[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH 00/11] Alternate p2m: support multiple copies of host p2m
At 10:41 -0700 on 25 Mar (1427280115), Ed White wrote: > >> > >> The second thing is how similar some of this is to nested p2m code, > >> making me wonder whether it could share more code with that. It's not > >> as much duplication as I had feared, but e.g. altp2m_write_p2m_entry() > >> is _identical_ to nestedp2m_write_p2m_entry(), (making the > >> copyright claim at the top of the file quite dubious, BTW). > >> > > > > I did initially use nestedp2m_write_p2m_entry directly, but I knew > > that wouldn't be acceptable! On this specific point, I would be more > > inclined to refactor the normal write entry routine so you can call > > it everywhere, since both the nested and alternate ones are simply > > a copy of a part of the normal one. > > > > I started to look into this again. What I described as the normal write > routine is the one for HAP, and that is actually a domain-level routine > (akin to the paging mode-specific ones), and takes a domain as its first > parameter. The nestedp2m routine is a p2m-level routine that takes a p2m > as its first parameter, and that's what I had copied. > > However, looking at the code, the p2m-level write routine is only ever > called from the domain-level one, but the HAP routine doesn't make such > calls, and nestedp2m and altp2m are only available in HAP mode. > > Therefore, I have dropped the altp2m write routine with no ill effects. > I don't think the nestedp2m one can ever be called. The write_entry() hook is called from the p2m-pt.c implementation (i.e. on AMD SVM), so with s/HAP/EPT/g your explanation is correct. In EPT, the equivalent is the atomic_write_p2m_entry() function. Cheers, Tim. _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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