Re: [Qemu-devel] [PATCH 24/26] acpi, acpi_piix: factor out GPE logic

[Isaku Yamahata]

On Sun, Apr 17, 2011 at 04:17:51PM +0300, Avi Kivity wrote:
> On 03/16/2011 11:29 AM, Isaku Yamahata wrote:
>> factor out ACPI GPE logic. Later it will be used by ICH9 ACPI.
>>
>
> I think this patch is causing qemu-kvm failures on migration:
> (gdb) bt
> #0  0x000000000049aff4 in qemu_put_be16s (f=0x1a74490, pv=0x2c02580,  
> size=2) at hw/hw.h:108
> #1  put_uint16 (f=0x1a74490, pv=0x2c02580, size=2) at savevm.c:855
> #2  0x000000000049c3e4 in vmstate_save_state (f=0x1a74490,  
> vmsd=0x6f0b00, opaque=0x1842ef0) at savevm.c:1436
> #3  0x000000000049c3b6 in vmstate_save_state (f=0x1a74490,  
> vmsd=0x6f0aa0, opaque=0x1842b90) at savevm.c:1434
> #4  0x000000000049c6f1 in vmstate_save (mon=<value optimized out>,  
> f=0x1a74490) at savevm.c:1459
> #5  qemu_savevm_state_complete (mon=<value optimized out>, f=0x1a74490)  
> at savevm.c:1600
> #6  0x000000000049455a in migrate_fd_put_ready (opaque=0x1847890) at  
> migration.c:383
> #7  0x00000000004ce2eb in qemu_run_timers (clock=<value optimized out>)  
> at qemu-timer.c:505
> #8  0x00000000004ce806 in qemu_run_all_timers () at qemu-timer.c:619
> #9  0x0000000000419463 in main_loop_wait (nonblocking=<value optimized  
> out>) at /build/home/tlv/akivity/qemu-kvm/vl.c:1339
> #10 0x0000000000433927 in kvm_main_loop () at  
> /build/home/tlv/akivity/qemu-kvm/qemu-kvm.c:1590
> #11 0x000000000041a3a6 in main_loop (argc=<value optimized out>,  
> argv=<value optimized out>, envp=<value optimized out>)
>     at /build/home/tlv/akivity/qemu-kvm/vl.c:1369
> #12 main (argc=<value optimized out>, argv=<value optimized out>,  
> envp=<value optimized out>) at /build/home/tlv/akivity/qemu-kvm/vl.c:3257
>
> The vmstate being migrated is "gpe".
>
>
>
>>
>> +#define VMSTATE_GPE_ARRAY(_field, _state)                            \
>> + {                                                                   \
>> +     .name       = (stringify(_field)),                              \
>> +     .version_id = 0,                                                \
>> +     .num        = GPE_LEN,                                          \
>> +     .info       =&vmstate_info_uint16,                             \
>> +     .size       = sizeof(uint16_t),                                 \
>> +     .flags      = VMS_ARRAY | VMS_POINTER,                          \
>> +     .offset     = vmstate_offset_pointer(_state, _field, uint8_t),  \
>> + }
>> +
>>   static const VMStateDescription vmstate_gpe = {
>>       .name = "gpe",
>>       .version_id = 1,
>>       .minimum_version_id = 1,
>>       .minimum_version_id_old = 1,
>>       .fields      = (VMStateField []) {
>> -        VMSTATE_UINT16(sts, struct gpe_regs),
>> -        VMSTATE_UINT16(en, struct gpe_regs),
>> +        VMSTATE_GPE_ARRAY(sts, ACPIGPE),
>> +        VMSTATE_GPE_ARRAY(en, ACPIGPE),
>>           VMSTATE_END_OF_LIST()
>>       }
>>   };
>
> I'm no vmstate expert, but this does look odd.  Why both VMS_ARRAY and  
> VMS_POINTER? aren't we trying to save/restore a simple 16-bit value?  Or  
> at least we did before this patch.

That's right. the difference is, the new member type became uint8_t*.
Does the following help?

diff --git a/hw/acpi_piix4.c b/hw/acpi_piix4.c
index 96f5222..3a8fece 100644
--- a/hw/acpi_piix4.c
+++ b/hw/acpi_piix4.c
@@ -214,10 +214,9 @@ static int vmstate_acpi_post_load(void *opaque, int 
version_id)
  {                                                                   \
      .name       = (stringify(_field)),                              \
      .version_id = 0,                                                \
-     .num        = GPE_LEN,                                          \
      .info       = &vmstate_info_uint16,                             \
      .size       = sizeof(uint16_t),                                 \
-     .flags      = VMS_ARRAY | VMS_POINTER,                          \
+     .flags      = VMS_SINGLE | VMS_POINTER,                         \
      .offset     = vmstate_offset_pointer(_state, _field, uint8_t),  \
  }
 


-- 
yamahata