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>

3 files changed, 11 insertions, 0 deletions

diff --git a/arch/powerpc/include/asm/kvm_ppc.h b/arch/powerpc/include/asm/kvm_ppc.h
index 8931ba729d2b..bb62ad876de3 100644
--- a/arch/powerpc/include/asm/kvm_ppc.h
+++ b/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__ */
diff --git a/arch/powerpc/kvm/44x_tlb.c b/arch/powerpc/kvm/44x_tlb.c
index 2e227a412bc2..ad72c6f9811f 100644
--- a/arch/powerpc/kvm/44x_tlb.c
+++ b/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;
diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index 90a6fc422b23..fda9baada132 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/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