iommu/amd: Use 4K page for completion wait write-back semaphore

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IOMMU SNP support requires the completion wait write-back semaphore to be
implemented using a 4K-aligned page, where the page address is to be
programmed into the newly introduced MMIO base/range registers.

This new scheme uses a per-iommu atomic variable to store the current
semaphore value, which is incremented for every completion wait command.

Since this new scheme is also compatible with non-SNP mode,
generalize the driver to use 4K page for completion-wait semaphore in
both modes.

Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Link: https://lore.kernel.org/r/20200923121347.25365-2-suravee.suthikulpanit@amd.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>

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This commit is contained in:

Suravee Suthikulpanit 2020-09-23 12:13:45 +00:00 • committed by Joerg Roedel

parent 06ce8a62ce

commit c69d89aff3

3 changed files with 31 additions and 13 deletions

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3

drivers/iommu/amd/amd_iommu_types.h

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18

drivers/iommu/amd/init.c

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23

drivers/iommu/amd/iommu.c

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