Kernel dynamic xfeatures now are __ONLY__ enabled for guest fpstate, i.e., never for normal kernel fpstate. The bits are added when guest FPU config is initialized. Guest fpstate is allocated with fpstate->is_guest set to %true. For normal fpstate, the bits should have been removed when initializes kernel FPU config settings, WARN_ONCE() if kernel detects normal fpstate xfeatures contains kernel dynamic xfeatures before executes xsaves. Signed-off-by: Yang Weijiang <weijiang.yang@xxxxxxxxx> Reviewed-by: Rick Edgecombe <rick.p.edgecombe@xxxxxxxxx> --- arch/x86/kernel/fpu/xstate.h | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/x86/kernel/fpu/xstate.h b/arch/x86/kernel/fpu/xstate.h index 3518fb26d06b..83ebf1e1cbb4 100644 --- a/arch/x86/kernel/fpu/xstate.h +++ b/arch/x86/kernel/fpu/xstate.h @@ -185,6 +185,9 @@ static inline void os_xsave(struct fpstate *fpstate) WARN_ON_FPU(!alternatives_patched); xfd_validate_state(fpstate, mask, false); + WARN_ON_FPU(!fpstate->is_guest && + (mask & XFEATURE_MASK_KERNEL_DYNAMIC)); + XSTATE_XSAVE(&fpstate->regs.xsave, lmask, hmask, err); /* We should never fault when copying to a kernel buffer: */ -- 2.39.3
