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: Tue, 1 Dec 2015 18:47:51 +0100 Message-ID: <565DDD47.1080104@redhat.com> References: <20151201180915.53692097@wiggum> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: QUOTED-PRINTABLE To: =?UTF-8?Q?Michael_B=c3=bcsch?= , kvm@vger.kernel.org Return-path: Received: from mail-wm0-f54.google.com ([74.125.82.54]:37563 "EHLO mail-wm0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752550AbbLARse (ORCPT ); Tue, 1 Dec 2015 12:48:34 -0500 Received: by wmww144 with SMTP id w144so23835704wmw.0 for ; Tue, 01 Dec 2015 09:48:33 -0800 (PST) In-Reply-To: <20151201180915.53692097@wiggum> Sender: kvm-owner@vger.kernel.org List-ID: On 01/12/2015 18:09, Michael B=FCsch wrote: > Hi, >=20 > 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.=20 > If PCI forwarding is disabled, everything is fine. This has been reported already, I'm going to look at it this week. Paolo