WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

[Xen-devel] Re: [PATCH 0/2] x86/microcode: support for microcode update

To: "H. Peter Anvin" <hpa@xxxxxxxxx>
Subject: [Xen-devel] Re: [PATCH 0/2] x86/microcode: support for microcode update in Xen dom0
From: Jeremy Fitzhardinge <jeremy@xxxxxxxx>
Date: Wed, 02 Feb 2011 12:05:23 -0800
Cc: Jeremy Fitzhardinge <jeremy@xxxxxxxx>, Xen Devel <Xen-devel@xxxxxxxxxxxxxxxxxxx>, the arch/x86 maintainers <x86@xxxxxxxxxx>, Linux Kernel Mailing List <linux-kernel@xxxxxxxxxxxxxxx>, Borislav Petkov <bp@xxxxxxxxx>, Keir Fraser <keir.fraser@xxxxxxxxxxxxx>, Ingo Molnar <mingo@xxxxxxx>
Delivery-date: Wed, 02 Feb 2011 12:06:11 -0800
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <4D49B5F6.5010606@xxxxxxxxx>
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
References: <cover.1296259339.git.jeremy.fitzhardinge@xxxxxxxxxx> <20110130113356.GA27967@xxxxxxxxxxxx> <4D461FB9.5050807@xxxxxxxx> <20110131070241.GA22071@xxxxxxxxxxxx> <4D46FC9F.6090309@xxxxxxxx> <20110131234131.GA16095@xxxxxxxxxxxx> <4D475099.1080004@xxxxxxxx> <4D475DB5.1020300@xxxxxxxxx> <4D488EB1.9020803@xxxxxxxx> <4D49B5F6.5010606@xxxxxxxxx>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
User-agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.13) Gecko/20101209 Fedora/3.1.7-0.35.b3pre.fc14 Lightning/1.0b3pre Thunderbird/3.1.7
On 02/02/2011 11:52 AM, H. Peter Anvin wrote:
> As I mentioned on IRC...
>
> 1. Xen already uses Multiboot, so it's a fairly trivial thing to add
> another item to the list for the boot loader to get.
>
> 2. The only reason we don't currently install microcode from the boot
> loader is because of the considerable complexity in adding SMP support
> to boot loaders, as it requires handling the APIC system.
>
> 3. Arguably on native hardware we should still load the microcode into
> RAM in the boot loader, and install it on the very early CPU bringup
> path.  That means locking down some (currently) 400K of RAM to handle
> different combinations of CPUs, or the additional complexity of
> jettisoning microcode which cannot be used while still be able to deal
> with hotplug.  I think there is a strong case for this model, which
> would mean moving the microcode into /boot anyway.

If we can come up with a scheme that works for both native and Xen (or
at least v. similar) that we can get distros to support, then we can
work with that.  That principally means getting the microcode images
into /boot in a pre-digested form (binary, not text, and maybe pack the
Intel and AMD files together in some extensible way - or at least give
them self-describing headers).

But in the meantime it would be nice to have microcode updates under Xen
within the existing model (or failing that, a little patch to prevent
the spew of spurious errors when the kernel tries and fails - but it
would be strongly preferable to actually update microcode).

My main concern is that I want Xen to Just Work - ideally by not
requiring users/admins to do anything.

    J

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel

<Prev in Thread] Current Thread [Next in Thread>