Re: [PATCH 3/7] KVM: arm64: Add cached_page_invalidated counter for kvm_stat

Add some counter for when a dpage get invalidated. The counter isn't
in the function that actually do it though because it doesn't have
either a kvm or vcpu argument, so we would have no way to access the
counters. For this reason, the counter have been added to the calling
functions instead.

Signed-off-by: Yoan Picchi <redacted>
---
 arch/arm64/include/asm/kvm_host.h | 1 +
 arch/arm64/kvm/guest.c            | 1 +
 arch/arm64/kvm/mmu.c              | 5 ++++-
 3 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 863603285..3609aa89d 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h

@@ -547,6 +547,7 @@ static inline bool __vcpu_write_sys_reg_to_cpu(u64 val, int reg)
 
 struct kvm_vm_stat {
 	ulong remote_tlb_flush;
+	ulong cached_page_invalidated;
 };
 
 struct kvm_vcpu_stat {

diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
index 1029976ca..f6b1f0b63 100644
--- a/arch/arm64/kvm/guest.c
+++ b/arch/arm64/kvm/guest.c

@@ -41,6 +41,7 @@ struct kvm_stats_debugfs_item debugfs_entries[] = {
 	VCPU_STAT("regular_page_mapped", regular_page_mapped),
 	VCPU_STAT("huge_page_mapped", huge_page_mapped),
 	VM_STAT("remote_tlb_flush", remote_tlb_flush),
+	VM_STAT("cached_page_invalidated", cached_page_invalidated),
 	VCPU_STAT("exits", exits),
 	VCPU_STAT("halt_poll_success_ns", halt_poll_success_ns),
 	VCPU_STAT("halt_poll_fail_ns", halt_poll_fail_ns),

diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index 55d7fe63b..d6ddf5ab8 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c

@@ -893,8 +893,10 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
 	if (writable)
 		prot |= KVM_PGTABLE_PROT_W;
 
-	if (fault_status != FSC_PERM && !device)
+	if (fault_status != FSC_PERM && !device) {
 		clean_dcache_guest_page(pfn, vma_pagesize);
+		kvm->stat.cached_page_invalidated++;
+	}
 
 	if (exec_fault) {
 		prot |= KVM_PGTABLE_PROT_X;

@@ -1166,6 +1168,7 @@ int kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte)
 	 * just like a translation fault and clean the cache to the PoC.
 	 */
 	clean_dcache_guest_page(pfn, PAGE_SIZE);
+	kvm->stat.cached_page_invalidated++;
 	handle_hva_to_gpa(kvm, hva, end, &kvm_set_spte_handler, &pfn);
 	return 0;
 }