Reading the 'spec_rstack_overflow' sysfs file can trigger an unnecessary
MSR write, and possibly even a (handled) exception if the microcode
hasn't been updated.
Avoid all that by just checking X86_FEATURE_IBPB_BRTYPE instead, which
gets set by srso_select_mitigation() if the updated microcode exists.
Fixes: fb3bd914b3ec ("x86/srso: Add a Speculative RAS Overflow mitigation")
Reviewed-by: Nikolay Borisov <[email protected]>
Signed-off-by: Josh Poimboeuf <[email protected]>
---
arch/x86/kernel/cpu/bugs.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index f081d26616ac..bdd3e296f72b 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -2717,7 +2717,7 @@ static ssize_t srso_show_state(char *buf)
return sysfs_emit(buf, "%s%s\n",
srso_strings[srso_mitigation],
- (cpu_has_ibpb_brtype_microcode() ? "" : ", no microcode"));
+ boot_cpu_has(X86_FEATURE_IBPB_BRTYPE) ? "" : ", no microcode");
}
static ssize_t gds_show_state(char *buf)
--
2.41.0