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// SPDX-License-Identifier: GPL-2.0
#ifndef __KVM_X86_MMU_TDP_ITER_H
#define __KVM_X86_MMU_TDP_ITER_H
#include <linux/kvm_host.h>
#include "mmu.h"
/*
* TDP MMU SPTEs are RCU protected to allow paging structures (non-leaf SPTEs)
* to be zapped while holding mmu_lock for read, and to allow TLB flushes to be
* batched without having to collect the list of zapped SPs. Flows that can
* remove SPs must service pending TLB flushes prior to dropping RCU protection.
*/
static inline u64 kvm_tdp_mmu_read_spte(tdp_ptep_t sptep)
{
return READ_ONCE(*rcu_dereference(sptep));
}
static inline void kvm_tdp_mmu_write_spte(tdp_ptep_t sptep, u64 val)
{
WRITE_ONCE(*rcu_dereference(sptep), val);
}
/*
* A TDP iterator performs a pre-order walk over a TDP paging structure.
*/
struct tdp_iter {
/*
* The iterator will traverse the paging structure towards the mapping
* for this GFN.
*/
gfn_t next_last_level_gfn;
/*
* The next_last_level_gfn at the time when the thread last
* yielded. Only yielding when the next_last_level_gfn !=
* yielded_gfn helps ensure forward progress.
*/
gfn_t yielded_gfn;
/* Pointers to the page tables traversed to reach the current SPTE */
tdp_ptep_t pt_path[PT64_ROOT_MAX_LEVEL];
/* A pointer to the current SPTE */
tdp_ptep_t sptep;
/* The lowest GFN mapped by the current SPTE */
gfn_t gfn;
/* The level of the root page given to the iterator */
int root_level;
/* The lowest level the iterator should traverse to */
int min_level;
/* The iterator's current level within the paging structure */
int level;
/* The address space ID, i.e. SMM vs. regular. */
int as_id;
/* A snapshot of the value at sptep */
u64 old_spte;
/*
* Whether the iterator has a valid state. This will be false if the
* iterator walks off the end of the paging structure.
*/
bool valid;
/*
* True if KVM dropped mmu_lock and yielded in the middle of a walk, in
* which case tdp_iter_next() needs to restart the walk at the root
* level instead of advancing to the next entry.
*/
bool yielded;
};
/*
* Iterates over every SPTE mapping the GFN range [start, end) in a
* preorder traversal.
*/
#define for_each_tdp_pte_min_level(iter, root, min_level, start, end) \
for (tdp_iter_start(&iter, root, min_level, start); \
iter.valid && iter.gfn < end; \
tdp_iter_next(&iter))
#define for_each_tdp_pte(iter, root, start, end) \
for_each_tdp_pte_min_level(iter, root, PG_LEVEL_4K, start, end)
tdp_ptep_t spte_to_child_pt(u64 pte, int level);
void tdp_iter_start(struct tdp_iter *iter, struct kvm_mmu_page *root,
int min_level, gfn_t next_last_level_gfn);
void tdp_iter_next(struct tdp_iter *iter);
void tdp_iter_restart(struct tdp_iter *iter);
#endif /* __KVM_X86_MMU_TDP_ITER_H */
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