3.16.7-ckt14 -stable review patch. If anyone has any objections, please let me know.
------------------
From: David Woodhouse <David.Woodhouse@xxxxxxxxx>
commit 4ed6a540fab8ea4388c1703b73ecfed68a2009d1 upstream.
When we use 'intel_iommu=igfx_off' to disable translation for the
graphics, and when we discover that the BIOS has misconfigured the DMAR
setup for I/OAT, we use a special DUMMY_DEVICE_DOMAIN_INFO value in
dev->archdata.iommu to indicate that translation is disabled.
With passthrough mode, we were attempting to dereference that as a
normal pointer to a struct device_domain_info when setting up an
identity mapping for the affected device.
This fixes the problem by making device_to_iommu() explicitly check for
the special value and indicate that no IOMMU was found to handle the
devices in question.
Signed-off-by: David Woodhouse <David.Woodhouse@xxxxxxxxx>
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
---
drivers/iommu/intel-iommu.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index afbde3730b11..baffab3948d7 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -666,6 +666,11 @@ static void domain_update_iommu_cap(struct dmar_domain *domain)
domain_update_iommu_superpage(domain);
}
+static int iommu_dummy(struct device *dev)
+{
+ return dev->archdata.iommu == DUMMY_DEVICE_DOMAIN_INFO;
+}
+
static struct intel_iommu *device_to_iommu(struct device *dev, u8 *bus, u8 *devfn)
{
struct dmar_drhd_unit *drhd = NULL;
@@ -675,6 +680,9 @@ static struct intel_iommu *device_to_iommu(struct device *dev, u8 *bus, u8 *devf
u16 segment;
int i;
+ if (iommu_dummy(dev))
+ return NULL;
+
if (dev_is_pci(dev)) {
pdev = to_pci_dev(dev);
segment = pci_domain_nr(pdev->bus);
@@ -2965,11 +2973,6 @@ static inline struct dmar_domain *get_valid_domain_for_dev(struct device *dev)
return __get_valid_domain_for_dev(dev);
}
-static int iommu_dummy(struct device *dev)
-{
- return dev->archdata.iommu == DUMMY_DEVICE_DOMAIN_INFO;
-}
-
/* Check if the dev needs to go through non-identity map and unmap process.*/
static int iommu_no_mapping(struct device *dev)
{
--
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