From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [Qemu-devel] virtio breakage with 2.6.25 guest kernel Date: Tue, 13 Jan 2009 16:00:42 +0200 Message-ID: <496C9E8A.6000200@redhat.com> References: <496C9813.7000609@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: kvm-devel , rusty@rustcorp.com.au To: qemu-devel@nongnu.org Return-path: In-Reply-To: <496C9813.7000609@suse.de> Sender: kvm-owner@vger.kernel.org List-ID: Alexander Graf wrote: > Hi, > > while I don't fully understand the problem, here's what I experience so far: > > When using an openSUSE 11.0 kernel (2.6.25) in the guest, virtio on tap > breaks with current KVM git, while it used to work before (haven't > bisected, definitely worked in kvm-78, but is probably due to Anthony's > rewrite). It shows the following message (comes from qemu): > > virtio-net header not in first element > > This is because qemu expects a message with mergeable rx bufs (12 > bytes), but if I see things correctly the old kernel doesn't support > that feature (sends 10 bytes). I put in some debug messages on IO > reads/writes in the qemu virtio handler and got these: > > virtio IO read: 0 = 0x100bba3 > virtio IO write: 0x4 = 0x100bba3 > virtio: setting features 0x100bba3 > > So I believe the feature masking is somewhat non-functional? Or did I > read the masking code in qemu's virtio-net wrong? > > Basically for me, current KVM git broke old guest support, which is a > clear regression and should not happen. Does anybody with more expertise > in virtio want to take on this? > I think this was reported and fixed, possibly by c45a681. -- error compiling committee.c: too many arguments to function