diff --git a/xen/arch/x86/traps.c b/xen/arch/x86/traps.c
index fe9457cdb6..e73f07f28a 100644
--- a/xen/arch/x86/traps.c
+++ b/xen/arch/x86/traps.c
@@ -686,6 +686,20 @@ const char *trapstr(unsigned int trapnr)
     return trapnr < ARRAY_SIZE(strings) ? strings[trapnr] : "???";
 }
 
+static const char *vec_name(unsigned int vec)
+{
+    static const char names[][4] = {
+#define N(x) [X86_EXC_ ## x] = #x
+        N(DE),  N(DB),  N(NMI), N(BP),  N(OF),  N(BR),  N(UD),  N(NM),
+        N(DF),  N(CSO), N(TS),  N(NP),  N(SS),  N(GP),  N(PF),  N(SPV),
+        N(MF),  N(AC),  N(MC),  N(XM),  N(VE),  N(CP),
+                                        N(HV),  N(VC),  N(SX),
+#undef N
+    };
+
+    return (vec < ARRAY_SIZE(names) && names[vec][0]) ? names[vec] : "??";
+}
+
 /*
  * This is called for faults at very unexpected times (e.g., when interrupts
  * are disabled). In such situations we can't do much that is safe. We try to
@@ -743,10 +757,9 @@ void fatal_trap(const struct cpu_user_regs *regs, bool show_remote)
         }
     }
 
-    panic("FATAL TRAP: vector = %d (%s)\n"
-          "[error_code=%04x] %s\n",
-          trapnr, trapstr(trapnr), regs->error_code,
-          (regs->eflags & X86_EFLAGS_IF) ? "" : ", IN INTERRUPT CONTEXT");
+    panic("FATAL TRAP: vec %u, #%s[%04x]%s\n",
+          trapnr, vec_name(trapnr), regs->error_code,
+          (regs->eflags & X86_EFLAGS_IF) ? "" : " IN INTERRUPT CONTEXT");
 }
 
 static void do_reserved_trap(struct cpu_user_regs *regs)
@@ -757,7 +770,8 @@ static void do_reserved_trap(struct cpu_user_regs *regs)
         return;
 
     show_execution_state(regs);
-    panic("FATAL RESERVED TRAP %#x: %s\n", trapnr, trapstr(trapnr));
+    panic("FATAL RESERVED TRAP: vec %u, #%s[%04x]\n",
+          trapnr, vec_name(trapnr), regs->error_code);
 }
 
 static void do_trap(struct cpu_user_regs *regs)
diff --git a/xen/include/asm-x86/processor.h b/xen/include/asm-x86/processor.h
index 8f6f5a97dd..12b55e1022 100644
--- a/xen/include/asm-x86/processor.h
+++ b/xen/include/asm-x86/processor.h
@@ -43,11 +43,7 @@
 #define TRAP_virtualisation   20
 #define TRAP_nr               32
 
-#define TRAP_HAVE_EC                                                    \
-    ((1u << TRAP_double_fault) | (1u << TRAP_invalid_tss) |             \
-     (1u << TRAP_no_segment) | (1u << TRAP_stack_error) |               \
-     (1u << TRAP_gp_fault) | (1u << TRAP_page_fault) |                  \
-     (1u << TRAP_alignment_check))
+#define TRAP_HAVE_EC X86_EXC_HAVE_EC
 
 /* Set for entry via SYSCALL. Informs return code to use SYSRETQ not IRETQ. */
 /* NB. Same as VGCF_in_syscall. No bits in common with any other TRAP_ defn. */
diff --git a/xen/include/asm-x86/x86-defns.h b/xen/include/asm-x86/x86-defns.h
index 8bf503220a..84e15b15be 100644
--- a/xen/include/asm-x86/x86-defns.h
+++ b/xen/include/asm-x86/x86-defns.h
@@ -118,4 +118,39 @@
 
 #define X86_NR_VECTORS 256
 
+/* Exception Vectors */
+#define X86_EXC_DE             0 /* Divide Error. */
+#define X86_EXC_DB             1 /* Debug Exception. */
+#define X86_EXC_NMI            2 /* NMI. */
+#define X86_EXC_BP             3 /* Breakpoint. */
+#define X86_EXC_OF             4 /* Overflow. */
+#define X86_EXC_BR             5 /* BOUND Range. */
+#define X86_EXC_UD             6 /* Invalid Opcode. */
+#define X86_EXC_NM             7 /* Device Not Available. */
+#define X86_EXC_DF             8 /* Double Fault. */
+#define X86_EXC_CSO            9 /* Coprocessor Segment Overrun. */
+#define X86_EXC_TS            10 /* Invalid TSS. */
+#define X86_EXC_NP            11 /* Segment Not Present. */
+#define X86_EXC_SS            12 /* Stack-Segment Fault. */
+#define X86_EXC_GP            13 /* General Porection Fault. */
+#define X86_EXC_PF            14 /* Page Fault. */
+#define X86_EXC_SPV           15 /* PIC Spurious Interrupt Vector. */
+#define X86_EXC_MF            16 /* Maths fault (x87 FPU). */
+#define X86_EXC_AC            17 /* Alignment Check. */
+#define X86_EXC_MC            18 /* Machine Check. */
+#define X86_EXC_XM            19 /* SIMD Exception. */
+#define X86_EXC_VE            20 /* Virtualisation Exception. */
+#define X86_EXC_CP            21 /* Control-flow Protection. */
+#define X86_EXC_HV            28 /* Hypervisor Injection. */
+#define X86_EXC_VC            29 /* VMM Communication. */
+#define X86_EXC_SX            30 /* Security Exception. */
+
+/* Bitmap of exceptions which have error codes. */
+#define X86_EXC_HAVE_EC                                             \
+    ((1u << X86_EXC_DF) | (1u << X86_EXC_TS) | (1u << X86_EXC_NP) | \
+     (1u << X86_EXC_SS) | (1u << X86_EXC_GP) | (1u << X86_EXC_PF) | \
+     (1u << X86_EXC_AC) | (1u << X86_EXC_CP) |                      \
+     (1u << X86_EXC_VC) | (1u << X86_EXC_SX))
+
+
 #endif	/* __XEN_X86_DEFNS_H__ */
