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Re: [Xen-devel] [PATCH] VT-d: make remap_entry_to_msi_msg() return consistent message


  • To: Jan Beulich <jbeulich@xxxxxxxx>
  • From: Keir Fraser <keir.xen@xxxxxxxxx>
  • Date: Wed, 03 Oct 2012 15:33:23 +0100
  • Cc: xen-devel@xxxxxxxxxxxxx
  • Delivery-date: Wed, 03 Oct 2012 14:33:50 +0000
  • List-id: Xen developer discussion <xen-devel.lists.xen.org>
  • Thread-index: Ac2hdAqdZqxvk+zzlU2H13WEuwuTrw==
  • Thread-topic: [Xen-devel] [PATCH] VT-d: make remap_entry_to_msi_msg() return consistent message

On 03/10/2012 13:58, "Jan Beulich" <jbeulich@xxxxxxxx> wrote:

>>>> Keir Fraser <keir@xxxxxxx> 10/02/12 7:01 PM >>>
>> On 02/10/2012 15:55, "Jan Beulich" <JBeulich@xxxxxxxx> wrote:
>> 
>>> During debugging of another problem I found that in x2APIC mode, the
>>> destination field of the low address value wasn't passed back
>>> correctly. While this is benign in most cases (as the value isn't being
>>> used anywhere), it can be confusing (and misguiding) when printing the
>>> value read or when comparing it to the one previously passed into the
>>> inverse function.
>>> 
>>> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
>> 
>> Acked-by: Keir Fraser <keir@xxxxxxx>
> 
> Actually on my way home yesterday I realized that this is not consistent, i.e.
> fails to cover symmetrically the !x2apic case. Therefore, I'd like to adjust
> this
> to pull out the msg->dest32 assignment from the conditional. Will that be okay
> to commit without re-submission?

Yes, that's fine by me.

 -- Keir

> Jan
> 
>> --- a/xen/drivers/passthrough/vtd/intremap.c
>> +++ b/xen/drivers/passthrough/vtd/intremap.c
>> @@ -504,7 +504,11 @@ static int remap_entry_to_msi_msg(
>>              MSI_ADDR_REDIRECTION_CPU:
>>              MSI_ADDR_REDIRECTION_LOWPRI);
>>      if ( x2apic_enabled )
>> +    {
>>          msg->dest32 = iremap_entry->lo.dst;
>> +        msg->address_lo |=
>> +            (iremap_entry->lo.dst & 0xff) << MSI_ADDR_DEST_ID_SHIFT;
>> +    }
>>      else
>>          msg->address_lo |=
>>              ((iremap_entry->lo.dst >> 8) & 0xff ) << MSI_ADDR_DEST_ID_SHIFT;
>> 
>> 
>> 
>> _______________________________________________
>> Xen-devel mailing list
>> Xen-devel@xxxxxxxxxxxxx
>> http://lists.xen.org/xen-devel
> 
> 
> 
> 
> 



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