From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paolo Bonzini Subject: Re: KVM with PCI forwarding really slow after 4.1 Date: Wed, 16 Dec 2015 19:11:52 +0100 Message-ID: <5671A968.3090404@redhat.com> References: <20151201180915.53692097@wiggum> <565DDD47.1080104@redhat.com> <20151216185528.75edf799@wiggum> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: kvm@vger.kernel.org To: =?UTF-8?Q?Michael_B=c3=bcsch?= Return-path: Received: from mx1.redhat.com ([209.132.183.28]:42036 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934658AbbLPSL4 (ORCPT ); Wed, 16 Dec 2015 13:11:56 -0500 In-Reply-To: <20151216185528.75edf799@wiggum> Sender: kvm-owner@vger.kernel.org List-ID: On 16/12/2015 18:55, Michael B=C3=BCsch wrote: >>> On 01/12/2015 18:09, Michael B=C3=BCsch wrote: >>>>> I use "-device pci-assign,host=3D00:1a.0" to forward a USB >>>>> host chip to a Win7 32 bit inside of qemu/kvm. That used to >>>>> work pretty well, but it broke horribly somewhere after >>>>> 4.1. With recent kernels the virtual machine boots, but is >>>>> _very_ slow. It takes hours to boot. If PCI forwarding is >>>>> disabled, everything is fine. >>>=20 >>> This has been reported already, I'm going to look at it this >>> week. >=20 > Are there any news regarding this issue? It's being discussed in Bugzilla (https://bugzilla.kernel.org/show_bug.cgi?id=3D107561). Paolo