Messages in this thread | | | Date | Mon, 19 Nov 2007 17:14:15 -0800 | From | Jeremy Fitzhardinge <> | Subject | Re: [PATCH] x86/paravirt: revert exports to restore old behaviour |
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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.
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