Re: [Xen-devel] [PATCH][BIOS]Fix TPMD and QEMU connection

[Kouichi Yasaki <yasaki.kouichi@xxxxxxxxxxxxxx>]

Hi Stefan-san,

Thank you for correcting my patch.
I also think that it should not try to connect endlessly in a busy loop.

attached file is the corrected patch.

Thanks
  Kouichi YASAKI

> xen-devel-bounces@xxxxxxxxxxxxxxxxxxx wrote on 12/19/2007 07:53:11 PM:
>
>  > Hi,
>  >
>  > In HVM domain, MA_Transmit function in tcgbios sometimes become an error
>  > (TCG_NO_RESPONSE). The cause of the error is not to make connection of
>  > QEMU and TPMD instance within a timeout of MA_Transmit function.
>  >
>  > Before the MA_Transmit function was called, the attached patch 
> corrected so
>  > that connection of QEMU and TPMD might be completed.
>  >
>  > Signed-off-by: Kouichi YASAKI <yasaki.kouichi@xxxxxxxxxxxxxx>
>  >
>  > Thanks
>  >   Kouichi YASAKI
>  >
>  > diff -r d9ab9eb2bfee tools/ioemu/hw/tpm_tis.c
>  > --- a/tools/ioemu/hw/tpm_tis.c   Sat Dec 15 18:29:27 2007 +0000
>  > +++ b/tools/ioemu/hw/tpm_tis.c   Mon Dec 17 19:46:42 2007 +0900
>  > @@ -904,6 +904,10 @@ void tpm_tis_init(SetIRQFunc *set_irq, v
>  >      memset(s->buffer.buf,0,sizeof(s->buffer.buf));
>  >  
>  >      register_savevm("tpm-tis", 0, 1, tpm_save, tpm_load, s);
>  > +
>  > +    while(!IS_COMM_WITH_VTPM(s)){
>  > +       open_vtpm_channel(s);
>  > +    }
>  >  }
>
> I'll have a look at this. The problem probably stems from the vTPM 
> manager starting the vTPM up too late while qemu is already up and 
> running, so it's a timing problem between the two processes. I don't 
> think it should try to connect endlessly in a busy loop. At least there 
> should be a counter that tries this for maybe 5 times followed by a 
> [u]sleep() in the loop.
>     int ctr = 0;
>     while(!IS_COMM_WITH_VTPM(s) && ctr < 5){
>       open_vtpm_channel(s);
>        ctr ++;
>        sleep(1);
>    }
>
>
>    Stefan
>
>  >  
>  >  
>  > 
> /****************************************************************************/
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>  > Xen-devel@xxxxxxxxxxxxxxxxxxx
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diff -r 966a6d3b7408 tools/ioemu/hw/tpm_tis.c
--- a/tools/ioemu/hw/tpm_tis.c  Fri Dec 14 11:50:24 2007 +0000
+++ b/tools/ioemu/hw/tpm_tis.c  Thu Dec 20 11:56:24 2007 +0900
@@ -904,6 +904,13 @@ void tpm_tis_init(SetIRQFunc *set_irq, v
     memset(s->buffer.buf,0,sizeof(s->buffer.buf));
 
     register_savevm("tpm-tis", 0, 1, tpm_save, tpm_load, s);
+
+    int ctr = 0;
+    while(!IS_COMM_WITH_VTPM(s) && ctr < 5){
+       open_vtpm_channel(s);
+       ctr++;
+       sleep(1);
+    }
 }
 
 /****************************************************************************/

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