From: Gleb Natapov <gleb@redhat.com>
To: Anthony Liguori <anthony@codemonkey.ws>
Cc: qemu-devel@nongnu.org, Gerd Hoffmann <kraxel@redhat.com>,
"Richard W.M. Jones" <rjones@redhat.com>,
kvm@vger.kernel.org, Avi Kivity <avi@redhat.com>
Subject: Re: [Qemu-devel] Anyone seeing huge slowdown launching qemu with Linux 2.6.35?
Date: Wed, 4 Aug 2010 18:01:54 +0300 [thread overview]
Message-ID: <20100804150154.GZ10499@redhat.com> (raw)
In-Reply-To: <4C597E4F.2050108@codemonkey.ws>
On Wed, Aug 04, 2010 at 09:50:55AM -0500, Anthony Liguori wrote:
> On 08/04/2010 09:38 AM, Gleb Natapov wrote:
> >>
> >>But even if it wasn't it can potentially create havoc. I think we
> >>currently believe that the northbridge likely never forwards RAM
> >>access to a device so this doesn't fit how hardware would work.
> >>
> >Good point.
> >
> >>More importantly, BIOSes and ROMs do very funny things with RAM.
> >>It's not unusual for a ROM to muck with the e820 map to allocate RAM
> >>for itself which means there's always the chance that we're going to
> >>walk over RAM being used for something else.
> >>
> >ROM does not muck with the e820. It uses PMM to allocate memory and the
> >memory it gets is marked as reserved in e820 map.
>
> PMM allocations are only valid during the init function's execution.
> It's intention is to enable the use of scratch memory to decompress
> or otherwise modify the ROM to shrink its size.
>
Hm, may be. I read seabios code differently, but may be I misread it.
> If a ROM needs memory after the init function, it needs to use the
> traditional tricks to allocate long term memory and the most popular
> one is modifying the e820 tables.
>
e820 has no in memory format,
> See src/arch/i386/firmware/pcbios/e820mangler.S in gPXE.
so this ugly code intercepts int15 and mangle result. OMG. How this can
even work if more then two ROMs want to do that?
--
Gleb.
next prev parent reply other threads:[~2010-08-04 15:02 UTC|newest]
Thread overview: 151+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-08-03 11:13 [Qemu-devel] Anyone seeing huge slowdown launching qemu with Linux 2.6.35? Richard W.M. Jones
2010-08-03 11:33 ` Gleb Natapov
2010-08-03 12:10 ` Richard W.M. Jones
2010-08-03 12:37 ` Gleb Natapov
2010-08-03 12:48 ` Richard W.M. Jones
2010-08-03 13:19 ` Avi Kivity
2010-08-03 14:05 ` Richard W.M. Jones
2010-08-03 14:38 ` Avi Kivity
2010-08-03 14:53 ` Richard W.M. Jones
2010-08-03 16:10 ` Avi Kivity
2010-08-03 16:28 ` Richard W.M. Jones
2010-08-03 16:44 ` Avi Kivity
2010-08-03 16:46 ` Anthony Liguori
2010-08-03 16:50 ` Avi Kivity
2010-08-03 16:53 ` Anthony Liguori
2010-08-03 17:01 ` Avi Kivity
2010-08-03 17:42 ` Anthony Liguori
2010-08-03 17:58 ` Avi Kivity
2010-08-03 18:11 ` Richard W.M. Jones
2010-08-03 18:26 ` Anthony Liguori
2010-08-03 18:43 ` Avi Kivity
2010-08-03 18:47 ` Avi Kivity
2010-08-03 18:55 ` Anthony Liguori
2010-08-03 19:00 ` Avi Kivity
2010-08-03 19:05 ` Gleb Natapov
2010-08-03 19:09 ` Avi Kivity
2010-08-03 19:15 ` Anthony Liguori
2010-08-03 19:24 ` Avi Kivity
2010-08-03 19:38 ` Anthony Liguori
2010-08-03 19:41 ` Avi Kivity
2010-08-03 19:47 ` Anthony Liguori
2010-08-04 5:47 ` Avi Kivity
2010-08-03 21:24 ` Gerd Hoffmann
2010-08-03 21:20 ` Gerd Hoffmann
2010-08-04 5:53 ` Avi Kivity
2010-08-04 7:56 ` Gerd Hoffmann
2010-08-04 8:17 ` Avi Kivity
2010-08-04 8:43 ` Gleb Natapov
2010-08-04 9:22 ` Gerd Hoffmann
2010-08-04 13:04 ` Anthony Liguori
2010-08-04 13:07 ` Gleb Natapov
2010-08-04 13:15 ` Anthony Liguori
2010-08-04 13:24 ` Richard W.M. Jones
2010-08-04 13:26 ` Gleb Natapov
2010-08-04 14:22 ` Anthony Liguori
