[PATCH 2/4 v3] KVM: X86: Add a utility function to read current RIP

[Krish Sadhukhan <krish.sadhukhan@oracle.com>]

Some tests may require to know the current RIP to compares tests results. Add
a function to read current RIP. This will be used by a test in this series.

Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
---
 lib/x86/processor.h | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/lib/x86/processor.h b/lib/x86/processor.h
index 87112bd..5604874 100644
--- a/lib/x86/processor.h
+++ b/lib/x86/processor.h
@@ -489,6 +489,13 @@ static inline unsigned long long rdtsc(void)
 	return r;
 }
 
+static inline u64 read_rip(void)
+{
+	u64 val;
+	asm volatile ("lea (%%rip),%0" : "=r"(val) : : "memory");
+	return val;
+}
+
 /*
  * Per the advice in the SDM, volume 2, the sequence "mfence; lfence"
  * executed immediately before rdtsc ensures that rdtsc will be
-- 
2.27.0