lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <474234E7.4070505@goop.org>
Date:	Mon, 19 Nov 2007 17:14:15 -0800
From:	Jeremy Fitzhardinge <jeremy@...p.org>
To:	Takashi Iwai <tiwai@...e.de>
CC:	Zachary Amsden <zach@...are.com>,
	Christoph Hellwig <hch@...radead.org>,
	Tobias Powalowski <t.powa@....de>,
	linux-kernel@...r.kernel.org, Ingo Molnar <mingo@...e.hu>,
	Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [PATCH] x86/paravirt: revert exports to restore old behaviour

Takashi Iwai wrote:
> I took at this problem (as I have an nvidia card on one of my
> workstations), and found out that the following suffer from
> EXPORT_SYMBOL_GPL changes:
>   

Which kernel version are you using?  This is different in .24-rc
compared to .23.

> * local_disable_irq(), local_irq_save*(), etc.
>   

These should be OK either way.  pv_irq_ops is not _GPL.

> * MSR-related macros like rdmsr(), wrmsr(), read_cr0(), etc.
>   wbinvd(), too.
>   

These could reasonably use the the native_* versions anyway, since the
driver won't be being used in an environment where these won't work. 
Perhaps they should be split out separate from the gdt/ldt operations,
which they should have no business touching.

> * pmd_val(), pgd_val(), etc are all involved with pv_mm_ops.
>   pmd_large() and pmd_bad() is also indirectly involved.
>   __flush_tlb() and friends suffer, too.
>   

Yeah, I guess they can be expected to play with pagetables.

> The easiest workaround I found was to undefine CONFIG_PARAVIRT before
> inclusion of linux kernel headers, but it is really ugly and hacky.
>   

Yeah.  It will explode if you are running in a virtual environment which
still gives the virtual machine graphics hardware access.

> Redefinig with raw_*() and native_*() is another way, but it takes
> much more work than defining these primitive functions in assembly.
>
> So, in short, with EXPORT_SYMBOL_GPL change, it's pretty hard to write
> a non-GPL driver in a same manner...
>   

Yeah.  I think removing the difference between PARAVIRT and non-PARAVIRT
is enough to justify the exports.  If we want to make the policy
decision that modules can't use pagetable or msr operations at all, then
that's a separate decision which can be applied uniformly to PARAVIRT
and non-PARAVIRT.

    J
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