Commit d6b4bd3f authored by Quentin Perret's avatar Quentin Perret Committed by Marc Zyngier
Browse files

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.

Acked-by: default avatarWill Deacon <will@kernel.org>
Signed-off-by: default avatarQuentin Perret <qperret@google.com>
Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211215161232.1480836-4-qperret@google.com
parent 2ea2ff91

arch/arm64/kvm/hyp/nvhe/setup.c

+16 −5
Original line number Diff line number Diff line
@@ -165,6 +165,7 @@ 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;
@@ -173,6 +174,15 @@ 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;
@@ -205,7 +215,8 @@ 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;
@@ -240,10 +251,6 @@ void __noreturn __pkvm_init_finalise(void) 
	if (ret)

		goto out;



	ret = finalize_host_mappings();

	if (ret)

		goto out;



	pkvm_pgtable_mm_ops = (struct kvm_pgtable_mm_ops) {

		.zalloc_page = hyp_zalloc_hyp_page,

		.phys_to_virt = hyp_phys_to_virt,
@@ -253,6 +260,10 @@ void __noreturn __pkvm_init_finalise(void) 
	};

	pkvm_pgtable.mm_ops = &pkvm_pgtable_mm_ops;



	ret = finalize_host_mappings();

	if (ret)

		goto out;



out:

	/*

	 * We tail-called to here from handle___pkvm_init() and will not return,