mshv: Fix create memory region overlap check

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: mshv: Fix create memory region overlap check The current check is incorrect; it only checks if the beginning or end of a region is within an existing region. This doesn't account for userspace specifying a region that begins before and ends after an existing region. Change the logic to a range intersection check against gfns and uaddrs for each region. Remove mshv_partition_region_by_uaddr() as it is no longer used.

References

• https://git.kernel.org/stable/c/2183924dd834e0703f87e17c17e689bcbf55d69d
• https://git.kernel.org/stable/c/ab3e7a78d83a61d335458cfe2e4d17eba69ae73d
• https://git.kernel.org/stable/c/ba9eb9b86d232854e983203dc2fb1ba18e316681