Re: [PATCH v10 0/9] mm: introduce memfd_secret system call to create "secret" memory areas

Mike Rapoport
2020-11-24T09:29:42Z

On Mon, Nov 23, 2020 at 07:28:22AM -0800, Andy Lutomirski wrote:
> On Mon, Nov 23, 2020 at 1:54 AM Mike Rapoport <rppt@kernel.org> wrote:
> >
> > From: Mike Rapoport <rppt@linux.ibm.com>
> >
> > Hi,
> >
> > This is an implementation of "secret" mappings backed by a file descriptor.
> >
> > The file descriptor backing secret memory mappings is created using a
> > dedicated memfd_secret system call The desired protection mode for the
> > memory is configured using flags parameter of the system call. The mmap()
> > of the file descriptor created with memfd_secret() will create a "secret"
> > memory mapping. The pages in that mapping will be marked as not present in
> > the direct map and will have desired protection bits set in the user page
> > table. For instance, current implementation allows uncached mappings.
>
> I'm still not ready to ACK uncached mappings on x86. I'm fine with
> the concept of allowing privileged users to create UC memory on x86
> for testing and experimentation, but it's a big can of worms in
> general.

Ok, let's move forward without UC.

--
Sincerely yours,
Mike.