Phil Winterfield (winterfi)
2010-Aug-27 00:07 UTC
[Xen-devel] Error expanding grant table frames
When I start up a 32-bit PV guest with a pair of passthrough NIC ports, I am seeing the following error: (XEN) grant_table.c:1121:d1 Expanding dom (1) grant table from (4) to (16) frames. (XEN) mm.c:883:d1 Error getting mfn 212ef (pfn 1d210) from L1 entry 00000000212ef023 for l1e_owner=1, pg_owner=1 (XEN) grant_table.c:266:d0 Bad flags (0) or dom (0). (expected dom 0) I am running the 64-bit linux-2.6.32.17 pvops kernel for dom0 along with xen-unstable c/s 22068. This problem has been around for quite a long time and was fixed in the OpenSuse11.1 release which had the linux-2.6.27 kernel for dom0 paired with xen-3.4. In all of the subsequent releases that I have tried, the problem has returned. A few searches have shown that the problem has been observed by others, usually when running 32-bit guests with passthrough NICs. In some instances the error was observed when dom0 was mapping shared RX ring buffers. Any ideas as to where something like this might be originating? _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
On 27/08/2010 01:07, "Phil Winterfield (winterfi)" <winterfi@cisco.com> wrote:> When I start up a 32-bit PV guest with a pair of passthrough NIC ports, I am > seeing the following error: > > (XEN) grant_table.c:1121:d1 Expanding dom (1) grant table from (4) to (16) > frames. > (XEN) mm.c:883:d1 Error getting mfn 212ef (pfn 1d210) from L1 entry > 00000000212ef023 for l1e_owner=1, pg_owner=1Domain 1 presented a pagetable entry mapping a page that either it does not own, or is unable to map with write permissions (e.g., because it is already a pagetable page and permitting write mappings would be unsafe).> (XEN) grant_table.c:266:d0 Bad flags (0) or dom (0). (expected dom 0)Dom0 tried to map a page via a grant reference passed to it by another domain (probably dom1). When Xen checked the permissions in dom1''s grant table, it found all zeroes, which is invalid. This is probably related to the above page-table error: perhaps the failed mapping is of dom1''s extended grant table and hence it failed to write grant details into the grant table. That''s the angle I would investigate with further tracing in Xen and in dom0''s grant-table code. -- Keir> I am running the 64-bit linux-2.6.32.17 pvops kernel for dom0 along with > xen-unstable c/s 22068. This problem has been around for quite a long time > and was fixed in the OpenSuse11.1 release which had the linux-2.6.27 kernel > for dom0 paired with xen-3.4. In all of the subsequent releases that I have > tried, the problem has returned. A few searches have shown that the problem > has been observed by others, usually when running 32-bit guests with > passthrough NICs. In some instances the error was observed when dom0 was > mapping shared RX ring buffers. > > Any ideas as to where something like this might be originating?_______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel