Messages in this thread | | | From | Zhenzhong Duan <> | Date | Mon, 9 Nov 2020 10:27:51 +0800 | Subject | Re: [PATCH] iommu/vt-d: avoid unnecessory panic if iommu init fail in tboot |
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+intel iommu maintainers,
Can anyone help review this patch? Thanks
Zhenzhong
On Wed, Nov 4, 2020 at 4:15 PM Zhenzhong Duan <zhenzhong.duan@gmail.com> wrote: > > "intel_iommu=off" command line is used to disable iommu and iommu is force > enabled in a tboot system. Meanwhile "intel_iommu=tboot_noforce,off" > could be used to force disable iommu in tboot for better performance. > > 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 it by return 0 in tboot_force_iommu() so that force_on is not set. > > Fixes: 7304e8f28bb2 ("iommu/vt-d: Correctly disable Intel IOMMU force on") > Signed-off-by: Zhenzhong Duan <zhenzhong.duan@gmail.com> > --- > 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 992fb1415c0f..9fd4d162b331 100644 > --- a/arch/x86/kernel/tboot.c > +++ b/arch/x86/kernel/tboot.c > @@ -511,12 +511,9 @@ struct acpi_table_header *tboot_get_dmar_table(struct acpi_table_header *dmar_tb > > int tboot_force_iommu(void) > { > - if (!tboot_enabled()) > + if (!tboot_enabled() || intel_iommu_tboot_noforce) > return 0; > > - if (intel_iommu_tboot_noforce) > - return 1; > - > if (no_iommu || swiotlb || dmar_disabled) > pr_warn("Forcing Intel-IOMMU to enabled\n"); > > -- > 2.25.1 >
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