entity mappings. The reasons we do not want to set the identity mapping from 0-> ISA_END_ADDRESS when running as PV is b/c that the kernel would try to read DMI information and fail (no permissions to read that). There is a lot of gnarly code to deal with that weird region so we won't try to do a cleanup in this patch. This code ends up calling 'set_phys_to_identity' with the start and end PFN of the the E820 that are non-RAM or have gaps. On 99% of machines that means one big region right underneath the 4GB mark. Usually starts at 0xc0000 (or 0x80000) and goes to 0x100000. [v2: Fix for E820 crossing 1MB region and clamp the start] [v3: Squshed in code that does this over ranges] [v4: Moved the comment to the correct spot] [v5: Use the "raw" E820 from the hypervisor] [v6: Added Review-by tag] Reviewed-by: Ian Campbell Signed-off-by: Konrad Rzeszutek Wilk فرِ‘9x