From: Paolo Bonzini <pbonzini@redhat.com>
To: "H. Peter Anvin" <hpa@linux.intel.com>
Cc: Jarkko Sakkinen <jarkko.sakkinen@intel.com>,
linux-kernel@vger.kernel.org, linux-kbuild@vger.kernel.org,
Michal Marek <mmarek@suse.cz>, Sam Ravnborg <sam@ravnborg.org>,
Joseph Cihula <joseph.cihula@intel.com>,
Shane Wang <shane.wang@intel.com>
Subject: Re: [PATCH 04/23] x86, realmode: Move reboot_32.S to unified realmode code
Date: Wed, 09 May 2012 16:15:34 +0200 [thread overview]
Message-ID: <4FAA7C06.1060209@redhat.com> (raw)
In-Reply-To: <4FAA76E7.1070807@linux.intel.com>
Il 09/05/2012 15:53, H. Peter Anvin ha scritto:
>> > It's true that it doesn't matter much but still it is a
>> > regression. And it doesn't cause any kind of overhead
>> > or bloat to fix this.
>> >
> However, the big thing is that we jump to the BIOS with caches off. I
> personally think it is the wrong thing to do (we don't jump to the real
> reset vector anyway) but it is what has been tested for a long time.
I'm not sure I understand. The code has
andl $0x60000000, %edx ; clear ET/PE
jz 2f
...
2:
andb $0x10, %dl ; clear CD/WT, %edx is always 0
What I've suggested is:
testl $0x60000000, %edx
jz 2f
...
2:
andb $0x10, %dl ; clear PE only
What would jump to the BIOS with caches on is:
testl $0x60000000, %edx
jz 2f
...
2:
andl $0x10, %edx ; Clear CD/WT/PE
Am I missing something?
Paolo
next prev parent reply other threads:[~2012-05-09 14:16 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-08 18:22 [PATCH 00/23] x86, realmode: new infrastructure for realmode code Jarkko Sakkinen
2012-05-08 18:22 ` [PATCH 01/23] x86, realmode: 16-bit real-mode code support for relocs tool Jarkko Sakkinen
2012-05-08 22:13 ` [tip:x86/trampoline] " tip-bot for H. Peter Anvin
2012-05-08 18:22 ` [PATCH 02/23] x86, realmode: realmode.bin infrastructure Jarkko Sakkinen
2012-05-08 18:53 ` Sam Ravnborg
2012-05-08 19:14 ` H. Peter Anvin
2012-05-08 20:15 ` H. Peter Anvin
2012-05-08 21:11 ` Sam Ravnborg
2012-05-08 21:21 ` H. Peter Anvin
2012-05-08 22:14 ` [tip:x86/trampoline] " tip-bot for Jarkko Sakkinen
2012-05-09 15:49 ` [PATCH 02/23] " H. Peter Anvin
[not found] ` <alpine.DEB.2.02.1205092256240.31031@jsakkine-mobl1.(null)>
2012-05-09 20:06 ` H. Peter Anvin
2012-05-08 18:22 ` [PATCH 03/23] x86, realmode: Relocator for realmode code Jarkko Sakkinen
2012-05-08 22:15 ` [tip:x86/trampoline] " tip-bot for Jarkko Sakkinen
2012-05-08 18:22 ` [PATCH 04/23] x86, realmode: Move reboot_32.S to unified " Jarkko Sakkinen
2012-05-08 22:16 ` [tip:x86/trampoline] x86, realmode: Move reboot_32. S " tip-bot for Jarkko Sakkinen
2012-05-09 7:12 ` [PATCH 04/23] x86, realmode: Move reboot_32.S " Paolo Bonzini
[not found] ` <alpine.DEB.2.02.1205091525100.6943@jsakkine-mobl2.(null)>
2012-05-09 13:53 ` H. Peter Anvin
2012-05-09 14:15 ` Paolo Bonzini [this message]
2012-05-09 14:18 ` H. Peter Anvin
2012-05-08 18:22 ` [PATCH 05/23] x86, realmode: Move SMP trampoline " Jarkko Sakkinen
2012-05-08 22:17 ` [tip:x86/trampoline] " tip-bot for Jarkko Sakkinen
2012-05-08 18:22 ` [PATCH 06/23] x86, realmode: Move ACPI wakeup " Jarkko Sakkinen
2012-05-08 22:18 ` [tip:x86/trampoline] " tip-bot for Jarkko Sakkinen
