[Qemu-devel] sparc64/virtio: unable to init msix vectors to 2

[Qemu-devel] sparc64/virtio: unable to init msix vectors to 2

[Mark Cave-Ayland]

Hi all,

When creating a qemu-system-sparc64 machine with a virtio interface, 
both QEMU 2.1.0 and current git master emit the above warning:

$ ./qemu-system-sparc64 -drive file=/tmp/file.txt,if=virtio,index=0 
-nographic
qemu-system-sparc64: -drive file=/tmp/file.txt,if=virtio,index=0: unable 
to init msix vectors to 2
OpenBIOS for Sparc64
Configuration device id QEMU version 1 machine id 0
kernel cmdline
CPUs: 1 x SUNW,UltraSPARC-IIi
UUID: 00000000-0000-0000-0000-000000000000
Welcome to OpenBIOS v1.1 built on Aug 26 2014 12:48
   Type 'help' for detailed information
Trying disk:a...
No valid state has been set by load or init-program

0 >

Is this harmless? At a superficial level, the interface seems to work if 
you boot with a virtio-enabled -kernel.


Many thanks,

Mark.

Re: [Qemu-devel] sparc64/virtio: unable to init msix vectors to 2

[Mark Cave-Ayland]

On 27/08/14 07:15, Mark Cave-Ayland wrote:

> Hi all,
>
> When creating a qemu-system-sparc64 machine with a virtio interface,
> both QEMU 2.1.0 and current git master emit the above warning:
>
> $ ./qemu-system-sparc64 -drive file=/tmp/file.txt,if=virtio,index=0
> -nographic
> qemu-system-sparc64: -drive file=/tmp/file.txt,if=virtio,index=0: unable
> to init msix vectors to 2
> OpenBIOS for Sparc64
> Configuration device id QEMU version 1 machine id 0
> kernel cmdline
> CPUs: 1 x SUNW,UltraSPARC-IIi
> UUID: 00000000-0000-0000-0000-000000000000
> Welcome to OpenBIOS v1.1 built on Aug 26 2014 12:48
>    Type 'help' for detailed information
> Trying disk:a...
> No valid state has been set by load or init-program
>
> 0 >
>
> Is this harmless? At a superficial level, the interface seems to work if
> you boot with a virtio-enabled -kernel.

Ping? A quick look at the source code indicates that MSI setup for 
virtio is only performed if nvectors > 0, and since the default value is 
2 then this is why the error appears on the console.

 From reading the relevant datasheets, I see no mention of MSI 
interrupts which makes me think they may not be supported by the Sun 
sabre bridge that QEMU emulates.


ATB,

Mark.