On 06/15/2010 05:46 AM, Xiao Guangrong wrote:
Introduce gfn_to_page_atomic() and gfn_to_pfn_atomic(), those
functions is fast path and can used in atomic context, the later
patch will use those
@@ -942,6 +942,41 @@ unsigned long gfn_to_hva(struct kvm *kvm, gfn_t gfn)
}
EXPORT_SYMBOL_GPL(gfn_to_hva);
+static pfn_t hva_to_pfn_atomic(struct kvm *kvm, unsigned long addr)
+{
+ struct page *page[1];
+ int npages;
+ pfn_t pfn;
+
+ npages = __get_user_pages_fast(addr, 1, 1, page);
+
+ if (unlikely(npages != 1)) {
+ if (is_hwpoison_address(addr)) {
+ get_page(hwpoison_page);
+ return page_to_pfn(hwpoison_page);
+ }
+ get_page(bad_page);
+ return page_to_pfn(bad_page);
+ } else
+ pfn = page_to_pfn(page[0]);
+
+ return pfn;
+}
Too much duplication. How about putting the tail end of the function in
a common helper (with an inatomic flag)?
btw, is_hwpoison_address() is racy. While it looks up the address, some
other task can unmap the page tables under us.
Andi/Huang?
One way of fixing it is get_user_pages_ptes_fast(), which also returns
the pte, also atomically. I want it for other reasons as well (respond
to a read fault by gupping the page for read, but allowing write access
if the pte indicates it is writeable).
--
error compiling committee.c: too many arguments to function
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