On 2022/6/14 14:49, Tian, Kevin wrote:
From: Lu Baolu<baolu...@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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