Commit 63db506e authored by Marc Zyngier's avatar Marc Zyngier
Browse files

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



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: default avatarMarc Zyngier <maz@kernel.org>
Reviewed-by: default avatarQuentin Perret <qperret@google.com>
Reviewed-by: default avatarAlexandru Elisei <alexandru.elisei@arm.com>
Link: https://lore.kernel.org/r/20210726153552.1535838-2-maz@kernel.org
parent c500bee1

arch/arm64/include/asm/kvm_pgtable.h

+20 −0
Original line number Diff line number Diff line
@@ -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

arch/arm64/kvm/hyp/pgtable.c

+39 −0
Original line number Diff line number Diff line
@@ -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;