From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Tian, Kevin" Subject: RE: [PATCH 1 of 3] apic: record local apic state on boot Date: Thu, 19 May 2011 08:54:04 +0800 Message-ID: <625BA99ED14B2D499DC4E29D8138F1505C9BBF8DA9@shsmsx502.ccr.corp.intel.com> References: <62a8ce6595ad940a76db.1305742094@andrewcoop> <20110518184950.GC14013@dumpdata.com> <4DD42BCC.6020106@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <4DD42BCC.6020106@citrix.com> Content-Language: en-US List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Andrew Cooper , Konrad Rzeszutek Wilk Cc: "xen-devel@lists.xensource.com" List-Id: xen-devel@lists.xenproject.org > From: Andrew Cooper > Sent: Thursday, May 19, 2011 4:28 AM >=20 > On 18/05/11 19:49, Konrad Rzeszutek Wilk wrote: > > On Wed, May 18, 2011 at 07:08:14PM +0100, Andrew Cooper wrote: > >> Xen does not store the boot local apic state which leads to problems > >> when shutting down for a kexec jump. This patch records the boot > >> state so we can return to the boot state when kexec'ing. > >> > >> This is per CPU because all 3 bioses on the boxes I have tested dont > >> enabled all local apics on boot. As a result, we have to return to > >> the bios state so the ACPI tables match up with the hardware state > >> for the booting kernel. > > Which ACPI table requires this? > Cant remember offhand but linux (2.6.32) was doing finger pointing at the > multi-processor tables it would be good to understand exactly how CPU states don't match the ACPI table. As Keir commented, your current patch is bogus which may just work around the issue in another way. Thanks Kevin