Re: [PATCH v2 06/30] s390/airq: allow for airq structure that uses an input vector

[Matthew Rosato]

On 1/17/22 7:29 AM, Claudio Imbrenda wrote:
> On Fri, 14 Jan 2022 15:31:21 -0500
> Matthew Rosato <mjrosato@xxxxxxxxxxxxx> wrote:
>
> > When doing device passthrough where interrupts are being forwarded
> > from host to guest, we wish to use a pinned section of guest memory
> > as the vector (the same memory used by the guest as the vector).
>
> maybe expand the description of the patch to explain what exactly is
> being done in this patch. Namely: you add a parameter to a function
> (and some logic in the function to use the new parameter), but the
> function is not being used yet. And pinning is also done somewhere else.
>
> maybe you can add something like
>
> 	This patch adds a new parameter for airq_iv_create to pass the
> 	existing vector pinned in guest memory and to use it when
> 	needed instead of allocating a new one.
>
> Apart from that, the patch looks good.

Thanks, will re-work to:

When doing device passthrough where interrupts are being forwarded from 
host to guest, we wish to use a pinned section of guest memory as the 
vector (the same memory used by the guest as the vector).
To accomplish this, add a new parameter for airq_iv_create which allows 
passing an existing vector to be used instead of allocating a new one. 
The caller is responsible for ensuring the vector is pinned in memory as 
well as for unpinning the memory when the vector is no longer needed.
A subsequent patch will use this new parameter for zPCI interpretation.