On Thu, 28 Jul 2011 16:11:17 +0100
Ian Campbell <ijc@xxxxxxxxxxxxxx> wrote:
> On Wed, 2011-07-27 at 15:17 -0700, Greg Rose wrote:
> > Device drivers that create and destroy SR-IOV virtual functions via
> > calls to pci_enable_sriov() and pci_disable_sriov can cause catastrophic
> > failures if they attempt to destroy VFs while they are assigned to
> > guest virtual machines. By adding a flag for use by the KVM module
> > to indicate that a device is assigned a device driver can check that
> > flag and avoid destroying VFs while they are assigned and avoid system
> > failures.
> >
> > Signed-off-by: Greg Rose <gregory.v.rose@xxxxxxxxx>
> > ---
> >
> > include/linux/pci.h | 2 ++
>
> I added Jesse and linux-pci to CC.
>
> > virt/kvm/assigned-dev.c | 2 ++
> > virt/kvm/iommu.c | 4 ++++
> > 3 files changed, 8 insertions(+), 0 deletions(-)
>
> I suppose this would also be useful in Xen's pciback or any other system
> which does passthrough? (Konrad CC'd for pciback)
>
> Is there some common lower layer we could hook this in to? (does
> iommu_attach/detach_device make sense?) Or shall we just add the flag
> manipulations to pciback as well?
>
> Ian.
>
> >
> > diff --git a/include/linux/pci.h b/include/linux/pci.h
> > index 2d29218..a297ca2 100644
> > --- a/include/linux/pci.h
> > +++ b/include/linux/pci.h
> > @@ -174,6 +174,8 @@ enum pci_dev_flags {
> > PCI_DEV_FLAGS_MSI_INTX_DISABLE_BUG = (__force pci_dev_flags_t) 1,
> > /* Device configuration is irrevocably lost if disabled into D3 */
> > PCI_DEV_FLAGS_NO_D3 = (__force pci_dev_flags_t) 2,
> > + /* Provide indication device is assigned by KVM */
> > + PCI_DEV_FLAGS_ASSIGNED = (__force pci_dev_flags_t) 4,
> > };
Looks fine, but I'd make the comment less redundant with the code, e.g.
"set when the device is assigned to a guest instance" or somesuch.
--
Jesse Barnes, Intel Open Source Technology Center
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