Date: Tue, 8 Nov 2005 08:19:35 +0100
From: Ingo Molnar <mingo@elte.hu>
To: Zachary Amsden <zach@vmware.com>
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 4/21] i386 Broken bios common
Message-ID: <20051108071935.GB28201@elte.hu>
References: <200511080422.jA84MQxK009859@zach-dev.vmware.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <200511080422.jA84MQxK009859@zach-dev.vmware.com>
User-Agent: Mutt/1.4.2.1i
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 839
Lines: 22


* Zachary Amsden <zach@vmware.com> wrote:

>  	gdt = get_cpu_gdt_table(cpu);
>  	save_desc_40 = gdt[0x40 / 8];
> -	gdt[0x40 / 8] = bad_bios_desc;
> +	gdt[0x40 / 8] = gdt[GDT_ENTRY_BAD_BIOS_CACHE];
>  

i like the cleanup, but wouldnt it be simpler to dedicate GDT entry #8 
to the 0x40 descriptor, and hence be compatible with such broken BIOSes 
by default? Right now entry #8 is taken up by TLS segment #2, but we 
could change GDT_ENTRY_TLS_MIN from 6 to 9 and push the TLS segments to 
entries 9,10,11. [ Could there be any buggy SMM code that relies on 
having something at 0x40? ]

	Ingo
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/