Messages in this thread | | | Date | Wed, 30 Sep 2020 10:09:59 +0200 | From | Borislav Petkov <> | Subject | Re: [PATCH v4 03/17] x86/acrn: Introduce an API to check if a VM is privileged |
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On Tue, Sep 22, 2020 at 07:42:57PM +0800, shuo.a.liu@intel.com wrote: > +static u32 acrn_cpuid_base(void) > +{ > + static u32 acrn_cpuid_base; > + > + if (!acrn_cpuid_base && boot_cpu_has(X86_FEATURE_HYPERVISOR)) > + acrn_cpuid_base = hypervisor_cpuid_base("ACRNACRNACRN", 0); > + > + return acrn_cpuid_base; > +} > + > +bool acrn_is_privileged_vm(void) > +{ > + return cpuid_eax(acrn_cpuid_base() | ACRN_CPUID_FEATURES) &
What's that dance and acrn_cpuid_base static thing needed for? Why not simply:
cpuid_eax(ACRN_CPUID_FEATURES) & ...
?
> + ACRN_FEATURE_PRIVILEGED_VM; > +} > +EXPORT_SYMBOL_GPL(acrn_is_privileged_vm);
Also, if you're going to need more of those bit checkers acrn_is_<something> which look at ACRN_CPUID_FEATURES, just stash CPUID_0x40000001_EAX locally and use a
acrn_has(ACRN_FEATURE_PRIVILEGED_VM)
which does the bit testing.
-- Regards/Gruss, Boris.
https://people.kernel.org/tglx/notes-about-netiquette
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