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From: Gerd Hoffmann <kraxel@redhat.com>
Date: Wed, 11 Sep 2013 12:37:40 +0200
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Subject: Re: [Qemu-devel] [RFC PATCH v5 5/6] configure: introduce
	--enable-modules
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To: Peter Maydell <peter.maydell@linaro.org>
Cc: Fam Zheng <famz@redhat.com>, Michael Tokarev <mjt@tls.msk.ru>, QEMU Developers <qemu-devel@nongnu.org>, Stefan Hajnoczi <stefanha@redhat.com>, Paolo Bonzini <pbonzini@redhat.com>, =?ISO-8859-1?Q?Llu=EDs?= Vilanova <vilanova@ac.upc.edu>, Richard Henderson <rth@twiddle.net>

> >  (3) rom->num_pages field.  That one will change for arm.  The linux
> >      kernel qxl kms driver seems not to care at all.  Not surprising,
> >      it is more convenient to use the offsets in the rom to figure how
> >      the qxl memory layout looks like.
> 
> Note that the ARM Linux *kernel* will (probably) be using 4K pages
> anyway. It's just that QEMU's TARGET_PAGE_SIZE means "smallest
> page size this CPU family could possibly support", which for ARM
> is 1K, even if 99.9% of guests won't use 1K pages. This is one
> of the reasons it's not very useful for devices -- it's almost just
> an internal implementation detail of QEMU's TLB/memory system.
> 
> What is the num_pages field supposed to mean, given that
> "page size" isn't a well defined platform independent value
> (for hardware or for QEMU)?

It's 4k on x86 and not really defined on !x86 (with the !x86 installed
base being pretty close to zero).

I think we should just define it to be 4k everywhere.

cheers,
  Gerd