[Xen-devel] [PATCH v3] Fix acpi_dmar_zap/reinstate() (fixes S3 regression)

[Tomasz Wroblewski <tomasz.wroblewski@xxxxxxxxxx>]

Thanks, attaching version 3 of the patch using your suggestions, which 
simplify it considerably. This one uses map_pages_to_xen in favour of 
ioremap, so it works on both tip as well as older trees from before 
ioremap() rework (tested both).
Changes from v2/v1:
- keeping global dmar_table pointer and initializing it in acpi_dmar_init()
- use map_pages_to_xen to add a static mapping (instead of ioremap)
- moved acpi_get_table_physical_location to tbxface.c. Added instance 
argument to make it symmetric with acpi_get_table.
- coding convention fixes

Commit message:

Fix S3 regression introduced by cs 23013:65d26504e843 (ACPI: large 
cleanup). The dmar virtual pointer returned from acpi_get_table cannot 
be safely stored away and used later, as the underlying 
acpi_os_map_memory / __acpi_map_table functions overwrite the mapping 
causing it to point to different tables than dmar (last fetched table is 
used). This subsequently causes acpi_dmar_reinstate() and 
acpi_dmar_zap() to write data to wrong table, causing its corruption and 
problems with consecutive s3 resumes.
Added a new function to fetch ACPI table physical address, and 
establishing separate static mapping for dmar_table pointer instead of 
using acpi_get_table().
Signed-off-by: Tomasz Wroblewski <tomasz.wroblewski@xxxxxxxxxx>

Attachment: fix-dmar-zap-reinstate-v3.patch
Description: Text Data

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