[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] Fwd: Question regarding the behavior of guest_physmap_remove_page on x86
(Resending with this time xen-devel in CC) Hi, On ARM, it's possible to fail when removing a page from the P2M. It's happening if we are trying to shatter a superpage and we don't have memory to allocate the table. Therefore the mapping won't be removed from the P2M. However on ARM (and until recently on x86 [1]), the function guest_physmap_remove_page is not supposed to return an error. So we would free the page even if we fail to remove the page. This will end up to re-use the page by someone else even though the mapping is still present in the P2M. I looked to the x86 version and I'm not sure how the function is behaving. Maybe an x86 maintainers could give me insight here. I'm thinking to fix the problem by checking the return of guest_physmap_remove_page to avoid the page being reallocate to someone else (see for instance guest_remove_page in xen/common/memory.c). Is it a sensible way to fix it? Regards, [1] 5ae03990 "xen/vtd: create RMRR mapping" -- Julien Grall _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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