diff options
author | Quentin Perret <qperret@google.com> | 2021-12-15 16:12:19 +0000 |
---|---|---|
committer | Marc Zyngier <maz@kernel.org> | 2021-12-16 12:58:55 +0000 |
commit | 2ea2ff91e82293909d4879b0b4c6c94b02d52b7e (patch) | |
tree | 73399b1522cc9227e84a46f3273097ff3fda9f9c /arch/arm64 | |
parent | 1fac3cfb9cc60d71b66ee5127b2bc5b5f9f79df8 (diff) | |
download | linux-2ea2ff91e82293909d4879b0b4c6c94b02d52b7e.tar.bz2 |
KVM: arm64: Refcount hyp stage-1 pgtable pages
To prepare the ground for allowing hyp stage-1 mappings to be removed at
run-time, update the KVM page-table code to maintain a correct refcount
using the ->{get,put}_page() function callbacks.
Signed-off-by: Quentin Perret <qperret@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211215161232.1480836-3-qperret@google.com
Diffstat (limited to 'arch/arm64')
-rw-r--r-- | arch/arm64/kvm/hyp/pgtable.c | 39 |
1 files changed, 19 insertions, 20 deletions
diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c index f8ceebe4982e..e50e9158fc56 100644 --- a/arch/arm64/kvm/hyp/pgtable.c +++ b/arch/arm64/kvm/hyp/pgtable.c @@ -383,21 +383,6 @@ enum kvm_pgtable_prot kvm_pgtable_hyp_pte_prot(kvm_pte_t pte) return prot; } -static bool hyp_pte_needs_update(kvm_pte_t old, kvm_pte_t new) -{ - /* - * Tolerate KVM recreating the exact same mapping, or changing software - * bits if the existing mapping was valid. - */ - if (old == new) - return false; - - if (!kvm_pte_valid(old)) - return true; - - return !WARN_ON((old ^ new) & ~KVM_PTE_LEAF_ATTR_HI_SW); -} - static bool hyp_map_walker_try_leaf(u64 addr, u64 end, u32 level, kvm_pte_t *ptep, struct hyp_map_data *data) { @@ -407,11 +392,16 @@ static bool hyp_map_walker_try_leaf(u64 addr, u64 end, u32 level, if (!kvm_block_mapping_supported(addr, end, phys, level)) return false; + data->phys += granule; new = kvm_init_valid_leaf_pte(phys, data->attr, level); - if (hyp_pte_needs_update(old, new)) - smp_store_release(ptep, new); + if (old == new) + return true; + if (!kvm_pte_valid(old)) + data->mm_ops->get_page(ptep); + else if (WARN_ON((old ^ new) & ~KVM_PTE_LEAF_ATTR_HI_SW)) + return false; - data->phys += granule; + smp_store_release(ptep, new); return true; } @@ -433,6 +423,7 @@ static int hyp_map_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep, return -ENOMEM; kvm_set_table_pte(ptep, childp, mm_ops); + mm_ops->get_page(ptep); return 0; } @@ -482,8 +473,16 @@ static int hyp_free_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep, enum kvm_pgtable_walk_flags flag, void * const arg) { struct kvm_pgtable_mm_ops *mm_ops = arg; + kvm_pte_t pte = *ptep; + + if (!kvm_pte_valid(pte)) + return 0; + + mm_ops->put_page(ptep); + + if (kvm_pte_table(pte, level)) + mm_ops->put_page(kvm_pte_follow(pte, mm_ops)); - mm_ops->put_page((void *)kvm_pte_follow(*ptep, mm_ops)); return 0; } @@ -491,7 +490,7 @@ void kvm_pgtable_hyp_destroy(struct kvm_pgtable *pgt) { struct kvm_pgtable_walker walker = { .cb = hyp_free_walker, - .flags = KVM_PGTABLE_WALK_TABLE_POST, + .flags = KVM_PGTABLE_WALK_LEAF | KVM_PGTABLE_WALK_TABLE_POST, .arg = pgt->mm_ops, }; |