From: Arnd Bergmann <arnd@arndb.de>
To: Mike Rapoport <rppt@kernel.org>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Andrew Morton <akpm@linux-foundation.org>,
Andy Lutomirski <luto@kernel.org>, Borislav Petkov <bp@alien8.de>,
Catalin Marinas <catalin.marinas@arm.com>,
Christopher Lameter <cl@linux.com>,
Dan Williams <dan.j.williams@intel.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Elena Reshetova <elena.reshetova@intel.com>,
"H. Peter Anvin" <hpa@zytor.com>, Idan Yaniv <idan.yaniv@ibm.com>,
Ingo Molnar <mingo@redhat.com>,
James Bottomley <jejb@linux.ibm.com>,
"Kirill A. Shutemov" <kirill@shutemov.name>,
Matthew Wilcox <willy@infradead.org>,
Mike Rapoport <rppt@linux.ibm.com>,
Palmer Dabbelt <palmer@dabbelt.com>,
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Linux ARM <linux-arm-kernel@lists.infradead.org>,
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"the arch/x86 maintainers" <x86@kernel.org>,
linaro-mm-sig@lists.linaro.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 13:30:13 +0200 [thread overview]
Message-ID: <CAK8P3a0NyvRMqH7X0YNO5E6DGtvZXD5ZcD6Y6n7AkocufkMnHA@mail.gmail.com> (raw)
In-Reply-To: <20200720092435.17469-4-rppt@kernel.org>
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.
Arnd
next prev parent reply other threads:[~2020-07-20 11:30 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-20 9:24 [PATCH 0/6] mm: introduce secretmemfd system call to create "secret" memory areas 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 [this message]
2020-07-20 14:20 ` Mike Rapoport
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
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