[Xen-devel] RE: [PATCH] to put dmar hidding/restoring into Xen to fix S3 w/ TXT (Resend)

["Wang, Shane" <shane.wang@xxxxxxxxx>]

Oh, forget that. I saw acpi_dmar_zap() in enter_state().

Thanks.
Shane

Wang, Shane wrote on 2011-01-11:

> OK. Then restoring DMAR is not necessary before S3.
> But I am thinking whether we need to hide DMAR again after S3 resume.
> 
> Thanks.
> Shane
> 
> Keir Fraser wrote on 2011-01-10:
> 
>> On 10/01/2011 03:32, "Wang, Shane" <shane.wang@xxxxxxxxx> wrote:
>> 
>>> Put the code for hidding and restoring DMAR table from tboot into
>>> Xen in order to fix S3 broken issue with TXT launch.
>> 
>> We already do this in arch/x86/acpi/power.c:enter_state(). Since
>> enter_state() is in the call stack of tboot_shutdown(), via
>> tboot_sleep(), this patch is unnecessary. In fact acpi_dmar_reinstate()
>> is not idempotent, so I actually think this patch takes a reinstated
>> DMAR and breaks its checksum!
>> 
>>  -- Keir
>>  
>>> Signed-off-by: Shane Wang <shane.wang@xxxxxxxxx>
>>> 
>>> diff -r 946d84529a07 xen/arch/x86/tboot.c
>>> --- a/xen/arch/x86/tboot.c Sat Jan 08 11:07:18 2011 +0000
>>> +++ b/xen/arch/x86/tboot.c Wed Jan 12 01:37:14 2011 +0800
>>> @@ -352,6 +352,9 @@ void tboot_shutdown(uint32_t shutdown_ty
>>> 
>>>      /* if this is S3 then set regions to MAC */
>>>      if ( shutdown_type == TB_SHUTDOWN_S3 ) {
>>> +        /* restore DMAR table */
>>> +        acpi_dmar_reinstate();
>>> +
>>>          /*
>>>           * Xen regions for tboot to MAC
>>>           */
>>> @@ -484,6 +487,7 @@ int tboot_s3_resume(void)  int
>>> tboot_s3_resume(void)  {
>>>      vmac_t mac;
>>> +    int ret = 0;
>>> 
>>>      if ( !tboot_in_measured_env() )
>>>          return 0;
>>> @@ -492,22 +496,30 @@ int tboot_s3_resume(void)
>>>      tboot_gen_xenheap_integrity(g_tboot_shared->s3_key, &mac);
>>>      printk("MAC for xenheap before S3 is: 0x%08"PRIx64"\n",
>>>      xenheap_mac); printk("MAC for xenheap after S3 is:
>>>      0x%08"PRIx64"\n", mac);
>>> -    if ( mac != xenheap_mac )
>>> -        return -1;
>>> +    if ( mac != xenheap_mac ) {
>>> +        ret = -1;
>>> +        goto exit;
>>> +    }
>>> 
>>>      tboot_gen_frametable_integrity(g_tboot_shared->s3_key, &mac);
>>>      printk("MAC for frametable before S3 is: 0x%08"PRIx64"\n",
>>>      frametable_mac); printk("MAC for frametable after S3 is:
>>>      0x%08"PRIx64"\n", mac);
>>> -    if ( mac != frametable_mac )
>>> -        return -2;
>>> +    if ( mac != frametable_mac ) {
>>> +        ret = -2;
>>> +        goto exit;
>>> +    }
>>> 
>>>      tboot_gen_domain_integrity(g_tboot_shared->s3_key, &mac);
>>>      printk("MAC for domains before S3 is: 0x%08"PRIx64"\n",
>>>      domain_mac); printk("MAC for domains after S3 is:
>>>      0x%08"PRIx64"\n", mac);
>>> -    if ( mac != domain_mac )
>>> -        return -3;
>>> +    if ( mac != domain_mac ) {
>>> +        ret = -3;
>>> +        goto exit;
>>> +    }
>>> 
>>> -    return 0;
>>> +exit:
>>> +    acpi_dmar_zap();
>>> +    return ret;
>>>  }
>>>  
>>>  /*
>> 
>



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