@@ -97,6 +97,19 @@ static __always_inline void __wrmsr(unsigned int msr, u32 low, u32 high)
: : "c" (msr), "a"(low), "d" (high) : "memory");
}
+/*
+ * WRMSRNS behaves exactly like WRMSR with the only difference being
+ * that it is not a serializing instruction by default.
+ */
+static __always_inline void __wrmsrns(u32 msr, u32 low, u32 high)
+{
+ /* Instruction opcode for WRMSRNS; supported in binutils >= 2.40. */
+ asm volatile("1: .byte 0x0f,0x01,0xc6\n"
+ "2:\n"
+ _ASM_EXTABLE_TYPE(1b, 2b, EX_TYPE_WRMSR)
+ : : "c" (msr), "a"(low), "d" (high));
+}
+
#define native_rdmsr(msr, val1, val2) \
do { \
u64 __val = __rdmsr((msr)); \
@@ -297,6 +310,11 @@ do { \
#endif /* !CONFIG_PARAVIRT_XXL */
+static __always_inline void wrmsrns(u32 msr, u64 val)
+{
+ __wrmsrns(msr, val, val >> 32);
+}
+
/*
* 64-bit version of wrmsr_safe():
*/