From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1LvXdX-0001VA-UH for qemu-devel@nongnu.org; Sun, 19 Apr 2009 10:04:47 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1LvXdV-0001SP-8k for qemu-devel@nongnu.org; Sun, 19 Apr 2009 10:04:45 -0400 Received: from [199.232.76.173] (port=56789 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1LvXdV-0001SE-4A for qemu-devel@nongnu.org; Sun, 19 Apr 2009 10:04:45 -0400 Received: from yw-out-1718.google.com ([74.125.46.158]:8503) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1LvXdU-0004za-Es for qemu-devel@nongnu.org; Sun, 19 Apr 2009 10:04:44 -0400 Received: by yw-out-1718.google.com with SMTP id 9so929740ywk.82 for ; Sun, 19 Apr 2009 07:04:43 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20090419111249.GD10126@redhat.com> References: <1240001860-2280-1-git-send-email-glommer@redhat.com> <1240001860-2280-2-git-send-email-glommer@redhat.com> <20090419111249.GD10126@redhat.com> Date: Sun, 19 Apr 2009 23:34:43 +0930 Message-ID: From: Brendan Trotter Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: [Qemu-devel] Re: [Bochs-developers] [PATCH 1/2] create acpi cpu definitions Reply-To: qemu-devel@nongnu.org List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Gleb Natapov Cc: bochs-developers@lists.sourceforge.net, aliguori@us.ibm.com, qemu-devel@nongnu.org Hi, On Sun, Apr 19, 2009 at 8:42 PM, Gleb Natapov wrote: > On Sun, Apr 19, 2009 at 11:01:09AM +0930, Brendan Trotter wrote: >> For some reason (unknown to me) some Linux developers made wild >> assumptions about disabled "Processor Local APIC" entries, and now >> they're inventing fictitious hardware to support their unfounded >> assumptions. >> >> Please, correct me if I'm wrong... >> > Windows 2008 supports CPU hot plug (but not unplug IIRC). How they do it > if there is not specification about how it should work on 80x86? Unfortunately, "no specification" typically means hardware manufacturers are free to make up their own way of doing it - for all I know Windows 2008 needs a special driver for each system. I've been unable to find any 80x86 hardware that supports hot-add and hot-remove of CPUs, and therefore I haven't been able to attempt to find out how this hardware notifies the OS of capabilities, changes, etc. The closest thing I did find is redundant CPUs, but I couldn't find anything with details on how this works, and don't know if the OS itself is made aware of it at all (the chipset and firmware might replaced a failing CPU with a spare/redundant CPU without the OS's knowledge). I did find a little information for hot add/remove for Itanium systems, but nothing very detailed. From "http://www.itaniumsolutions.org/resources/focus_on_dynamic_hardware_partitioning__nec_microsoft_intel": "The NEC Express5800/1000 Series of servers, utilizes the Intel Itanium Machine Check Architecture (for error handling), and adds another layer of intelligence through a service processor and related software called the GlobalMaster (managed via either a GUI or CLI), as shown in Figure 1. The GlobalMaster also communicates with Microsoft Windows Server 2008 to convey to the operating system that a hot add (of processors, memory, or I/O) or hot replace (of processors and memory) is taking place." This sounds like a lot more involved than just misappropriating a flag in an ACPI table... Cheers, Brendan