From: Andrew Morton <akpm@osdl.org>
To: Rusty Russell <rusty@rustcorp.com.au>
Cc: zach@vmware.com, virtualization@lists.osdl.org,
torvalds@osdl.org, mingo@elte.hu, linux-kernel@vger.kernel.org
Subject: Re: [patch] i386, vdso=[0|1] boot option and /proc/sys/vm/vdso_enabled
Date: Sun, 21 May 2006 02:52:22 -0700 [thread overview]
Message-ID: <20060521025222.1e2790f0.akpm@osdl.org> (raw)
In-Reply-To: <1148204118.31087.8.camel@localhost.localdomain>
Rusty Russell <rusty@rustcorp.com.au> wrote:
>
> Hypervisors want to use memory at the top of the address space
> (eg. 64MB for Xen, or 168MB for Xen w/ PAE). Creating this hole means
> moving the vsyscall page away from 0xffffe000.
>
> If we create this hole statically with a config option, we give up,
> say, 256MB of lowmem for the case where a hypervisor-capable kernel is
> actually running on native hardware.
>
> If we create this hole dynamically and leave the vsyscall page at the
> top of kernel memory, we would have to patch up the vsyscall elf
> header at boot time to reflect where we put it.
>
> Instead, this patch moves the vsyscall page into the user address
> region, just below PAGE_OFFSET: it's still at a fixed address, but
> it's not where the hypervisor wants to be, so resizing the hole is
> trivial.
Seems to work.
next prev parent reply other threads:[~2006-05-21 9:52 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-05-16 6:03 [PATCH] Gerd Hoffman's move-vsyscall-into-user-address-range patch Rusty Russell
2006-05-16 6:47 ` Ingo Molnar
2006-05-16 8:16 ` Zachary Amsden
2006-05-16 8:40 ` Chris Wright
2006-05-16 8:59 ` Zachary Amsden
2006-05-17 7:49 ` Rusty Russell
2006-05-18 7:54 ` Ingo Molnar
2006-05-18 8:29 ` Gerd Hoffmann
2006-05-20 0:43 ` Andrew Morton
2006-05-20 1:03 ` Ingo Molnar
2006-05-20 1:11 ` Andrew Morton
2006-05-20 1:15 ` Linus Torvalds
2006-05-20 8:53 ` [patch] i386, vdso=[0|1] boot option and /proc/sys/vm/vdso_enabled Ingo Molnar
2006-05-20 9:26 ` Andrew Morton
2006-05-20 9:30 ` Zachary Amsden
2006-05-20 9:43 ` Zachary Amsden
2006-05-20 9:48 ` Andrew Morton
2006-05-20 10:04 ` Zachary Amsden
2006-05-21 4:38 ` Rusty Russell
2006-05-21 9:35 ` Rusty Russell
2006-05-21 9:52 ` Andrew Morton [this message]
2006-05-21 10:41 ` Ingo Molnar
2006-05-21 11:06 ` Rusty Russell
2006-05-20 9:54 ` Ingo Molnar
2006-05-20 10:16 ` [patch] add print_fatal_signals support Ingo Molnar
2006-05-21 11:03 ` [patch] i386, vdso=[0|1] boot option and /proc/sys/vm/vdso_enabled Ingo Molnar
2006-05-21 11:38 ` Ingo Molnar
2006-05-21 12:33 ` Andrew Morton
2006-05-21 14:10 ` Arjan van de Ven
2006-05-22 14:32 ` Alexey Kuznetsov
2006-05-20 1:16 ` [PATCH] Gerd Hoffman's move-vsyscall-into-user-address-range patch Zachary Amsden
2006-05-20 1:49 ` Andi Kleen
2006-05-20 1:24 ` Arjan van de Ven
2006-05-22 16:29 ` Jakub Jelinek
2006-05-22 16:44 ` Zachary Amsden
2006-05-22 17:14 ` Andrew Morton
2006-05-22 17:27 ` Ingo Molnar
2006-05-22 17:46 ` Linus Torvalds
2006-05-22 19:09 ` Ingo Molnar
2006-05-22 19:40 ` Linus Torvalds
2006-05-22 19:14 ` Adrian Bunk
2006-05-22 19:45 ` Linus Torvalds
2006-05-22 17:53 ` Andrew Morton
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