Re: [Xen-devel] Passing Xen memory map and resource map to OVMF

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Tue, 2013-11-12 at 14:22 -0500, Konrad Rzeszutek Wilk wrote:
> On Tue, Nov 12, 2013 at 06:33:21PM +0000, Wei Liu wrote:
> > Hi all
> > 
> > Currently OVMF determines memory size by consulting CMOS, then it makes
> > up memory map of its own.
> > 
> > Consulting memory size by reading CMOS limits the RAM size to 1TB as
> > there's only 3 bytes from 0x5b-0x5d in CMOS, where the upper memory size
> > is stored.
> > 
> > And from Xen's point of view, OVMF should use the memory mapped passed
> > by hypervisor (from hvmloader) instead of making up its own.
> > 
> > To solve the above two problems all in one go, I plan to pass necessary
> > information (io resource, mmio resource) to OVMF from Xen.  I will
> > construct the table / structure in hvmloader then hook up platform pei
> > code when OVMF is running on Xen.
> 
> /me nods. The nice thing about that is that it could also allow us
> to modify the E820 from the toolstack for any combination we want.

Note that the right way to do that would be for the toolstack to
communicate the base e820 to hvmloader, which would then do what it
needs to do modifying as it went and plumb the result through to the
BIOS.

Ian.


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