x86/bugs: Fix the AMD SSBD usage of the SPEC_CTRL MSR

[linux-2.6-microblaze.git] / arch / x86 / kernel / cpu / bugs.c

diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index cd0fda1..5c0ea39 100644 (file)
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -27,6 +27,7 @@
 #include <asm/pgtable.h>
 #include <asm/set_memory.h>
 #include <asm/intel-family.h>
+#include <asm/hypervisor.h>
 
 static void __init spectre_v2_select_mitigation(void);
 static void __init ssb_select_mitigation(void);
@@ -154,7 +155,8 @@ x86_virt_spec_ctrl(u64 guest_spec_ctrl, u64 guest_virt_spec_ctrl, bool setguest)
                guestval |= guest_spec_ctrl & x86_spec_ctrl_mask;
 
                /* SSBD controlled in MSR_SPEC_CTRL */
-               if (static_cpu_has(X86_FEATURE_SPEC_CTRL_SSBD))
+               if (static_cpu_has(X86_FEATURE_SPEC_CTRL_SSBD) ||
+                   static_cpu_has(X86_FEATURE_AMD_SSBD))
                        hostval |= ssbd_tif_to_spec_ctrl(ti->flags);
 
                if (hostval != guestval) {
@@ -532,9 +534,10 @@ static enum ssb_mitigation __init __ssb_select_mitigation(void)
                 * Intel uses the SPEC CTRL MSR Bit(2) for this, while AMD may
                 * use a completely different MSR and bit dependent on family.
                 */
-               if (!static_cpu_has(X86_FEATURE_MSR_SPEC_CTRL))
+               if (!static_cpu_has(X86_FEATURE_SPEC_CTRL_SSBD) &&
+                   !static_cpu_has(X86_FEATURE_AMD_SSBD)) {
                        x86_amd_ssb_disable();
-               else {
+               } else {
                        x86_spec_ctrl_base |= SPEC_CTRL_SSBD;
                        x86_spec_ctrl_mask |= SPEC_CTRL_SSBD;
                        wrmsrl(MSR_IA32_SPEC_CTRL, x86_spec_ctrl_base);
@@ -664,6 +667,9 @@ static ssize_t cpu_show_common(struct device *dev, struct device_attribute *attr
                if (boot_cpu_has(X86_FEATURE_PTI))
                        return sprintf(buf, "Mitigation: PTI\n");
 
+               if (hypervisor_is_type(X86_HYPER_XEN_PV))
+                       return sprintf(buf, "Unknown (XEN PV detected, hypervisor mitigation required)\n");
+
                break;
 
        case X86_BUG_SPECTRE_V1: