From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=48026 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1OLp0j-0005lc-4H for qemu-devel@nongnu.org; Mon, 07 Jun 2010 22:57:53 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.69) (envelope-from ) id 1OLp0i-0000l9-1W for qemu-devel@nongnu.org; Mon, 07 Jun 2010 22:57:53 -0400 Received: from mail.codesourcery.com ([38.113.113.100]:33249) by eggs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1OLp0h-0000kx-Pq for qemu-devel@nongnu.org; Mon, 07 Jun 2010 22:57:52 -0400 From: Paul Brook Subject: Re: [Qemu-devel] [PATCH 15/22] machine: make max_cpus a -machine option Date: Tue, 8 Jun 2010 03:56:55 +0100 References: <1275954730-8196-1-git-send-email-aliguori@us.ibm.com> <201006080201.08018.paul@codesourcery.com> <4C0DA356.8030506@codemonkey.ws> In-Reply-To: <4C0DA356.8030506@codemonkey.ws> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-15" Content-Transfer-Encoding: 7bit Message-Id: <201006080356.55475.paul@codesourcery.com> List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Anthony Liguori Cc: Glauber Costa , qemu-devel@nongnu.org > max_cpus is complicated because it was used for multiple purposes. I don't see any such uses. > > This is a fundamental property/limitation of the hardware. Expect qemu to > > crash if the value is modified. > > In this case, the machine cores should be rejecting totally invalid > values to prevent crashes from occurring. My reading of realview does > not suggest that a crash would occur. Are you speaking in general terms > or do you think it will actually fail in realview? qemu_irq cpu_irq[4]; ... for (n = 0; n < smp_cpus; n++) { cpu_irq[n] = irqp[ARM_PIC_CPU_IRQ]; I'm pretty sure bad things will happen there if smp_cpus is > 4. Similar assumptions exist in apic.c, and probably others. Paul