[PATCH v5 08/20] x86/bugs: Add attack vector controls for RFDS
From: David Kaplan
Date: Fri May 09 2025 - 12:31:34 EST
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 | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index bb5d58abaab6..e807176bc845 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -726,13 +726,17 @@ 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;
@@ -743,7 +747,7 @@ 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)
--
2.34.1