From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:50733) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fhqHx-0001to-6I for qemu-devel@nongnu.org; Tue, 24 Jul 2018 01:55:14 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fhqHt-0000Ox-VM for qemu-devel@nongnu.org; Tue, 24 Jul 2018 01:55:13 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:46410 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fhqHt-0000Mj-R9 for qemu-devel@nongnu.org; Tue, 24 Jul 2018 01:55:09 -0400 Date: Tue, 24 Jul 2018 13:55:01 +0800 From: Peter Xu Message-ID: <20180724055501.GA2479@xz-mi> References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Subject: Re: [Qemu-devel] Virtual IOMMU + Virtio-net devices in a Windows VM doesn't work List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jintack Lim Cc: QEMU Devel Mailing List , Jason Wang , "Michael S. Tsirkin" On Mon, Jul 23, 2018 at 04:13:18PM -0400, Jintack Lim wrote: > Hi, > > I'm running a Windows VM on top of KVM on x86, and one of virtio-net > device in the Windows VM doesn't seem to work. I provided virtual > IOMMU and two virtio-net devices to the VM: one bypassing the virtual > IOMMU and the other one behind the virtual IOMMU[1]. It turned out > that the virtio-net device behind virtual IOMMU didn't work while the > one bypassing the virtual IOMMU worked well. In a linux VM with the > same configuration, both of virtio-net device worked well. > > I found that there is a subtle difference between virtio-net devices > bypassing and behind virtual IOMMU in a Linux VM. The lscpu command in > the Linux VM shows different device names for them; the first line is > for the bypassing one, and the second line is for the one behind the > virtual IOMMU > > 00:03.0 Ethernet controller: Red Hat, Inc Virtio network device > 01:00.0 Ethernet controller: Red Hat, Inc Device 1041 (rev 01) > > I wonder if this difference somehow caused the problem in the Windows > VM. I've installed the latest virtio drivers (0.1.149) from the fedora > project [2] > > Any thoughts? > > I'm using v4.15 Linux kernel as a host, and QEMU 2.11.0. Have you tried the latest QEMU? Also CC Jason and Michael. > > Thanks, > Jintack > > [1] https://wiki.qemu.org/Features/VT-d > [2] https://docs.fedoraproject.org/quick-docs/en-US/creating-windows-virtual-machines-using-virtio-drivers.html > > Regards, -- Peter Xu