vmmon: use get_user_pages to get page PFN
As a side effect of mainline commit 0d940a9b270b ("mm/pgtable: allow pte_offset_map[_lock]() to fail") in 6.5-rc1, __pte_offset_map(), called by pte_offset_map(), is no longer exported. Based on an upstream IRC discussion and the hva_to_pfn_*() family of functions in KVM code, what PgtblVa2MPNLocked() does seems to be an incomplete and partial open coded logic of get_user_pages() and as it is only used to get PFN from a virtual address, it can be easily implemented using get_user_pages() family. Without knowledge what exactly are the PFNs used for in VMware, it is hard to guess the right flags, these seem to work and have been tested by multiple users over last few weeks. We could likely use get_user_pages() also on older kernels and it might be actually cleaner and more reliable as existing open coded implementation does not seem to handle some corner cases but without knowledge of VMware internals, it will be safer to stick to existing code where possible.
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@ -25,6 +25,7 @@
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#include "compat_pgtable.h"
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#include "compat_spinlock.h"
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#include "compat_page.h"
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#include "compat_version.h"
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/*
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@ -45,6 +46,7 @@
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*-----------------------------------------------------------------------------
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*/
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#if COMPAT_LINUX_VERSION_CHECK_LT(6, 5, 0) // only used by PgtblVa2MPN() below
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static INLINE MPN
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PgtblVa2MPNLocked(struct mm_struct *mm, // IN: Mm structure of a process
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VA addr) // IN: Address in the virtual address
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@ -106,6 +108,7 @@ PgtblVa2MPNLocked(struct mm_struct *mm, // IN: Mm structure of a process
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}
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return mpn;
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}
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#endif
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/*
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@ -125,6 +128,8 @@ PgtblVa2MPNLocked(struct mm_struct *mm, // IN: Mm structure of a process
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*-----------------------------------------------------------------------------
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*/
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#if COMPAT_LINUX_VERSION_CHECK_LT(6, 5, 0)
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static INLINE MPN
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PgtblVa2MPN(VA addr) // IN
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{
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@ -139,4 +144,24 @@ PgtblVa2MPN(VA addr) // IN
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return mpn;
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}
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#else /* COMPAT_LINUX_VERSION_CHECK_LT(6, 5, 0) */
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static INLINE MPN
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PgtblVa2MPN(VA addr) // IN
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{
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struct page *page;
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int npages;
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MPN mpn;
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npages = get_user_pages_unlocked(addr, 1, &page, FOLL_HWPOISON);
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if (npages != 1)
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return INVALID_MPN;
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mpn = page_to_pfn(page);
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put_page(page);
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return mpn;
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}
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#endif /* COMPAT_LINUX_VERSION_CHECK_LT(6, 5, 0) */
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#endif /* __PGTBL_H__ */
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