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KVM: arm64: Fixup hyp stage-1 refcount

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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: Will Deacon <will@kernel.org>
Signed-off-by: Quentin Perret <qperret@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211215161232.1480836-4-qperret@google.com
This commit is contained in:
Quentin Perret 2021-12-15 16:12:20 +00:00 committed by Marc Zyngier
parent 2ea2ff91e8
commit d6b4bd3f48
1 changed files with 16 additions and 5 deletions
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21
arch/arm64/kvm/hyp/nvhe/setup.c
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@ -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,