diff --git a/hw/pc.c b/hw/pc.c
index 203627d..76d0790 100644
--- a/hw/pc.c
+++ b/hw/pc.c
@@ -43,6 +43,7 @@
 #include "ui/qemu-spice.h"
 #include "memory.h"
 #include "exec-memory.h"
+#include "trace.h"
 
 /* output Bochs bios info messages */
 //#define DEBUG_BIOS
@@ -516,6 +517,16 @@ static void handle_a20_line_change(void *opaque, int irq, int level)
 
 /***********************************************************/
 /* Bochs BIOS debug ports */
+enum {
+  PROBE_SEABIOS_POST = 1001,
+  PROBE_SEABIOS_INT_18 = 1002,
+  PROBE_SEABIOS_INT_19 = 1003,
+  PROBE_SEABIOS_BOOT_OS = 1004,
+
+  PROBE_LINUXBOOT_COPY_KERNEL = 2001,
+  PROBE_LINUXBOOT_COPY_INITRD = 2002,
+  PROBE_LINUXBOOT_BOOT_OS = 2003,
+};
 
 static void bochs_bios_write(void *opaque, uint32_t addr, uint32_t val)
 {
@@ -534,6 +545,31 @@ static void bochs_bios_write(void *opaque, uint32_t addr, uint32_t val)
         fprintf(stderr, "%c", val);
 #endif
         break;
+    case 0x404: {
+	switch (val) {
+	case PROBE_SEABIOS_POST:
+	    trace_seabios_post();
+	    break;
+	case PROBE_SEABIOS_INT_18:
+	    trace_seabios_int_18();
+	    break;
+	case PROBE_SEABIOS_INT_19:
+	    trace_seabios_int_19();
+	    break;
+	case PROBE_SEABIOS_BOOT_OS:
+	    trace_seabios_boot_OS();
+	    break;
+	case PROBE_LINUXBOOT_COPY_KERNEL:
+	    trace_linuxboot_copy_kernel();
+	    break;
+	case PROBE_LINUXBOOT_COPY_INITRD:
+	    trace_linuxboot_copy_initrd();
+	    break;
+	case PROBE_LINUXBOOT_BOOT_OS:
+	    trace_linuxboot_boot_OS();
+	    break;
+	}
+    }   break;
     case 0x8900:
         /* same as Bochs power off */
         if (val == shutdown_str[shutdown_index]) {
@@ -589,6 +625,7 @@ static void *bochs_bios_init(void)
     register_ioport_write(0x401, 1, 2, bochs_bios_write, NULL);
     register_ioport_write(0x402, 1, 1, bochs_bios_write, NULL);
     register_ioport_write(0x403, 1, 1, bochs_bios_write, NULL);
+    register_ioport_write(0x404, 1, 4, bochs_bios_write, NULL);
     register_ioport_write(0x8900, 1, 1, bochs_bios_write, NULL);
 
     register_ioport_write(0x501, 1, 1, bochs_bios_write, NULL);
diff --git a/pc-bios/linuxboot.bin b/pc-bios/linuxboot.bin
index e7c3669..40b9217 100644
Binary files a/pc-bios/linuxboot.bin and b/pc-bios/linuxboot.bin differ
diff --git a/pc-bios/optionrom/linuxboot.S b/pc-bios/optionrom/linuxboot.S
index 748c831..5c39fb1 100644
--- a/pc-bios/optionrom/linuxboot.S
+++ b/pc-bios/optionrom/linuxboot.S
@@ -108,11 +108,21 @@ copy_kernel:
 	/* We're now running in 16-bit CS, but 32-bit ES! */
 
 	/* Load kernel and initrd */
+	mov		$0x7d1,%eax
+	mov		$0x404,%edx
+	outl		%eax,(%dx)
 	read_fw_blob_addr32(FW_CFG_KERNEL)
+	mov		$0x7d2,%eax
+	mov		$0x404,%edx
+	outl		%eax,(%dx)
 	read_fw_blob_addr32(FW_CFG_INITRD)
 	read_fw_blob_addr32(FW_CFG_CMDLINE)
 	read_fw_blob_addr32(FW_CFG_SETUP)
 
+	mov		$0x7d3,%eax
+	mov		$0x404,%edx
+	outl		%eax,(%dx)
+
 	/* And now jump into Linux! */
 	mov		$0, %eax
 	mov		%eax, %cr0
diff --git a/trace-events b/trace-events
index a31d9aa..34ca28b 100644
--- a/trace-events
+++ b/trace-events
@@ -289,6 +289,11 @@ scsi_request_sense(int target, int lun, int tag) "target %d lun %d tag %d"
 
 # vl.c
 vm_state_notify(int running, int reason) "running %d reason %d"
+main_start(void) "startup"
+main_loop(void) "loop"
+main_stop(void) "stop"
+qemu_shutdown_request(void) "shutdown request"
+qemu_powerdown_request(void) "powerdown request"
 
 # block/qed-l2-cache.c
 qed_alloc_l2_cache_entry(void *l2_cache, void *entry) "l2_cache %p entry %p"
@@ -502,3 +507,12 @@ escc_sunkbd_event_in(int ch) "Untranslated keycode %2.2x"
 escc_sunkbd_event_out(int ch) "Translated keycode %2.2x"
 escc_kbd_command(int val) "Command %d"
 escc_sunmouse_event(int dx, int dy, int buttons_state) "dx=%d dy=%d buttons=%01x"
+
+seabios_post(void) "BIOS post"
+seabios_int_18(void) "BIOS int18"
+seabios_int_19(void) "BIOS int19"
+seabios_boot_OS(void) "BIOS boot OS"
+
+linuxboot_copy_kernel(void) "LinuxBoot Copy Kernel"
+linuxboot_copy_initrd(void) "LinuxBoot Copy InitRD"
+linuxboot_boot_OS(void) "LinuxBoot boot OS"
diff --git a/vl.c b/vl.c
index bd4a5ce..91e6f5e 100644
--- a/vl.c
+++ b/vl.c
@@ -162,7 +162,7 @@ int main(int argc, char **argv)
 #include "qemu-queue.h"
 #include "cpus.h"
 #include "arch_init.h"
-
+#include "trace.h"
 #include "ui/qemu-spice.h"
 
 //#define DEBUG_NET
@@ -1414,12 +1414,14 @@ void qemu_system_killed(int signal, pid_t pid)
 
 void qemu_system_shutdown_request(void)
 {
+    trace_qemu_shutdown_request();
     shutdown_requested = 1;
     qemu_notify_event();
 }
 
 void qemu_system_powerdown_request(void)
 {
+    trace_qemu_powerdown_request();
     powerdown_requested = 1;
     qemu_notify_event();
 }
@@ -2313,6 +2315,8 @@ int main(int argc, char **argv, char **envp)
     const char *trace_events = NULL;
     const char *trace_file = NULL;
 
+    trace_main_start();
+
     atexit(qemu_run_exit_notifiers);
     error_set_progname(argv[0]);
 
@@ -3571,10 +3575,12 @@ int main(int argc, char **argv, char **envp)
 
     os_setup_post();
 
+    trace_main_loop();
     main_loop();
     quit_timers();
     net_cleanup();
     res_free();
 
+    trace_main_stop();
     return 0;
 }