From: Alexander van Heukelum <heukelum@mailshack.com>
To: Jeremy Fitzhardinge <jeremy@goop.org>, Ingo Molnar <mingo@elte.hu>
Cc: Alexander van Heukelum <heukelum@fastmail.fm>,
Mark McLoughlin <markmc@redhat.com>,
Ian Campbell <ijc@hellion.org.uk>,
"H. Peter Anvin" <hpa@zytor.com>, Andi Kleen <ak@suse.de>,
Thomas Gleixner <tglx@linutronix.de>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] reserve end-of-conventional-memory to 1MB, 32-bit, use paravirt_enabled
Date: Tue, 4 Mar 2008 19:57:42 +0100 [thread overview]
Message-ID: <20080304185742.GA12193@mailshack.com> (raw)
In-Reply-To: <47CD82C5.8060605@goop.org>
Jeremy Fitzhardinge pointed out that looking at the boot_params
struct to determine if the system is running in a paravirtual
environment is not reliable for the Xen case, currently. He also
points out that there already exists a function to determine if
the system is running in a paravirtual environment. So let's use
that instead. This gets rid of the preprocessor test too.
Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm>
---
On Tue, Mar 04, 2008 at 09:11:33AM -0800, Jeremy Fitzhardinge wrote:
> Alexander van Heukelum wrote:
> >On Tue, 04 Mar 2008 07:18:48 -0800, "Jeremy Fitzhardinge"
> ><jeremy@goop.org> said:
> >>Yes, is_paravirt() already exists for this purpose.
> >
> >Hi,
> >
> >If it exists, it is well-hidden. A grep for is_paravirt on the testing
> >tree turns up nothing. Did you get the name right?
> >
>
> Nope. paravirt_enabled().
Duh, I should have been able to find that :-/. Thanks for the pointer.
> Just because something is paravirtualized and uses a non-PC
> hardware_subarch doesn't mean this stuff isn't present. Even the
> paravirt_enabled() test isn't accurate, because the environment may
> still choose to emulate these things (or in the Xen dom0 case, it may
> directly expose the real hardware).
paravirt_enabled() returns 0 if CONFIG_PARAVIRT is not set, or if a
paravirt-enabled kernel is run on bare hardware: dom0. If that is right,
then it is exactly what is needed.
Greetings,
Alexander
diff --git a/arch/x86/kernel/setup_32.c b/arch/x86/kernel/setup_32.c
index 20e537b..f595d7b 100644
--- a/arch/x86/kernel/setup_32.c
+++ b/arch/x86/kernel/setup_32.c
@@ -64,6 +64,7 @@
#include <setup_arch.h>
#include <bios_ebda.h>
#include <asm/cacheflush.h>
+#include <asm/processor.h>
/* This value is set up by the early boot code to point to the value
immediately after the boot time page tables. It contains a *physical*
@@ -408,12 +409,8 @@ static void __init reserve_ebda_region(void)
/* that area is absent. We'll just have to assume */
/* that the paravirt case can handle memory setup */
/* correctly, without our help. */
-#ifdef CONFIG_PARAVIRT
- if ((boot_params.hdr.version >= 0x207) &&
- (boot_params.hdr.hardware_subarch != 0)) {
+ if (paravirt_enabled())
return;
- }
-#endif
/* end of low (conventional) memory */
lowmem = *(unsigned short *)__va(BIOS_LOWMEM_KILOBYTES);
next prev parent reply other threads:[~2008-03-04 18:59 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
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 ` Alexander van Heukelum [this message]
2008-03-04 19:12 ` [PATCH] reserve end-of-conventional-memory to 1MB, 64-bit, use paravirt_enabled Alexander van Heukelum
2008-02-27 14:25 ` [PATCH] Fix alignment of early reservation for EBDA Andi Kleen
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