x86/bugs: Add attack vector controls for MMIO

Use attack vectors controls to determine if MMIO 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/20250707183316.1349127-8-david.kaplan@amd.com

diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index 438c482d4bb0992f7e98059124efb8a4b0bfea08..39ff556f35c115395444df86ab230bf1e8a12dfa 100644 (file)
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -639,8 +639,12 @@ static void __init mmio_select_mitigation(void)
        }
 
        /* Microcode will be checked in mmio_update_mitigation(). */
-       if (mmio_mitigation == MMIO_MITIGATION_AUTO)
-               mmio_mitigation = MMIO_MITIGATION_VERW;
+       if (mmio_mitigation == MMIO_MITIGATION_AUTO) {
+               if (should_mitigate_vuln(X86_BUG_MMIO_STALE_DATA))
+                       mmio_mitigation = MMIO_MITIGATION_VERW;
+               else
+                       mmio_mitigation = MMIO_MITIGATION_OFF;
+       }
 
        if (mmio_mitigation == MMIO_MITIGATION_OFF)
                return;
@@ -655,7 +659,7 @@ static void __init mmio_select_mitigation(void)
 
 static void __init mmio_update_mitigation(void)
 {
-       if (!boot_cpu_has_bug(X86_BUG_MMIO_STALE_DATA) || cpu_mitigations_off())
+       if (!boot_cpu_has_bug(X86_BUG_MMIO_STALE_DATA))
                return;
 
        if (verw_clear_cpu_buf_mitigation_selected)
@@ -703,7 +707,7 @@ static void __init mmio_apply_mitigation(void)
        if (!(x86_arch_cap_msr & ARCH_CAP_FBSDP_NO))
                static_branch_enable(&cpu_buf_idle_clear);
 
-       if (mmio_nosmt || cpu_mitigations_auto_nosmt())
+       if (mmio_nosmt || smt_mitigations == SMT_MITIGATIONS_ON)
                cpu_smt_disable(false);
 }