Commit 22dd8365088b ("x86/speculation/mds: Add mitigation mode VMWERV") add an internal mitigation mode VWWERV which enables the invocation of the CPU buffer clearing even if X86_FEATURE_MD_CLEAR is not set.
This wastes a few CPU cycles for native machine with an old microcode unnecessorily. Avoid it by checking if it's running in native machine. Signed-off-by: Zhenzhong Duan <zhenzhong.d...@oracle.com> --- arch/x86/kernel/cpu/bugs.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index 03b4cc0..03f5a77 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -233,7 +233,9 @@ static void x86_amd_ssb_disable(void) static void __init mds_select_mitigation(void) { - if (!boot_cpu_has_bug(X86_BUG_MDS) || cpu_mitigations_off()) { + if (!boot_cpu_has_bug(X86_BUG_MDS) || cpu_mitigations_off() || + (hypervisor_is_type(X86_HYPER_NATIVE) && + !boot_cpu_has(X86_FEATURE_MD_CLEAR))) { mds_mitigation = MDS_MITIGATION_OFF; return; } -- 1.8.3.1