diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c
index 8397188..61980ea 100644
--- a/xen/arch/arm/traps.c
+++ b/xen/arch/arm/traps.c
@@ -1452,119 +1452,6 @@ static void do_debug_trap(struct cpu_user_regs *regs, unsigned int code)
 }
 #endif
 
-#define PSCI_SET_RESULT(reg, val) set_user_reg(reg, 0, val)
-#define PSCI_ARG(reg,n) get_user_reg(reg, n)
-
-#ifdef CONFIG_ARM_64
-#define PSCI_ARG32(reg,n) (uint32_t)get_user_reg(reg,n)
-#else
-#define PSCI_ARG32(reg,n) PSCI_ARG(reg,n)
-#endif
-
-/* helper function for checking arm mode 32/64 bit */
-static inline int psci_mode_check(struct domain *d, register_t fid)
-{
-        return !( is_64bit_domain(d)^( (fid & PSCI_0_2_64BIT) >> 30 ) );
-}
-
-static void do_trap_psci(struct cpu_user_regs *regs)
-{
-    register_t fid = PSCI_ARG(regs,0);
-
-    /* preloading in case psci_mode_check fails */
-    PSCI_SET_RESULT(regs, PSCI_INVALID_PARAMETERS);
-    switch( fid )
-    {
-    case PSCI_cpu_off:
-        {
-            uint32_t pstate = PSCI_ARG32(regs,1);
-            perfc_incr(vpsci_cpu_off);
-            PSCI_SET_RESULT(regs, do_psci_cpu_off(pstate));
-        }
-        break;
-    case PSCI_cpu_on:
-        {
-            uint32_t vcpuid = PSCI_ARG32(regs,1);
-            register_t epoint = PSCI_ARG(regs,2);
-            perfc_incr(vpsci_cpu_on);
-            PSCI_SET_RESULT(regs, do_psci_cpu_on(vcpuid, epoint));
-        }
-        break;
-    case PSCI_0_2_FN_PSCI_VERSION:
-        perfc_incr(vpsci_version);
-        PSCI_SET_RESULT(regs, do_psci_0_2_version());
-        break;
-    case PSCI_0_2_FN_CPU_OFF:
-        perfc_incr(vpsci_cpu_off);
-        PSCI_SET_RESULT(regs, do_psci_0_2_cpu_off());
-        break;
-    case PSCI_0_2_FN_MIGRATE_INFO_TYPE:
-        perfc_incr(vpsci_migrate_info_type);
-        PSCI_SET_RESULT(regs, do_psci_0_2_migrate_info_type());
-        break;
-    case PSCI_0_2_FN_MIGRATE_INFO_UP_CPU:
-    case PSCI_0_2_FN64_MIGRATE_INFO_UP_CPU:
-        perfc_incr(vpsci_migrate_info_up_cpu);
-        if ( psci_mode_check(current->domain, fid) )
-            PSCI_SET_RESULT(regs, do_psci_0_2_migrate_info_up_cpu());
-        break;
-    case PSCI_0_2_FN_SYSTEM_OFF:
-        perfc_incr(vpsci_system_off);
-        do_psci_0_2_system_off();
-        PSCI_SET_RESULT(regs, PSCI_INTERNAL_FAILURE);
-        break;
-    case PSCI_0_2_FN_SYSTEM_RESET:
-        perfc_incr(vpsci_system_reset);
-        do_psci_0_2_system_reset();
-        PSCI_SET_RESULT(regs, PSCI_INTERNAL_FAILURE);
-        break;
-    case PSCI_0_2_FN_CPU_ON:
-    case PSCI_0_2_FN64_CPU_ON:
-        perfc_incr(vpsci_cpu_on);
-        if ( psci_mode_check(current->domain, fid) )
-        {
-            register_t vcpuid = PSCI_ARG(regs,1);
