KVM: arm64: Use kvm_arch_flush_remote_tlbs()

Stop depending on CONFIG_HAVE_KVM_ARCH_TLB_FLUSH_ALL and opt to
standardize on kvm_arch_flush_remote_tlbs() since it avoids
duplicating the generic TLB stats across architectures that implement
their own remote TLB flush.

This adds an extra function call to the ARM64 kvm_flush_remote_tlbs()
path, but that is a small cost in comparison to flushing remote TLBs.

In addition, instead of just incrementing remote_tlb_flush_requests
stat, the generic interface would also increment the
remote_tlb_flush stat.
Signed-off-by: Raghavendra Rao Ananta <rananta@google.com>
Reviewed-by: Shaoqin Huang <shahuang@redhat.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230811045127.3308641-4-rananta@google.com

arch/arm64/include/asm/kvm_host.h

@@ -1113,6 +1113,8 @@ int __init kvm_set_ipa_limit(void);
 #define __KVM_HAVE_ARCH_VM_ALLOC
 struct kvm *kvm_arch_alloc_vm(void);
 
+#define __KVM_HAVE_ARCH_FLUSH_REMOTE_TLBS
+
 static inline bool kvm_vm_is_protected(struct kvm *kvm)
 {
 	return false;

arch/arm64/kvm/Kconfig

@@ -25,7 +25,6 @@ menuconfig KVM
 	select MMU_NOTIFIER
 	select PREEMPT_NOTIFIERS
 	select HAVE_KVM_CPU_RELAX_INTERCEPT
-	select HAVE_KVM_ARCH_TLB_FLUSH_ALL
 	select KVM_MMIO
 	select KVM_GENERIC_DIRTYLOG_READ_PROTECT
 	select KVM_XFER_TO_GUEST_WORK

arch/arm64/kvm/mmu.c

@@ -161,15 +161,15 @@ static bool memslot_is_logging(struct kvm_memory_slot *memslot)
 }
 
 /**
- * kvm_flush_remote_tlbs() - flush all VM TLB entries for v7/8
+ * kvm_arch_flush_remote_tlbs() - flush all VM TLB entries for v7/8
  * @kvm:	pointer to kvm structure.
  *
  * Interface to HYP function to flush all VM TLB entries
  */
-void kvm_flush_remote_tlbs(struct kvm *kvm)
+int kvm_arch_flush_remote_tlbs(struct kvm *kvm)
 {
-	++kvm->stat.generic.remote_tlb_flush_requests;
 	kvm_call_hyp(__kvm_tlb_flush_vmid, &kvm->arch.mmu);
+	return 0;
 }
 
 static bool kvm_is_device_pfn(unsigned long pfn)