Fix two bugs that cause x86 PV guest crashes.
1. Ballooning a 32-bit guest would eventually crash it. 2. Revert a broken fix for a regression with NUMA_BALACING. The bad fix caused PV guests to crash after migration. This is not ideal but unpicking the madness that is _PAGE_NUMA == _PAGE_PROTNONE will take a while longer. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (GNU/Linux) iQEcBAABAgAGBQJTMXIFAAoJEFxbo/MsZsTR+9EH/jRBJIF1hWhBEH9DCbnlMA7x yQD30pcI/CjhaOp+5bJhfk/8IUqGX9ODgEt54kauzDuapkERMncUrlLaOz3nay3p BrD3yoaSSwgHTATbVFiqHhu2/Qrwb0RgmdaXrwpeF//5wN9/+OvTQhcJdYMv1I6u ajDl28LH26tBCswz9a6sFMNqIplU3qKuUhC6n/oBLjF+ZQe8g3AUQtkQX0Jg9MPH cyn9s6BxwtDptcMwYoaeIIFXiMC5onwZvO0vn9U4SOk45xHyruu3/F76M/zHE/zO Mv+8iotAEEEp8sgntXeldaXfh0xG9ikmf32eIfOq7KR3ecMT8JSa9Q7jPurKaWo= =YQuC -----END PGP SIGNATURE----- Merge tag 'stable/for-linus-3.14-rc8-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip Pull Xen bugfixes from David Vrabel: "Fix two bugs that cause x86 PV guest crashes. 1. Ballooning a 32-bit guest would eventually crash it. 2. Revert a broken fix for a regression with NUMA_BALACING. The bad fix caused PV guests to crash after migration. This is not ideal but unpicking the madness that is _PAGE_NUMA == _PAGE_PROTNONE will take a while longer" * tag 'stable/for-linus-3.14-rc8-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: Revert "xen: properly account for _PAGE_NUMA during xen pte translations" xen/balloon: flush persistent kmaps in correct position
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commit
81250437a5
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@ -445,20 +445,10 @@ static inline int pte_same(pte_t a, pte_t b)
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return a.pte == b.pte;
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}
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static inline int pteval_present(pteval_t pteval)
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{
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/*
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* Yes Linus, _PAGE_PROTNONE == _PAGE_NUMA. Expressing it this
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* way clearly states that the intent is that protnone and numa
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* hinting ptes are considered present for the purposes of
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* pagetable operations like zapping, protection changes, gup etc.
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*/
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return pteval & (_PAGE_PRESENT | _PAGE_PROTNONE | _PAGE_NUMA);
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}
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static inline int pte_present(pte_t a)
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{
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return pteval_present(pte_flags(a));
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return pte_flags(a) & (_PAGE_PRESENT | _PAGE_PROTNONE |
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_PAGE_NUMA);
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}
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#define pte_accessible pte_accessible
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@ -365,7 +365,7 @@ void xen_ptep_modify_prot_commit(struct mm_struct *mm, unsigned long addr,
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/* Assume pteval_t is equivalent to all the other *val_t types. */
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static pteval_t pte_mfn_to_pfn(pteval_t val)
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{
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if (pteval_present(val)) {
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if (val & _PAGE_PRESENT) {
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unsigned long mfn = (val & PTE_PFN_MASK) >> PAGE_SHIFT;
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unsigned long pfn = mfn_to_pfn(mfn);
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@ -381,7 +381,7 @@ static pteval_t pte_mfn_to_pfn(pteval_t val)
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static pteval_t pte_pfn_to_mfn(pteval_t val)
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{
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if (pteval_present(val)) {
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if (val & _PAGE_PRESENT) {
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unsigned long pfn = (val & PTE_PFN_MASK) >> PAGE_SHIFT;
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pteval_t flags = val & PTE_FLAGS_MASK;
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unsigned long mfn;
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@ -399,12 +399,26 @@ static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp)
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state = BP_EAGAIN;
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break;
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}
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pfn = page_to_pfn(page);
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frame_list[i] = pfn_to_mfn(pfn);
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scrub_page(page);
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frame_list[i] = page_to_pfn(page);
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}
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/*
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* Ensure that ballooned highmem pages don't have kmaps.
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*
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* Do this before changing the p2m as kmap_flush_unused()
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* reads PTEs to obtain pages (and hence needs the original
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* p2m entry).
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*/
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kmap_flush_unused();
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/* Update direct mapping, invalidate P2M, and add to balloon. */
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for (i = 0; i < nr_pages; i++) {
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pfn = frame_list[i];
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frame_list[i] = pfn_to_mfn(pfn);
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page = pfn_to_page(pfn);
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#ifdef CONFIG_XEN_HAVE_PVMMU
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/*
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* Ballooned out frames are effectively replaced with
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@ -429,11 +443,9 @@ static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp)
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}
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#endif
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balloon_append(pfn_to_page(pfn));
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balloon_append(page);
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}
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/* Ensure that ballooned highmem pages don't have kmaps. */
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kmap_flush_unused();
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flush_tlb_all();
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set_xen_guest_handle(reservation.extent_start, frame_list);
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