Later commits will cause objtool to warn about static keys being used in .noinstr sections in order to safely defer instruction patching IPIs targeted at NOHZ_FULL CPUs.
These keys are used in .noinstr code, and can be modified at runtime (/proc/kernel/vmx* write). However it is not expected that they will be flipped during latency-sensitive operations, and thus shouldn't be a source of interference wrt the text patching IPI.
Mark it to let objtool know not to warn about it.
Reported-by: Josh Poimboeuf jpoimboe@kernel.org Signed-off-by: Valentin Schneider vschneid@redhat.com --- arch/x86/kvm/vmx/vmx.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 5c5766467a61d..00053458cd10c 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -225,8 +225,15 @@ module_param(pt_mode, int, S_IRUGO);
struct x86_pmu_lbr __ro_after_init vmx_lbr_caps;
-static DEFINE_STATIC_KEY_FALSE(vmx_l1d_should_flush); -static DEFINE_STATIC_KEY_FALSE(vmx_l1d_flush_cond); +/* + * Both of these static keys end up being used in .noinstr sections, however + * they are only modified: + * - at init + * - from a /proc/kernel/vmx* write + * thus during latency-sensitive operations they should remain stable. + */ +static DEFINE_STATIC_KEY_FALSE_NOINSTR(vmx_l1d_should_flush); +static DEFINE_STATIC_KEY_FALSE_NOINSTR(vmx_l1d_flush_cond); static DEFINE_MUTEX(vmx_l1d_flush_mutex);
/* Storage for pre module init parameter parsing */