From mboxrd@z Thu Jan 1 00:00:00 1970 From: Boris Ostrovsky Subject: Re: [PATCH v2 0/2] Support of RO MMCFG access for PVH/HVMlite dom0s Date: Fri, 18 Dec 2015 09:30:01 -0500 Message-ID: <56741869.1020208@oracle.com> References: <1450383771-3636-1-git-send-email-boris.ostrovsky@oracle.com> <5673E9F202000078000C10EC@prv-mh.provo.novell.com> <567403D4.9070708@citrix.com> <56740FE7.60301@oracle.com> <5674236502000078000C143B@prv-mh.provo.novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <5674236502000078000C143B@prv-mh.provo.novell.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Jan Beulich Cc: Andrew Cooper , keir@xen.org, xen-devel@lists.xen.org List-Id: xen-devel@lists.xenproject.org On 12/18/2015 09:16 AM, Jan Beulich wrote: >>>> On 18.12.15 at 14:53, wrote: >> On 12/18/2015 08:02 AM, Andrew Cooper wrote: >>> On 18/12/15 10:11, Jan Beulich wrote: >>>>>>> On 17.12.15 at 21:22, wrote: >>>>> * Left non-MMCFG RO accesses unhandled (we havent't encountered those >> accesses >>>>> yet with PVH dom0 and it's probably better to fault on them and >> investigate >>>>> whether they are guest's issues). >>>> I seriously question this being a good approach, >>> I concur. All accesses should be terminated somehow, even if this is >>> the hypervisor dropping writes and completing reads with ~0's. >>> >>> This is the expected behaviour from the x86 architecture. >> OK, I'll add that in. >> >> To answer Jan's question, I did try 'vga=keep' and that worked fine. > Interesting. Does your system not load/use a DRM driver for the > card? Or is the driver so minimalistic that no extended config > space write ever occurs? It does load the driver: 0b:00.0 VGA compatible controller: Matrox Graphics, Inc. MGA G200e [Pilot] ServerEngines (SEP1) (rev 04) Subsystem: Intel Corporation Device 0101 Kernel driver in use: mgag200 .. root@ovs104> lsmod | grep mgag mgag200 45056 1 ttm 90112 1 mgag200 drm_kms_helper 122880 1 mgag200 drm 335872 4 mgag200,ttm,drm_kms_helper i2c_algo_bit 16384 2 igb,mgag200 but I don't know what it does to the config space. I configured my kernel for a fairly minimal configuration so perhaps I disabled something that limits what the driver does. -boris