Re: [PATCH v4 10/10] x86/xsaves: Re-enable XSAVES

From: Yu-cheng Yu
Date: Mon May 02 2016 - 12:15:55 EST


On Fri, Apr 29, 2016 at 05:40:44PM -0700, Dave Hansen wrote:
> That's better than what we had before, but it relies entirely on testing
> coverage and runtime checks.
>
> Is it too much to ask that you also take a look and audit all the places
> the XSAVE buffer is accessed in the kernel and ensure that they either
> have code to handle standard vs. compacted/supervisor or don't care for
> some reason?
>
> I did such an audit once upon a time, but I think it would be a good
> exercise to repeat both by a second set of eyes and because some time
> has passed.

I think there are 12 files that can be directly impacted by XSAVES.

arch/x86/include/asm/fpu/internal.h
arch/x86/include/asm/fpu/types.h
arch/x86/include/asm/fpu/xstate.h
arch/x86/include/uapi/asm/sigcontext.h
arch/x86/kernel/traps.c
arch/x86/kernel/fpu/core.c
arch/x86/kernel/fpu/init.c
arch/x86/kernel/fpu/regset.c
arch/x86/kernel/fpu/signal.c
arch/x86/kernel/fpu/xstate.c
arch/x86/kvm/x86.c
arch/x86/mm/mpx.c

They have been reviewed from the perspective of the compacted format.
Please let me know anything else.