Re: [PATCH v5 1/7] efi: Use early_mem*() instead of early_io*()

From: Matthew Garrett
Date: Sun Jun 15 2014 - 21:20:05 EST


On Fri, Jun 13, 2014 at 07:00:17PM +0200, Daniel Kiper wrote:
> Use early_mem*() instead of early_io*() because all mapped EFI regions
> are true RAM not I/O regions. Additionally, I/O family calls do not work
> correctly under Xen in our case. AIUI, early_io*() maps/unmaps real machine
> addresses. However, all artificial EFI structures created under Xen live
> in dom0 memory and should be mapped/unmapped using early_mem*() family
> calls which map domain memory.

Mapped EFI regions may include memory mapped flash, not merely true RAM.

--
Matthew Garrett | mjg59@xxxxxxxxxxxxx
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