iommu/vt-d: Avoid panic if iommu init fails in tboot system (4d213e76) · Commits · 戴 / test

"intel_iommu=off" command line is used to disable iommu but iommu is force enabled in a tboot system for security reason. However for better performance on high speed network device, a new option "intel_iommu=tboot_noforce" is introduced to disable the force on. By default kernel should panic if iommu init fail in tboot for security reason, but it's unnecessory if we use "intel_iommu=tboot_noforce,off". Fix the code setting force_on and move intel_iommu_tboot_noforce from tboot code to intel iommu code. Fixes: ("iommu/vt-d: Correctly disable Intel IOMMU force on") Signed-off-by:

Zhenzhong Duan <zhenzhong.duan@gmail.com> Tested-by:

Lukasz Hawrylko <lukasz.hawrylko@linux.intel.com> Acked-by:

Lu Baolu <baolu.lu@linux.intel.com> Link: https://lore.kernel.org/r/20201110071908.3133-1-zhenzhong.duan@gmail.com Signed-off-by:

Will Deacon <will@kernel.org>

arch/x86/kernel/tboot.c

+0 −3

Original line number	Diff line number	Diff line
		@@ -514,9 +514,6 @@ int tboot_force_iommu(void)
		if (!tboot_enabled())
		return 0;

		if (intel_iommu_tboot_noforce)
		return 1;

		if (no_iommu \|\| swiotlb \|\| dmar_disabled)
		pr_warn("Forcing Intel-IOMMU to enabled\n");

drivers/iommu/intel/iommu.c

+3 −2

Original line number	Diff line number	Diff line
		@@ -179,7 +179,7 @@ static int rwbf_quirk;
		* (used when kernel is launched w/ TXT)
		*/
		static int force_on = 0;
		int intel_iommu_tboot_noforce;
		static int intel_iommu_tboot_noforce;
		static int no_platform_optin;

		#define ROOT_ENTRY_NR (VTD_PAGE_SIZE/sizeof(struct root_entry))
		@@ -4885,7 +4885,8 @@ int __init intel_iommu_init(void)
		* Intel IOMMU is required for a TXT/tboot launch or platform
		* opt in, so enforce that.
		*/
		force_on = tboot_force_iommu() \|\| platform_optin_force_iommu();
		force_on = (!intel_iommu_tboot_noforce && tboot_force_iommu()) \|\|
		platform_optin_force_iommu();

		if (iommu_init_mempool()) {
		if (force_on)

include/linux/intel-iommu.h

+0 −1

Original line number	Diff line number	Diff line
		@@ -798,7 +798,6 @@ extern int iommu_calculate_agaw(struct intel_iommu *iommu);
		extern int iommu_calculate_max_sagaw(struct intel_iommu *iommu);
		extern int dmar_disabled;
		extern int intel_iommu_enabled;
		extern int intel_iommu_tboot_noforce;
		extern int intel_iommu_gfx_mapped;
		#else
		static inline int iommu_calculate_agaw(struct intel_iommu *iommu)

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