[PATCH v4 24/36] x86/bugs: Add attack vector controls for rfds

[David Kaplan]

Use attack vector controls to determine if rfds mitigation is required.

Signed-off-by: David Kaplan <david.kaplan@xxxxxxx>
---
 arch/x86/kernel/cpu/bugs.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index ba7c2a1ea98f..32f850c80b86 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -712,13 +712,20 @@ static bool __init rfds_has_ucode(void)
 
 static void __init rfds_select_mitigation(void)
 {
-	if (!boot_cpu_has_bug(X86_BUG_RFDS) || cpu_mitigations_off()) {
+	if (!boot_cpu_has_bug(X86_BUG_RFDS)) {
 		rfds_mitigation = RFDS_MITIGATION_OFF;
 		return;
 	}
 
-	if (rfds_mitigation == RFDS_MITIGATION_AUTO)
-		rfds_mitigation = RFDS_MITIGATION_VERW;
+	if (rfds_mitigation == RFDS_MITIGATION_AUTO) {
+		if (should_mitigate_vuln(X86_BUG_RFDS))
+			rfds_mitigation = RFDS_MITIGATION_VERW;
+		else
+			rfds_mitigation = RFDS_MITIGATION_OFF;
+	}
+
+	if (rfds_mitigation == RFDS_MITIGATION_OFF)
+		return;
 
 	if (rfds_has_ucode())
 		verw_mitigation_selected = true;
@@ -726,7 +733,7 @@ static void __init rfds_select_mitigation(void)
 
 static void __init rfds_update_mitigation(void)
 {
-	if (!boot_cpu_has_bug(X86_BUG_RFDS) || cpu_mitigations_off())
+	if (!boot_cpu_has_bug(X86_BUG_RFDS))
 		return;
 
 	if (verw_mitigation_selected)
-- 
2.34.1