci/drivers/pci-stub/unbind
> *** $ echo "0000:01:05.0" > /sys/bus/pci/drivers/pci-stub/bind
> *** $ echo "8086 1229" > /sys/bus/pci/drivers/pci-stub/remove_id
> ***
> qemu-system-x86_64: -device pci-assign,host=01:05.0: Device 'pci-assign' could not be initialized
> root@prasad-kvm:~/VMDisks# echo $?
> 1
> root@prasad-kvm:~/VMDisks#
>
> The VM does not boot.
> Are you still seeing the same errors in dmesg? Your first dmesg showed
> that the e100 driver couldn't allocate BAR0:
No I must have done something terribly wrong, the first time I ran those assignment commands.
> e100 0000:01:05.0: BAR 0: can't reserve [mem 0xf9cff000-0xf9cfffff]
> If the host driver can't, then kvm_vm_ioctl_assign_device() will fail as
> well. Seems as if there's a resource conflict on your machine.
> Can you include a full dmesg, /proc/iomem, and lspci -vvv -xxxx?
Please note the files attached. Please ignore few messages in dmesg file, I was trying to debug the problem by adding few printks.
The following condition from __attach_device() returns the error.
static int __attach_device(struct device *dev,
struct protection_domain *domain)
{
...
if (alias_data->domain != NULL &&
alias_data->domain != domain)
goto out_unlock;
...
}
Besides when I insert the pci_stub module, it emits a messages
[ 49.197112] pci-stub: invalid id string ""
I don't know why?
Thanks and Regards,
Prasad
> thanks,
> -chris
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