On Tue, Feb 21, 2023, Mingwei Zhang wrote: > Fix the checks to XFD_ERR using logical AND operation because XFD_ERR might > contain more information in the future. According Intel SDM Vol 1. 13.14: If that happens, then the future change is responsible for updating the check. The test very clearly does a straight write of MSR_IA32_XFD. If there are extra bits set then something is broken. wrmsr(MSR_IA32_XFD, XFEATURE_MASK_XTILEDATA);