From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gordon Messmer Subject: Re: Device pass-through Date: Tue, 03 Jan 2012 16:29:26 -0800 Message-ID: <4F039D66.103@eburg.com> References: <4F02086A.6050607@eburg.com> <1325626484.4305.15.camel@bling.home> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org To: Alex Williamson Return-path: Received: from home.dragonsdawn.net ([173.160.248.33]:60473 "EHLO ascension.private.dragonsdawn.net" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755063Ab2ADA3a (ORCPT ); Tue, 3 Jan 2012 19:29:30 -0500 In-Reply-To: <1325626484.4305.15.camel@bling.home> Sender: kvm-owner@vger.kernel.org List-ID: Thanks, Alex. I really appreciate the reply. On 01/03/2012 01:34 PM, Alex Williamson wrote: > This is actually the GART aperture, which Linux will try to use as an > IOMMU. You can pretty much ignore this, but it may be wasting memory > for no good reason if it's really hiding usable memory and allocating a > bounce buffer area. It does look that way, but I doubt I'll miss it. Would you suggest that I boot with swiotlb=0 ? > The host is potentially exposed to a malicious guest trying to trigger > MSI interrupts for denial of service or exploit probing. If you trust > your guest, it's safe to allow this. I do. It's a Fedora guest that I'm personally using. Suppose I didn't. My kernel was built with CONFIG_INTR_REMAP=y but the kernel said "kvm_iommu_map_guest: No interrupt remapping support, disallowing device assignment." Does that mean that the motherboard doesn't support interrupt remapping? >> 4: What do these errors mean, and is there any way I can correct the >> problem? >>> create_userspace_phys_mem: File exists >>> assigned_dev_iomem_map: Error: create new mapping failed > > Might mean the resources for the graphics card are getting mapped to > overlap with guest memory. What does lspci -v for the graphics card > show? More recent changes upstream might make better use of the space > we have for devices, might be worth a test. 05:00.0 VGA compatible controller: ATI Technologies Inc RV620 PRO [Radeon HD 3470] (prog-if 00 [VGA controller]) Subsystem: Dell Device 3243 Flags: fast devsel, IRQ 17 Memory at c0000000 (64-bit, prefetchable) [disabled] [size=256M] Memory at fd9f0000 (64-bit, non-prefetchable) [disabled] [size=64K] I/O ports at ae00 [disabled] [size=256] Expansion ROM at fd900000 [disabled by cmd] [size=128K] Capabilities: [50] Power Management version 3 Capabilities: [58] Express Legacy Endpoint, MSI 00 Capabilities: [a0] MSI: Enable- Count=1/1 Maskable- 64bit+ Capabilities: [100] Vendor Specific Information Kernel modules: radeon