This commit fixes issue with usage of Xen hypervisor shared info page.
Previously U-boot did not unmap it at the end of OS boot process. Xen
did not prevent guest from this. So, it worked, but caused wierd
issues - one memory page, that was returned by memalign in U-boot
for Enlighten mapping was not unmaped by Xen (shared_info values was
not removed from there) and returned to allocator. During the Linux
boot, it uses shared_info page as regular RAM page, which leads to
hypervisor shared info corruption.
So, to fix this issue, as discussed on the xen-devel mailing list, the
code should:
1) Unmap the page
2) Populate the area with memory using XENMEM_populate_physmap
This patch adds page unmapping via XENMEM_remove_from_physmap, fills
hole in address space where page was mapped via XENMEM_populate_physmap
and return this address to memory allocator for freeing.
Signed-off-by: Dmytro Firsov <dmytro_firsov@epam.com>
Reviewed-by: Anastasiia Lukianenko <vicooodin@gmail.com>
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