Re: [Xen-devel] [PATCH v11 0/3] xen: better grant v2 support

[Juergen Gross <jgross@xxxxxxxx>]

On 28/09/17 21:02, Andrew Cooper wrote:
> On 28/09/17 11:02, Juergen Gross wrote:
>> Currently Linux has no support for grant v2 as this would reduce the
>> maximum number of active grants by a factor of 2 compared to v1,
>> because the number of possible grants are limited by the allowed number
>> of grant frames and grant entries of v2 need twice as much bytes as
>> those of v1.
>>
>> Unfortunately grant v2 is the only way to support either guests with
>> more than 16TB memory size or PV guests with memory above the 16TB
>> border, as grant v1 limits the frame number to be 32 bits wide.
>>
>> In order to remove the disadvantage of grant v2 this patch series
>> adds support for setting per-domain values regarding grant limits.
>> Additionally the default limit of grant frames is doubled in case
>> of hosts with potential memory above the 16TB border.
>>
>> Changes in V11:
>> - dropped patches 1-8, as already committed
>> - patch 1: add comment in include/asm-arm/grant_table.h (Julien Grall)
>> - patch 2: return max. subleaf number in EAX (Andrew Cooper)
>> - patch 2: use flsl() instead of generic_flsl() (Jan Beulich)
> 
> Jan: You appear to have committed v10 of this series, which amongst
> other things, is missing the max subleaf assignment.

While not stating it explicitly, the subleaf stuff is okay: res->a
isn't touched, so it will be 0. The address width is put into res->b.

> Juergen: Would you mind rebasing v11 over staging, just to see what else
> got missed?

As this was the only modification in v11 regarding the applied patches
we are fine.


Juergen

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