# xen, qemu-xen-traditionnal, quemu upstream [SOLVED]

## CaptainBlood

Hi,

Since my former laptop died, I had to renew the device.

Unfortunately new Mediatek MT7630e WIFI chipset remains unknown to the linux kernel.

Consequently I had to fall back to an usb wifi adapter.

Formerly I used to pci passthrough WIFI to a domU PV.

I now have to translate my pci passthrough to usb passthrough.

According to http://wiki.xen.org/wiki/XL_vs_Xend_Feature_Comparison, there are many way how to achieve this.

To sum up I can :

- Fallback to xend since xl isn't PVUSB ready yet. (regressive, to be avoided as much as possible IMHO)

- use qemu whether xen-traditionnal or upstream.

My current choice is qemu, and I'm about to start working on it.

My guess would favor qemu upstream, at leat as a second step to achieve once feature has been activated with qemu-xen-traditionnal

However stable qemu package requires setting KVM kernel flag on, which I don't understand since I'm doing Xen not KVM

Anyone to explain what I should do to succeed qemu upstream install?

Thks 4 ur attention.Last edited by CaptainBlood on Sun Jan 18, 2015 2:47 pm; edited 2 times in total

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## charles17

 *CaptainBlood wrote:*   

> Unfortunately new Mediatek MT7630e WIFI chipset remains unknown to the linux kernel.

 But you could get it from the manufacturer's site: http://www.mediatek.com/en/downloads/mt7630-pcie/

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## szatox

 *Quote:*   

> However stable qemu package requires setting KVM kernel flag on, which I don't understand since I'm doing Xen not KVM
> 
> 

  Quite funny, my qemu doesn't seem to even have kvm flag, even though I definitely have kvm active when I run some vms. Obviously you can't have both hypervisors active at the same time as they will always conflict. Show us your errors

 *Quote:*   

> USE="xen" emerge -pvDN qemu
> 
> These are the packages that would be merged, in order:
> 
> Calculating dependencies... done!
> ...

 

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## CaptainBlood

 *charles17 wrote:*   

>  *CaptainBlood wrote:*   Unfortunately new Mediatek MT7630e WIFI chipset remains unknown to the linux kernel. But you could get it from the manufacturer's site: http://www.mediatek.com/en/downloads/mt7630-pcie/

 

Indeed , but WIFI doesn't compile out of the box on my laptop.(BT does).

ASAIR I succeeded once somehow but I can't remember the trick   :Sad: 

I've already started a thread in this respect, coz I''m probably not the only one facing this issue.

https://forums.gentoo.org/viewtopic-t-1005188-highlight-.html

No reply as of today  :Sad: 

Thks 4 ur attention, interest  & supportLast edited by CaptainBlood on Sun Jan 18, 2015 2:49 pm; edited 1 time in total

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## CaptainBlood

 *szatox wrote:*   

>  *Quote:*   However stable qemu package requires setting KVM kernel flag on, which I don't understand since I'm doing Xen not KVM
> 
>   Quite funny, my qemu doesn't seem to even have kvm flag, even though I definitely have kvm active when I run some vms. Obviously you can't have both hypervisors active at the same time as they will always conflict. Show us your errors
> 
>  *Quote:*   USE="xen" emerge -pvDN qemu
> ...

 Here's the message i was referring to. *Quote:*   

> ~ # emerge -1 qemu
> 
>  * IMPORTANT: 1 news items need reading for repository 'gentoo-zh'.
> 
>  * Use eselect news to read news items.
> ...

 Nevertheless is seems it was missleading to identify the origin of install failure.

My system is configured for LTO, which generally requires libraries to be compiled with -ffat-lto-objects.

And qemu pulled 2 libs:

 *Quote:*   

> sys-libs/libseccomp
> 
> dev-libs/libaio

 But in the case of qemu, -ffat-lto-objects was not enough for libaio.

I finally succeeded to install qemu by reconfiguring sys-libs/libaio compilation flag to -fno-lto

Although I probably remain very far from solving my passthrough issue, at least this step seems solved.

For the record I would not be surprised to fail using qemu upstream for my purpose, but this is another story.

Thks 4 ur attention, interest & supportLast edited by CaptainBlood on Sun Jan 18, 2015 2:56 pm; edited 1 time in total

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## szatox

 *Quote:*   

> * If you have an AMD CPU, you must enable KVM_AMD in your kernel configuration.
> 
> * If you have an Intel CPU, you must enable KVM_INTEL in your kernel configuration. 

  I see those every time I compile qemu. This message is purely informational. It doesn't check kernel config. It's just qemu is typicaly used with kvm, so they remind the kernel module is necessary.

Launch that qemu/xen you installed and see what would happen.

From qemu manual:

       -machine [type=]name[,prop=value[,...]]

           Select the emulated machine by name. Use "-machine help" to list available machines. Supported machine properties are:

           accel=accels1[:accels2[:...]]

               This is used to enable an accelerator. Depending on the target architecture, kvm, xen, or tcg can be available. By default,

               tcg is used. If there is more than one accelerator specified, the next one is used if the previous one fails to initialize.

So, -machine accel=xen and go. I suppose you will know if it's using xen when you see it running

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