linux-kernel - Re: [Xen-devel] [PATCH] xen/x86: Zero out .bss for PV guests

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Message-ID: <56CDBA5A.1000600@citrix.com>
Date:	Wed, 24 Feb 2016 14:12:42 +0000
From:	David Vrabel <david.vrabel@...rix.com>
To:	Boris Ostrovsky <boris.ostrovsky@...cle.com>,
	<konrad.wilk@...cle.com>, <david.vrabel@...rix.com>
CC:	<xen-devel@...ts.xenproject.org>, <mcgrof@...nel.org>,
	<linux-kernel@...r.kernel.org>
Subject: Re: [Xen-devel] [PATCH] xen/x86: Zero out .bss for PV guests

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