[PATCH v5 08/20] x86/bugs: Add attack vector controls for RFDS

David Kaplan posted 20 patches 7 months, 1 week ago
There is a newer version of this series
[PATCH v5 08/20] x86/bugs: Add attack vector controls for RFDS
Posted by David Kaplan 7 months, 1 week ago
Use attack vector controls to determine if RFDS mitigation is required.

Signed-off-by: David Kaplan <david.kaplan@amd.com>
---
 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