[PATCH v3 14/15] KVM: arm64: Make table->block changes parallel-aware

Oliver Upton
2022-10-27T22:23:46Z

stage2_map_walk_leaf() and friends now handle stage-2 PTEs generically,
and perform the correct flush when a table PTE is removed. Additionally,
they've been made parallel-aware, using an atomic break to take
ownership of the PTE.

Stop clearing the PTE in the pre-order callback and instead let
stage2_map_walk_leaf() deal with it.

Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
---
arch/arm64/kvm/hyp/pgtable.c | 15 +++------------
1 file changed, 3 insertions(+), 12 deletions(-)

diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c
index 581ba688c6f7..d08e14008bfb 100644
--- a/arch/arm64/kvm/hyp/pgtable.c
+++ b/arch/arm64/kvm/hyp/pgtable.c
@@ -841,21 +841,12 @@ static int stage2_map_walk_table_pre(const struct kvm_pgtable_visit_ctx *ctx,
if (!stage2_leaf_mapping_allowed(ctx, data))
return 0;

- kvm_clear_pte(ctx->ptep);
-
- /*
- * Invalidate the whole stage-2, as we may have numerous leaf
- * entries below us which would otherwise need invalidating
- * individually.
- */
- kvm_call_hyp(__kvm_tlb_flush_vmid, data->mmu);
-
ret = stage2_map_walker_try_leaf(ctx, data);
+ if (ret)
+ return ret;

- mm_ops->put_page(ctx->ptep);
mm_ops->free_removed_table(childp, ctx->level + 1);
-
- return ret;
+ return 0;
}

static int stage2_map_walk_leaf(const struct kvm_pgtable_visit_ctx *ctx,
--
2.38.1.273.g43a17bfeac-goog