From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:33823) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Wwsx2-0006uQ-RV for qemu-devel@nongnu.org; Tue, 17 Jun 2014 08:57:31 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Wwsww-0006yA-07 for qemu-devel@nongnu.org; Tue, 17 Jun 2014 08:57:24 -0400 Received: from cantor2.suse.de ([195.135.220.15]:59455 helo=mx2.suse.de) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Wwswv-0006xy-LT for qemu-devel@nongnu.org; Tue, 17 Jun 2014 08:57:17 -0400 Message-ID: <53A03B2C.80007@suse.de> Date: Tue, 17 Jun 2014 14:57:16 +0200 From: Alexander Graf MIME-Version: 1.0 References: <1402933252-1079-1-git-send-email-ming.lei@canonical.com> <1402933252-1079-3-git-send-email-ming.lei@canonical.com> <20140616180447.3346dbb2.cornelia.huck@de.ibm.com> <20140617090741.0c5a4b4b.cornelia.huck@de.ibm.com> <20140617104615.10fc3946.cornelia.huck@de.ibm.com> <20140617122521.13c6342b.cornelia.huck@de.ibm.com> <20140617140413.42c0b518.cornelia.huck@de.ibm.com> <53A02F41.7000908@suse.de> <20140617145613.113f5058.cornelia.huck@de.ibm.com> In-Reply-To: <20140617145613.113f5058.cornelia.huck@de.ibm.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 2/4] s390-virtio-bus: move common virtio properties to virtio s390 device class List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Cornelia Huck Cc: Peter Maydell , Ming Lei , qemu-devel@nongnu.org, Paolo Bonzini On 17.06.14 14:56, Cornelia Huck wrote: > On Tue, 17 Jun 2014 14:06:25 +0200 > Alexander Graf wrote: > >> On 17.06.14 14:04, Cornelia Huck wrote: >>> On Tue, 17 Jun 2014 18:45:09 +0800 >>> Ming Lei wrote: >>> >>>> On Tue, Jun 17, 2014 at 6:40 PM, Ming Lei wrote: >>>>> On Tue, Jun 17, 2014 at 6:25 PM, Cornelia Huck wrote: >>>>>> On Tue, 17 Jun 2014 18:15:39 +0800 >>>>>> Ming Lei wrote: >>>>>> >>>>>>> On Tue, Jun 17, 2014 at 4:46 PM, Cornelia Huck wrote: >>>>>>>>> Looks like s390 virtio-blk never enables the two common features, is >>>>>>>>> there any reason the two features can't be supported by s390? >>>>>>>> Indirect descriptors are fine. event_idx will not work IIUC because we >>>>>>>> always need to do a sync before we see changes, and this needs an >>>>>>>> interrupt to trigger. >>>>>>> Sounds like the old s390 isn't cache coherent? Because you mean >>>>>>> write in one side can only be observed from another side with an >>>>>>> explicit notification or interrupt. >>>>>>> >>>>>>> On arm/arm64, we didn't see any problem with event_idx. >>>>>> But you probably have the queues in guest memory, as on other >>>>>> transports (including virtio-ccw)? The old s390-virtio transport keeps >>>>>> the devices and their virtqueues in a memory area behind the guest >>>>>> memory - the guest does not see that memory directly, but a sync has to >>>>>> be performed to see virtqueue movement (see s390_virtio_device_sync()). >>>>> OK, it looks like a real physical device, :-) >>>>> >>>>> I will keep s390-virtio as it is, thanks for your explanation. >>>> BTW, do you want me to add DEFINE_VIRTIO_COMMON_FEATURES() >>>> to s390_virtio_net_properties and s390_virtio_scsi_properties since >>>> I remove them from their default properties? >>> It might be better to remove them for good :) >>> >>> Nobody has probably tried to use them for some time... >>> I just start a very minimal guest with a virtio-console and a >>> virtio-blk device. Don't know whether Alex has a more advanced setup >>> at hand? >> It's the only target that works with TCG, no? > Yup. Do you have a test setup with net, scsi, ...? I usually test > networking (for example) only via a libvirt setup, which will only work > with virtio-ccw. I don't regularly test it, but OBS uses that target for example. Alex