Messages in this thread | | | Date | Tue, 14 Jun 2022 15:21:23 +0800 | Subject | Re: [PATCH v2 03/12] iommu/vt-d: Remove clearing translation data in disable_dmar_iommu() | From | Baolu Lu <> |
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On 2022/6/14 14:49, Tian, Kevin wrote: >> From: Lu Baolu<baolu.lu@linux.intel.com> >> Sent: Tuesday, June 14, 2022 10:51 AM >> >> The disable_dmar_iommu() is called when IOMMU initialization fails or >> the IOMMU is hot-removed from the system. In both cases, there is no >> need to clear the IOMMU translation data structures for devices. >> >> On the initialization path, the device probing only happens after the >> IOMMU is initialized successfully, hence there're no translation data >> structures. > Out of curiosity. With kexec the IOMMU may contain stale mappings > from the old kernel. Then is it meaningful to disable IOMMU after the > new kernel fails to initialize it properly?
For kexec kernel, if the IOMMU is detected to be pre-enabled, the IOMMU driver will try to copy tables from the old kernel. If copying table fails, the IOMMU driver will disable IOMMU and do the normal initialization.
Best regards, baolu
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