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KVM: arm64: Hook up reclaim hypercall to pkvm_pgtable_stage2_destroy()

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During teardown of a protected guest, its memory pages must be reclaimed
from the hypervisor by issuing the '__pkvm_reclaim_dying_guest_page'
hypercall.

Add a new helper, __pkvm_pgtable_stage2_reclaim(), which is called
during the VM teardown operation to reclaim pages from the hypervisor
and drop the GUP pin on the host.

Tested-by: Fuad Tabba <tabba@google.com>
Tested-by: Mostafa Saleh <smostafa@google.com>
Signed-off-by: Will Deacon <will@kernel.org>
Link: https://patch.msgid.link/20260330144841.26181-17-will@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>
This commit is contained in:
Will Deacon
2026-03-30 15:48:17 +01:00
committed by Marc Zyngier
parent 0bf5f4d400
commit 4e6e03f9ea
1 changed files with 30 additions and 1 deletions
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31
arch/arm64/kvm/pkvm.c
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@@ -328,6 +328,32 @@ int pkvm_pgtable_stage2_init(struct kvm_pgtable *pgt, struct kvm_s2_mmu *mmu,
return 0;
}
static int __pkvm_pgtable_stage2_reclaim(struct kvm_pgtable *pgt, u64 start, u64 end)
{
struct kvm *kvm = kvm_s2_mmu_to_kvm(pgt->mmu);
pkvm_handle_t handle = kvm->arch.pkvm.handle;
struct pkvm_mapping *mapping;
int ret;
for_each_mapping_in_range_safe(pgt, start, end, mapping) {
struct page *page;
ret = kvm_call_hyp_nvhe(__pkvm_reclaim_dying_guest_page,
handle, mapping->gfn);
if (WARN_ON(ret))
continue;
page = pfn_to_page(mapping->pfn);
WARN_ON_ONCE(mapping->nr_pages != 1);
unpin_user_pages_dirty_lock(&page, 1, true);
account_locked_vm(current->mm, 1, false);
pkvm_mapping_remove(mapping, &pgt->pkvm_mappings);
kfree(mapping);
}
return 0;
}
static int __pkvm_pgtable_stage2_unshare(struct kvm_pgtable *pgt, u64 start, u64 end)
{
struct kvm *kvm = kvm_s2_mmu_to_kvm(pgt->mmu);
@@ -361,7 +387,10 @@ void pkvm_pgtable_stage2_destroy_range(struct kvm_pgtable *pgt,
kvm->arch.pkvm.is_dying = true;
}
__pkvm_pgtable_stage2_unshare(pgt, addr, addr + size);
if (kvm_vm_is_protected(kvm))
__pkvm_pgtable_stage2_reclaim(pgt, addr, addr + size);
else
__pkvm_pgtable_stage2_unshare(pgt, addr, addr + size);
}
void pkvm_pgtable_stage2_destroy_pgd(struct kvm_pgtable *pgt)