From: Dan Williams <dan.j.williams@intel.com>
To: Davidlohr Bueso <dave@stgolabs.net>, <dan.j.williams@intel.com>
Cc: <x86@kernel.org>, <nvdimm@lists.linux.dev>,
<linux-cxl@vger.kernel.org>, <peterz@infradead.org>,
<bp@alien8.de>, <akpm@linux-foundation.org>,
<dave.jiang@intel.com>, <Jonathan.Cameron@huawei.com>,
<vishal.l.verma@intel.com>, <ira.weiny@intel.com>,
<a.manzanares@samsung.com>, <linux-kernel@vger.kernel.org>,
<dave@stgolabs.net>, <hch@lst.de>
Subject: RE: [PATCH -next] memregion: Add arch_flush_memregion() interface
Date: Mon, 29 Aug 2022 16:02:22 -0700 [thread overview]
Message-ID: <630d457ee7739_259e5b29444@dwillia2-xfh.jf.intel.com.notmuch> (raw)
In-Reply-To: <20220829212918.4039240-1-dave@stgolabs.net>
[ add Christoph ]
Davidlohr Bueso wrote:
> With CXL security features, global CPU cache flushing nvdimm requirements
> are no longer specific to that subsystem, even beyond the scope of
> security_ops. CXL will need such semantics for features not necessarily
> limited to persistent memory.
>
> The functionality this is enabling is to be able to instantaneously
> secure erase potentially terabytes of memory at once and the kernel
> needs to be sure that none of the data from before the secure is still
> present in the cache. It is also used when unlocking a memory device
> where speculative reads and firmware accesses could have cached poison
> from before the device was unlocked.
>
> This capability is typically only used once per-boot (for unlock), or
> once per bare metal provisioning event (secure erase), like when handing
> off the system to another tenant or decommissioning a device.
>
> Users must first call arch_has_flush_memregion() to know whether this
> functionality is available on the architecture. Only enable it on x86-64
> via the wbinvd() hammer.
>
> Signed-off-by: Davidlohr Bueso <dave@stgolabs.net>
> ---
>
> Changes from v2 (https://lore.kernel.org/all/20220819171024.1766857-1-dave@stgolabs.net/):
> - Redid to use memregion based interfaces + VMM check on x86 (Dan)
> - Restricted the flushing to x86-64.
>
> Note: Since we still are dealing with a physical "range" at this level,
> added the spa range for nfit even though this is unused.
Looks reasonable to me.
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
next prev parent reply other threads:[~2022-08-29 23:02 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-29 21:29 [PATCH -next] memregion: Add arch_flush_memregion() interface Davidlohr Bueso
2022-08-29 23:02 ` Dan Williams [this message]
2022-09-07 14:36 ` Davidlohr Bueso
2022-09-07 16:46 ` Dan Williams
2022-09-07 16:05 ` Borislav Petkov
2022-09-07 16:22 ` Davidlohr Bueso
2022-09-07 16:52 ` Dan Williams
2022-09-07 17:24 ` Davidlohr Bueso
2022-09-08 4:35 ` Borislav Petkov
2022-09-08 6:53 ` Dan Williams
2022-09-08 13:00 ` Jonathan Cameron
2022-09-08 4:31 ` Borislav Petkov
2022-09-07 22:30 ` Andrew Morton
2022-09-08 1:07 ` Dan Williams
2022-09-08 13:13 ` Jonathan Cameron
2022-09-08 22:51 ` Dan Williams
2022-09-08 23:00 ` Andrew Morton
2022-09-08 23:22 ` Dan Williams
2022-09-09 11:43 ` Jonathan Cameron
2022-09-13 15:56 ` Davidlohr Bueso
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