1 files changed, 67 insertions, 6 deletions

diff --git a/arch/i386/lib/msr-on-cpu.c b/arch/i386/lib/msr-on-cpu.c
index 1c46bda409ff..7767962f25d3 100644
--- a/arch/i386/lib/msr-on-cpu.c
+++ b/arch/i386/lib/msr-on-cpu.c
@@ -6,6 +6,7 @@
 struct msr_info {
         u32 msr_no;
         u32 l, h;
+        int err;
 };
 
 static void __rdmsr_on_cpu(void *info)
@@ -15,20 +16,38 @@ static void __rdmsr_on_cpu(void *info)
         rdmsr(rv->msr_no, rv->l, rv->h);
 }
 
-void rdmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h)
+static void __rdmsr_safe_on_cpu(void *info)
 {
+        struct msr_info *rv = info;
+
+        rv->err = rdmsr_safe(rv->msr_no, &rv->l, &rv->h);
+}
+
+static int _rdmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h, int safe)
+{
+        int err = 0;
         preempt_disable();
         if (smp_processor_id() == cpu)
-                rdmsr(msr_no, *l, *h);
+                if (safe)
+                        err = rdmsr_safe(msr_no, l, h);
+                else
+                        rdmsr(msr_no, *l, *h);
         else {
                 struct msr_info rv;
 
                 rv.msr_no = msr_no;
-                smp_call_function_single(cpu, __rdmsr_on_cpu, &rv, 0, 1);
+                if (safe) {
+                        smp_call_function_single(cpu, __rdmsr_safe_on_cpu,
+                                                 &rv, 0, 1);
+                        err = rv.err;
+                } else {
+                        smp_call_function_single(cpu, __rdmsr_on_cpu, &rv, 0, 1);
+                }
                 *l = rv.l;
                 *h = rv.h;
         }
         preempt_enable();
+        return err;
 }
 
 static void __wrmsr_on_cpu(void *info)
@@ -38,21 +57,63 @@ static void __wrmsr_on_cpu(void *info)
         wrmsr(rv->msr_no, rv->l, rv->h);
 }
 
-void wrmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h)
+static void __wrmsr_safe_on_cpu(void *info)
 {
+        struct msr_info *rv = info;
+
+        rv->err = wrmsr_safe(rv->msr_no, rv->l, rv->h);
+}
+
+static int _wrmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h, int safe)
+{
+        int err = 0;
         preempt_disable();
         if (smp_processor_id() == cpu)
-                wrmsr(msr_no, l, h);
+                if (safe)
+                        err = wrmsr_safe(msr_no, l, h);
+                else
+                        wrmsr(msr_no, l, h);
         else {
                 struct msr_info rv;
 
                 rv.msr_no = msr_no;
                 rv.l = l;
                 rv.h = h;
-                smp_call_function_single(cpu, __wrmsr_on_cpu, &rv, 0, 1);
+                if (safe) {
+                        smp_call_function_single(cpu, __wrmsr_safe_on_cpu,
+                                                 &rv, 0, 1);
+                        err = rv.err;
+                } else {
+                        smp_call_function_single(cpu, __wrmsr_on_cpu, &rv, 0, 1);
+                }
         }
         preempt_enable();
+        return err;
+}
+
+void wrmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h)
+{
+        _wrmsr_on_cpu(cpu, msr_no, l, h, 0);
+}
+
+void rdmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h)
+{
+        _rdmsr_on_cpu(cpu, msr_no, l, h, 0);
+}
+
+/* These "safe" variants are slower and should be used when the target MSR
+   may not actually exist. */
+int wrmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h)
+{
+        return _wrmsr_on_cpu(cpu, msr_no, l, h, 1);
+}
+
+int rdmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h)
+{
+        return _rdmsr_on_cpu(cpu, msr_no, l, h, 1);
 }
 
 EXPORT_SYMBOL(rdmsr_on_cpu);
 EXPORT_SYMBOL(wrmsr_on_cpu);
+EXPORT_SYMBOL(rdmsr_safe_on_cpu);
+EXPORT_SYMBOL(wrmsr_safe_on_cpu);