From e2be2a833ab5338fa5b8b99ba622b911d96f1795 Mon Sep 17 00:00:00 2001 From: Lu Baolu Date: Wed, 25 Nov 2020 09:41:24 +0800 Subject: x86/tboot: Don't disable swiotlb when iommu is forced on 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 Signed-off-by: Lu Baolu 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 --- 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 420be871d9d4..ae64f98ec2ab 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; -- cgit v1.2.3