Messages in this thread | | | Subject | Re: [PATCH 17/21] x86/fpu: Use proper mask to replace full instruction mask | From | "Liang, Kan" <> | Date | Mon, 22 Jun 2020 10:52:24 -0400 |
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On 6/19/2020 3:31 PM, Peter Zijlstra wrote: > On Fri, Jun 19, 2020 at 07:04:05AM -0700, kan.liang@linux.intel.com wrote: > >> KVM includes the header file fpu/internal.h. To avoid 'undefined >> xfeatures_mask_all' compiling issue, xfeatures_mask_all has to be >> exported. > >> diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c >> index 587e03f..eb2e44e 100644 >> --- a/arch/x86/kernel/fpu/xstate.c >> +++ b/arch/x86/kernel/fpu/xstate.c >> @@ -58,6 +58,7 @@ static short xsave_cpuid_features[] __initdata = { >> * XSAVE buffer, both supervisor and user xstates. >> */ >> u64 xfeatures_mask_all __read_mostly; >> +EXPORT_SYMBOL_GPL(xfeatures_mask_all); > > *groan*... > > AFAICT KVM doesn't actually use any of those functions,
It seems KVM may eventually invoke copy_xregs_to_kernel() as below.
kvm_save_current_fpu() copy_fpregs_to_fpstate() copy_xregs_to_kernel()
I think we have to export the xfeatures_mask_all.
Thanks, Kan
> can't we have > something like BUILD_KVM (like BUILD_VDSO) and exclude those functions > from the KVM build? > > I so detest exporting random crap because kvm.. >
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