[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH 1/2] memory: exit early from memory_exchange() upon write-back error
On 04/04/17 14:13, Jan Beulich wrote: > There's no point in continuing if in the end we'll return -EFAULT > anyway. It also seems wrong to report a chunk for which at least one > write-back failed as successfully exchanged (albeit the indication of > an error is also not fully correct, as the exchange happened in that > case at least partially - retrieving the GFN to assign the memory to > and/or handing back the information on the replacement memory didn't > work). In any case limiting the amount of damage done to the guest > can't be all that bad an idea. > > Reported-by: Jann Horn <jannh@xxxxxxxxxx> > Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx> Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> > --- > I'm additionally surprised we don't require input GFNs to be order > aligned for both IN- and OUT-chunks (similarly for populate-physmap > and decrease-reservation). This sounds like a bug, rather than being intentional. > > --- a/xen/common/memory.c > +++ b/xen/common/memory.c As an observation, I find it amusing that there is a comment just above this which states /* * Success! Beyond this point we cannot fail for this chunk. */ > @@ -639,6 +639,9 @@ static long memory_exchange(XEN_GUEST_HA > } > } > BUG_ON( !(d->is_dying) && (j != (1UL << out_chunk_order)) ); > + > + if ( rc ) > + goto fail; > } > > exch.nr_exchanged = exch.in.nr_extents; > > > _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx https://lists.xen.org/xen-devel
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