From mboxrd@z Thu Jan 1 00:00:00 1970 From: Anthony Liguori Subject: Re: Virtio with multiple devices of the same type Date: Tue, 12 Feb 2008 23:17:06 -0600 Message-ID: <47B27D52.7070809@codemonkey.ws> References: <1202873568.3319.280.camel@athas> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel@lists.sourceforge.net, Dor Laor , Avi Kivity To: Will Trives Return-path: In-Reply-To: <1202873568.3319.280.camel@athas> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces@lists.sourceforge.net Errors-To: kvm-devel-bounces@lists.sourceforge.net List-Id: kvm.vger.kernel.org Hi Will, > Example command line: > > This is observed : > > * On a 64 bit host with an Intel Q6600 cpu > * Host is 64 bit, guest 64 bit. > * latest Linux git kernel (which has the new virtio code in it from Rusty) both for host and guest > * the latest KVM userspace (with --with-patched-kernel or by syncing to the latest kvm git tree) > * the behaviour with the network devices is observed regardless of whether the network drive is compiled in or modular. > > I was wondering if this is helpful or can be replicated, if not perhaps my guest which is running Archlinux64 is doing something strange. > Here's what I'm observing: * I can create two block devices just fine. * There are IRQ routing issues when I try to create 3 block devices, if I pass -no-acpi when starting the guest, I can use 24 virtio block devices without a problem * hw/virtio-net.c needs to be aware of reset to cancel any pending tx timers. I have a patch that fixes this. I'll send it out tomorrow after more testing * I can't seem to use more than two virtio_net devices when using -net tap. When using -net user, I can create up to 8 virtio network devices (and they seem to work). * QEMU has a hard limit of 32 PCI devices. Right now, we just get a SEGV when we exceed this. So I think our problems are: * Something is goofy with ACPI and PCI interrupt routing. -no-kvm-irqchip does not help the situation * I need to send out a patch to make virtio_net reset aware * -net tap is broken for more than 1 network device (at least with virtio) * QEMU should allow more than 32 PCI devices. Please try your tests again with -no-acpi and -net user and let me know if that prevents the problem. Thanks for testing! Regards, Anthony Liguori > Regards, > > Will Trives > > > > > ------------------------------------------------------------------------- > This SF.net email is sponsored by: Microsoft > Defy all challenges. Microsoft(R) Visual Studio 2008. > http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ > _______________________________________________ > kvm-devel mailing list > kvm-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/kvm-devel > ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/