[libvirt] [PATCH v4 0/5] PCI hostdev partial assignment support

[Daniel Henrique Barboza]

On 12/16/19 9:48 PM, Alex Williamson wrote:
> On Mon, 16 Dec 2019 21:09:20 -0300
> 
> Yes, but libvirt should not assume that it can manipulate the bindings
> of adjacent devices without being explicitly directed to do so.  The
> error may be a hindrance to you, but it might also prevent, for
> example, the only other NIC in the system being detached from the host
> driver.  Is it worth making the VM run without explicitly listing all
> devices to assign at the cost of disrupting host services or subverting
> the additional isolation a user might be attempting to configure with
> having unused devices bound to vfio-pci.  This seems like a bad idea,
> the VM should be configured to explicitly list every device it needs to
> have assigned or partially assigned.  Thanks,
> 

Thanks Alex. I know what's going wrong with this patch series after your messages and
a close inspection of what Libvirt is already doing. Libvirt does a sanity
check for PCI endpoint devices before assigning them to vfio-pci, but the
new detection code I am adding isn't. The result is that Cole can't run his
VM because this new detection code is demanding that a PCI Bridge, that belongs
to the same IOMMU of the devices Cole wants to passthrough, be assigned
to vfio-pci. Which is wrong.


I'll re-send this series fixing that.


Thanks,


DHB


> Alex
>