2012-05-08 18:22 ` [PATCH 07/23] x86, realmode: Set permission for real mode pages Jarkko Sakkinen
2012-05-08 22:19 ` [tip:x86/trampoline] " tip-bot for Jarkko Sakkinen
2012-05-08 18:22 ` [PATCH 08/23] x86, realmode: Allow absolute pa_* symbols in the realmode code Jarkko Sakkinen
2012-05-08 22:19 ` [tip:x86/trampoline] " tip-bot for H. Peter Anvin
2012-05-08 18:22 ` [PATCH 09/23] x86, realmode: Add .text64 section, make barrier symbols absolute Jarkko Sakkinen
2012-05-08 22:20 ` [tip:x86/trampoline] " tip-bot for H. Peter Anvin
2012-05-08 18:22 ` [PATCH 10/23] x86, realmode: Move bits to the proper sections in trampoline_64.S Jarkko Sakkinen
2012-05-08 22:21 ` [tip:x86/trampoline] " tip-bot for H. Peter Anvin
2012-05-08 18:22 ` [PATCH 11/23] x86, realmode: Align .data section in trampoline_32.S Jarkko Sakkinen
2012-05-08 22:22 ` [tip:x86/trampoline] x86, realmode: Align . data " tip-bot for H. Peter Anvin
2012-05-08 18:22 ` [PATCH 12/23] x86, realmode: Remove indirect jumps in trampoline_64.S Jarkko Sakkinen
2012-05-08 22:23 ` [tip:x86/trampoline] " tip-bot for H. Peter Anvin
2012-05-08 18:22 ` [PATCH 13/23] x86, realmode: Remove indirect jumps in trampoline_32 and wakeup_asm Jarkko Sakkinen
2012-05-08 22:24 ` [tip:x86/trampoline] " tip-bot for H. Peter Anvin
2012-05-08 18:22 ` [PATCH 14/23] x86, realmode: Replace open-coded ljmpw with a macro Jarkko Sakkinen
2012-05-08 22:24 ` [tip:x86/trampoline] " tip-bot for H. Peter Anvin
2012-05-08 18:22 ` [PATCH 15/23] x86, realmode: Move trampoline_*.S early in the link order Jarkko Sakkinen
2012-05-08 22:25 ` [tip:x86/trampoline] x86, realmode: Move trampoline_*. S " tip-bot for H. Peter Anvin
2012-05-08 18:22 ` [PATCH 16/23] x86, realmode: Fix always-zero test in reboot_32.S Jarkko Sakkinen
2012-05-08 22:26 ` [tip:x86/trampoline] " tip-bot for H. Peter Anvin
2012-05-08 18:22 ` [PATCH 17/23] x86, realmode: fix 64-bit wakeup sequence Jarkko Sakkinen
2012-05-08 22:27 ` [tip:x86/trampoline] " tip-bot for Jarkko Sakkinen
2012-05-08 18:22 ` [PATCH 18/23] x86, realmode: don't copy real_mode_header Jarkko Sakkinen
2012-05-08 22:28 ` [tip:x86/trampoline] " tip-bot for Jarkko Sakkinen
2012-05-08 18:22 ` [PATCH 19/23] x86, realmode: flattened rm hierachy Jarkko Sakkinen
2012-05-08 22:29 ` [tip:x86/trampoline] " tip-bot for Jarkko Sakkinen
2012-05-08 18:22 ` [PATCH 20/23] x86, realmode: header for trampoline code Jarkko Sakkinen
2012-05-08 22:29 ` [tip:x86/trampoline] " tip-bot for Jarkko Sakkinen
2012-05-08 18:22 ` [PATCH 21/23] x86, realmode: move relocs from scripts/ to arch/x86/tools Jarkko Sakkinen
2012-05-08 22:30 ` [tip:x86/trampoline] " tip-bot for Jarkko Sakkinen
2012-05-08 18:22 ` [PATCH 22/23] x86, realmode: fixes compilation issue in tboot.c Jarkko Sakkinen
2012-05-08 22:31 ` [tip:x86/trampoline] " tip-bot for Jarkko Sakkinen
2012-05-08 18:22 ` [PATCH 23/23] x86, realmode: read cr4 and EFER from kernel for 64-bit trampoline Jarkko Sakkinen
2012-05-08 22:32 ` [tip:x86/trampoline] " tip-bot for Jarkko Sakkinen
2012-05-16 20:37 ` [tip:x86/trampoline] x86, realmode: Mask out EFER. LMA when saving trampoline EFER tip-bot for H. Peter Anvin
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