xref: /openbmc/linux/arch/x86/kvm/mmu/tdp_iter.h (revision bf459478)
1 // SPDX-License-Identifier: GPL-2.0
2 
3 #ifndef __KVM_X86_MMU_TDP_ITER_H
4 #define __KVM_X86_MMU_TDP_ITER_H
5 
6 #include <linux/kvm_host.h>
7 
8 #include "mmu.h"
9 
10 typedef u64 __rcu *tdp_ptep_t;
11 
12 /*
13  * A TDP iterator performs a pre-order walk over a TDP paging structure.
14  */
15 struct tdp_iter {
16 	/*
17 	 * The iterator will traverse the paging structure towards the mapping
18 	 * for this GFN.
19 	 */
20 	gfn_t next_last_level_gfn;
21 	/*
22 	 * The next_last_level_gfn at the time when the thread last
23 	 * yielded. Only yielding when the next_last_level_gfn !=
24 	 * yielded_gfn helps ensure forward progress.
25 	 */
26 	gfn_t yielded_gfn;
27 	/* Pointers to the page tables traversed to reach the current SPTE */
28 	tdp_ptep_t pt_path[PT64_ROOT_MAX_LEVEL];
29 	/* A pointer to the current SPTE */
30 	tdp_ptep_t sptep;
31 	/* The lowest GFN mapped by the current SPTE */
32 	gfn_t gfn;
33 	/* The level of the root page given to the iterator */
34 	int root_level;
35 	/* The lowest level the iterator should traverse to */
36 	int min_level;
37 	/* The iterator's current level within the paging structure */
38 	int level;
39 	/* A snapshot of the value at sptep */
40 	u64 old_spte;
41 	/*
42 	 * Whether the iterator has a valid state. This will be false if the
43 	 * iterator walks off the end of the paging structure.
44 	 */
45 	bool valid;
46 };
47 
48 /*
49  * Iterates over every SPTE mapping the GFN range [start, end) in a
50  * preorder traversal.
51  */
52 #define for_each_tdp_pte_min_level(iter, root, root_level, min_level, start, end) \
53 	for (tdp_iter_start(&iter, root, root_level, min_level, start); \
54 	     iter.valid && iter.gfn < end;		     \
55 	     tdp_iter_next(&iter))
56 
57 #define for_each_tdp_pte(iter, root, root_level, start, end) \
58 	for_each_tdp_pte_min_level(iter, root, root_level, PG_LEVEL_4K, start, end)
59 
60 tdp_ptep_t spte_to_child_pt(u64 pte, int level);
61 
62 void tdp_iter_start(struct tdp_iter *iter, u64 *root_pt, int root_level,
63 		    int min_level, gfn_t next_last_level_gfn);
64 void tdp_iter_next(struct tdp_iter *iter);
65 tdp_ptep_t tdp_iter_root_pt(struct tdp_iter *iter);
66 
67 #endif /* __KVM_X86_MMU_TDP_ITER_H */
68