[xen stable-4.8] hvmloader: use base instead of pci_mem_start for find_next_rmrr()
Author: Xiong Zhang <[hidden email]>
AuthorDate: Fri Oct 6 15:04:09 2017 +0200
Commit: Jan Beulich <[hidden email]>
CommitDate: Fri Oct 6 15:04:09 2017 +0200
hvmloader: use base instead of pci_mem_start for find_next_rmrr()
find_next_rmrr(base) is used to find the lowest RMRR ending above base
but below 4G. Current method couldn't cover the following situation:
a. two rmrr exist, small gap between them
b. pci_mem_start and mem_resource.base is below the first rmrr.base
c. find_next_rmrr(pci_mem_start) will find the first rmrr
d. After aligning mem_resource.base to bar size,
first_rmrr.end < new_base < second_rmrr.base and
new_base + bar_sz > second_rmrr.base.
So the new bar will overlap with the second rmrr and doesn't overlap
with the first rmrr.
But the next_rmrr point to the first rmrr, then check_overlap() couldn't
find the overlap. Finally assign a wrong address to bar.
This patch using aligned new base to find the next rmrr, could fix the
above case and find all the overlapped rmrr with new base.