KVM: nVMX: Fix bad cleanup on error of get/set nested state IOCTLs

The handlers of IOCTLs in kvm_arch_vcpu_ioctl() are expected to set
their return value in "r" local var and break out of switch block
when they encounter some error.
This is because vcpu_load() is called before the switch block which
have a proper cleanup of vcpu_put() afterwards.

However, KVM_{GET,SET}_NESTED_STATE IOCTLs handlers just return
immediately on error without performing above mentioned cleanup.

Thus, change these handlers to behave as expected.

Fixes: 8fcc4b5923af ("kvm: nVMX: Introduce KVM_CAP_NESTED_STATE")
Reviewed-by: Mark Kanda <mark.kanda@oracle.com>
Reviewed-by: Patrick Colp <patrick.colp@oracle.com>
Signed-off-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 4c39ec5fc4fe6f0dbf7b22fe9340d7fb11d4a928..edbf00ec56b34f7765551280e2872b28d1cb0740 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4010,19 +4010,23 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
                        break;
 
                BUILD_BUG_ON(sizeof(user_data_size) != sizeof(user_kvm_nested_state->size));
+               r = -EFAULT;
                if (get_user(user_data_size, &user_kvm_nested_state->size))
-                       return -EFAULT;
+                       break;
 
                r = kvm_x86_ops->get_nested_state(vcpu, user_kvm_nested_state,
                                                  user_data_size);
                if (r < 0)
-                       return r;
+                       break;
 
                if (r > user_data_size) {
                        if (put_user(r, &user_kvm_nested_state->size))
-                               return -EFAULT;
-                       return -E2BIG;
+                               r = -EFAULT;
+                       else
+                               r = -E2BIG;
+                       break;
                }
+
                r = 0;
                break;
        }
@@ -4034,19 +4038,21 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
                if (!kvm_x86_ops->set_nested_state)
                        break;
 
+               r = -EFAULT;
                if (copy_from_user(&kvm_state, user_kvm_nested_state, sizeof(kvm_state)))
-                       return -EFAULT;
+                       break;
 
+               r = -EINVAL;
                if (kvm_state.size < sizeof(kvm_state))
-                       return -EINVAL;
+                       break;
 
                if (kvm_state.flags &
                    ~(KVM_STATE_NESTED_RUN_PENDING | KVM_STATE_NESTED_GUEST_MODE))
-                       return -EINVAL;
+                       break;
 
                /* nested_run_pending implies guest_mode.  */
                if (kvm_state.flags == KVM_STATE_NESTED_RUN_PENDING)
-                       return -EINVAL;
+                       break;
 
                r = kvm_x86_ops->set_nested_state(vcpu, user_kvm_nested_state, &kvm_state);
                break;