[PATCH v3 4/8] iommu/vt-d: Enable DMA remapping after rmrr mapped

Lu Baolu
2019-04-29T02:19:02Z

The rmrr devices require identity map of the rmrr regions before
enabling DMA remapping. Otherwise, there will be a window during
which DMA from/to the rmrr regions will be blocked. In order to
alleviate this, we move enabling DMA remapping after all rmrr
regions get mapped.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
drivers/iommu/intel-iommu.c | 16 ++++++++++------
1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index e9f31b062305..847e4a326d29 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -3527,11 +3527,6 @@ static int __init init_dmars(void)
ret = dmar_set_interrupt(iommu);
if (ret)
goto free_iommu;
-
- if (!translation_pre_enabled(iommu))
- iommu_enable_translation(iommu);
-
- iommu_disable_protect_mem_regions(iommu);
}

return 0;
@@ -4933,7 +4928,6 @@ int __init intel_iommu_init(void)
goto out_free_reserved_range;
}
up_write(&dmar_global_lock);
- pr_info("Intel(R) Virtualization Technology for Directed I/O\n");

#if defined(CONFIG_X86) && defined(CONFIG_SWIOTLB)
swiotlb = 0;
@@ -4956,6 +4950,16 @@ int __init intel_iommu_init(void)
register_memory_notifier(&intel_iommu_memory_nb);
cpuhp_setup_state(CPUHP_IOMMU_INTEL_DEAD, "iommu/intel:dead", NULL,
intel_iommu_cpu_dead);
+
+ /* Finally, we enable the DMA remapping hardware. */
+ for_each_iommu(iommu, drhd) {
+ if (!translation_pre_enabled(iommu))
+ iommu_enable_translation(iommu);
+
+ iommu_disable_protect_mem_regions(iommu);
+ }
+ pr_info("Intel(R) Virtualization Technology for Directed I/O\n");
+
intel_iommu_enabled = 1;
intel_iommu_debugfs_init();