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Date: Tue, 02 Aug 2011 14:49:33 +0200
From: Jan Kiszka <jan.kiszka@siemens.com>
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Subject: Re: [Qemu-devel] [PATCH] xen: Avoid useless allocation in Xen case.
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To: Anthony PERARD <anthony.perard@citrix.com>
Cc: Xen Devel <xen-devel@lists.xensource.com>, Alexander Graf <agraf@suse.de>, Stefano Stabellini <stefano.stabellini@eu.citrix.com>, QEMU-devel <qemu-devel@nongnu.org>

On 2011-08-02 14:13, Anthony PERARD wrote:
> On Tue, Aug 2, 2011 at 11:49, Jan Kiszka <jan.kiszka@siemens.com> wrote:
>>> The same applies to kvm, please generalize.
>>
>> Actually, qemu-kvm avoids this overhead today by making code_gen_alloc
>> return immediately when kvm is on. Also not very beautiful.
>>
>> Can't we simply skip cpu_exec_init_all for any accel != TCG, e.g. by
>> moving that call to tcg_init?
> 
> In the function cpu_exec_init_all(), the call to cpu_gen_init() (and I
> suppose to io_mem_init()) is still required. So we can not move the
> whole function to tcg_init().
> 
> But I can maybe use "if (!tcg_enabled())" instead of a check to xen.
> Until no tcg code is use when kvm/xen is enabled.

I would prefer to take the chance and clean up. Anything TCG related
belongs to tcg_init (or a function called from it). Shared services
should be initialized as before. Will send a patch to make a start.

Jan

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