From: Lu Baolu baolu.lu@linux.intel.com
[ Upstream commit e2be2a833ab5338fa5b8b99ba622b911d96f1795 ]
After commit 327d5b2fee91c ("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: 327d5b2fee91 ("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 Signed-off-by: Sasha Levin sashal@kernel.org --- arch/x86/kernel/tboot.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-)
diff --git a/arch/x86/kernel/tboot.c b/arch/x86/kernel/tboot.c index 420be871d9d45..ae64f98ec2ab6 100644 --- a/arch/x86/kernel/tboot.c +++ b/arch/x86/kernel/tboot.c @@ -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;