-            register_t epoint = PSCI_ARG(regs,2);
-            register_t cid = PSCI_ARG(regs,3);
-            PSCI_SET_RESULT(regs, do_psci_0_2_cpu_on(vcpuid, epoint, cid));
-        }
-        break;
-    case PSCI_0_2_FN_CPU_SUSPEND:
-    case PSCI_0_2_FN64_CPU_SUSPEND:
-        perfc_incr(vpsci_cpu_suspend);
-        if ( psci_mode_check(current->domain, fid) )
-        {
-            uint32_t pstate = PSCI_ARG32(regs,1);
-            register_t epoint = PSCI_ARG(regs,2);
-            register_t cid = PSCI_ARG(regs,3);
-            PSCI_SET_RESULT(regs, do_psci_0_2_cpu_suspend(pstate, epoint, cid));
-        }
-        break;
-    case PSCI_0_2_FN_AFFINITY_INFO:
-    case PSCI_0_2_FN64_AFFINITY_INFO:
-        perfc_incr(vpsci_cpu_affinity_info);
-        if ( psci_mode_check(current->domain, fid) )
-        {
-            register_t taff = PSCI_ARG(regs,1);
-            uint32_t laff = PSCI_ARG32(regs,2);
-            PSCI_SET_RESULT(regs, do_psci_0_2_affinity_info(taff, laff));
-        }
-        break;
-    case PSCI_0_2_FN_MIGRATE:
-    case PSCI_0_2_FN64_MIGRATE:
-        perfc_incr(vpsci_cpu_migrate);
-        if ( psci_mode_check(current->domain, fid) )
-        {
-            uint32_t tcpu = PSCI_ARG32(regs,1);
-            PSCI_SET_RESULT(regs, do_psci_0_2_migrate(tcpu));
-        }
-        break;
-    default:
-        domain_crash_synchronous();
-        return;
-    }
-}
-
 #ifdef CONFIG_ARM_64
 #define HYPERCALL_RESULT_REG(r) (r)->x0
 #define HYPERCALL_ARG1(r) (r)->x0
@@ -2270,7 +2157,7 @@ void do_trap_guest_sync(struct cpu_user_regs *regs)
             return do_debug_trap(regs, hsr.iss & 0x00ff);
 #endif
         if ( hsr.iss == 0 )
-            return do_trap_psci(regs);
+            return do_trap_hvc_smccc(regs);
         do_trap_hypercall(regs, (register_t *)&regs->r12, hsr.iss);
         break;
 #ifdef CONFIG_ARM_64
@@ -2282,7 +2169,7 @@ void do_trap_guest_sync(struct cpu_user_regs *regs)
             return do_debug_trap(regs, hsr.iss & 0x00ff);
 #endif
         if ( hsr.iss == 0 )
-            return do_trap_psci(regs);
+            return do_trap_hvc_smccc(regs);
         do_trap_hypercall(regs, &regs->x16, hsr.iss);
         break;
     case HSR_EC_SMC64:
diff --git a/xen/arch/arm/vsmc.c b/xen/arch/arm/vsmc.c
index 38df821..6ab7c55 100644
--- a/xen/arch/arm/vsmc.c
+++ b/xen/arch/arm/vsmc.c
@@ -19,6 +19,7 @@
 #include <xen/types.h>
 #include <public/arch-arm/smccc.h>
 #include <asm/monitor.h>
+#include <asm/psci.h>
 #include <asm/regs.h>
 #include <asm/smccc.h>
 #include <asm/traps.h>
@@ -26,6 +27,9 @@
 /* Number of functions currently supported by Hypervisor Service. */
 #define XEN_SMCCC_FUNCTION_COUNT 3
 
