The kernel dynamic xfeatures are supported by host, i.e., they're enabled in xsaves/xrstors operating xfeature set (XCR0 | XSS), but the corresponding CPU features are disabled for the time-being in host kernel so the bits are not necessarily set by default. Remove the bits from fpu_kernel_cfg.default_features so that the bits in xstate_bv and xcomp_bv are cleared and xsaves/xrstors can be optimized by HW for normal fpstate. Signed-off-by: Yang Weijiang <weijiang.yang@xxxxxxxxx> --- arch/x86/kernel/fpu/xstate.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index eaec05bc1b3c..4753c677e2e1 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -845,6 +845,7 @@ void __init fpu__init_system_xstate(unsigned int legacy_size) /* Clean out dynamic features from default */ fpu_kernel_cfg.default_features = fpu_kernel_cfg.max_features; fpu_kernel_cfg.default_features &= ~XFEATURE_MASK_USER_DYNAMIC; + fpu_kernel_cfg.default_features &= ~fpu_kernel_dynamic_xfeatures; fpu_user_cfg.default_features = fpu_user_cfg.max_features; fpu_user_cfg.default_features &= ~XFEATURE_MASK_USER_DYNAMIC; -- 2.27.0
