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KVM: arm64: Introduce helper to retrieve a PTE and its level

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It is becoming a common need to fetch the PTE for a given address
together with its level. Add such a helper.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Quentin Perret <qperret@google.com>
Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com>
Link: https://lore.kernel.org/r/20210726153552.1535838-2-maz@kernel.org
This commit is contained in:
Marc Zyngier 2021-07-26 16:35:47 +01:00
parent c500bee1c5
commit 63db506e07
2 changed files with 59 additions and 0 deletions
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20
arch/arm64/include/asm/kvm_pgtable.h
View file

@ -432,6 +432,26 @@ int kvm_pgtable_stage2_flush(struct kvm_pgtable *pgt, u64 addr, u64 size);
int kvm_pgtable_walk(struct kvm_pgtable *pgt, u64 addr, u64 size,
struct kvm_pgtable_walker *walker);
/**
* kvm_pgtable_get_leaf() - Walk a page-table and retrieve the leaf entry
* with its level.
* @pgt: Page-table structure initialised by kvm_pgtable_*_init()
* or a similar initialiser.
* @addr: Input address for the start of the walk.
* @ptep: Pointer to storage for the retrieved PTE.
* @level: Pointer to storage for the level of the retrieved PTE.
*
* The offset of @addr within a page is ignored.
*
* The walker will walk the page-table entries corresponding to the input
* address specified, retrieving the leaf corresponding to this address.
* Invalid entries are treated as leaf entries.
*
* Return: 0 on success, negative error code on failure.
*/
int kvm_pgtable_get_leaf(struct kvm_pgtable *pgt, u64 addr,
kvm_pte_t *ptep, u32 *level);
/**
* kvm_pgtable_stage2_find_range() - Find a range of Intermediate Physical
* Addresses with compatible permission

39
arch/arm64/kvm/hyp/pgtable.c
View file

@ -326,6 +326,45 @@ int kvm_pgtable_walk(struct kvm_pgtable *pgt, u64 addr, u64 size,
return _kvm_pgtable_walk(&walk_data);
}
struct leaf_walk_data {
kvm_pte_t pte;
u32 level;
};
static int leaf_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep,
enum kvm_pgtable_walk_flags flag, void * const arg)
{
struct leaf_walk_data *data = arg;
data->pte = *ptep;
data->level = level;
return 0;
}
int kvm_pgtable_get_leaf(struct kvm_pgtable *pgt, u64 addr,
kvm_pte_t *ptep, u32 *level)
{
struct leaf_walk_data data;
struct kvm_pgtable_walker walker = {
.cb = leaf_walker,
.flags = KVM_PGTABLE_WALK_LEAF,
.arg = &data,
};
int ret;
ret = kvm_pgtable_walk(pgt, ALIGN_DOWN(addr, PAGE_SIZE),
PAGE_SIZE, &walker);
if (!ret) {
if (ptep)
*ptep = data.pte;
if (level)
*level = data.level;
}
return ret;
}
struct hyp_map_data {
u64 phys;
kvm_pte_t attr;