tree 30c3f1622c525036e1cefc8ade5853c0be700cb4
parent b1e495b2fae578b1bd3ab1906cb15aac43f96fee
author Annie Li <annie.li@oracle.com> 1321927161 +0800
committer Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 1321971891 -0500

xen/granttable: Grant tables V2 implementation

Receiver-side copying of packets is based on this implementation, it gives
better performance and better CPU accounting. It totally supports three types:
full-page, sub-page and transitive grants.

However this patch does not cover sub-page and transitive grants, it mainly
focus on Full-page part and implements grant table V2 interfaces corresponding
to what already exists in grant table V1, such as: grant table V2
initialization, mapping, releasing and exported interfaces.

Each guest can only supports one type of grant table type, every entry in grant
table should be the same version. It is necessary to set V1 or V2 version before
initializing the grant table.

Grant table exported interfaces of V2 are same with those of V1, Xen is
responsible to judge what grant table version guests are using in every grant
operation.

V2 fulfills the same role of V1, and it is totally backwards compitable with V1.
If dom0 support grant table V2, the guests runing on it can run with either V1
or V2.

Acked-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Annie Li <annie.li@oracle.com>
[v1: Modified alloc_vm_area call (new parameters), indentation, and cleanpatch
     warnings]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>