svm: increment RIP over PAUSE instruction when emulating it

Signed-off-by: Christoph Egger <Christoph.Egger@amd.com>

xen/arch/x86/hvm/svm/emulate.c

@@ -100,6 +100,7 @@ MAKE_INSTR(VMCALL, 3, 0x0f, 0x01, 0xd9);
 MAKE_INSTR(HLT,    1, 0xf4);
 MAKE_INSTR(INT3,   1, 0xcc);
 MAKE_INSTR(RDTSC,  2, 0x0f, 0x31);
+MAKE_INSTR(PAUSE,  1, 0x90);
 
 static const u8 *opc_bytes[INSTR_MAX_COUNT] = 
 {
@@ -111,7 +112,8 @@ static const u8 *opc_bytes[INSTR_MAX_COUNT] =
     [INSTR_VMCALL] = OPCODE_VMCALL,
     [INSTR_HLT]    = OPCODE_HLT,
     [INSTR_INT3]   = OPCODE_INT3,
-    [INSTR_RDTSC]  = OPCODE_RDTSC
+    [INSTR_RDTSC]  = OPCODE_RDTSC,
+    [INSTR_PAUSE]  = OPCODE_PAUSE,
 };
 
 static int fetch(struct vcpu *v, u8 *buf, unsigned long addr, int len)

xen/arch/x86/hvm/svm/svm.c

@@ -1261,6 +1261,22 @@ static void svm_vmexit_do_rdtsc(struct cpu_user_regs *regs)
     hvm_rdtsc_intercept(regs);
 }
 
+static void svm_vmexit_do_pause(struct cpu_user_regs *regs)
+{
+    unsigned int inst_len;
+
+    if ( (inst_len = __get_instruction_length(current, INSTR_PAUSE)) == 0 )
+        return;
+    __update_guest_eip(regs, inst_len);
+
+    /*
+     * The guest is running a contended spinlock and we've detected it.
+     * Do something useful, like reschedule the guest
+     */
+    perfc_incr(pauseloop_exits);
+    do_sched_op_compat(SCHEDOP_yield, 0);
+}
+
 static void svm_vmexit_ud_intercept(struct cpu_user_regs *regs)
 {
     struct hvm_emulate_ctxt ctxt;
@@ -1655,12 +1671,7 @@ asmlinkage void svm_vmexit_handler(struct cpu_user_regs *regs)
         break;
 
     case VMEXIT_PAUSE:
-        /*
-         * The guest is running a contended spinlock and we've detected it.
-         * Do something useful, like reschedule the guest
-         */
-        perfc_incr(pauseloop_exits);
-        do_sched_op_compat(SCHEDOP_yield, 0);
+        svm_vmexit_do_pause(regs);
         break;
 
     default:

xen/include/asm-x86/hvm/svm/emulate.h

@@ -31,6 +31,7 @@ enum instruction_index {
     INSTR_HLT,
     INSTR_INT3,
     INSTR_RDTSC,
+    INSTR_PAUSE,
     INSTR_MAX_COUNT /* Must be last - Number of instructions supported */
 };