+/* Number of functions currently supported by Standard Service Service Calls. */
+#define SSSC_SMCCC_FUNCTION_COUNT 13
+
 static bool fill_uid(struct cpu_user_regs *regs, xen_uuid_t uuid)
 {
     int n;
@@ -94,6 +98,148 @@ static bool handle_hypervisor(struct cpu_user_regs *regs)
     }
 }
 
+#define PSCI_SET_RESULT(reg, val) set_user_reg(reg, 0, val)
+#define PSCI_ARG(reg, n) get_user_reg(reg, n)
+
+#ifdef CONFIG_ARM_64
+#define PSCI_ARG32(reg, n) (uint32_t)(get_user_reg(reg, n))
+#else
+#define PSCI_ARG32(reg, n) PSCI_ARG(reg, n)
+#endif
+
+/* Existing (pre SMCCC) APIs. This includes PSCI 0.1 interface */
+static bool handle_existing_apis(struct cpu_user_regs *regs)
+{
+    switch ( get_user_reg(regs, 0) )
+    {
+    case PSCI_cpu_off:
+    {
+        uint32_t pstate = PSCI_ARG32(regs, 1);
+
+        perfc_incr(vpsci_cpu_off);
+        PSCI_SET_RESULT(regs, do_psci_cpu_off(pstate));
+        return true;
+    }
+    case PSCI_cpu_on:
+    {
+        uint32_t vcpuid = PSCI_ARG32(regs, 1);
+        register_t epoint = PSCI_ARG(regs, 2);
+
+        perfc_incr(vpsci_cpu_on);
+        PSCI_SET_RESULT(regs, do_psci_cpu_on(vcpuid, epoint));
+        return true;
+    }
+    default:
+        return false;
+    }
+}
+
+/* helper function for checking arm mode 32/64 bit */
+static inline int psci_mode_check(struct domain *d, register_t fid)
+{
+    return !( is_64bit_domain(d)^( (fid & PSCI_0_2_64BIT) >> 30 ) );
+}
+
+/* PSCI 0.2 interface and other Standard Secure Calls */
+static bool handle_sssc(struct cpu_user_regs *regs)
+{
+    register_t fid = PSCI_ARG(regs, 0);
+
+    switch ( fid )
+    {
+    case PSCI_0_2_FN_PSCI_VERSION:
+        perfc_incr(vpsci_version);
+        PSCI_SET_RESULT(regs, do_psci_0_2_version());
+        return true;
+
+    case PSCI_0_2_FN_CPU_OFF:
+        perfc_incr(vpsci_cpu_off);
+        PSCI_SET_RESULT(regs, do_psci_0_2_cpu_off());
+        return true;
+
+    case PSCI_0_2_FN_MIGRATE_INFO_TYPE:
+        perfc_incr(vpsci_migrate_info_type);
+        PSCI_SET_RESULT(regs, do_psci_0_2_migrate_info_type());
+        return true;
+
+    case PSCI_0_2_FN_MIGRATE_INFO_UP_CPU:
+        perfc_incr(vpsci_migrate_info_up_cpu);
+        if ( psci_mode_check(current->domain, fid) )
+            PSCI_SET_RESULT(regs, do_psci_0_2_migrate_info_up_cpu());
+        return true;
+
+    case PSCI_0_2_FN_SYSTEM_OFF:
+        perfc_incr(vpsci_system_off);
+        do_psci_0_2_system_off();
+        PSCI_SET_RESULT(regs, PSCI_INTERNAL_FAILURE);
+        return true;
+
+    case PSCI_0_2_FN_SYSTEM_RESET:
+        perfc_incr(vpsci_system_reset);
+        do_psci_0_2_system_reset();
+        PSCI_SET_RESULT(regs, PSCI_INTERNAL_FAILURE);
+        return true;
+
+    case PSCI_0_2_FN_CPU_ON:
+        perfc_incr(vpsci_cpu_on);
+        if ( psci_mode_check(current->domain, fid) )
+        {
+            register_t vcpuid = PSCI_ARG(regs, 1);
+            register_t epoint = PSCI_ARG(regs, 2);
+            register_t cid = PSCI_ARG(regs, 3);
+
+            PSCI_SET_RESULT(regs, do_psci_0_2_cpu_on(vcpuid, epoint, cid));
+        }
+        return true;
+
+    case PSCI_0_2_FN_CPU_SUSPEND:
+        perfc_incr(vpsci_cpu_suspend);
+        if ( psci_mode_check(current->domain, fid) )
+        {
+            uint32_t pstate = PSCI_ARG32(regs, 1);
+            register_t epoint = PSCI_ARG(regs, 2);
+            register_t cid = PSCI_ARG(regs, 3);
+
+            PSCI_SET_RESULT(regs, do_psci_0_2_cpu_suspend(pstate, epoint, cid));
+        }
+        return true;
+
+    case PSCI_0_2_FN_AFFINITY_INFO:
+        perfc_incr(vpsci_cpu_affinity_info);
+        if ( psci_mode_check(current->domain, fid) )
+        {
+            register_t taff = PSCI_ARG(regs, 1);
+            uint32_t laff = PSCI_ARG32(regs, 2);
+            PSCI_SET_RESULT(regs, do_psci_0_2_affinity_info(taff, laff));
+        }
+        return true;
+
+    case PSCI_0_2_FN_MIGRATE:
+        perfc_incr(vpsci_cpu_migrate);
+        if ( psci_mode_check(current->domain, fid) )
+        {
+            uint32_t tcpu = PSCI_ARG32(regs, 1);
+
+            PSCI_SET_RESULT(regs, do_psci_0_2_migrate(tcpu));
+        }
+        return true;
+
+    case ARM_SMCCC_FUNC_CALL_COUNT:
+        return fill_function_call_count(regs, SSSC_SMCCC_FUNCTION_COUNT);
+        return true;
+
+    case ARM_SMCCC_FUNC_CALL_UID:
+        return fill_uid(regs, SSSC_SMCCC_UID);
+
+    case ARM_SMCCC_FUNC_CALL_REVISION:
+        return fill_revision(regs, SSSC_SMCCC_MAJOR_REVISION,
+                             SSSC_SMCCC_MINOR_REVISION);
+
+    default:
+        return false;
+    }
+}
+
 /*
  * vsmccc_handle_call() - handle SMC/HVC call according to ARM SMCCC.
  * returns true if that was valid SMCCC call (even if function number
@@ -133,11 +279,26 @@ static bool vsmccc_handle_call(struct cpu_user_regs *regs)
         return true;
     }
 
