x86/bugs: Add attack vector controls for RFDS

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

Signed-off-by: David Kaplan <david.kaplan@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/20250707183316.1349127-9-david.kaplan@amd.com

diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index 39ff556f35c115395444df86ab230bf1e8a12dfa..a557d174a7519e3fc8f32572b423c4f28f50905a 100644 (file)
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -748,13 +748,17 @@ static inline bool __init verw_clears_cpu_reg_file(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;
@@ -765,7 +769,7 @@ 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_clear_cpu_buf_mitigation_selected)