Message-ID: <43709FD7.1030905@vmware.com>
Date: Tue, 08 Nov 2005 04:53:43 -0800
From: Zachary Amsden <zach@vmware.com>
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To: Ingo Molnar <mingo@elte.hu>
Cc: Andrew Morton <akpm@osdl.org>, Chris Wright <chrisw@osdl.org>,
       Linus Torvalds <torvalds@osdl.org>,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
       Virtualization Mailing List <virtualization@lists.osdl.org>,
       "H. Peter Anvin" <hpa@zytor.com>,
       Zwane Mwaikambo <zwane@arm.linux.org.uk>,
       Martin Bligh <mbligh@mbligh.org>,
       Pratap Subrahmanyam <pratap@vmware.com>,
       Christopher Li <chrisl@vmware.com>,
       "Eric W. Biederman" <ebiederm@xmission.com>
Subject: Re: [PATCH 14/21] i386 Apm is on cpu zero only
References: <200511080433.jA84Xwm7009921@zach-dev.vmware.com> <20051108073315.GE28201@elte.hu>
In-Reply-To: <20051108073315.GE28201@elte.hu>
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Ingo Molnar wrote:

>* Zachary Amsden <zach@vmware.com> wrote:
>
>  
>
>>APM BIOS code has a protective wrapper that runs it only on CPU zero.  
>>Thus, no need to set APM BIOS segments in the GDT for other CPUs.
>>    
>>
>
>hm, do we want (need) to have that CPU#0 assumption forever?
>  
>

Can't hurt, and APM is largely obsolete because of ACPI, so I'm only 
concerned with trimming and keeping adequate protection of the kernel 
from APM code while maintaining correctness.  I don't have a nice set of 
old machines with enough wacky APM BIOSen to validate that unpinning the 
CPU is ok.

Zach
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