-    switch ( smccc_get_owner(funcid) )
+    /*
+     * Special case: identifier range for existing APIs.
+     * This range is described in SMCCC (ARM DEN 0028B, page 16),
+     * but it does not conforms to standard function identifier
+     * encoding.
+     */
+    if ( funcid >= ARM_SMCCC_RESERVED_RANGE_START &&
+         funcid <= ARM_SMCCC_RESERVED_RANGE_END )
+        handled = handle_existing_apis(regs);
+    else
     {
-    case ARM_SMCCC_OWNER_HYPERVISOR:
-        handled = handle_hypervisor(regs);
-        break;
+        switch ( smccc_get_owner(funcid) )
+        {
+        case ARM_SMCCC_OWNER_HYPERVISOR:
+            handled = handle_hypervisor(regs);
+            break;
+        case ARM_SMCCC_OWNER_STANDARD:
+            handled = handle_sssc(regs);
+            break;
+        }
     }
 
     if ( !handled )
@@ -181,6 +342,20 @@ void do_trap_smc(struct cpu_user_regs *regs, const union hsr hsr)
         inject_undef_exception(regs, hsr);
 }
 
+void do_trap_hvc_smccc(struct cpu_user_regs *regs)
+{
+    const union hsr hsr = { .bits = regs->hsr };
+
+    /*
+     * vsmccc_handle_call() will return false if this call is not
+     * SMCCC compatible (e.g. immediate value != 0). As it is not
+     * compatible, we can't be sure that guest will understand
+     * ARM_SMCCC_ERR_UNKNOWN_FUNCTION.
+     */
+    if ( !vsmccc_handle_call(regs) )
+        inject_undef_exception(regs, hsr);
+}
+
 /*
  * Local variables:
  * mode: C
diff --git a/xen/include/asm-arm/traps.h b/xen/include/asm-arm/traps.h
index 6efd1c5..0b91aa7 100644
--- a/xen/include/asm-arm/traps.h
+++ b/xen/include/asm-arm/traps.h
@@ -33,6 +33,7 @@ void do_cp(struct cpu_user_regs *regs, const union hsr hsr);
 
 /* SMCCC handling */
 void do_trap_smc(struct cpu_user_regs *regs, const union hsr hsr);
+void do_trap_hvc_smccc(struct cpu_user_regs *regs);
 
 #endif /* __ASM_ARM_TRAPS__ */
 /*
diff --git a/xen/include/public/arch-arm/smccc.h b/xen/include/public/arch-arm/smccc.h
index 2bee5b3..17dc6d8 100644
--- a/xen/include/public/arch-arm/smccc.h
+++ b/xen/include/public/arch-arm/smccc.h
@@ -46,6 +46,14 @@
 #define XEN_SMCCC_UID XEN_DEFINE_UUID(0xa71812dc, 0xc698, 0x4369, 0x9acf, \
                                       0x79, 0xd1, 0x8d, 0xde, 0xe6, 0x67)
 
+/* Standard Service Service Call version. */
+#define SSSC_SMCCC_MAJOR_REVISION 0
+#define SSSC_SMCCC_MINOR_REVISION 1
+
+/* Standard Service Call UID. Randomly generated with uuidgen. */
+#define SSSC_SMCCC_UID XEN_DEFINE_UUID(0xf863386f, 0x4b39, 0x4cbd, 0x9220,\
+                                       0xce, 0x16, 0x41, 0xe5, 0x9f, 0x6f)
+
 #endif /* __XEN_PUBLIC_ARCH_ARM_SMCCC_H__ */
 
 /*
