Messages in this thread | | | From | Zhenzhong Duan <> | Date | Thu, 5 Nov 2020 10:19:36 +0800 | Subject | Re: [PATCH] iommu/vt-d: remove redundant variable no_platform_optin |
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Hi Baolu,
On Thu, Nov 5, 2020 at 9:47 AM Lu Baolu <baolu.lu@linux.intel.com> wrote: > > Hi Zhenzhong, > > On 11/4/20 4:19 PM, Zhenzhong Duan wrote: > > no_platform_optin is redundant with dmar_disabled and it's only used in > > platform_optin_force_iommu(), remove it and use dmar_disabled instead. > > It's actually not. > > If CONFIG_INTEL_IOMMU_DEFAULT_ON is not set, we will get "dmar_disable = > 1" and "no_platform_optin = 0". In this case, we must force the iommu on > and set dmar_disable = 0. > > The real use case: if a kernel built with [CONFIG_INTEL_IOMMU_DEFAULT_ON > = n] running on a platform with thunderbolt ports, we must force IOMMU > on so that the system could be protected from possible malicious > peripherals.
Thanks for your explanation, clear now and sorry for the noise.
Regards Zhenzhong
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