2010-08-04 14:38 ` Gleb Natapov
2010-08-04 14:50 ` Anthony Liguori
2010-08-04 15:01 ` Gleb Natapov [this message]
2010-08-04 15:07 ` Anthony Liguori
2010-08-04 15:15 ` Gleb Natapov
2010-08-04 22:41 ` Kevin O'Connor
2010-08-04 16:26 ` Avi Kivity
2010-08-04 13:34 ` Gleb Natapov
2010-08-04 13:52 ` Anthony Liguori
2010-08-04 14:00 ` Gleb Natapov
2010-08-04 14:14 ` Anthony Liguori
2010-08-04 14:36 ` Gleb Natapov
2010-08-04 14:22 ` Paolo Bonzini
2010-08-04 14:39 ` Anthony Liguori
2010-08-04 16:33 ` Avi Kivity
2010-08-04 16:30 ` Avi Kivity
2010-08-04 16:36 ` Avi Kivity
2010-08-04 16:44 ` Anthony Liguori
2010-08-04 16:52 ` Avi Kivity
2010-08-04 17:37 ` Gleb Natapov
2010-08-05 7:28 ` Gerd Hoffmann
2010-08-05 7:34 ` Gleb Natapov
2010-08-05 7:56 ` Avi Kivity
2010-08-05 7:59 ` Gleb Natapov
2010-08-05 8:45 ` Avi Kivity
2010-08-05 8:48 ` Gleb Natapov
2010-08-05 13:43 ` Anthony Liguori
2010-08-04 16:45 ` Alexander Graf
2010-08-04 16:54 ` Avi Kivity
2010-08-04 17:01 ` Alexander Graf
2010-08-04 17:14 ` Avi Kivity
2010-08-04 17:27 ` Alexander Graf
2010-08-04 17:34 ` Avi Kivity
2010-08-04 20:06 ` David S. Ahern
2010-08-04 20:16 ` Richard W.M. Jones
2010-08-05 2:38 ` Avi Kivity
2010-08-04 17:26 ` Anthony Liguori
2010-08-04 17:31 ` Alexander Graf
2010-08-04 17:35 ` Avi Kivity
2010-08-04 17:36 ` Anthony Liguori
2010-08-04 17:36 ` Alexander Graf
2010-08-04 17:46 ` Richard W.M. Jones
2010-08-04 17:50 ` Avi Kivity
2010-08-04 18:13 ` Alexander Graf
2010-08-04 18:16 ` Anthony Liguori
2010-08-04 18:18 ` Alexander Graf
2010-08-04 18:19 ` Avi Kivity
2010-08-04 18:18 ` Avi Kivity
2010-08-04 16:42 ` Anthony Liguori
2010-08-04 13:22 ` Richard W.M. Jones
2010-08-04 13:29 ` Gleb Natapov
2010-08-04 16:25 ` Avi Kivity
2010-08-03 22:06 ` Richard W.M. Jones
2010-08-04 5:54 ` Avi Kivity
2010-08-04 9:24 ` Richard W.M. Jones
2010-08-04 9:27 ` Gleb Natapov
2010-08-04 9:52 ` Avi Kivity
2010-08-04 11:33 ` Richard W.M. Jones
2010-08-04 11:36 ` Avi Kivity
2010-08-04 12:07 ` Gleb Natapov
2010-08-04 12:59 ` Anthony Liguori
2010-08-03 19:26 ` Gleb Natapov
2010-08-03 19:13 ` Richard W.M. Jones
2010-08-03 19:17 ` Gleb Natapov
2010-08-03 19:19 ` Anthony Liguori
2010-08-03 19:22 ` Avi Kivity
2010-08-03 20:00 ` Richard W.M. Jones
2010-08-03 20:49 ` Anthony Liguori
2010-08-03 21:13 ` Paolo Bonzini
2010-08-03 21:34 ` Anthony Liguori
2010-08-04 7:57 ` Paolo Bonzini
2010-08-04 8:19 ` Avi Kivity
2010-08-04 12:53 ` Anthony Liguori
2010-08-04 16:44 ` Avi Kivity
2010-08-04 16:46 ` Anthony Liguori
2010-08-04 16:48 ` Alexander Graf
2010-08-04 16:49 ` Anthony Liguori
2010-08-04 16:51 ` Alexander Graf
2010-08-04 17:01 ` Paolo Bonzini
2010-08-04 17:19 ` Avi Kivity
2010-08-04 17:25 ` Alexander Graf
2010-08-04 17:27 ` Anthony Liguori
2010-08-04 17:37 ` Avi Kivity
2010-08-04 17:53 ` Anthony Liguori
2010-08-04 18:05 ` Alexander Graf
2010-08-04 5:56 ` Avi Kivity
2010-08-04 1:17 ` Jamie Lokier
2010-08-04 8:21 ` Avi Kivity
2010-08-04 14:51 ` David S. Ahern
2010-08-04 14:57 ` Anthony Liguori
2010-08-04 15:25 ` Gleb Natapov
2010-08-04 15:31 ` Alexander Graf
2010-08-04 15:48 ` Gleb Natapov
2010-08-04 15:59 ` Alexander Graf
2010-08-04 16:08 ` Gleb Natapov
2010-08-04 16:48 ` Avi Kivity
2010-08-04 23:17 ` Kevin O'Connor
2010-08-05 5:26 ` Gleb Natapov
2010-08-03 16:56 ` Anthony Liguori
2010-08-03 16:48 ` Avi Kivity
2010-08-03 17:00 ` Richard W.M. Jones
2010-08-03 17:05 ` Avi Kivity
2010-08-03 16:56 ` Richard W.M. Jones
2010-08-03 17:08 ` Avi Kivity
2010-08-03 16:39 ` Anthony Liguori
2010-08-03 16:43 ` Richard W.M. Jones
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