Re: [RFC PATCH 16/27] KVM: arm64: Prepare Hyp memory protection

From: Will Deacon
Date: Tue Dec 08 2020 - 04:41:15 EST


On Mon, Dec 07, 2020 at 02:11:20PM +0000, Quentin Perret wrote:
> On Monday 07 Dec 2020 at 13:40:52 (+0000), Will Deacon wrote:
> > Why not use the RESERVEDMEM_OF_DECLARE() interface for the hypervisor
> > memory? That way, the hypervisor memory can either be statically partitioned
> > as a carveout or allocated dynamically for us -- we wouldn't need to care.
>
> Yup, I did consider that, but the actual amount of memory we need to
> reserve for the hypervisor depends on things such as the size of struct
> hyp_page, which depends on the kernel you're running (that is, it might
> change over time). So, that really felt like something the kernel should
> be doing, to keep the DT backward compatible, ... Or did you have
> something more elaborate in mind?

No, that's fair. Just wanted to make sure we had a good reason not to use
the existing memory reservation code.

Will