Re: [PATCH v10 5/5] KVM: arm64: Register ptdump with debugfs on guest creation

While arch/*/mem/ptdump handles the kernel pagetable dumping code,
introduce KVM/ptdump to show the guest stage-2 pagetables. The
separation is necessary because most of the definitions from the
stage-2 pagetable reside in the KVM path and we will be invoking
functionality specific to KVM. Introduce the PTDUMP_STAGE2_DEBUGFS config.

When a guest is created, register a new file entry under the guest
debugfs dir which allows userspace to show the contents of the guest
stage-2 pagetables when accessed.

Signed-off-by: Sebastian Ene <redacted>
Reviewed-by: Vincent Donnefort <redacted>
---
 arch/arm64/include/asm/kvm_host.h |   6 +
 arch/arm64/kvm/Kconfig            |  17 ++
 arch/arm64/kvm/Makefile           |   1 +
 arch/arm64/kvm/arm.c              |   1 +
 arch/arm64/kvm/ptdump.c           | 268 ++++++++++++++++++++++++++++++
 5 files changed, 293 insertions(+)
 create mode 100644 arch/arm64/kvm/ptdump.c

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index a33f5996ca9f..4acd589f086b 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h

@@ -1473,4 +1473,10 @@ void kvm_set_vm_id_reg(struct kvm *kvm, u32 reg, u64 val);
 		(pa + pi + pa3) == 1;					\
 	})
 
+#ifdef CONFIG_PTDUMP_STAGE2_DEBUGFS
+void kvm_s2_ptdump_create_debugfs(struct kvm *kvm);
+#else
+static inline void kvm_s2_ptdump_create_debugfs(struct kvm *kvm) {}
+#endif /* CONFIG_PTDUMP_STAGE2_DEBUGFS */
+