[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH 0 of 2] Fix correctness race in xc_mem_paging_prep
On Tue, Nov 29, Andres Lagar-Cavilla wrote: > P2m_mem_paging_prep ensures that an mfn is backing the paged-out gfn, and > transitions to the next state in the paging state machine for this page. > Foreign mappings of the gfn will now succeed. This is the key idea, as it > allows the pager to now map the gfn and fill in its contents. > > Unfortunately, it also allows any other foreign mapper to map the gfn and read > its contents. This is particularly dangerous when the populate is launched > by a foreign mapper in the first place, which will be actively retrying the > map operation and might race with the pager. Qemu-dm being a prime example. Yes, I think thats a real issue. The concept looks ok to me. Olaf _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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