[PATCH v3 05/32] KVM: arm64: Avoid free_page() in page-table allocator

Quentin Perret
2021-03-03T20:50:26Z

Currently, the KVM page-table allocator uses a mix of put_page() and
free_page() calls depending on the context even though page-allocation
is always achieved using variants of __get_free_page().

Make the code consistent by using put_page() throughout, and reduce the
memory management API surface used by the page-table code. This will
ease factoring out page-allocation from pgtable.c, which is a
pre-requisite to creating page-tables at EL2.

Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Quentin Perret <qperret@google.com>
---
arch/arm64/kvm/hyp/pgtable.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c
index 4d177ce1d536..81fe032f34d1 100644
--- a/arch/arm64/kvm/hyp/pgtable.c
+++ b/arch/arm64/kvm/hyp/pgtable.c
@@ -413,7 +413,7 @@ int kvm_pgtable_hyp_init(struct kvm_pgtable *pgt, u32 va_bits)
static int hyp_free_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep,
enum kvm_pgtable_walk_flags flag, void * const arg)
{
- free_page((unsigned long)kvm_pte_follow(*ptep));
+ put_page(virt_to_page(kvm_pte_follow(*ptep)));
return 0;
}

@@ -425,7 +425,7 @@ void kvm_pgtable_hyp_destroy(struct kvm_pgtable *pgt)
};

WARN_ON(kvm_pgtable_walk(pgt, 0, BIT(pgt->ia_bits), &walker));
- free_page((unsigned long)pgt->pgd);
+ put_page(virt_to_page(pgt->pgd));
pgt->pgd = NULL;
}

@@ -577,7 +577,7 @@ static int stage2_map_walk_table_post(u64 addr, u64 end, u32 level,
if (!data->anchor)
return 0;

- free_page((unsigned long)kvm_pte_follow(*ptep));
+ put_page(virt_to_page(kvm_pte_follow(*ptep)));
put_page(virt_to_page(ptep));

if (data->anchor == ptep) {
@@ -700,7 +700,7 @@ static int stage2_unmap_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep,
}

if (childp)
- free_page((unsigned long)childp);
+ put_page(virt_to_page(childp));

return 0;
}
@@ -897,7 +897,7 @@ static int stage2_free_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep,
put_page(virt_to_page(ptep));

if (kvm_pte_table(pte, level))
- free_page((unsigned long)kvm_pte_follow(pte));
+ put_page(virt_to_page(kvm_pte_follow(pte)));

return 0;
}