Re: [PATCH v5 06/10] KVM: xen: allow shared_info to be mapped by fixed HVA

[Paul Durrant]

On 23/09/2023 08:07, David Woodhouse wrote:
> On Fri, 2023-09-22 at 15:00 +0000, Paul Durrant wrote:
> > From: Paul Durrant <pdurrant@xxxxxxxxxx>
> >
> > The shared_info page is not guest memory as such. It is a dedicated page
> > allocated by the VMM and overlaid onto guest memory in a GFN chosen by the
> > guest. The guest may even request that shared_info be moved from one GFN
> > to another, but the HVA is never going to change. Thus it makes much more
> > sense to map the shared_info page in kernel once using this fixed HVA.
>
> The words "makes much more sense" are doing a *lot* of work there. :)
>
> When heckling the cover letter in
> https://lore.kernel.org/kvm/d13e459e221f28fb1865eedea023e583a2277ab1.camel@xxxxxxxxxxxxx/
> I suggested that the explanation probably wants to make it into a
> commit message rather than just the cover letter which tends not to be
> preserved in the commit history. It's *this* commit which needs it, I
> think.

Ok, I'll try to come up with some concise wording.

  Paul