From edffd3888c43b65d9092dbd6d40ea1e7a708ae2d Mon Sep 17 00:00:00 2001 From: Quentin Perret Date: Wed, 1 Dec 2021 17:03:58 +0000 Subject: [PATCH] BACKPORT: FROMLIST: KVM: arm64: Fixup hyp stage-1 refcount In nVHE-protected mode, the hyp stage-1 page-table refcount is broken due to the lack of refcount support in the early allocator. Fix-up the refcount in the finalize walker, once the 'hyp_vmemmap' is up and running. [ qperret: BACKPORT because of conflict with S2MPU init ] Signed-off-by: Quentin Perret Link: https://lore.kernel.org/r/20211201170411.1561936-5-qperret@google.com Bug: 209599700 Change-Id: Ib31ace99838f397d7a2e48bfd43c6f4eaf730878 --- arch/arm64/kvm/hyp/nvhe/setup.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kvm/hyp/nvhe/setup.c b/arch/arm64/kvm/hyp/nvhe/setup.c index 4e7687bc8ac6..6bcbf959821c 100644 --- a/arch/arm64/kvm/hyp/nvhe/setup.c +++ b/arch/arm64/kvm/hyp/nvhe/setup.c @@ -166,6 +166,7 @@ static int finalize_host_mappings_walker(u64 addr, u64 end, u32 level, enum kvm_pgtable_walk_flags flag, void * const arg) { + struct kvm_pgtable_mm_ops *mm_ops = arg; enum kvm_pgtable_prot prot; enum pkvm_page_state state; kvm_pte_t pte = *ptep; @@ -174,6 +175,15 @@ static int finalize_host_mappings_walker(u64 addr, u64 end, u32 level, if (!kvm_pte_valid(pte)) return 0; + /* + * Fix-up the refcount for the page-table pages as the early allocator + * was unable to access the hyp_vmemmap and so the buddy allocator has + * initialised the refcount to '1'. + */ + mm_ops->get_page(ptep); + if (flag != KVM_PGTABLE_WALK_LEAF) + return 0; + if (level != (KVM_PGTABLE_MAX_LEVELS - 1)) return -EINVAL; @@ -206,7 +216,8 @@ static int finalize_host_mappings(void) { struct kvm_pgtable_walker walker = { .cb = finalize_host_mappings_walker, - .flags = KVM_PGTABLE_WALK_LEAF, + .flags = KVM_PGTABLE_WALK_LEAF | KVM_PGTABLE_WALK_TABLE_POST, + .arg = pkvm_pgtable.mm_ops, }; int i, ret;