x86: re-add rdmsrl_safe

RDMSR for 64bit values with exception handling.

Makes it easier to deal with 64bit valued MSRs. The old 64bit code
base had that too as checking_rdmsrl(), but it got dropped somehow.

Signed-off-by: Andi Kleen <andi@firstfloor.org>
Cc: andreas.herrmann3@amd.com
Cc: mingo@elte.hu
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 7 insertions, 0 deletions

diff --git a/include/asm-x86/paravirt.h b/include/asm-x86/paravirt.h
index 0c23f7940bc4..3d419398499b 100644
--- a/include/asm-x86/paravirt.h
+++ b/include/asm-x86/paravirt.h
@@ -693,6 +693,13 @@ do {						\
         _err;                                   \
 })
 
+static inline int rdmsrl_safe(unsigned msr, unsigned long long *p)
+{
+        int err;
+
+        *p = paravirt_read_msr(msr, &err);
+        return err;
+}
 
 static inline u64 paravirt_read_tsc(void)
 {