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From: Paul Brook <paul@codesourcery.com>
To: qemu-devel@nongnu.org
Cc: Blue Swirl <blauwirbel@gmail.com>, Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: [Qemu-devel] Re: [PATCH 0/5] *** SUBJECT HERE ***
Date: Thu, 1 Apr 2010 12:48:05 +0000	[thread overview]
Message-ID: <201004011348.05539.paul@codesourcery.com> (raw)
In-Reply-To: <r2hf43fc5581003311008k2e0a1f64xfc6d68151648c3cc@mail.gmail.com>

> >  One example is the openpic page size pointed out downthread.
> >
> >  What about something like this (doesn't change all the places affected
> >  by your series, compile-tested only)?
> 
> In general (with vmport and maybe virtio as the only exceptions), the
> devices have no business knowing _any_ CPU properties, like page size
> or endianness. If there really was a device that really cared about
> CPU page size, the size should be also known by the board and should
> be passed down from there via qdev property. Byte swapping should be
> handled by the bus, bus controller or memory controller.

I agree. Most of the uses of TARGET_PAGE_SIZE are simply an optimization - 
it's a convenient buffer size for DMA transfers. Other uses are probably 
incorrect.

None of virtio.c, virtio-{blk,net,serial} or virtio-{pci,syborg} should know 
about CPU properties. Virtio-s390 might because it's implementing magic CPU 
instructions.

Paul

      parent reply	other threads:[~2010-04-01 12:48 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-03-26 19:02 [Qemu-devel] [PATCH 00/10] Today's compilation fixes Blue Swirl
2010-03-31 16:23 ` [Qemu-devel] [PATCH 0/5] *** SUBJECT HERE *** Paolo Bonzini
2010-03-31 17:08   ` [Qemu-devel] " Blue Swirl
2010-03-31 19:08     ` Aurelien Jarno
2010-04-01 12:48     ` Paul Brook [this message]

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