From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:58979) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1a4Axb-0000D4-Ez for qemu-devel@nongnu.org; Wed, 02 Dec 2015 12:12:56 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1a4AxX-0000A0-Sp for qemu-devel@nongnu.org; Wed, 02 Dec 2015 12:12:55 -0500 Received: from mail-wm0-x231.google.com ([2a00:1450:400c:c09::231]:35236) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1a4AxX-00009r-KW for qemu-devel@nongnu.org; Wed, 02 Dec 2015 12:12:51 -0500 Received: by wmuu63 with SMTP id u63so224043883wmu.0 for ; Wed, 02 Dec 2015 09:12:51 -0800 (PST) Date: Wed, 2 Dec 2015 19:12:47 +0200 From: Shmulik Ladkani Message-ID: <20151202191247.7326c7a3@halley> In-Reply-To: <20151202184610-mutt-send-email-mst@redhat.com> References: <1449066801-3002-1-git-send-email-shmulik.ladkani@ravellosystems.com> <565F0A20.8050507@redhat.com> <20151202184610-mutt-send-email-mst@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v2 for-2.5] virtio-pci: Set the QEMU_PCI_CAP_EXPRESS capability early in its DeviceClass realize method List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Michael S. Tsirkin" Cc: Marcel Apfelbaum , qemu-devel@nongnu.org Hi Michael, On Wed, 2 Dec 2015 18:49:24 +0200 "Michael S. Tsirkin" wrote: > On Wed, Dec 02, 2015 at 05:11:28PM +0200, Marcel Apfelbaum wrote: > > The only thing I want to mention here, (see earlier discussion: https://www.mail-archive.com/qemu-devel@nongnu.org/msg338963.html) > > is that in some cases the PCI config space will have PCIe length, even if the device is not express. > > > > To be more precise, the only interesting scenario is when we plug a virtio device directly into > > the root complex, in this case we'll have a PCI device with a PCIe config space. > > > > However this happens for other devices as well, it looks like a common practice. > > Problem is, if this happens migration breaks as we > changed config space size from 2.4. Correct me if wrong, but as long as a pre 2.5 hardware is used, Marcel's x-disable-pcie gets on (see HW_COMPAT_2_4), thus the device will not be a "pci_is_express", and it will have a small config space size. Isn't it so? Regards, Shmulik