From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54685) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Yj6up-00078O-Cf for qemu-devel@nongnu.org; Fri, 17 Apr 2015 10:06:49 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Yj6uj-0004F4-Qq for qemu-devel@nongnu.org; Fri, 17 Apr 2015 10:06:43 -0400 Received: from mail-la0-f47.google.com ([209.85.215.47]:33509) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Yj6uj-0004Ea-Hy for qemu-devel@nongnu.org; Fri, 17 Apr 2015 10:06:37 -0400 Received: by layy10 with SMTP id y10so81145885lay.0 for ; Fri, 17 Apr 2015 07:06:36 -0700 (PDT) Date: Fri, 17 Apr 2015 16:06:48 +0200 From: Christoffer Dall Message-ID: <20150417140648.GJ6186@cbox> References: <552FDD13.4090006@redhat.com> <20150417092910.GI6186@cbox> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Subject: Re: [Qemu-devel] ARM: PCI devices emulation broken with KVM due to cache issue List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: =?iso-8859-1?B?Suly6W15IEZhbmd16GRl?= Cc: Paolo Bonzini , VirtualOpenSystems Technical Team , QEMU Developers , kvmarm@lists.cs.columbia.edu On Fri, Apr 17, 2015 at 03:48:35PM +0200, Jérémy Fanguède wrote: > On Fri, Apr 17, 2015 at 11:29 AM, Christoffer Dall > wrote: > > On Thu, Apr 16, 2015 at 06:02:27PM +0200, Paolo Bonzini wrote: > >> > >> > >> On 16/04/2015 17:54, Jérémy Fangučde wrote: > >> > The guest kernel driver of the lsi device fails to enable it correctly > >> > with a cache error: > >> > [...] > >> > sym53c8xx 0000:00:01.0: enabling device (0100 -> 0103) > >> > sym0: <895a> rev 0x0 at pci 0000:00:01.0 irq 54 > >> > sym0: No NVRAM, ID 7, Fast-40, LVD, parity checking > >> > CACHE TEST FAILED: chip wrote 2, host read 1. > >> > sym0: CACHE INCORRECTLY CONFIGURED. > >> > sym0: giving up ... > >> > [...] > >> > >> Note that this is just a failure in the driver self-test. It has > >> nothing to do with the processor cache (though there are other problems > >> with PCI and the processor cache in KVM mode). > >> > >> Do not use this QEMU device. The emulation is incomplete and it's slow. > >> Use virtio-scsi or megasas instead. Still, I'm not sure that would > >> work with KVM; as far as I know, most work on the ARM PCI host bridge > >> was done using UEFI firmware. > >> > > I've been running a number of tests lately using virtio-net-pci and > > virtio-blk-pci on XGene at it works like a charm. > > It should be noted that all these devices work fine on x86 with KVM > enabled. > > Of course, not all PCI devices are affected, e.g. virtio-* devices > work fine for me also. However, should this failure be considered > normal with KVM on ARM, while it works on x86? > > For instance, let's take the use case where there is no virtio > alternative: USB devices (passthrough or emulated) attached to a PCI > USB controller, how is this supposed to work with KVM on ARM? > The only way to make usb-ehci working that I am aware, is > with this cache hack. As Paolo said, we know there are cache issues on KVM/ARM and we are working through. Patches are as always welcome ;) -Christoffer