From mboxrd@z Thu Jan  1 00:00:00 1970
From: Keir Fraser <keir@xensource.com>
Subject: Re: trap bounce flags
Date: Wed, 25 Apr 2007 11:16:46 +0100
Message-ID: <C254E91E.DD02%keir@xensource.com>
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On 25/4/07 11:10, "Keir Fraser" <keir@xensource.com> wrote:

>> - from the above, why is it that only the lower byte (if anything) needs
>> clearing?
> 
> Really it's a one-byte field: it's consistently treated that way in asm
> code. The upper byte is always zero. We should probably make the field
> explicitly uint8_t. Agree?

FYI, we need to clear that field usually because the contents are one-shot
but the structure itself is permanent and checked on every return to guest.
A non-zero flags field is what we use to indicate whether the structure is
'primed' or not. So the passing in of a different, non-one-shot, structure
on the direct-int80 path is a bit abusive of the interface. But I think we
can live with it if we reset the flags field manually and include a comment.
:-)

 -- Keir