From: Dave Hansen <dave.hansen@intel.com>
To: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>,
linux-kernel@vger.kernel.org, x86@kernel.org
Cc: tglx@linutronix.de, mingo@redhat.com, bp@alien8.de,
hpa@zytor.com, jon.grimm@amd.com,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Thomas Lendacky <Thomas.Lendacky@amd.com>
Subject: AMD / Memory Protection Keys
Date: Wed, 29 Apr 2020 12:18:06 -0700 [thread overview]
Message-ID: <178377ad-efd6-d473-e10d-2928c171437e@intel.com> (raw)
In-Reply-To: <4b20cff5-6e16-3599-4fc1-4f51d7c18d1d@intel.com>
The docs for AMD's implementation of protection keys showed up[1].
Welcome to the party!
It all looks fine, except for this nugget:
The MPK mechanism is ignored in the following cases:
... for pages marked in the paging structures as read-only
(R/W=0) or as supervisor addresses (U/S=0)
That R/W=0 would mean that you can't access-disable read-only pages,
which seems a bit goofy. It's certainly a feature that I could imagine
folks wanting to have. Read-only pages might happen in unexpected
places for things like mmap(PROT_WRITE)'d files or even CoW pages after
fork().
Is this an error in the docs?
1. https://www.amd.com/system/files/TechDocs/24593.pdf
next prev parent reply other threads:[~2020-04-29 19:18 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-03 9:01 [PATCH] x86/fpu: Warn only when CPU-provided sizes less than struct declaration Suravee Suthikulpanit
2019-12-03 10:34 ` Sebastian Andrzej Siewior
2019-12-06 8:14 ` Suravee Suthikulpanit
2019-12-03 17:27 ` Dave Hansen
2019-12-06 8:14 ` Suravee Suthikulpanit
2019-12-06 15:28 ` Dave Hansen
2019-12-11 5:24 ` Suravee Suthikulpanit
2019-12-11 14:13 ` Dave Hansen
2019-12-12 6:52 ` Suravee Suthikulpanit
2020-01-13 9:54 ` Suravee Suthikulpanit
2020-01-15 16:54 ` Dave Hansen
2020-04-29 19:18 ` Dave Hansen [this message]
2020-05-01 23:50 ` AMD / Memory Protection Keys Suravee Suthikulpanit
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