From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sasha Levin Subject: Re: [PATCH V2 0/2] kvm tools: PPC64 basic support Date: Wed, 14 Dec 2011 08:35:55 +0200 Message-ID: <1323844555.3992.13.camel@lappy> References: <1323759627-12752-1-git-send-email-matt@ozlabs.org> <1323771792.3263.1.camel@lappy> <4EE7EEF8.9090804@ozlabs.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org, kvm-ppc@vger.kernel.org, penberg@kernel.org, asias.hejun@gmail.com, gorcunov@gmail.com, Alexander Graf To: Matt Evans Return-path: Received: from mail-ee0-f46.google.com ([74.125.83.46]:45295 "EHLO mail-ee0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751956Ab1LNGgD (ORCPT ); Wed, 14 Dec 2011 01:36:03 -0500 In-Reply-To: <4EE7EEF8.9090804@ozlabs.org> Sender: kvm-owner@vger.kernel.org List-ID: On Wed, 2011-12-14 at 11:34 +1100, Matt Evans wrote: > On 13/12/11 21:23, Sasha Levin wrote: > > On Tue, 2011-12-13 at 18:00 +1100, Matt Evans wrote: > >> The second patch is a small fix for generic virtio code (now that we have a > >> PPC build) which removes reliance on ioeventfds for PPC, which doesn't provide > >> them. > > > > Hm... ioeventfds are located in the generic code and should be available > > on all archs (it doesn't use any arch specific code at all afaik). > > > > Why don't they work on ppc? > > > > Well, there are two problems: you're right that it's generic code, but it's > configurable and CONFIG_HAVE_KVM_EVENTFD isn't set for PPC KVM (thus the ioctl > fails). That's probably off because ioevents won't work anyway-- the in-kernel > MMIO exit route isn't wired up to kvm_io_bus_read/write() yet. (It looks like > KVM_IRQFD will also fail, which virtio-pci /would/ use if I supported MSIs, > which I currently don't.) > > Yes, this can be fixed, but relying on it means that virtio on kvmtool/PPC won't > work on today's kernels. :( In that case, KVM_CAP_IOEVENTFD is simply not set, so we're better off checking the cap dynamically instead of having it defined statically in the makefile. I'll send a short patch that does that. -- Sasha.