RE: [Xen-devel] [PATCH] vmwrite high 32 bits of 64bit VMCS fields when in PAE mode

["Li, Xin B" <xin.b.li@xxxxxxxxx>]

>> Is this necessary? Writes to low halves clear top halves, and these
data
>> structures will always be below 4GB, right?
>> 
>> Are you just being super safe? :-)
>
>Oh, furthermore with a 32-bit build of Xen we have to be safe for the
case
>that VMX_BASIC_MSR[48]==1 (which Vol 3B Appendix G.1 says is true for
non
>Intel64 CPUs like Yonah). In this case the physical pointers poked into
the
>VMCS are limited to 32 bits. We may as well limit all such structures
to
>below 4GB in all cases with a 32-bit build of Xen.
>

So we need keep this mind for all data structures referenced by pointers
in a VMCS when on 32bit Xen, or maybe how about add a memory allocation
function wrapper for this purpose?
-Xin

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