[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: RMRRs and Phantom Functions


  • To: Andrew Cooper <Andrew.Cooper3@xxxxxxxxxx>
  • From: Roger Pau Monné <roger.pau@xxxxxxxxxx>
  • Date: Wed, 27 Apr 2022 12:50:53 +0200
  • Arc-authentication-results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=citrix.com; dmarc=pass action=none header.from=citrix.com; dkim=pass header.d=citrix.com; arc=none
  • Arc-message-signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=SjnXHUcCFjxyuujOHquhftOVGMvvskz6Ww51NGPCPos=; b=aUEFA31WHgIVw+1/8Igq8B+DMMtguELR/zE9rKXurD9WRsdsavcnsoL0LVloq9kmjuDd9u7zpMvJ3T/7VmM3yUwLnKU5oWqecg+FcEnC6ZaXAAFJf1Hsuqcx+Xa09XYdnq1rlkQ39HkcGb5AtLrHPVc4ErAL0PfMk9SJqetzwiqIdCkO7BCn7cBv/dddJVYR8UG961RGgKUD5qpGXGrfT1plfGPeMVCBNpDtmyyDDx3RiPhdIorjN3O3HKz6bJEAYgAr+NSfAcw9CYDyEEZowQ6M5dgnzQHz6XqvfjONikSAqhAA4h/RY/K94oTYEgVHRIuSejPppNKqwmS4OCWOKg==
  • Arc-seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=j+uWBHemHiZ/gq4fGVvJs3oplT8PHz1EHBBQY6xuvbeQn4xtRe17oSbKHAy3z3h1jSYU6rK+9hJPJgoC1CsBo1zWbk7ztUpM+IeKjstEGI4Fx7vR5Hib1vgRj79j4uRZksJeWejyJU1Tc4a0y8mO5dPKOf5er9Nu7yi3vZMmlFklHyQUQ5xmYcWeDe9xgBjKpLsnVd1ICtwNqcenq/jy2J4zLwXlDTzk1F7BOvd/0aeJfkBWVvMcUFHwuBMbsCqi1psq9ffpKDHEFO1ZLGVw0J5PYDLHLJETcGSMP7Xttj9TzCd81p0dKQ4Uux3u4S5l4lBXlxC3/9UDBbpFtgxFBQ==
  • Authentication-results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=citrix.com;
  • Cc: xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxxx>, Jan Beulich <jbeulich@xxxxxxxx>, Kevin Tian <kevin.tian@xxxxxxxxx>, Edwin Torok <edvin.torok@xxxxxxxxxx>
  • Delivery-date: Wed, 27 Apr 2022 10:51:17 +0000
  • Ironport-data: A9a23:DHGppKuYeVxn8pP+69O9Y9QBpufnVChfMUV32f8akzHdYApBsoF/q tZmKWGAOviMMWqnftx1PNy2pk8A6JPTyNRqT1dp+S00F34S+JbJXdiXEBz9bniYRiHhoOOLz Cm8hv3odp1coqr0/0/1WlTZhSAgk/nOHNIQMcacUsxLbVYMpBwJ1FQyw4bVvqYy2YLjW1/X5 4upyyHiEATNNwBcYzp8B52r8HuDjNyq0N/PlgVjDRzjlAa2e0g9VPrzF4noR5fLatA88tqBb /TC1NmEElbxpH/BPD8HfoHTKSXmSpaKVeSHZ+E/t6KK2nCurQRquko32WZ1he66RFxlkvgoo Oihu6BcRi8UGLCXxuBGaiV1TSBeL5F48rLGDyOw5Jn7I03uKxMAwt1IJWRuZ8gj3L8yBmtDs /sFNDoKcxaPwfqsx662QfVtgcJlK9T3OIQYuTdryjSx4fQOGMifBfmVo4IHmmtg7ixNNa+2i 84xcz1gYQ6GexRSElwWFIg/jKGjgXyXnzhw9wrJ/vduujO7IApZjYXyF8vfRNezeeptol+ev CHCol7VK0RPXDCY4X/fmp62vcffkCW+VI8MGbmQ8v9xnEbV1mEVEAcRV1awvb++kEHWc9BVJ lEQ+yEuhbMv70HtRd74NzW7rWCFuFgAWtNWO+w89AyJjKHT5m6k6nMsSzdAbJk9spY/QzUvj gWNh4mxWWwpt6CJQ3WA8LvStSm1JSUeMW4FY2kDUBcB5N7g5oo0i3ojU+peLUJ8tfWtcRmY/ txAhHZWa2k75SLT65iGwA==
  • Ironport-hdrordr: A9a23:9YB6h650I9JgHDxumAPXwUGBI+orL9Y04lQ7vn2ZFiY5TiXIra qTdaogviMc6Ax/ZJjvo6HkBEClewKlyXcT2/hrAV7CZniehILMFu1fBOTZowEIdxeOldK1kJ 0QCZSWa+eAcmSS7/yKhzVQeuxIqLfnzEnrv5a5854Ed3AXV0gK1XYcNu/0KDwVeOEQbqBJaa Z0q/A37wZJPh8sH7eGL0hAe9KGi8zAlZrgbxJDLxk76DOWhTftzLLhCRCX0joXTjsKmN4ZgC L4uj28wp/mn+Cwyxfa2WOWx5NKmOH5wt8GIMCXkMAaJhjllw7tToV8XL+puiwzvYiUmR0Xue iJhy1lE9V46nvXcG3wiRzx2zP42DJr0HPmwU/wuwqVneXJABYBT+ZRj4NQdRXUr2A6ustn7a 5N12WF87JKEBLphk3Glpb1fiAvsnDxjWspkOYVgXAae5AZcqVtoYsW+14QOIscHRj99JssHI BVfY7hDc5tABOnhk3izypSKITGZAVwIv7GeDlPhiWt6UkWoJgjpHFogfD2nR87heYAotd/lq D5259T5cBzp/8tHNxA7dg6MLuK40z2MGTx2TGpUB3a/J9uAQO+l7fHpJMI2cqNRLskiLMPpb WpaiIsiYd1QTOiNfGz
  • List-id: Xen developer discussion <xen-devel.lists.xenproject.org>

On Wed, Apr 27, 2022 at 10:17:49AM +0000, Andrew Cooper wrote:
> On 27/04/2022 09:03, Roger Pau Monne wrote:
> > On Tue, Apr 26, 2022 at 05:51:32PM +0000, Andrew Cooper wrote:
> >> Specifying pci-phantom=04:00,1 does appear to work around the faults,
> >> but it's not right, because functions 1 thru 3 aren't actually phantom.
> >>
> >> Also, I don't see any logic which actually wires up phantom functions
> >> like this to share RMRRs/IVMDs in IO contexts.  The faults only
> >> disappear as a side effect of 04:00.0 and 04:00.4 being in dom0, as far
> >> as I can tell.
> > I think I'm slightly confused, so those faults only happen when the
> > devices are assigned to domains different than dom0?
> >
> > It would seem to me that functions 4 to 7 not being recognized by Xen
> > should also lead to their context entries not being setup in the dom0
> > case, and thus the faults should also happen.
> 
> Functions 4 thru 7 do not exist in the system.  Their config space is
> all ~0's.

Yup.

> As they appear to be non-existent, no IOMMU context is set up for them,
> hence the DMA faults when their source id is actually used.

Right, somehow I read your initial description as the faults only
happening when the devices are assigned to guest, but not when in
dom0.

Thanks, Roger.



 


Rackspace

Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.