On Thu, 2018-09-13 at 00:00 +0300, Liran Alon wrote:
> 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@xxxxxxxxxx>
> Signed-off-by: Liran Alon <liran.alon@xxxxxxxxxx>
Reviewed-by: Patrick Colp <patrick.colp@xxxxxxxxxx>
> ---
> arch/x86/kvm/x86.c | 21 +++++++++++++--------
> 1 file changed, 13 insertions(+), 8 deletions(-)
>
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 805c1df7c77e..8f3acdae8b14 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -4007,19 +4007,22 @@ 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) {
> + r = -E2BIG;
> if (put_user(r, &user_kvm_nested_state->size))
> - return -EFAULT;
> - return -E2BIG;
> + r = -EFAULT;
> + break;
> }
> +
> r = 0;
> break;
> }
> @@ -4031,19 +4034,21 @@ 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;
