From: Dan Williams <dan.j.williams@intel.com>
To: Taeho Hwang <taeho1224@gmail.com>
Cc: linux-nvdimm <linux-nvdimm@lists.01.org>
Subject: Re: [PATCH] pmem: emulating usable memory as persistent memory
Date: Wed, 25 Sep 2019 20:58:09 -0700 [thread overview]
Message-ID: <CAPcyv4ia511-iZDu7czMvOViKyxNDKGbYBT3cL90R+X-dDLVsA@mail.gmail.com> (raw)
In-Reply-To: <1569468653-3489-1-git-send-email-taeho1224@gmail.com>
On Wed, Sep 25, 2019 at 8:31 PM Taeho Hwang <taeho1224@gmail.com> wrote:
>
> This patch checks whether the specified memory (memmap) is
> userable or not. This patch prevents non-existing memory
> from being emulated as persistent memory.
> If non-existing memory is specified by memmap without
> this patch, struct nd_namespace_io and struct pmem_device
> will have invalid values.
The whole point of the memmap= option is that the person specifying it
knows more about the memory map than either the kernel or the platform
BIOS. Validating the memmap= parameter against the very same memory
map that is trying to be overridden violates that assumption. So
memmap= is a dangerous interface on purpose. Now, if you want to
define a new option that requires the base type to be E820_RAM that
might be defensible, but at this point given the age of the
memmap=ss!nn option and the wikis available to picking a valid value,
I'd advocate leaving it as is.
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prev parent reply other threads:[~2019-09-26 3:58 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-26 3:30 [PATCH] pmem: emulating usable memory as persistent memory Taeho Hwang
2019-09-26 3:58 ` Dan Williams [this message]
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