From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gleb Natapov Subject: Re: [PATCH] cpu hotplug issue Date: Thu, 4 Aug 2011 11:01:56 +0300 Message-ID: <20110804080156.GE4404@redhat.com> References: <4E3193B9.5040407@siemens.com> <4E37D053.1050106@siemens.com> <20110803100702.GC19574@dhcp-192-168-178-175.profitbricks.localdomain> <4E3924D9.7000302@siemens.com> <20110803103847.GD4404@redhat.com> <4E392603.5010102@siemens.com> <20110803162507.GA21463@dhcp-192-168-178-175.profitbricks.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: Jan Kiszka , seabios@seabios.org, armbru@redhat.com, kvm@vger.kernel.org To: Vasilis Liaskovitis Return-path: Content-Disposition: inline In-Reply-To: <20110803162507.GA21463@dhcp-192-168-178-175.profitbricks.localdomain> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: seabios-bounces@seabios.org Sender: seabios-bounces@seabios.org List-Id: kvm.vger.kernel.org On Wed, Aug 03, 2011 at 06:25:07PM +0200, Vasilis Liaskovitis wrote: > On Wed, Aug 03, 2011 at 12:42:11PM +0200, Jan Kiszka wrote: > > >> Why can't Seabios read to true number online CPUs from the PIIX4 device? > > >> The information is there already, no need for addition PV here. > > >> > > > Where is it in PIIX4 device? > > > > PROC registers (or however they are called). > > In qemu-kvm, the cpus_sts bitmap array in PIIX4PMState/ACPIGPE has the true > number of online CPUS. This is accessed from the DSDT hotplug method in Seabios > as "OperationRegion SystemIO" with address 0xaf00. Is this i/o address in the > piix4 spec? How can it be accessed from the rest of SeaBIOS? It seems to reside > in ACPI_PM space. > 0xaf00 is not part of PIIX4. PIIX4 supports nor cpu host plug neither pci hot plug. I haven't found any PROC register in PIIX4 spec so far. -- Gleb.