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From: Mark McLoughlin <markmc@redhat.com>
To: Alexander van Heukelum <heukelum@fastmail.fm>
Cc: Alexander van Heukelum <heukelum@mailshack.com>,
Ingo Molnar <mingo@elte.hu>, Ian Campbell <ijc@hellion.org.uk>,
"H. Peter Anvin" <hpa@zytor.com>, Andi Kleen <ak@suse.de>,
Thomas Gleixner <tglx@linutronix.de>,
Jeremy Fitzhardinge <jeremy@goop.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] reserve end-of-conventional-memory to 1MB on 32-bit
Date: Fri, 29 Feb 2008 22:06:59 +0000 [thread overview]
Message-ID: <1204322819.6299.1.camel@muff> (raw)
In-Reply-To: <1204310323.24514.1239870063@webmail.messagingengine.com>
On Fri, 2008-02-29 at 19:38 +0100, Alexander van Heukelum wrote:
> On Fri, 29 Feb 2008 17:14:07 +0000, "Mark McLoughlin"
> <markmc@redhat.com> said:
>
> > I haven't investigated in any detail, but with 2.6.25-rc3 and your
> > patch I'm seeing a Xen guest hit this BUG:
> >
> > void __init smp_alloc_memory(void)
> > {
> > trampoline_base = alloc_bootmem_low_pages(PAGE_SIZE);
> > /*
> > * Has to be in very low memory so we can execute
> > * real-mode AP code.
> > */
> > if (__pa(trampoline_base) >= 0x9F000)
> > BUG();
> > }
> >
> > Stack looks like:
> >
> > [<c137ef97>] smp_alloc_memory+0x25 <--
> > [<c137ef97>] smp_alloc_memory+0x25
> > [<c137a500>] setup_arch+0x28e
> > [<c13735f7>] start_kernel+0x7a
> > [<c1379240>] xen_start_kernel+0x300
>
> Ouch.
>
> My first guess is that the BIOS data area is completely non-existent for
> Xen.
> Is it guaranteed that the memory is zeroed out on boot?
Yep, that seems to be the case
> In that case we can special-case it easily:
>
> change:
> /* Paranoia: should never happen, but... */
> if (lowmem >= 0x100000)
> lowmem = 0xa0000;
>
> into:
> /* Strange case, like Xen ;) */
> if (lowmem == 0 || lowmem >= 0x100000)
> lowmem = 0x9f000;
>
> Can you test that?
Yes, that fixes boot for me.
Thanks,
Mark.
next prev parent reply other threads:[~2008-02-29 22:07 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-02-24 17:46 [PATCH] Fix alignment of early reservation for EBDA Alexander van Heukelum
2008-02-24 19:27 ` Andi Kleen
2008-02-24 19:41 ` Ingo Molnar
2008-02-24 20:53 ` Alexander van Heukelum
2008-02-25 2:18 ` H. Peter Anvin
2008-02-25 16:54 ` Alexander van Heukelum
2008-02-25 17:01 ` Ingo Molnar
2008-02-25 18:07 ` [PATCH] reserve_early end-of-conventional-memory to 1MB Alexander van Heukelum
2008-02-25 18:13 ` H. Peter Anvin
2008-02-25 19:46 ` Alexander van Heukelum
2008-02-25 21:17 ` H. Peter Anvin
2008-02-26 9:30 ` Ingo Molnar
2008-02-27 14:26 ` Andi Kleen
2008-02-27 14:38 ` [PATCH] reserve_early end-of-conventional-memory to 1MB II - some numbers to put it into perspective Andi Kleen
2008-02-27 16:44 ` H. Peter Anvin
2008-02-27 20:01 ` Alexander van Heukelum
2008-02-28 13:13 ` [PATCH] reserve end-of-conventional-memory to 1MB on 32-bit Alexander van Heukelum
2008-02-28 13:28 ` [RFC] use realmode code to reserve end-of-conventional-memory to 1MB Alexander van Heukelum
2008-02-28 21:12 ` Ian Campbell
2008-02-28 21:14 ` H. Peter Anvin
2008-02-28 23:16 ` Ian Campbell
2008-02-29 20:00 ` Ingo Molnar
2008-03-04 11:41 ` Mark McLoughlin
2008-03-04 14:33 ` Ingo Molnar
2008-03-04 15:12 ` Ian Campbell
2008-03-04 15:13 ` Jeremy Fitzhardinge
2008-03-04 15:25 ` Ingo Molnar
2008-03-04 16:02 ` Jeremy Fitzhardinge
2008-03-04 16:15 ` Ingo Molnar
2008-03-04 16:15 ` Mark McLoughlin
2008-03-04 16:23 ` Ingo Molnar
2008-03-04 17:44 ` Jeremy Fitzhardinge
2008-03-05 15:59 ` Eduardo Habkost
2008-03-05 16:08 ` H. Peter Anvin
2008-03-05 16:53 ` Eduardo Habkost
2008-03-05 17:28 ` H. Peter Anvin
2008-03-05 17:28 ` Jeremy Fitzhardinge
2008-03-05 17:38 ` H. Peter Anvin
2008-03-05 16:38 ` Jeremy Fitzhardinge
2008-03-05 17:27 ` H. Peter Anvin
2008-02-28 21:09 ` [PATCH] reserve end-of-conventional-memory to 1MB on 32-bit Ian Campbell
2008-02-29 11:49 ` Alexander van Heukelum
2008-02-29 17:14 ` Mark McLoughlin
2008-02-29 18:38 ` Alexander van Heukelum
2008-02-29 18:44 ` H. Peter Anvin
2008-02-29 18:56 ` Alexander van Heukelum
2008-02-29 22:06 ` Mark McLoughlin [this message]
2008-02-29 22:26 ` Alexander van Heukelum
2008-03-01 16:09 ` [PATCH] reserve end-of-conventional-memory to 1MB on 32-bit v2 Alexander van Heukelum
2008-03-01 16:12 ` [PATCH] reserve end-of-conventional-memory to 1MB on 64-bit add-on Alexander van Heukelum
2008-03-04 11:44 ` [PATCH] reserve end-of-conventional-memory to 1MB on 32-bit v2 Mark McLoughlin
2008-03-04 13:31 ` Alexander van Heukelum
2008-03-04 14:49 ` Ingo Molnar
2008-03-04 15:16 ` Mark McLoughlin
2008-03-04 15:24 ` Ingo Molnar
2008-03-04 15:18 ` Jeremy Fitzhardinge
2008-03-04 16:51 ` Alexander van Heukelum
2008-03-04 17:05 ` H. Peter Anvin
2008-03-04 17:11 ` Jeremy Fitzhardinge
2008-03-04 18:57 ` [PATCH] reserve end-of-conventional-memory to 1MB, 32-bit, use paravirt_enabled Alexander van Heukelum
2008-03-04 19:12 ` [PATCH] reserve end-of-conventional-memory to 1MB, 64-bit, " Alexander van Heukelum
2008-02-27 14:25 ` [PATCH] Fix alignment of early reservation for EBDA Andi Kleen
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