From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ian Campbell Subject: Re: [PATCH OSSTEST] Arrange to upgrade microcode on x86 test hosts. Date: Thu, 11 Jun 2015 12:26:48 +0100 Message-ID: <1434022008.30003.147.camel@citrix.com> References: <1434019943-10803-1-git-send-email-ian.campbell@citrix.com> <55798A940200007800083983@mail.emea.novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <55798A940200007800083983@mail.emea.novell.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Jan Beulich Cc: ian.jackson@eu.citrix.com, xen-devel@lists.xen.org List-Id: xen-devel@lists.xenproject.org On Thu, 2015-06-11 at 12:18 +0100, Jan Beulich wrote: > >>> On 11.06.15 at 12:52, wrote: > > Both Xen and Linux support extracting a microcode update from an > > initramfs early during boot. This requires prepending a suitable > > uncompressed cpio archive containing the necessary files to the > > initrd. > > > > Xen also supports loading the microcode cpio from any multiboot > > module, but for in order to allow the possibility of loading on native > > boots (e.g. for build jobs) we prefer the prepend method. > > > > This patch provides mg-cpu-microcode-update which creates a suitable > > microcode cpio in the images directory and arranges for it to be added > > to the host during installation (so it is done before the kernel is > > installed and initramfs generated etc, saving faff). It also adds > > "ucode=scan" to the Xen command line when necessary. > > > > The version of initramfs-tools in Wheezy does not yet support > > prepending things to the initrm, so we use a custom compression > > command which sneakily does it for us. This could be done better from > > Jessie onwards. > > > > Note that Linux only supports this from v3.8 onwards, so this doesn't > > work for Wheezy (which uses v3.2). From Jessie onwards we should > > benefit from microcode updates even for native (build) jobs. > > > > Tested on both Intel and AMD where it appeared to have the desired > > effect under Xen. Under native I only tried Wheezy which doesn't > > support early microcode. > > > > Note that I've not bothered to implement late microcode updates, which > > would work on v3.2 too, since that would need a different set of files > > etc and it doesn't seem especially pressing. > > > > Signed-off-by: Ian Campbell > > Cc: Jan Beulich > > Thanks for doing this so quickly, Ian! No problem, it actually turned out to be easier than I had feared it would be. Ian.