4 files changed, 46 insertions, 14 deletions

diff --git a/arch/x86/xen/enlighten_hvm.c b/arch/x86/xen/enlighten_hvm.c
index 9e87ab010c82..e68ea5f4ad1c 100644
--- a/arch/x86/xen/enlighten_hvm.c
+++ b/arch/x86/xen/enlighten_hvm.c
@@ -164,10 +164,10 @@ static int xen_cpu_up_prepare_hvm(unsigned int cpu)
 	else
 		per_cpu(xen_vcpu_id, cpu) = cpu;
 	rc = xen_vcpu_setup(cpu);
-	if (rc)
+	if (rc || !xen_have_vector_callback)
 		return rc;
 
-	if (xen_have_vector_callback && xen_feature(XENFEAT_hvm_safe_pvclock))
+	if (xen_feature(XENFEAT_hvm_safe_pvclock))
 		xen_setup_timer(cpu);
 
 	rc = xen_smp_intr_init(cpu);
@@ -188,6 +188,8 @@ static int xen_cpu_dead_hvm(unsigned int cpu)
        return 0;
 }
 
+static bool no_vector_callback __initdata;
+
 static void __init xen_hvm_guest_init(void)
 {
 	if (xen_pv_domain())
@@ -207,7 +209,7 @@ static void __init xen_hvm_guest_init(void)
 
 	xen_panic_handler_init();
 
-	if (xen_feature(XENFEAT_hvm_callback_vector))
+	if (!no_vector_callback && xen_feature(XENFEAT_hvm_callback_vector))
 		xen_have_vector_callback = 1;
 
 	xen_hvm_smp_init();
@@ -233,6 +235,13 @@ static __init int xen_parse_nopv(char *arg)
 }
 early_param("xen_nopv", xen_parse_nopv);
 
+static __init int xen_parse_no_vector_callback(char *arg)
+{
+	no_vector_callback = true;
+	return 0;
+}
+early_param("xen_no_vector_callback", xen_parse_no_vector_callback);
+
 bool __init xen_hvm_need_lapic(void)
 {
 	if (xen_pv_domain())
diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
index 4409306364dc..9a5a50cdaab5 100644
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -583,6 +583,13 @@ DEFINE_IDTENTRY_RAW(xenpv_exc_debug)
 		exc_debug(regs);
 }
 
+DEFINE_IDTENTRY_RAW(exc_xen_unknown_trap)
+{
+	/* This should never happen and there is no way to handle it. */
+	pr_err("Unknown trap in Xen PV mode.");
+	BUG();
+}
+
 struct trap_array_entry {
 	void (*orig)(void);
 	void (*xen)(void);
@@ -631,6 +638,7 @@ static bool __ref get_trap_addr(void **addr, unsigned int ist)
 {
 	unsigned int nr;
 	bool ist_okay = false;
+	bool found = false;
 
 	/*
 	 * Replace trap handler addresses by Xen specific ones.
@@ -645,6 +653,7 @@ static bool __ref get_trap_addr(void **addr, unsigned int ist)
 		if (*addr == entry->orig) {
 			*addr = entry->xen;
 			ist_okay = entry->ist_okay;
+			found = true;
 			break;
 		}
 	}
@@ -655,9 +664,13 @@ static bool __ref get_trap_addr(void **addr, unsigned int ist)
 		nr = (*addr - (void *)early_idt_handler_array[0]) /
 		     EARLY_IDT_HANDLER_SIZE;
 		*addr = (void *)xen_early_idt_handler_array[nr];
+		found = true;
 	}
 
-	if (WARN_ON(ist != 0 && !ist_okay))
+	if (!found)
+		*addr = (void *)xen_asm_exc_xen_unknown_trap;
+
+	if (WARN_ON(found && ist != 0 && !ist_okay))
 		return false;
 
 	return true;
diff --git a/arch/x86/xen/smp_hvm.c b/arch/x86/xen/smp_hvm.c
index f5e7db4f82ab..6ff3c887e0b9 100644
--- a/arch/x86/xen/smp_hvm.c
+++ b/arch/x86/xen/smp_hvm.c
@@ -33,9 +33,11 @@ static void __init xen_hvm_smp_prepare_cpus(unsigned int max_cpus)
 	int cpu;
 
 	native_smp_prepare_cpus(max_cpus);
-	WARN_ON(xen_smp_intr_init(0));
 
-	xen_init_lock_cpu(0);
+	if (xen_have_vector_callback) {
+		WARN_ON(xen_smp_intr_init(0));
+		xen_init_lock_cpu(0);
+	}
 
 	for_each_possible_cpu(cpu) {
 		if (cpu == 0)
@@ -50,9 +52,11 @@ static void __init xen_hvm_smp_prepare_cpus(unsigned int max_cpus)
 static void xen_hvm_cpu_die(unsigned int cpu)
 {
 	if (common_cpu_die(cpu) == 0) {
-		xen_smp_intr_free(cpu);
-		xen_uninit_lock_cpu(cpu);
-		xen_teardown_timer(cpu);
+		if (xen_have_vector_callback) {
+			xen_smp_intr_free(cpu);
+			xen_uninit_lock_cpu(cpu);
+			xen_teardown_timer(cpu);
+		}
 	}
 }
 #else
@@ -64,14 +68,19 @@ static void xen_hvm_cpu_die(unsigned int cpu)
 
 void __init xen_hvm_smp_init(void)
 {
-	if (!xen_have_vector_callback)
+	smp_ops.smp_prepare_boot_cpu = xen_hvm_smp_prepare_boot_cpu;
+	smp_ops.smp_prepare_cpus = xen_hvm_smp_prepare_cpus;
+	smp_ops.smp_cpus_done = xen_smp_cpus_done;
+	smp_ops.cpu_die = xen_hvm_cpu_die;
+
+	if (!xen_have_vector_callback) {
+#ifdef CONFIG_PARAVIRT_SPINLOCKS
+		nopvspin = true;
+#endif
 		return;
+	}
 
-	smp_ops.smp_prepare_cpus = xen_hvm_smp_prepare_cpus;
 	smp_ops.smp_send_reschedule = xen_smp_send_reschedule;
-	smp_ops.cpu_die = xen_hvm_cpu_die;
 	smp_ops.send_call_func_ipi = xen_smp_send_call_function_ipi;
 	smp_ops.send_call_func_single_ipi = xen_smp_send_call_function_single_ipi;
-	smp_ops.smp_prepare_boot_cpu = xen_hvm_smp_prepare_boot_cpu;
-	smp_ops.smp_cpus_done = xen_smp_cpus_done;
 }
diff --git a/arch/x86/xen/xen-asm.S b/arch/x86/xen/xen-asm.S
index 1cb0e84b9161..53cf8aa35032 100644
--- a/arch/x86/xen/xen-asm.S
+++ b/arch/x86/xen/xen-asm.S
@@ -178,6 +178,7 @@ xen_pv_trap asm_exc_simd_coprocessor_error
 #ifdef CONFIG_IA32_EMULATION
 xen_pv_trap entry_INT80_compat
 #endif
+xen_pv_trap asm_exc_xen_unknown_trap
 xen_pv_trap asm_exc_xen_hypervisor_callback
 
 	__INIT