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Subject: Re: [Xen-devel] [PATCH] xen/x86: Zero out .bss for PV guests
To: Boris Ostrovsky <boris.ostrovsky@oracle.com>, <konrad.wilk@oracle.com>,
        <david.vrabel@citrix.com>
References: <1456178767-8038-1-git-send-email-boris.ostrovsky@oracle.com>
CC: <xen-devel@lists.xenproject.org>, <mcgrof@kernel.org>,
        <linux-kernel@vger.kernel.org>
From: David Vrabel <david.vrabel@citrix.com>
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Date: Wed, 24 Feb 2016 14:12:42 +0000
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On 22/02/16 22:06, Boris Ostrovsky wrote:
> Baremetal kernels clear .bss early in the boot. Since Xen PV guests don't
> excecute that early code they should do it too.
> 
> (Since we introduce macros for specifying 32- and 64-bit registers we
> can get rid of ifdefs in startup_xen())

.bss must have been cleared for PV guests otherwise they would be
horribly broken.  What was the method and why is it no longer sufficient?

David