Linux-RISC-V Archive on lore.kernel.org
 help / color / Atom feed
From: Mike Rapoport <rppt@kernel.org>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Peter Zijlstra <peterz@infradead.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Linux-MM <linux-mm@kvack.org>, "H. Peter Anvin" <hpa@zytor.com>,
	Christopher Lameter <cl@linux.com>,
	Idan Yaniv <idan.yaniv@ibm.com>,
	Dan Williams <dan.j.williams@intel.com>,
	Elena Reshetova <elena.reshetova@intel.com>,
	linux-arch <linux-arch@vger.kernel.org>,
	Tycho Andersen <tycho@tycho.ws>,
	linux-nvdimm@lists.01.org, Will Deacon <will@kernel.org>,
	the arch/x86 maintainers <x86@kernel.org>,
	Matthew Wilcox <willy@infradead.org>,
	Mike Rapoport <rppt@linux.ibm.com>,
	Ingo Molnar <mingo@redhat.com>,
	James Bottomley <jejb@linux.ibm.com>,
	linaro-mm-sig@lists.linaro.org, Borislav Petkov <bp@alien8.de>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	Andy Lutomirski <luto@kernel.org>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	"Kirill A. Shutemov" <kirill@shutemov.name>,
	Thomas Gleixner <tglx@linutronix.de>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>,
	Linux API <linux-api@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	linux-riscv <linux-riscv@lists.infradead.org>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Linux FS-devel Mailing List <linux-fsdevel@vger.kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Sumit Semwal <sumit.semwal@linaro.org>
Subject: Re: [PATCH 3/6] mm: introduce secretmemfd system call to create "secret" memory areas
Date: Mon, 20 Jul 2020 17:20:53 +0300
Message-ID: <20200720142053.GC8593@kernel.org> (raw)
In-Reply-To: <CAK8P3a0NyvRMqH7X0YNO5E6DGtvZXD5ZcD6Y6n7AkocufkMnHA@mail.gmail.com>

On Mon, Jul 20, 2020 at 01:30:13PM +0200, Arnd Bergmann wrote:
> On Mon, Jul 20, 2020 at 11:25 AM Mike Rapoport <rppt@kernel.org> wrote:
> >
> > From: Mike Rapoport <rppt@linux.ibm.com>
> >
> > Introduce "secretmemfd" system call with the ability to create memory areas
> > visible only in the context of the owning process and not mapped not only
> > to other processes but in the kernel page tables as well.
> >
> > The user will create a file descriptor using the secretmemfd system call
> > where flags supplied as a parameter to this system call will define the
> > desired protection mode for the memory associated with that file
> > descriptor. Currently there are two protection modes:
> >
> > * exclusive - the memory area is unmapped from the kernel direct map and it
> >               is present only in the page tables of the owning mm.
> > * uncached  - the memory area is present only in the page tables of the
> >               owning mm and it is mapped there as uncached.
> >
> > For instance, the following example will create an uncached mapping (error
> > handling is omitted):
> >
> >         fd = secretmemfd(SECRETMEM_UNCACHED);
> >         ftruncate(fd, MAP_SIZE);
> >         ptr = mmap(NULL, MAP_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED,
> >                    fd, 0);
> >
> > Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
> 
> I wonder if this should be more closely related to dmabuf file
> descriptors, which
> are already used for a similar purpose: sharing access to secret memory areas
> that are not visible to the OS but can be shared with hardware through device
> drivers that can import a dmabuf file descriptor.

TBH, I didn't think about dmabuf, but my undestanding is that is this
case memory areas are not visible to the OS because they are on device
memory rather than normal RAM and when dmabuf is backed by the normal
RAM, the memory is visible to the OS.

Did I miss anything?


>       Arnd

-- 
Sincerely yours,
Mike.

_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

  reply index

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-20  9:24 [PATCH 0/6] " Mike Rapoport
2020-07-20  9:24 ` [PATCH 1/6] mm: add definition of PMD_PAGE_ORDER Mike Rapoport
2020-07-20  9:24 ` [PATCH 2/6] mmap: make mlock_future_check() global Mike Rapoport
2020-07-20  9:24 ` [PATCH 3/6] mm: introduce secretmemfd system call to create "secret" memory areas Mike Rapoport
2020-07-20 11:30   ` Arnd Bergmann
2020-07-20 14:20     ` Mike Rapoport [this message]
2020-07-20 14:34       ` Arnd Bergmann
2020-07-20 17:46         ` Mike Rapoport
2020-07-20 15:51     ` James Bottomley
2020-07-20 18:08       ` Arnd Bergmann
2020-07-20 19:16         ` James Bottomley
2020-07-20 20:05           ` Arnd Bergmann
2020-07-21 10:59   ` Michael Kerrisk (man-pages)
2020-07-20  9:24 ` [PATCH 4/6] arch, mm: wire up secretmemfd system call were relevant Mike Rapoport
2020-07-26 17:44   ` Palmer Dabbelt
2020-07-20  9:24 ` [PATCH 5/6] mm: secretmem: use PMD-size pages to amortize direct map fragmentation Mike Rapoport
2020-07-20  9:24 ` [PATCH 6/6] mm: secretmem: add ability to reserve memory at boot Mike Rapoport

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200720142053.GC8593@kernel.org \
    --to=rppt@kernel.org \
    --cc=akpm@linux-foundation.org \
    --cc=arnd@arndb.de \
    --cc=bp@alien8.de \
    --cc=catalin.marinas@arm.com \
    --cc=cl@linux.com \
    --cc=dan.j.williams@intel.com \
    --cc=dave.hansen@linux.intel.com \
    --cc=elena.reshetova@intel.com \
    --cc=hpa@zytor.com \
    --cc=idan.yaniv@ibm.com \
    --cc=jejb@linux.ibm.com \
    --cc=kirill@shutemov.name \
    --cc=linaro-mm-sig@lists.linaro.org \
    --cc=linux-api@vger.kernel.org \
    --cc=linux-arch@vger.kernel.org \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=linux-nvdimm@lists.01.org \
    --cc=linux-riscv@lists.infradead.org \
    --cc=luto@kernel.org \
    --cc=mingo@redhat.com \
    --cc=palmer@dabbelt.com \
    --cc=paul.walmsley@sifive.com \
    --cc=peterz@infradead.org \
    --cc=rppt@linux.ibm.com \
    --cc=sumit.semwal@linaro.org \
    --cc=tglx@linutronix.de \
    --cc=tycho@tycho.ws \
    --cc=viro@zeniv.linux.org.uk \
    --cc=will@kernel.org \
    --cc=willy@infradead.org \
    --cc=x86@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-RISC-V Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-riscv/0 linux-riscv/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-riscv linux-riscv/ https://lore.kernel.org/linux-riscv \
		linux-riscv@lists.infradead.org
	public-inbox-index linux-riscv

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.infradead.lists.linux-riscv


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git