RE: [Xen-devel] Intel VT-d Support

["Li, Haicheng" <haicheng.li@xxxxxxxxx>]

> There are no strings found
> even with VT-d enabled in BIOS.
>
> # xm dmesg | grep vt
> # xm dmesg | grep -i vt

Make sure you have added vtd=1 in xen line of grub entry; look into [1],
there is an example. 
 
> 
> How can I check if Xen-code was built with
> VT-d support?
> 
> (I have tried to use VT-d on precompiled Debian binaries of Xen 3.2
> and on xen-unstable with default build options)

Not sure debian binary but xen-unstable enables vt-d by default.
 
>> 
>>> 
>>> What a line should I look for?
>> 
>> Find the line "Intel VT-d has been enabled."
> 
> 
> So this line must be shown in xm dmesg.
> Thank you.
> 
> No I must find the reason why there no such a line.

Firstly make sure vt-d is enabled in bios. If your chipset really
supports vt-d and `xm dmesg` has such a line as "No DMAR devices found"
or any dmar related error, that would mean your bios needs to be
upgraded.

>> 
>>> And if my installation was really built with VT-d support,
>>> how can I be sure, that Xen has successfully
>>> initialized VT-d hardware?
>> 
>> Try assigning a pci device to hvm guest as [1] describes. If vt-d is
>> not enabled or the device is not hidden, the guest creation will
>> fail. otherwise, you can use `lspci` in the guest to find out the
>> device assigned.
> 
> 
> Yes, guest creation fails with the message:
> 
> # xm create win2k3_clone
> 
> Using config file "/etc/xen/win2k3_clone".
> Error: Fail to assign device(7:9.0): maybe VT-d is not enabled, or
> the device is not exist, or it has already been assigned to other
> domain

It is a correct behavior.

> 
> For pv domains all works fine.
> 
>> 
>>> I have read [1] and the lists archives
>>> and found no answers for my question.
>>> 
>>> 
>>> 
>>> Thank you in advance.
>>> 
>>> 
>>> 
>>> [1] http://wiki.xensource.com/xenwiki/VTdHowTo
>> 
>> 
>> 
>> -- haicheng



-- haicheng

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