[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <CAKv+Gu_G+Za43fUxBWiD-C=eDWv+bEMYWgUzvDOnXMPKDdagaw@mail.gmail.com>
Date: Tue, 12 Jan 2016 14:23:27 +0100
From: Ard Biesheuvel <ard.biesheuvel@...aro.org>
To: Mark Rutland <mark.rutland@....com>
Cc: "linux-arm-kernel@...ts.infradead.org" <linux-arm-kernel@...ts.infradead.org>,
kernel-hardening@...ts.openwall.com, Will Deacon <will.deacon@....com>,
Catalin Marinas <catalin.marinas@....com>, Leif Lindholm <leif.lindholm@...aro.org>,
Kees Cook <keescook@...omium.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, Stuart Yoder <stuart.yoder@...escale.com>,
Sharma Bhupesh <bhupesh.sharma@...escale.com>, Arnd Bergmann <arnd@...db.de>,
Marc Zyngier <marc.zyngier@....com>, Christoffer Dall <christoffer.dall@...aro.org>
Subject: Re: [PATCH v3 05/21] arm64: kvm: deal with kernel symbols outside of
linear mapping
On 12 January 2016 at 13:36, Mark Rutland <mark.rutland@....com> wrote:
> On Mon, Jan 11, 2016 at 02:18:58PM +0100, Ard Biesheuvel wrote:
>> KVM on arm64 uses a fixed offset between the linear mapping at EL1 and
>> the HYP mapping at EL2. Before we can move the kernel virtual mapping
>> out of the linear mapping, we have to make sure that references to kernel
>> symbols that are accessed via the HYP mapping are translated to their
>> linear equivalent.
>>
>> To prevent inadvertent direct references from sneaking in later, change
>> the type of all extern declarations to HYP kernel symbols to the opaque
>> 'struct kvm_ksym', which does not decay to a pointer type like char arrays
>> and function references. This is not bullet proof, but at least forces the
>> user to take the address explicitly rather than referencing it directly.
>>
>> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@...aro.org>
>
> Cool feature!
>
>> diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
>> index 5e377101f919..e3865845d3e1 100644
>> --- a/arch/arm64/include/asm/kvm_asm.h
>> +++ b/arch/arm64/include/asm/kvm_asm.h
>> @@ -105,24 +105,29 @@
>> #ifndef __ASSEMBLY__
>> struct kvm;
>> struct kvm_vcpu;
>> +struct kvm_ksym;
>
> So that one doesn't have to trawl git logs, it might be worth a comment
> as to the purpose of struct kvm_ksym (and thus why we never need to
> actually define it).
>
Yes, I can add something
> Either way:
>
> Reviewed-by: Mark Rutland <mark.rutland@....com>
>
Thanks
Powered by blists - more mailing lists
Confused about mailing lists and their use?
Read about mailing lists on Wikipedia
and check out these
guidelines on proper formatting of your messages.
