HV: Fix the incorrect operand-constraints for inline assembly

The RFLAGS will be touched in some inline assembly.(exec_vmxon/
RFLAGS_RESTORE). The "cc" constraint should be added. Otherwise
it won't be handled under -O2 option.
And "%%XXX" register should also be added into constraints.
Otherwise it will be optimized incorrectly.

Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
Signed-off-by: Zheng Gen <gen.zheng@intel.com>
Reviewed-by: Jason Chen CJ <jason.cj.chen@intel.com>
Acked-by: Anthony Xu <anthony.xu@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>

hypervisor/arch/x86/cpu.c

@@ -347,7 +347,9 @@ static uint64_t get_random_value(void)
 	asm volatile ("1: rdrand %%rax\n"
 			"jnc 1b\n"
 			"mov %%rax, %0\n"
-			: "=r"(random) :: );
+			: "=r"(random)
+			:
+			:"%rax");
 	return random;
 }
 

hypervisor/arch/x86/vmx.c

@@ -82,7 +82,7 @@ static inline int exec_vmxon(void *addr)
 			      "pushfq\n"
 			      "pop %0\n":"=r" (rflags)
 			      : "r"(addr)
-			      : "%rax");
+			      : "%rax", "cc", "memory");
 
 		/* if carry and zero flags are clear operation success */
 		if (rflags & (RFLAGS_C | RFLAGS_Z))
@@ -140,7 +140,7 @@ int exec_vmclear(void *addr)
 		"pushfq\n"
 		"pop %0\n":"=r" (rflags)
 		: "r"(addr)
-		: "%rax");
+		: "%rax", "cc", "memory");
 
 	/* if carry and zero flags are clear operation success */
 	if (rflags & (RFLAGS_C | RFLAGS_Z))
@@ -165,7 +165,7 @@ int exec_vmptrld(void *addr)
 		"pop %0\n"
 		: "=r" (rflags)
 		: "r"(addr)
-		: "%rax");
+		: "%rax", "cc");
 
 	/* if carry and zero flags are clear operation success */
 	if (rflags & (RFLAGS_C | RFLAGS_Z))

hypervisor/include/arch/x86/cpu.h

@@ -379,8 +379,9 @@ void load_cpu_state_data(void);
 /* Macro to restore rflags register */
 #define CPU_RFLAGS_RESTORE(rflags)                      \
 {                                                       \
-	asm volatile (" push %0" : : "r" (rflags));     \
-	asm volatile (" popf");                         \
+	asm volatile (" push %0\n\t"			\
+			"popf	\n\t": : "r" (rflags)	\
+			:"cc");				\
 }
 
 /* This macro locks out interrupts and saves the current architecture status