Re: [Xen-devel] [PATCh] Full 64 bits VMCS field operation

[Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>]

On 5 Jul 2006, at 15:04, Dong, Eddie wrote:

> Cleanup some mis-operation of full 64 bits VMCS fields in 32 bits VMM.
From VMWRITE description in Intel Reference Manual Volume 2:
"If the VMCS field specified by the secondary source operand is shorter 
than this effective operand size, the high bits of the primary source 
operand are ignored. If the VMCS field is longer, then the high bits of 
the field are cleared to 0."
Also from 20.10.1 of Volume 3:
"64-bit fields and natural-width fields using the full access type 
outside IA-32e mode.—A VMWRITE writes the value of its source operand 
to bits31:0 of the field and clears bits63:32 of the field. "
So your patch should be entirely unnecessary.

 -- Keir


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