Messages in this thread | | | Date | Thu, 07 Oct 2010 12:00:13 +0200 | From | Avi Kivity <> | Subject | Re: [PATCH v6 04/12] Add memory slot versioning and use it to provide fast guest write interface |
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On 10/06/2010 10:08 PM, Gleb Natapov wrote: > > Malicious userspace can cause entry to be cached, ioctl > > SET_USER_MEMORY_REGION 2^32 times, generation number will match, > > mark_page_dirty_in_slot will be called with pointer to freed memory. > > > Hmm. To zap all cached entires on overflow we need to track them. If we > will track then we can zap them on each slot update and drop "generation" > entirely.
To track them you need locking.
Isn't SET_USER_MEMORY_REGION so slow that calling it 2^32 times isn't really feasible?
In any case, can use u64 generation count.
-- I have a truly marvellous patch that fixes the bug which this signature is too narrow to contain.
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