[PATCH 3/3] KVM: arm64: Do a KVM_EXIT_MEMORY_FAULT when stage-2 fault handler EFAULTs

[Anish Moorthy <amoorthy@google.com>]

Right now userspace just gets a bare EFAULT when the stage-2 fault
handler fails to fault in the relevant page. Set up a memory fault exit
when this happens, which at the very least eases debugging and might
also let userspace decide on/take some specific action other than
crashing the VM.

Signed-off-by: Anish Moorthy <amoorthy@google.com>
---
 arch/arm64/kvm/mmu.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index 6981b1bc0946..52b4f8e648fb 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -1568,8 +1568,11 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
 		kvm_send_hwpoison_signal(hva, vma_shift);
 		return 0;
 	}
-	if (is_error_noslot_pfn(pfn))
+	if (is_error_noslot_pfn(pfn)) {
+		kvm_prepare_memory_fault_exit(vcpu, fault_ipa, vma_pagesize,
+					      write_fault, exec_fault, false);
 		return -EFAULT;
+	}
 
 	if (kvm_is_device_pfn(pfn)) {
 		/*
-- 
2.46.0.rc2.264.g509ed76dc8-goog