[PATCH v2 06/13] iommu: Make use of DMA quirking and ACS enabled check for groups

Alex Williamson
2012-05-22T05:05:15Z

Incorporate DMA quirking and ACS checking into amd_iommu and
intel-iommu. Note that IOMMU groups are not yet used for
streaming DMA, so this doesn't immediately solve the problems
with broken Ricoh devices. This a very strict implementation of
ACS checking, which will often result in multifunction devices
being grouped together. This is actually a good thing as we
generally have no reason to trust isolation between functions,
but I won't be surprised if we later add a boot option to relax
this if a user wants to opt-in to a less secure grouping.

Signed-off-by: Alex Williamson <alex.williamson-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
---

drivers/iommu/amd_iommu.c | 18 ++++++++++++++++++
drivers/iommu/intel-iommu.c | 18 ++++++++++++++++++
2 files changed, 36 insertions(+), 0 deletions(-)

diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index b7e5ddf..be72d6d 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -254,6 +254,8 @@ static bool check_device(struct device *dev)
return true;
}

+#define PCI_ACS_ENABLED (PCI_ACS_SV | PCI_ACS_RR | PCI_ACS_CR | PCI_ACS_UF)
+
static int iommu_init_device(struct device *dev)
{
struct pci_dev *dma_pdev, *pdev = to_pci_dev(dev);
@@ -291,6 +293,22 @@ static int iommu_init_device(struct device *dev)
dma_pdev = pci_get_slot(pdev->bus,
PCI_DEVFN(PCI_SLOT(pdev->devfn), 0));

+ dma_pdev = pci_dma_source(dma_pdev);
+
+ if (dma_pdev->multifunction &&
+ !pci_acs_enabled(dma_pdev, PCI_ACS_ENABLED))
+ dma_pdev = pci_get_slot(dma_pdev->bus,
+ PCI_DEVFN(PCI_SLOT(dma_pdev->devfn),
+ 0));
+
+ while (!pci_is_root_bus(dma_pdev->bus)) {
+ if (pci_acs_path_enabled(dma_pdev->bus->self,
+ NULL, PCI_ACS_ENABLED))
+ break;
+
+ dma_pdev = dma_pdev->bus->self;
+ }
+
group = iommu_group_get(&dma_pdev->dev);
if (!group) {
group = iommu_group_alloc();
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index e63b33b..cf2a650 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -4087,6 +4087,8 @@ static int intel_iommu_domain_has_cap(struct iommu_domain *domain,
return 0;
}

+#define PCI_ACS_ENABLED (PCI_ACS_SV | PCI_ACS_RR | PCI_ACS_CR | PCI_ACS_UF)
+
static int intel_iommu_add_device(struct device *dev)
{
struct pci_dev *pdev = to_pci_dev(dev);
@@ -4113,6 +4115,22 @@ static int intel_iommu_add_device(struct device *dev)
dma_pdev = pci_get_slot(pdev->bus,
PCI_DEVFN(PCI_SLOT(pdev->devfn), 0));

+ dma_pdev = pci_dma_source(dma_pdev);
+
+ if (dma_pdev->multifunction &&
+ !pci_acs_enabled(dma_pdev, PCI_ACS_ENABLED))
+ dma_pdev = pci_get_slot(dma_pdev->bus,
+ PCI_DEVFN(PCI_SLOT(dma_pdev->devfn),
+ 0));
+
+ while (!pci_is_root_bus(dma_pdev->bus)) {
+ if (pci_acs_path_enabled(dma_pdev->bus->self,
+ NULL, PCI_ACS_ENABLED))
+ break;
+
+ dma_pdev = dma_pdev->bus->self;
+ }
+
group = iommu_group_get(&dma_pdev->dev);
if (!group) {
group = iommu_group_alloc();