From: Pavel Machek <pavel@ucw.cz>
To: Thomas Garnier <thgarnie@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "H . Peter Anvin" <hpa@zytor.com>,
Jonathan Corbet <corbet@lwn.net>,
Andrey Ryabinin <aryabinin@virtuozzo.com>,
Alexander Potapenko <glider@google.com>,
Dmitry Vyukov <dvyukov@google.com>,
Lorenzo Stoakes <lstoakes@gmail.com>,
Kees Cook <keescook@chromium.org>,
Juergen Gross <jgross@suse.com>,
Andy Lutomirski <luto@kernel.org>,
Paul Gortmaker <paul.gortmaker@windriver.com>,
Andrew Morton <akpm@linux-foundation.org>,
Michal Hocko <mhocko@suse.com>, zijun_hu <zijun_hu@htc.com>,
Chris Wilson <chris@chris-wilson.co.uk>,
Andy Lutomirski <luto@amacapital.net>,
"Rafael J . Wysocki" <rjw@rjwysocki.net>,
Len Brown <len.brown@intel.com>, Jiri Kosina <jikos@kernel.org>,
Matt Fleming <matt@codeblueprint.co.uk>,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Rusty
Subject: Re: [PATCH v7 3/3] x86: Make the GDT remapping read-only on 64-bit
Date: Tue, 14 Mar 2017 22:04:24 +0100 [thread overview]
Message-ID: <20170314210424.GA5023@amd> (raw)
In-Reply-To: <20170314170508.100882-3-thgarnie@google.com>
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On Tue 2017-03-14 10:05:08, Thomas Garnier wrote:
> This patch makes the GDT remapped pages read-only to prevent corruption.
> This change is done only on 64-bit.
>
> The native_load_tr_desc function was adapted to correctly handle a
> read-only GDT. The LTR instruction always writes to the GDT TSS entry.
> This generates a page fault if the GDT is read-only. This change checks
> if the current GDT is a remap and swap GDTs as needed. This function was
> tested by booting multiple machines and checking hibernation works
> properly.
>
> KVM SVM and VMX were adapted to use the writeable GDT. On VMX, the
> per-cpu variable was removed for functions to fetch the original GDT.
> Instead of reloading the previous GDT, VMX will reload the fixmap GDT as
> expected. For testing, VMs were started and restored on multiple
> configurations.
>
> Signed-off-by: Thomas Garnier <thgarnie@google.com>
Can we get the same change for 32-bit, too? Growing differences
between 32 and 64 bit are a bit of a problem...
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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next prev parent reply other threads:[~2017-03-14 21:04 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-14 17:05 [PATCH v7 1/3] x86/mm: Adapt MODULES_END based on Fixmap section size Thomas Garnier
2017-03-14 17:05 ` [PATCH v7 2/3] x86: Remap GDT tables in the Fixmap section Thomas Garnier
2017-03-14 17:05 ` [PATCH v7 3/3] x86: Make the GDT remapping read-only on 64-bit Thomas Garnier
2017-03-14 21:04 ` Pavel Machek [this message]
2017-03-14 21:20 ` Thomas Garnier
2017-03-15 13:52 ` [PATCH v7 1/3] x86/mm: Adapt MODULES_END based on Fixmap section size Boris Ostrovsky
2017-03-16 8:10 ` Ingo Molnar
2017-03-16 15:33 ` Thomas Garnier
2017-03-17 7:34 ` Ingo Molnar
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