>>Dear Users,
>>
>>I use KVM with libvirt 9.0.0. The host and guest OS-es are also AGL
needlefish images. I am currently trying to virtualize a CAN driver and provide
virtual machines access to the physical CAN channels.
>>
>>I started with the virtual network handling as CAN interface is a
network interface, I tried to find analogies, solutions like
"traditional" network handling but it did not work.
>>I also tried out to define a nodedev device via .xml config file. The
interesting thing is, that when I list all the available nodedev devices with
'virsh nodedev-list', I can see 'net_can0' and
'net_can1' on the output as 'net' type device but I cannot
attach these devices to the guests, and I do not know how to define it in the
guest .xml file. I tried out many different things, but when I try to add it as
a 'hostdev' device with different mode and type settings, I always get
an error (e.g. not a PCI device or not supported device type etc.). It would be
long to write down all the configurations I tried out, so my first question
would be that does anybody know how could I provide access to guests to the
physical CAN interfaces? The aim is to be able to send CAN messages from guest
OS-es. If no direct access is possible, it would be also OK to have access to
virtual CAN interfaces on the host and then transfer messages to the physical
CAN channel.
>>
>Hi. CAN devices need a couple more specifications for how the device should
be created and even though your analogy went the right way libvirt does not
(yet) support CAN device emulation for any hypervisor driver. I had a plan to
write it at some point, but I saw nobody requesting that and did not have enough
free time to do that.
Thank you very much for your feedback. Is there any other solutions you know
about? Maybe any QEMU passthrough argument which could help to virtualize CAN
driver?
>For completeness sake; the fact that you see the devices in nodedev-list is
a consequence of us not filtering the devices at all, just reporting on what we
find on the host.
>Patches would be appreciated, I myself won't probably get to adding such
support any time soon.
>Have a nice day,
>Martin
Thank you!
M?rton
-----Original Message-----
From: Martin Kletzander <mkletzan at redhat.com>
Sent: Tuesday, August 29, 2023 9:16 AM
To: S?nta, M?rton (ext) <Marton.Santa at knorr-bremse.com>
Cc: libvirt-users at redhat.com
Subject: Re: CAN virtualization
On Wed, Aug 23, 2023 at 01:15:36PM +0000, S?nta, M?rton (ext)
wrote:>Dear Users,
>
>I use KVM with libvirt 9.0.0. The host and guest OS-es are also AGL
needlefish images. I am currently trying to virtualize a CAN driver and provide
virtual machines access to the physical CAN channels.
>
>I started with the virtual network handling as CAN interface is a network
interface, I tried to find analogies, solutions like "traditional"
network handling but it did not work.
>I also tried out to define a nodedev device via .xml config file. The
interesting thing is, that when I list all the available nodedev devices with
'virsh nodedev-list', I can see 'net_can0' and
'net_can1' on the output as 'net' type device but I cannot
attach these devices to the guests, and I do not know how to define it in the
guest .xml file. I tried out many different things, but when I try to add it as
a 'hostdev' device with different mode and type settings, I always get
an error (e.g. not a PCI device or not supported device type etc.). It would be
long to write down all the configurations I tried out, so my first question
would be that does anybody know how could I provide access to guests to the
physical CAN interfaces? The aim is to be able to send CAN messages from guest
OS-es. If no direct access is possible, it would be also OK to have access to
virtual CAN interfaces on the host and then transfer messages to the physical
CAN channel.
>
Hi. CAN devices need a couple more specifications for how the device should be
created and even though your analogy went the right way libvirt does not (yet)
support CAN device emulation for any hypervisor driver. I had a plan to write
it at some point, but I saw nobody requesting that and did not have enough free
time to do that.
For completeness sake; the fact that you see the devices in nodedev-list is a
consequence of us not filtering the devices at all, just reporting on what we
find on the host.
Patches would be appreciated, I myself won't probably get to adding such
support any time soon.
Have a nice day,
Martin
>Thank you in advance for an early reply!
>
>Best regard,
>
>M?rton S?nta
>
>
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