[SeaBIOS] [QUESTION]stuck in SeaBIOS and vm can not be reset any more

[Xulei (Stone)]

>On Tue, Aug 02, 2016 at 04:18:30AM +0000, Xulei (Stone) wrote:
>> >On Fri, Jul 29, 2016 at 04:04:59AM +0000, Xulei (Stone) wrote:
>> >> After one day, the vm is stuck. Looking from the following seabios log,
>> >> it seems seabios stops at "PCI: Using 00:02.0 for primary VGA", and can
>> >> not execute handle_smp() any more.
>> >> What may be the reason?
>> >
>> >More debugging info would be necessary to find this problem.  You
>> >could try reproducing and attaching gdb (
>> >http://www.seabios.org/Debugging#Debugging_with_gdb_on_QEMU ).
>> >Alternatively, a kvm trace log may help.
>> >
>> kvm trace (seems useful) indicates that cpu 0 keeps always to access 0x00b3 ioport.
>> 0x00b3 is PORT_SMI_STATUS, so i guess my bios is stuck in the function
>> smm_relocate_and_restore
>> {
>>       ...
>>       /* wait until SMM code executed */
>>     while (inb(PORT_SMI_STATUS) != 0x00)
>>       ...
>> }
>
>I'd try adding dprintf() statements around all the code at the top of
>smm_relocate_and_restore() and enable the dprintf() at the top of
>handle_smi().
>
>It would also be useful if you can extract the log from the last
>two working reboots to compare it to the failed case.
Following your suggestion, i'm now sure it is caused by missing SMI.
I'd try adding dprintf() like this:

--- a/roms/seabios/src/fw/smm.c
+++ b/roms/seabios/src/fw/smm.c
@@ -65,7 +65,8 @@ handle_smi(u16 cs)
     u8 cmd = inb(PORT_SMI_CMD);
     struct smm_layout *smm = MAKE_FLATPTR(cs, 0);
     u32 rev = smm->cpu.i32.smm_rev & SMM_REV_MASK;
-    dprintf(DEBUG_HDL_smi, "handle_smi cmd=%x smbase=%p\n", cmd, smm);
+    if(cmd == 0x00) {
+    	dprintf(1, "handle_smi cmd=%x smbase=%p\n", cmd, smm);
+    }
 
     if (smm == (void*)BUILD_SMM_INIT_ADDR) {
         // relocate SMBASE to 0xa0000
@@ -147,14 +148,14 @@ smm_relocate_and_restore(void)
 {
     /* init APM status port */
     outb(0x01, PORT_SMI_STATUS);
+   dprintf(1,"before SMI====\n");

     /* raise an SMI interrupt */
     outb(0x00, PORT_SMI_CMD);
+    dprintf(1,"after SMI=====\n");

     /* wait until SMM code executed */
     while (inb(PORT_SMI_STATUS) != 0x00)
         ;
+   dprintf(1,"smm code executes complete====\n");

And the failed case log output like this:
2016-08-03 16:23:15PCI: Using 00:02.0 for primary VGA
2016-08-03 16:23:15smm_device_setup start
2016-08-03 16:23:15init smm
2016-08-03 16:23:15before SMI====
2016-08-03 16:23:15after SMI=====

So, it's obviously that after outb(0x01, PORT_SMI_STATUS), bios does not
handle smi, so PORT_SMI_STATUS is always 0x01. What's more, when this
problem happens, reboot can not invoke SMI any more. My vm is always 
stuck at the same place util i destroy it.
 
Is this a kvm bug or qemu bug?
>
>-Kevin