From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([209.51.188.92]:49685) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gm17h-0007L7-OH for qemu-devel@nongnu.org; Tue, 22 Jan 2019 13:50:12 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gm17f-0007KA-WC for qemu-devel@nongnu.org; Tue, 22 Jan 2019 13:50:09 -0500 References: <20190122094143.8857-1-david@redhat.com> <20190122134457.212a60f3.cohuck@redhat.com> From: David Hildenbrand Message-ID: Date: Tue, 22 Jan 2019 13:52:34 +0100 MIME-Version: 1.0 In-Reply-To: <20190122134457.212a60f3.cohuck@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v1] s390x/pci: Warn when adding PCI devices without the 'zpci' feature List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Cornelia Huck Cc: qemu-devel@nongnu.org, qemu-s390x@nongnu.org, Collin Walling , Thomas Huth , Christian Borntraeger , Richard Henderson On 22.01.19 13:44, Cornelia Huck wrote: > On Tue, 22 Jan 2019 10:41:43 +0100 > David Hildenbrand wrote: > >> We decided to always create the PCI host bridge, even if 'zpci' is not >> enabled (due to migration compatibility). This however right now allows >> to add zPCI/PCI devices to a VM although the guest will never actually see >> them, confusing people that are using a simple CPU model that has no >> 'zpci' enabled - "Why isn't this working" (David Hildenbrand) >> >> Let's check for 'zpci' and at least print a warning that this will not >> work as expected. We could also bail out, however that might break >> existing QEMU commandlines. >> >> Signed-off-by: David Hildenbrand >> --- >> hw/s390x/s390-pci-bus.c | 5 +++++ >> 1 file changed, 5 insertions(+) >> >> diff --git a/hw/s390x/s390-pci-bus.c b/hw/s390x/s390-pci-bus.c >> index b86a8bdcd4..e7d4f49611 100644 >> --- a/hw/s390x/s390-pci-bus.c >> +++ b/hw/s390x/s390-pci-bus.c >> @@ -863,6 +863,11 @@ static void s390_pcihost_pre_plug(HotplugHandler *hotplug_dev, DeviceState *dev, >> { >> S390pciState *s = S390_PCI_HOST_BRIDGE(hotplug_dev); >> >> + if (!s390_has_feat(S390_FEAT_ZPCI)) { >> + warn_report("Adding PCI or zPCI devices without the 'zpci' CPU feature." >> + " The guest will not be able to see/use these devices."); >> + } >> + >> if (object_dynamic_cast(OBJECT(dev), TYPE_PCI_DEVICE)) { >> PCIDevice *pdev = PCI_DEVICE(dev); >> > > That's hotplug only, isn't it? IIRC coldplugging already fails? > No, applies also to coldplugging. -- Thanks, David / dhildenb