Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 4.0 039/105] iommu/vt-d: Fix passthrough mode with translation-disabled devices | Date | Fri, 19 Jun 2015 13:35:29 -0700 |
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4.0-stable review patch. If anyone has any objections, please let me know.
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From: David Woodhouse <David.Woodhouse@intel.com>
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@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/iommu/intel-iommu.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-)
--- a/drivers/iommu/intel-iommu.c +++ b/drivers/iommu/intel-iommu.c @@ -673,6 +673,11 @@ static void domain_update_iommu_cap(stru domain->iommu_superpage = domain_update_iommu_superpage(NULL); } +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; @@ -682,6 +687,9 @@ static struct intel_iommu *device_to_iom u16 segment = 0; int i; + if (iommu_dummy(dev)) + return NULL; + if (dev_is_pci(dev)) { pdev = to_pci_dev(dev); segment = pci_domain_nr(pdev->bus); @@ -2974,11 +2982,6 @@ static inline struct dmar_domain *get_va 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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