Re: [RFC PATCH v4 00/12] hardening: statically allocated protected memory

[Kees Cook]

On Mon, Feb 11, 2019 at 11:09 PM Igor Stoppa <igor.stoppa@xxxxxxxxx> wrote:
> wr_assign() does just that.
>
> However, reading again your previous mails, I realize that I might have
> misinterpreted what you were suggesting.
>
> If the advice is to have also a default memset_user() which relies on
> put_user(), but do not activate the feature by default for every
> architecture, I definitely agree that it would be good to have it.
> I just didn't think about it before.

Yeah, I just mean you could have an arch-agnostic memset_user() implementation.

> But I now realize that most likely you were just suggesting to have
> full, albeit inefficient default support and then let various archs
> review/enhance it. I can certainly do this.

Right.

> Regarding testing I have a question: how much can/should I lean on qemu?
> In most cases the MMU might not need to be fully emulated, so I wonder
> how well qemu-based testing can ensure that real life scenarios will work.

I think qemu lets you know if it works (kvm is using the real MMU),
and baremetal will give you more stable performance numbers.

-- 
Kees Cook