Re: [Xen-devel] Crash during boot in Debian lenny default dom0 kernel (2.6.26-2-xen-686)

["Jan Beulich" <JBeulich@xxxxxxxxxx>]

>>> George Dunlap <George.Dunlap@xxxxxxxxxxxxx> 25.02.10 00:57 >>>
>I realize dom0 is a privileged guest, but it still seems like we
>should try not to crash Xen as a result on guest input. :-)

While generally I agree, I think in the given case this is unavoidable -
Xen could apply some sanity check, but the passing of a machine
address from Dom0 to Xen implies that Dom0 knows what it does,
and Xen trusts it. Specifically, struct physdev_map_pirq has this
contents according to the trace

.domid = 00007ff0
.type = 00000000
.index = ffffffff
.pirq = ffffffff
.bus = 00000000
.devfn = 00000008
.entry_nr = 00000000
.table_base = f5861e4a00000001

table_base would seem like not having been initialized at all. I
would guess that they use the structure definition from before
c/s 18323 (which had, instead of a table_base member, an
int field indicating MSI vs. MSI-X. The original definition was
added with c/s 17534 and 17535, but all of those changes
happened during 3.3 development, so no-one should be using
the old definition in released code..

Jan


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