SR-PCIM support in KVM

SR-PCIM support in KVM

[Bharat Kumar Gogada]

Hi All,

Is there any support for software mailbox communication between PF and VF driver in kvm ?

As per the following link:
https://www.linux-kvm.org/images/6/6a/KvmForum2008$kdf2008_7.pdf

It says that for software based virtual mailbox we require SR-PCIM support.

So for this purpose is SR-PCIM implemented as part of KVM ?
Or is there any other method that KVM provides for communication between PF & VF ?

Thanks & regards,
Bharat

Re: SR-PCIM support in KVM

[Paolo Bonzini]

> Hi All,
> 
> Is there any support for software mailbox communication between PF and VF
> driver in kvm ?
> 
> As per the following link:
> https://www.linux-kvm.org/images/6/6a/KvmForum2008$kdf2008_7.pdf
> 
> It says that for software based virtual mailbox we require SR-PCIM support.
> 
> So for this purpose is SR-PCIM implemented as part of KVM ?
> Or is there any other method that KVM provides for communication between PF &
> VF ?

Hi, SR-IOV is not part of KVM (the virtual machine monitor kernel module).
In PCIe terms, when using KVM the "VI" or Virtualization Intermediary is the
Linux VFIO driver.  SR-IOV management is split between the PF driver and VFIO.

Paolo

RE: SR-PCIM support in KVM

[Bharat Kumar Gogada]

> > Hi All,
> >
> > Is there any support for software mailbox communication between PF and
> > VF driver in kvm ?
> >
> > As per the following link:
> > https://www.linux-kvm.org/images/6/6a/KvmForum2008$kdf2008_7.pdf
> >
> > It says that for software based virtual mailbox we require SR-PCIM support.
> >
> > So for this purpose is SR-PCIM implemented as part of KVM ?
> > Or is there any other method that KVM provides for communication
> > between PF & VF ?
> 
> Hi, SR-IOV is not part of KVM (the virtual machine monitor kernel module).
> In PCIe terms, when using KVM the "VI" or Virtualization Intermediary is the
> Linux VFIO driver.  SR-IOV management is split between the PF driver and VFIO.
> 
Thanks Paolo.

If Linux VIFO driver acts as VI, as per spec SR-PCIM is "Software responsible for the configuration of the SR-IOV capability, management of Physical Functions and Virtual Functions"
So if we use kvm who does above work of SR-PCIM ?

Does VIFO driver provide any methods for PF & VF communication.

Thanks & Regards,
Bharat

Re: SR-PCIM support in KVM

[Paolo Bonzini]

> > > As per the following link:
> > > https://www.linux-kvm.org/images/6/6a/KvmForum2008$kdf2008_7.pdf
> > >
> > > It says that for software based virtual mailbox we require SR-PCIM
> > > support.
> > >
> > > So for this purpose is SR-PCIM implemented as part of KVM ?
> > > Or is there any other method that KVM provides for communication
> > > between PF & VF ?
> > 
> > Hi, SR-IOV is not part of KVM (the virtual machine monitor kernel module).
> > In PCIe terms, when using KVM the "VI" or Virtualization Intermediary is
> > the Linux VFIO driver.  SR-IOV management is split between the PF driver
> > and VFIO.
> 
> Thanks Paolo.
> 
> If Linux VIFO driver acts as VI, as per spec SR-PCIM is "Software responsible
> for the configuration of the SR-IOV capability, management of Physical
> Functions and Virtual Functions" So if we use kvm who does above work of SR-PCIM ?

It's split between VFIO and the PF driver.

> Does VFIO driver provide any methods for PF & VF communication.

No, those are in the PF driver (ixgbe for example).

Paolo

RE: SR-PCIM support in KVM

[Bharat Kumar Gogada]

> > > > As per the following link:
> > > > https://www.linux-kvm.org/images/6/6a/KvmForum2008$kdf2008_7.pdf
> > > >
> > > > It says that for software based virtual mailbox we require SR-PCIM
> > > > support.
> > > >
> > > > So for this purpose is SR-PCIM implemented as part of KVM ?
> > > > Or is there any other method that KVM provides for communication
> > > > between PF & VF ?
> > >
> > > Hi, SR-IOV is not part of KVM (the virtual machine monitor kernel module).
> > > In PCIe terms, when using KVM the "VI" or Virtualization
> > > Intermediary is the Linux VFIO driver.  SR-IOV management is split
> > > between the PF driver and VFIO.
> >
> > Thanks Paolo.
> >
> > If Linux VIFO driver acts as VI, as per spec SR-PCIM is "Software
> > responsible for the configuration of the SR-IOV capability, management
> > of Physical Functions and Virtual Functions" So if we use kvm who does above
> work of SR-PCIM ?
> 
> It's split between VFIO and the PF driver.
> 
> > Does VFIO driver provide any methods for PF & VF communication.
> 
> No, those are in the PF driver (ixgbe for example).
> 
Thanks Paolo