Izik Eidus wrote: > Anthony Liguori wrote: > >> Izik Eidus wrote: >> >>> Anthony Liguori wrote: >>> >>>> I've been playing around with these patches. If I do an >>>> madvise(MADV_DONTNEED) in userspace, when I close the VM, I get the >>>> following bug. My knowledge of the mm is limited but since >>>> madvise(MADV_DONTNEED) effectively does a zap_page_range() I wonder >>>> if we're lacking the necessary callback to also remove any potential >>>> GPA covered by that range from shadow page cache. >>>> >>>> Regards, >>>> >>>> Anthony Liguori >>>> >>> it probably beacuse the changes of the first patch, ( that make all >>> present shadow pages rmapped ) >>> Anthony can you please check what happn if you run latest kvm with >>> the patch (of the rmap) and without the patch? >>> >> It looks like it's my patch for doing an in kernel mmap() to support >> older userspaces. I'll figure out what the problem is. >> >> But at any rate, would madvise() be able to evict the current contents >> of something in the shadow page cache or will the guest not pick up >> the new memory until the old gets evicted from the shadow page cache? >> > if i understand you right, then madvise() wont harm us, beacuse we > protect all our shadow memory by removing the writable bit from it. > therefor the guest cant change anything without we know it. >
The host userspace can, though, and we need to protect the kernel from that. -- Do not meddle in the internals of kernels, for they are subtle and quick to panic. ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ _______________________________________________ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel
