From: Julien Grall <julien.grall@linaro.org>
To: Ian Campbell <Ian.Campbell@citrix.com>,
Vijay Kilari <vijay.kilari@gmail.com>
Cc: Prasun Kapoor <Prasun.Kapoor@caviumnetworks.com>,
"xen-devel@lists.xen.org" <xen-devel@lists.xen.org>,
manishjaggi.oss@gmail.com,
Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Subject: Re: Criteria for dom0_gnttab_start
Date: Tue, 21 Oct 2014 13:12:38 +0100 [thread overview]
Message-ID: <54464DB6.7080509@linaro.org> (raw)
In-Reply-To: <1413893074.23337.31.camel@citrix.com>
On 10/21/2014 01:04 PM, Ian Campbell wrote:
> On Tue, 2014-10-21 at 17:24 +0530, Vijay Kilari wrote:
>> What is the criteria for setting dom0_gnttab_start and size for a
>> platform.
>
> It simply needs to be an area of the IPA address space which is not
> populated by anything else. Since dom0's MMIO space is mapped 1:1 with
> the host PA address space it seems easiest/safest to find a hole in the
> real physical space and use that.
>
> If there is no such hole available then using the space occupied by some
> device which is not passed to dom0 (e.g. is blacklisted, or used by Xen)
> will suffice.
>
> For an arm32 platform it should be below 4G.
Even on aarch64 platform, it will be better to have this range below 4G.
I'm thinking about having a 32 bit DOM0 on top on a 64 bit Xen. Though,
this may not happen often but we are currently supported this
possibility for DOM0.
Regards,
--
Julien Grall
next prev parent reply other threads:[~2014-10-21 12:12 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-21 11:54 Criteria for dom0_gnttab_start Vijay Kilari
2014-10-21 12:04 ` Ian Campbell
2014-10-21 12:12 ` Julien Grall [this message]
2014-10-21 12:14 ` Ian Campbell
2014-10-21 12:44 ` Vijay Kilari
2014-10-21 12:59 ` Ian Campbell
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