[PATCH v1] KVM: arm64: Disable stage-2 ptdump of pKVM

[PATCH v1] KVM: arm64: Disable stage-2 ptdump of pKVM

[Vincent Donnefort]

With pKVM enabled, guest stage-2 page tables are owned and managed by
the hypervisor. The host's pgt is uninitialised.

Skip registering stage-2 ptdump debugfs files when protected KVM is
enabled.

Fixes: 7c4f73548ed1 ("KVM: arm64: Register ptdump with debugfs on guest creation")
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
---
 arch/arm64/kvm/ptdump.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/arm64/kvm/ptdump.c b/arch/arm64/kvm/ptdump.c
index 69899797dbad..87e5e7a4e612 100644
--- a/arch/arm64/kvm/ptdump.c
+++ b/arch/arm64/kvm/ptdump.c
@@ -300,6 +300,10 @@ void kvm_nested_s2_ptdump_remove_debugfs(struct kvm_s2_mmu *mmu)
 
 void kvm_s2_ptdump_create_debugfs(struct kvm *kvm)
 {
+	/* pKVM handles the page-tables in the hypervisor */
+	if (is_protected_kvm_enabled())
+		return;
+
 	debugfs_create_file("stage2_page_tables", 0400, kvm->debugfs_dentry,
 			    &kvm->arch.mmu, &kvm_ptdump_guest_fops);
 	debugfs_create_file("ipa_range", 0400, kvm->debugfs_dentry,

base-commit: fd73f4a6659897191fa0d40695fe370925dd3780
-- 
2.55.0.1082.g2b9226bbc0-goog

Re: [PATCH v1] KVM: arm64: Disable stage-2 ptdump of pKVM

[Fuad Tabba]

Hi Vincent,

On Thu, 17 Sep 2026 09:15:10 +0100, Vincent Donnefort
<vdonnefort@google.com> wrote:
[...]
> Fixes: 7c4f73548ed1 ("KVM: arm64: Register ptdump with debugfs on guest creation")

I was wondering if this should be fce886a60207 ("KVM: arm64: Plumb the
pKVM MMU in KVM") instead? Before that commit EL2 ran the guest on the
host's kvm_s2_mmu, so the files dumped the tables in use.

> Signed-off-by: Vincent Donnefort <vdonnefort@google.com>

Reviewed-by: Fuad Tabba <fuad.tabba@linux.dev>
Tested-by: Fuad Tabba <fuad.tabba@linux.dev>

Cheers,
/fuad