Messages in this thread | | | Date | Mon, 12 Oct 2020 16:40:36 +0800 | From | Shuo A Liu <> | Subject | Re: [PATCH v4 03/17] x86/acrn: Introduce an API to check if a VM is privileged |
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Hi Boris,
On Wed 30.Sep'20 at 10:09:59 +0200, Borislav Petkov wrote: >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) & ... > >?
hypervisor_cpuid_base() searches reserved hypervisor cpuid region and return the base matched the right signature, the base might vary. So i put it here.
> >> + 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.
Thanks. Currently, there is only one feature bit. I will introduce that you suggested with more feature bits to be tested.
Thanks shuo
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