KVM: ppc: stop leaking host memory on VM exit

When the VM exits, we must call put_page() for every page referenced in the
shadow TLB.

Without this patch, we usually leak 30-50 host pages (120 - 200 KiB with 4 KiB
pages). The maximum number of pages leaked is the size of our shadow TLB, 64
pages.

Signed-off-by: Hollis Blanchard <hollisb@us.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

arch/powerpc/include/asm/kvm_ppc.h

@@ -104,4 +104,6 @@ static inline void kvmppc_set_pid(struct kvm_vcpu *vcpu, u32 new_pid)
 	}
 }
 
+extern void kvmppc_core_destroy_mmu(struct kvm_vcpu *vcpu);
+
 #endif /* __POWERPC_KVM_PPC_H__ */

arch/powerpc/kvm/44x_tlb.c

@@ -124,6 +124,14 @@ static void kvmppc_44x_shadow_release(struct kvm_vcpu *vcpu,
 	}
 }
 
+void kvmppc_core_destroy_mmu(struct kvm_vcpu *vcpu)
+{
+	int i;
+
+	for (i = 0; i <= tlb_44x_hwater; i++)
+		kvmppc_44x_shadow_release(vcpu, i);
+}
+
 void kvmppc_tlbe_set_modified(struct kvm_vcpu *vcpu, unsigned int i)
 {
     vcpu->arch.shadow_tlb_mod[i] = 1;

arch/powerpc/kvm/powerpc.c

@@ -238,6 +238,7 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
 
 void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu)
 {
+	kvmppc_core_destroy_mmu(vcpu);
 }
 
 /* Note: clearing MSR[DE] just means that the debug interrupt will not be