Re: [PATCH v2 03/13] iommu: IOMMU groups for VT-d and AMD-Vi

Alex Williamson
2012-05-24T21:49:28Z

On Thu, 2012-05-24 at 17:01 -0400, Don Dutile wrote:
> On 05/22/2012 01:04 AM, Alex Williamson wrote:
> > Add back group support for AMD& Intel. amd_iommu already tracks
> > devices and has init and uninit routines to manage groups.
> > intel-iommu does this on the fly, so we make use of the notifier
> > support built into iommu groups to create and remove groups.
> >
> > Signed-off-by: Alex Williamson<alex.williamson-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
> > ---
> >
> > drivers/iommu/amd_iommu.c | 28 +++++++++++++++++++++++++-
> > drivers/iommu/intel-iommu.c | 46 +++++++++++++++++++++++++++++++++++++++++++
> > 2 files changed, 73 insertions(+), 1 deletions(-)
> >
> > diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
> > index 32c00cd..b7e5ddf 100644
> > --- a/drivers/iommu/amd_iommu.c
> > +++ b/drivers/iommu/amd_iommu.c
> > @@ -256,9 +256,11 @@ static bool check_device(struct device *dev)
> >
> > static int iommu_init_device(struct device *dev)
> > {
> > - struct pci_dev *pdev = to_pci_dev(dev);
> > + struct pci_dev *dma_pdev, *pdev = to_pci_dev(dev);
> > struct iommu_dev_data *dev_data;
> > + struct iommu_group *group;
> > u16 alias;
> > + int ret;
> >
> > if (dev->archdata.iommu)
> > return 0;
> > @@ -279,8 +281,30 @@ static int iommu_init_device(struct device *dev)
> > return -ENOTSUPP;
> > }
> > dev_data->alias_data = alias_data;
> > +
> > + dma_pdev = pci_get_bus_and_slot(alias>> 8, alias& 0xff);
> > + } else
> > + dma_pdev = pdev;
> > +
> > + if (!pdev->is_virtfn&& PCI_FUNC(pdev->devfn)&& iommu_group_mf&&
> > + pdev->hdr_type == PCI_HEADER_TYPE_NORMAL)
> > + dma_pdev = pci_get_slot(pdev->bus,
> > + PCI_DEVFN(PCI_SLOT(pdev->devfn), 0));
> > +
> > + group = iommu_group_get(&dma_pdev->dev);
> > + if (!group) {
> > + group = iommu_group_alloc();
> > + if (IS_ERR(group))
> > + return PTR_ERR(group);
> > }
> >
> > + ret = iommu_group_add_device(group, dev);
> > +
> > + iommu_group_put(group);
> > +
> do you want to do a put if there is a failure in the iommu_group_add_device()?

Yes, this was intentional. iommu_group_alloc() adds a reference to the
group it returns so that it doesn't disappear while we're working on it
(documented in iommu.c). iommu_group_get() also gets a reference. So
this put will free the group if it was new or just drop the reference if
existing. Thanks,

Alex

> > + if (ret)
> > + return ret;
> > +
> > if (pci_iommuv2_capable(pdev)) {
> > struct amd_iommu *iommu;
> >
> > @@ -309,6 +333,8 @@ static void iommu_ignore_device(struct device *dev)
> >
> > static void iommu_uninit_device(struct device *dev)
> > {
> > + iommu_group_remove_device(dev);
> > +
> > /*
> > * Nothing to do here - we keep dev_data around for unplugged devices
> > * and reuse it when the device is re-plugged - not doing so would
> > diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
> > index d4a0ff7..e63b33b 100644
> > --- a/drivers/iommu/intel-iommu.c
> > +++ b/drivers/iommu/intel-iommu.c
> > @@ -4087,6 +4087,50 @@ static int intel_iommu_domain_has_cap(struct iommu_domain *domain,
> > return 0;
> > }
> >
> > +static int intel_iommu_add_device(struct device *dev)
> > +{
> > + struct pci_dev *pdev = to_pci_dev(dev);
> > + struct pci_dev *bridge, *dma_pdev = pdev;
> > + struct iommu_group *group;
> > + int ret;
> > +
> > + if (!device_to_iommu(pci_domain_nr(pdev->bus),
> > + pdev->bus->number, pdev->devfn))
> > + return -ENODEV;
> > +
> > + bridge = pci_find_upstream_pcie_bridge(pdev);
> > + if (bridge) {
> > + if (pci_is_pcie(bridge))
> > + dma_pdev = pci_get_domain_bus_and_slot(
> > + pci_domain_nr(pdev->bus),
> > + bridge->subordinate->number, 0);
> > + else
> > + dma_pdev = bridge;
> > + }
> > +
> > + if (!pdev->is_virtfn&& PCI_FUNC(pdev->devfn)&& iommu_group_mf&&
> > + pdev->hdr_type == PCI_HEADER_TYPE_NORMAL)
> > + dma_pdev = pci_get_slot(pdev->bus,
> > + PCI_DEVFN(PCI_SLOT(pdev->devfn), 0));
> > +
> > + group = iommu_group_get(&dma_pdev->dev);
> > + if (!group) {
> > + group = iommu_group_alloc();
> > + if (IS_ERR(group))
> > + return PTR_ERR(group);
> > + }
> > +
> > + ret = iommu_group_add_device(group, dev);
> > +
> ditto.
> > + iommu_group_put(group);
> > + return ret;
> > +}
> > +
> > +static void intel_iommu_remove_device(struct device *dev)
> > +{
> > + iommu_group_remove_device(dev);
> > +}
> > +
> > static struct iommu_ops intel_iommu_ops = {
> > .domain_init = intel_iommu_domain_init,
> > .domain_destroy = intel_iommu_domain_destroy,
> > @@ -4096,6 +4140,8 @@ static struct iommu_ops intel_iommu_ops = {
> > .unmap = intel_iommu_unmap,
> > .iova_to_phys = intel_iommu_iova_to_phys,
> > .domain_has_cap = intel_iommu_domain_has_cap,
> > + .add_device = intel_iommu_add_device,
> > + .remove_device = intel_iommu_remove_device,
> > .pgsize_bitmap = INTEL_IOMMU_PGSIZES,
> > };
> >
> >
>