From: Will Deacon <will@kernel.org>
Date: Mon, 30 Mar 2026 14:48:17 +0000 (+0100)
Subject: KVM: arm64: Hook up reclaim hypercall to pkvm_pgtable_stage2_destroy()
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4e6e03f9eaddb6be5ca8477dc5642e94ddece47e;p=thirdparty%2Fkernel%2Fstable.git

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

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>
---

diff --git a/arch/arm64/kvm/pkvm.c b/arch/arm64/kvm/pkvm.c
index 7d0fe36fd8dc..3cf23496f225 100644
--- a/arch/arm64/kvm/pkvm.c
+++ b/arch/arm64/kvm/pkvm.c
@@ -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)