path: root/drivers/pci/intel-iommu.c
diff options
authorJoseph Cihula <joseph.cihula@intel.com>2011-03-21 11:04:24 -0700
committerDavid Woodhouse <David.Woodhouse@intel.com>2011-04-21 13:51:40 +0100
commit51a63e67da6056c13b5b597dcc9e1b3bd7ceaa55 (patch)
tree88258f313963c0b67de3ba2f1ad57d4365b86496 /drivers/pci/intel-iommu.c
parent2fe9723df8e45fd247782adea244a5e653c30bf4 (diff)
intel_iommu: disable all VT-d PMRs when TXT launched
Intel VT-d Protected Memory Regions (PMRs) are supposed to be disabled, on each VT-d engine, after DMA remapping is enabled on the engines. This is because the behavior of having both enabled is not deterministic and because, if TXT has been used to launch the kernel, the PMRs may be programmed to cover memory regions that will be used for DMA. Under some circumstances (certain quirks detected, lack of multiple devices, etc.), the current code does not set up DMA remapping on some VT-d engines. In such cases it also skips disabling the PMRs. This causes failures when the kernel is launched with TXT (most often this occurs on the graphics engine and results in colored vertical bars on the display). This patch detects when the kernel has been launched with TXT and then disables the PMRs on all VT-d engines. In some cases where the reason that remapping is not being enabled is due to possible ACPI DMAR table errors, the VT-d engine addresses may not be correct and thus not able to be safely programmed even to disable PMRs. Because part of the TXT launch process is the verification of these addresses, it will always be safe to disable PMRs if the TXT launch has succeeded and hence only doing this in such cases. Signed-off-by: Joseph Cihula <joseph.cihula@intel.com> Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Diffstat (limited to 'drivers/pci/intel-iommu.c')
1 files changed, 29 insertions, 9 deletions
diff --git a/drivers/pci/intel-iommu.c b/drivers/pci/intel-iommu.c
index 5dc5d3e3508e..cdded1e2e660 100644
--- a/drivers/pci/intel-iommu.c
+++ b/drivers/pci/intel-iommu.c
@@ -1299,7 +1299,7 @@ static void iommu_detach_domain(struct dmar_domain *domain,
static struct iova_domain reserved_iova_list;
static struct lock_class_key reserved_rbtree_key;
-static void dmar_init_reserved_ranges(void)
+static int dmar_init_reserved_ranges(void)
struct pci_dev *pdev = NULL;
struct iova *iova;
@@ -1313,8 +1313,10 @@ static void dmar_init_reserved_ranges(void)
/* IOAPIC ranges shouldn't be accessed by DMA */
iova = reserve_iova(&reserved_iova_list, IOVA_PFN(IOAPIC_RANGE_START),
- if (!iova)
+ if (!iova) {
printk(KERN_ERR "Reserve IOAPIC range failed\n");
+ return -ENODEV;
+ }
/* Reserve all PCI MMIO to avoid peer-to-peer access */
for_each_pci_dev(pdev) {
@@ -1327,11 +1329,13 @@ static void dmar_init_reserved_ranges(void)
iova = reserve_iova(&reserved_iova_list,
- if (!iova)
+ if (!iova) {
printk(KERN_ERR "Reserve iova failed\n");
+ return -ENODEV;
+ }
+ return 0;
static void domain_reserve_special_ranges(struct dmar_domain *domain)
@@ -2213,7 +2217,7 @@ static int __init iommu_prepare_static_identity_mapping(int hw)
return 0;
-int __init init_dmars(void)
+static int __init init_dmars(int force_on)
struct dmar_drhd_unit *drhd;
struct dmar_rmrr_unit *rmrr;
@@ -2393,8 +2397,15 @@ int __init init_dmars(void)
* enable translation
for_each_drhd_unit(drhd) {
- if (drhd->ignored)
+ if (drhd->ignored) {
+ /*
+ * we always have to disable PMRs or DMA may fail on
+ * this device
+ */
+ if (force_on)
+ iommu_disable_protect_mem_regions(drhd->iommu);
+ }
iommu = drhd->iommu;
@@ -3303,12 +3314,21 @@ int __init intel_iommu_init(void)
if (no_iommu || dmar_disabled)
return -ENODEV;
- iommu_init_mempool();
- dmar_init_reserved_ranges();
+ if (iommu_init_mempool()) {
+ if (force_on)
+ panic("tboot: Failed to initialize iommu memory\n");
+ return -ENODEV;
+ }
+ if (dmar_init_reserved_ranges()) {
+ if (force_on)
+ panic("tboot: Failed to reserve iommu ranges\n");
+ return -ENODEV;
+ }
- ret = init_dmars();
+ ret = init_dmars(force_on);
if (ret) {
if (force_on)
panic("tboot: Failed to initialize DMARs\n");