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x86/tboot: Don't disable swiotlb when iommu is forced on

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After commit 327d5b2fee ("iommu/vt-d: Allow 32bit devices to uses DMA
domain"), swiotlb could also be used for direct memory access if IOMMU
is enabled but a device is configured to pass through the DMA translation.
Keep swiotlb when IOMMU is forced on, otherwise, some devices won't work
if "iommu=pt" kernel parameter is used.

Fixes: 327d5b2fee ("iommu/vt-d: Allow 32bit devices to uses DMA domain")
Reported-and-tested-by: Adrian Huang <ahuang12@lenovo.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Link: https://lore.kernel.org/r/20201125014124.4070776-1-baolu.lu@linux.intel.com
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=210237
Signed-off-by: Will Deacon <will@kernel.org>
This commit is contained in:
Lu Baolu 2020-11-25 09:41:24 +08:00 committed by Will Deacon
parent 77c38c8cf5
commit e2be2a833a
1 changed files with 1 additions and 4 deletions
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5
arch/x86/kernel/tboot.c
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@ -514,13 +514,10 @@ int tboot_force_iommu(void)
if (!tboot_enabled())
return 0;
if (no_iommu || swiotlb || dmar_disabled)
if (no_iommu || dmar_disabled)
pr_warn("Forcing Intel-IOMMU to enabled\n");
dmar_disabled = 0;
#ifdef CONFIG_SWIOTLB
swiotlb = 0;
#endif
no_iommu = 0;
return 1;