lkml.org 
[lkml]   [2015]   [Jun]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 4.0 039/105] iommu/vt-d: Fix passthrough mode with translation-disabled devices
Date
4.0-stable review patch.  If anyone has any objections, please let me know.

------------------

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)
{

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2015-06-19 23:41    [W:0.949 / U:0.076 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site