Re: [net-next 1/8] pci: Add flag indicating device has been assigned by KVM

[Jesse Barnes <jbarnes@virtuousgeek.org>]

[oops meant to cc everyone, yes this has my ack]

On Thu, 22 Sep 2011 21:16:18 -0700
Jeff Kirsher <jeffrey.t.kirsher@intel.com> wrote:

> On Wed, Sep 21, 2011 at 03:12, Jeff Kirsher
> <jeffrey.t.kirsher@intel.com> wrote:
> > From: Greg Rose <gregory.v.rose@intel.com>
> >
> > 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@intel.com>
> > Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
> > ---
> >  include/linux/pci.h     |    2 ++
> >  virt/kvm/assigned-dev.c |    2 ++
> >  virt/kvm/iommu.c        |    4 ++++
> >  3 files changed, 8 insertions(+), 0 deletions(-)
> >
> > diff --git a/include/linux/pci.h b/include/linux/pci.h
> > index f27893b..4f511da 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,
> >  };
> >
> >  enum pci_irq_reroute_variant {
> > diff --git a/virt/kvm/assigned-dev.c b/virt/kvm/assigned-dev.c
> > index 4e9eaeb..eaf3a50 100644
> > --- a/virt/kvm/assigned-dev.c
> > +++ b/virt/kvm/assigned-dev.c
> > @@ -205,6 +205,8 @@ static void kvm_free_assigned_device(struct kvm
> > *kvm, else
> >                pci_restore_state(assigned_dev->dev);
> >
> > +       assigned_dev->dev->dev_flags &= ~PCI_DEV_FLAGS_ASSIGNED;
> > +
> >        pci_release_regions(assigned_dev->dev);
> >        pci_disable_device(assigned_dev->dev);
> >        pci_dev_put(assigned_dev->dev);
> > diff --git a/virt/kvm/iommu.c b/virt/kvm/iommu.c
> > index 78c80f6..967aba1 100644
> > --- a/virt/kvm/iommu.c
> > +++ b/virt/kvm/iommu.c
> > @@ -187,6 +187,8 @@ int kvm_assign_device(struct kvm *kvm,
> >                        goto out_unmap;
> >        }
> >
> > +       pdev->dev_flags |= PCI_DEV_FLAGS_ASSIGNED;
> > +
> >        printk(KERN_DEBUG "assign device %x:%x:%x.%x\n",
> >                assigned_dev->host_segnr,
> >                assigned_dev->host_busnr,
> > @@ -215,6 +217,8 @@ int kvm_deassign_device(struct kvm *kvm,
> >
> >        iommu_detach_device(domain, &pdev->dev);
> >
> > +       pdev->dev_flags &= ~PCI_DEV_FLAGS_ASSIGNED;
> > +
> >        printk(KERN_DEBUG "deassign device %x:%x:%x.%x\n",
> >                assigned_dev->host_segnr,
> >                assigned_dev->host_busnr,
> > --
> > 1.7.6.2
> 
> Jesse/Konrad/Ian-
> 
> I sent this patch out as part of a pull request for David Miller's
> net-next tree.  I know that Greg sent this originally out to the
> linux-pci mailing list as a RFC. Since Greg also has a patch against
> ixgbe which implemented this flag, I sent both patches for inclusion
> into David Miller's net-next.
> 
> Dave is wanting to ensure that the PCI maintainers have reviewed this
> and are ok with it before pulls my series of patches.
>