KVM: Introduce kvm_arch_destroy_vcpu()

Simiar to how kvm_init_vcpu() calls kvm_arch_init_vcpu() to perform
arch-dependent initialisation, introduce kvm_arch_destroy_vcpu()
to be called from kvm_destroy_vcpu() to perform arch-dependent
destruction.

This was added because some architectures (Such as i386)
currently do not free memory that it have allocated in
kvm_arch_init_vcpu().

Suggested-by: Maran Wilson <maran.wilson@oracle.com>
Reviewed-by: Maran Wilson <maran.wilson@oracle.com>
Signed-off-by: Liran Alon <liran.alon@oracle.com>
Message-Id: <20190619162140.133674-3-liran.alon@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

accel/kvm/kvm-all.c

@@ -291,6 +291,11 @@ int kvm_destroy_vcpu(CPUState *cpu)
 
     DPRINTF("kvm_destroy_vcpu\n");
 
+    ret = kvm_arch_destroy_vcpu(cpu);
+    if (ret < 0) {
+        goto err;
+    }
+
     mmap_size = kvm_ioctl(s, KVM_GET_VCPU_MMAP_SIZE, 0);
     if (mmap_size < 0) {
         ret = mmap_size;

include/sysemu/kvm.h

@@ -371,6 +371,7 @@ int kvm_arch_put_registers(CPUState *cpu, int level);
 int kvm_arch_init(MachineState *ms, KVMState *s);
 
 int kvm_arch_init_vcpu(CPUState *cpu);
+int kvm_arch_destroy_vcpu(CPUState *cpu);
 
 bool kvm_vcpu_id_is_valid(int vcpu_id);
 

target/arm/kvm32.c

@@ -240,6 +240,11 @@ int kvm_arch_init_vcpu(CPUState *cs)
     return kvm_arm_init_cpreg_list(cpu);
 }
 
+int kvm_arch_destroy_vcpu(CPUState *cs)
+{
+	return 0;
+}
+
 typedef struct Reg {
     uint64_t id;
     int offset;

target/arm/kvm64.c

@@ -654,6 +654,11 @@ int kvm_arch_init_vcpu(CPUState *cs)
     return kvm_arm_init_cpreg_list(cpu);
 }
 
+int kvm_arch_destroy_vcpu(CPUState *cs)
+{
+    return 0;
+}
+
 bool kvm_arm_reg_syncs_via_cpreg_list(uint64_t regidx)
 {
     /* Return true if the regidx is a register we should synchronize

target/i386/kvm.c

@@ -1679,6 +1679,18 @@ int kvm_arch_init_vcpu(CPUState *cs)
     return r;
 }
 
+int kvm_arch_destroy_vcpu(CPUState *cs)
+{
+    X86CPU *cpu = X86_CPU(cs);
+
+    if (cpu->kvm_msr_buf) {
+        g_free(cpu->kvm_msr_buf);
+        cpu->kvm_msr_buf = NULL;
+    }
+
+    return 0;
+}
+
 void kvm_arch_reset_vcpu(X86CPU *cpu)
 {
     CPUX86State *env = &cpu->env;

target/mips/kvm.c

@@ -91,6 +91,11 @@ int kvm_arch_init_vcpu(CPUState *cs)
     return ret;
 }
 
+int kvm_arch_destroy_vcpu(CPUState *cs)
+{
+    return 0;
+}
+
 void kvm_mips_reset_vcpu(MIPSCPU *cpu)
 {
     CPUMIPSState *env = &cpu->env;

target/ppc/kvm.c

@@ -521,6 +521,11 @@ int kvm_arch_init_vcpu(CPUState *cs)
     return ret;
 }
 
+int kvm_arch_destroy_vcpu(CPUState *cs)
+{
+    return 0;
+}
+
 static void kvm_sw_tlb_put(PowerPCCPU *cpu)
 {
     CPUPPCState *env = &cpu->env;

target/s390x/kvm.c

@@ -368,6 +368,16 @@ int kvm_arch_init_vcpu(CPUState *cs)
     return 0;
 }
 
+int kvm_arch_destroy_vcpu(CPUState *cs)
+{
+    S390CPU *cpu = S390_CPU(cs);
+
+    g_free(cpu->irqstate);
+    cpu->irqstate = NULL;
+
+    return 0;
+}
+
 void kvm_s390_reset_vcpu(S390CPU *cpu)
 {
     CPUState *cs = CPU(cpu);