From: "H. Peter Anvin" <hpa@linux.intel.com>
To: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: Yinghai Lu <yinghai@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>,
"konrad.wilk@oracle.com" <konrad.wilk@oracle.com>,
"jeremy@goop.org" <jeremy@goop.org>,
"mingo@elte.hu" <mingo@elte.hu>, "H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [PATCH 2/4] x86,xen: introduce x86_init.mapping.pagetable_reserve
Date: Wed, 13 Apr 2011 11:28:22 -0700 [thread overview]
Message-ID: <4DA5EB46.6090302@linux.intel.com> (raw)
In-Reply-To: <alpine.DEB.2.00.1104131125080.22672@kaball-desktop>
On 04/13/2011 03:35 AM, Stefano Stabellini wrote:
> Yes, that would be ideal, but we cannot do that because we don't know
> exactly where is pgt_buf_end before allocating the pagetable pages and
> the pagetable pages need to be marked RO before being hooked into the
> pagetable. This is why we mark the whole range RO and after the
> pagetable allocation when we know for sure where is pgt_buf_end we
> modify the range pgt_buf_end-pgt_buf_top to RW.
The hell? You have to fill the pages before you hook them into the page
tables anyway (this means writing!) and then you have to mark them RO as
you add them to the page tables... anything else doesn't make any sense
at all.
-hpa
next prev parent reply other threads:[~2011-04-13 18:28 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-04-12 11:16 [PATCH 0/4] xen: critical bug fixes for 2.6.39-rc3 Stefano Stabellini
2011-04-12 11:19 ` [PATCH 1/4] xen: mask_rw_pte mark RO all pagetable pages up to pgt_buf_top stefano.stabellini
2011-04-12 16:47 ` Konrad Rzeszutek Wilk
2011-04-13 10:24 ` Stefano Stabellini
2011-04-12 11:19 ` [PATCH 2/4] x86,xen: introduce x86_init.mapping.pagetable_reserve stefano.stabellini
2011-04-12 11:50 ` [Xen-devel] [PATCH 2/4] x86, xen: " Jan Beulich
2011-04-12 17:41 ` Stefano Stabellini
2011-04-12 17:40 ` [PATCH 2/4] x86,xen: " Yinghai Lu
2011-04-13 10:35 ` Stefano Stabellini
2011-04-13 18:28 ` H. Peter Anvin [this message]
2011-04-14 11:05 ` Stefano Stabellini
2011-04-13 18:03 ` Konrad Rzeszutek Wilk
2011-04-13 18:35 ` [PATCH 2/4] x86, xen: " H. Peter Anvin
2011-04-13 20:19 ` [PATCH 2/4] x86,xen: " Konrad Rzeszutek Wilk
2011-04-13 18:26 ` H. Peter Anvin
2011-04-14 11:30 ` Stefano Stabellini
2011-04-14 14:49 ` Stefano Stabellini
2011-04-14 14:52 ` H. Peter Anvin
2011-04-14 18:09 ` Stefano Stabellini
2011-04-18 14:09 ` Stefano Stabellini
2011-04-18 14:42 ` H. Peter Anvin
2011-04-18 17:21 ` Stefano Stabellini
2011-04-20 16:50 ` Jeremy Fitzhardinge
2011-04-12 11:19 ` [PATCH 3/4] xen: more debugging in the e820 parsing stefano.stabellini
2011-04-12 16:39 ` Konrad Rzeszutek Wilk
2011-04-13 10:24 ` Stefano Stabellini
2011-04-13 17:54 ` Konrad Rzeszutek Wilk
2011-04-14 10:35 ` Stefano Stabellini
2011-04-12 11:19 ` [PATCH 4/4] xen: do not create the extra e820 region at an addr lower than 4G stefano.stabellini
2011-04-12 16:48 ` Konrad Rzeszutek Wilk
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