| Message ID | 20240327124853.11206-2-will@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: arm64: TLBI fixes for the pgtable code | expand |
diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c index 3fae5830f8d2..de0b667ba296 100644 --- a/arch/arm64/kvm/hyp/pgtable.c +++ b/arch/arm64/kvm/hyp/pgtable.c @@ -896,9 +896,11 @@ static void stage2_unmap_put_pte(const struct kvm_pgtable_visit_ctx *ctx, if (kvm_pte_valid(ctx->old)) { kvm_clear_pte(ctx->ptep); - if (!stage2_unmap_defer_tlb_flush(pgt)) + if (!stage2_unmap_defer_tlb_flush(pgt) || + kvm_pte_table(ctx->old, ctx->level)) { kvm_call_hyp(__kvm_tlb_flush_vmid_ipa, mmu, ctx->addr, ctx->level); + } } mm_ops->put_page(ctx->ptep);
Commit 7657ea920c54 ("KVM: arm64: Use TLBI range-based instructions for unmap") introduced deferred TLB invalidation for the stage-2 page-table so that range-based invalidation can be used for the accumulated addresses. This works fine if the structure of the page-tables remains unchanged, but if entire tables are zapped and subsequently freed then we transiently leave the hardware page-table walker with a reference to freed memory thanks to the translation walk caches. For example, stage2_unmap_walker() will free page-table pages: if (childp) mm_ops->put_page(childp); and issue the TLB invalidation later in kvm_pgtable_stage2_unmap(): if (stage2_unmap_defer_tlb_flush(pgt)) /* Perform the deferred TLB invalidations */ kvm_tlb_flush_vmid_range(pgt->mmu, addr, size); For now, take the conservative approach and invalidate the TLB eagerly when we clear a table entry. Note, however, that the existing level hint passed to __kvm_tlb_flush_vmid_ipa() is incorrect and will be fixed in a subsequent patch. Cc: Raghavendra Rao Ananta <rananta@google.com> Cc: Shaoqin Huang <shahuang@redhat.com> Cc: Marc Zyngier <maz@kernel.org> Cc: Oliver Upton <oliver.upton@linux.dev> Signed-off-by: Will Deacon <will@kernel.org> --- arch/arm64/kvm/hyp/pgtable.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)