From: Peter Zijlstra <peterz@infradead.org>
To: Nadav Amit <nadav.amit@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
LKML <linux-kernel@vger.kernel.org>,
hch@infradead.org,
Sean Christopherson <sean.j.christopherson@intel.com>,
mingo <mingo@redhat.com>, bp <bp@alien8.de>,
hpa@zytor.com, x86 <x86@kernel.org>,
"Kenneth R. Crudup" <kenny@panix.com>,
Jessica Yu <jeyu@kernel.org>,
Rasmus Villemoes <rasmus.villemoes@prevas.dk>,
Paolo Bonzini <pbonzini@redhat.com>,
Fenghua Yu <fenghua.yu@intel.com>,
Xiaoyao Li <xiaoyao.li@intel.com>,
Thomas Hellstrom <thellstrom@vmware.com>,
Tony Luck <tony.luck@intel.com>,
Steven Rostedt <rostedt@goodmis.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
jannh@google.com, keescook@chromium.org, David.Laight@aculab.com,
Doug Covelli <dcovelli@vmware.com>,
mhiramat@kernel.org
Subject: Re: [PATCH 4/4] x86,module: Detect CRn and DRn manipulation
Date: Tue, 7 Apr 2020 22:50:42 +0200 [thread overview]
Message-ID: <20200407205042.GT2452@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <90B32DAE-0BB5-4455-8F73-C43037695E7C@gmail.com>
On Tue, Apr 07, 2020 at 01:27:45PM -0700, Nadav Amit wrote:
> > On Apr 7, 2020, at 12:38 PM, Peter Zijlstra <peterz@infradead.org> wrote:
> >
> > On Tue, Apr 07, 2020 at 11:55:21AM -0700, Nadav Amit wrote:
> >>> On Apr 7, 2020, at 4:02 AM, Peter Zijlstra <peterz@infradead.org> wrote:
> >>>
> >>> Since we now have infrastructure to analyze module text, disallow
> >>> modules that write to CRn and DRn registers.
> >>
> >> Assuming the kernel is built without CONFIG_PARAVIRT, what is the right way
> >> for out-of-tree modules to write to CRs? Let’s say CR2?
> >
> > Most of them there is no real justification for ever writing to. CR2 I
> > suppose we can have an exception for given a sane rationale for why
> > you'd need to rewrite the fault address.
>
> For the same reason that KVM writes to CR2 - to restore CR2 before entering
> a guest, since CR2 not architecturally loaded from the VMCS. I suspect there
> are additional use-cases which are not covered by the kernel interfaces.
So I'm not much of a virt guy (clearly), and *groan*, that's horrible.
I'll go make an exception for CR2.
next prev parent reply other threads:[~2020-04-07 20:51 UTC|newest]
Thread overview: 74+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-07 11:02 [PATCH 0/4] x86/module: Out-of-tree module decode and sanitize Peter Zijlstra
2020-04-07 11:02 ` [PATCH 1/4] module: Expose load_info to arch module loader code Peter Zijlstra
2020-04-07 16:52 ` Kees Cook
2020-04-07 11:02 ` [PATCH 2/4] module: Convert module_finalize() to load_info Peter Zijlstra
2020-04-07 16:53 ` Kees Cook
2020-04-07 11:02 ` [PATCH 3/4] x86,module: Detect VMX vs SLD conflicts Peter Zijlstra
2020-04-07 14:35 ` Greg KH
2020-04-07 14:44 ` Paolo Bonzini
2020-04-07 14:55 ` Greg KH
2020-04-07 14:49 ` Steven Rostedt
2020-04-07 15:24 ` Peter Zijlstra
2020-04-07 15:28 ` Paolo Bonzini
2020-04-07 15:44 ` Greg KH
2020-04-07 16:51 ` Masami Hiramatsu
2020-04-07 17:16 ` Andrew Cooper
2020-04-07 23:59 ` Masami Hiramatsu
2020-04-08 7:25 ` Masami Hiramatsu
2020-04-07 18:26 ` kbuild test robot
2020-04-07 21:25 ` David Laight
2020-04-07 23:15 ` Kees Cook
2020-04-08 2:10 ` Xiaoyao Li
2020-04-08 8:09 ` Masami Hiramatsu
2020-04-08 9:56 ` Peter Zijlstra
2020-04-08 10:15 ` Andrew Cooper
2020-04-10 11:25 ` Masami Hiramatsu
2020-04-07 11:02 ` [PATCH 4/4] x86,module: Detect CRn and DRn manipulation Peter Zijlstra
2020-04-07 17:01 ` Kees Cook
2020-04-07 18:13 ` Peter Zijlstra
2020-04-07 18:49 ` Kees Cook
2020-04-07 18:55 ` Nadav Amit
2020-04-07 19:38 ` Peter Zijlstra
2020-04-07 20:27 ` Nadav Amit
2020-04-07 20:50 ` Peter Zijlstra [this message]
2020-04-07 21:22 ` Nadav Amit
2020-04-07 21:27 ` Peter Zijlstra
2020-04-07 22:12 ` Paolo Bonzini
2020-04-07 23:51 ` Nadav Amit
2020-04-08 8:45 ` Peter Zijlstra
2020-04-08 5:18 ` Christoph Hellwig
2020-04-07 23:15 ` Andrew Cooper
2020-04-08 0:22 ` Paolo Bonzini
2020-04-08 8:37 ` Peter Zijlstra
2020-04-08 9:52 ` Andrew Cooper
2020-04-07 21:48 ` Steven Rostedt
2020-04-08 5:58 ` Jan Kiszka
2020-04-08 8:03 ` Paolo Bonzini
2020-04-08 8:58 ` Jan Kiszka
2020-04-08 9:04 ` Paolo Bonzini
2020-04-08 10:45 ` Jan Kiszka
2020-04-08 8:51 ` Peter Zijlstra
2020-04-08 8:59 ` Jan Kiszka
2020-04-08 9:25 ` David Laight
2020-04-08 11:13 ` Jan Kiszka
2020-04-08 11:17 ` David Laight
2020-04-08 9:13 ` Peter Zijlstra
2020-04-08 10:50 ` Jan Kiszka
2020-04-08 13:27 ` Steven Rostedt
2020-04-08 15:44 ` Peter Zijlstra
2020-04-08 15:46 ` Christoph Hellwig
2020-04-08 16:02 ` Sean Christopherson
2020-04-08 16:15 ` Paolo Bonzini
2020-04-09 8:56 ` Peter Zijlstra
2020-04-09 10:13 ` Nadav Amit
2020-04-09 21:13 ` Thomas Gleixner
2020-04-09 22:18 ` Steven Rostedt
2020-04-10 5:37 ` Nadav Amit
2020-04-08 15:54 ` Jessica Yu
2020-04-07 17:23 ` [PATCH 0/4] x86/module: Out-of-tree module decode and sanitize Andrew Cooper
2020-04-07 19:41 ` Peter Zijlstra
2020-04-07 20:11 ` Andrew Cooper
2020-04-07 20:45 ` Peter Zijlstra
2020-04-07 21:21 ` Andrew Cooper
2020-04-07 20:21 ` Andrew Cooper
2020-04-07 20:48 ` Peter Zijlstra
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