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charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 4/22/2025 4:12 AM, Jürgen Groß wrote: >> + >> +static __always_inline bool __rdmsrq(u32 msr, u64 *val, int type) >> +{ >> +    bool ret; >> + >> +#ifdef CONFIG_XEN_PV >> +    if (cpu_feature_enabled(X86_FEATURE_XENPV)) >> +        return __xenpv_rdmsrq(msr, val, type); > > I don't think this will work for the Xen PV case. Well, I have been testing the code on xen-4.17 coming with Ubuntu 24.04.2 LTS :) > > X86_FEATURE_XENPV is set only after the first MSR is being read. No matter whether the code works or not, good catch! > > This can be fixed by setting the feature earlier, but it shows that the > paravirt feature has its benefits in such cases. See my other reply to let Xen handle all the details. Plus the code actually works, I would actually argue the opposite :-P