Add a helper to copy a kvm_tdx_cmd structure from userspace and verify that must-be-zero fields are indeed zero.
No functional change intended. Reviewed-by: Rick Edgecombe <[email protected]> Reviewed-by: Kai Huang <[email protected]> Signed-off-by: Sean Christopherson <[email protected]> --- arch/x86/kvm/vmx/tdx.c | 35 +++++++++++++++++++++-------------- 1 file changed, 21 insertions(+), 14 deletions(-) diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c index 97632fc6b520..390c934562c1 100644 --- a/arch/x86/kvm/vmx/tdx.c +++ b/arch/x86/kvm/vmx/tdx.c @@ -2782,20 +2782,29 @@ static int tdx_td_finalize(struct kvm *kvm, struct kvm_tdx_cmd *cmd) return 0; } +static int tdx_get_cmd(void __user *argp, struct kvm_tdx_cmd *cmd) +{ + if (copy_from_user(cmd, argp, sizeof(*cmd))) + return -EFAULT; + + /* + * Userspace should never set hw_error. KVM writes hw_error to report + * hardware-defined error back to userspace. + */ + if (cmd->hw_error) + return -EINVAL; + + return 0; +} + int tdx_vm_ioctl(struct kvm *kvm, void __user *argp) { struct kvm_tdx_cmd tdx_cmd; int r; - if (copy_from_user(&tdx_cmd, argp, sizeof(struct kvm_tdx_cmd))) - return -EFAULT; - - /* - * Userspace should never set hw_error. It is used to fill - * hardware-defined error by the kernel. - */ - if (tdx_cmd.hw_error) - return -EINVAL; + r = tdx_get_cmd(argp, &tdx_cmd); + if (r) + return r; mutex_lock(&kvm->lock); @@ -3171,11 +3180,9 @@ int tdx_vcpu_ioctl(struct kvm_vcpu *vcpu, void __user *argp) if (!is_hkid_assigned(kvm_tdx) || kvm_tdx->state == TD_STATE_RUNNABLE) return -EINVAL; - if (copy_from_user(&cmd, argp, sizeof(cmd))) - return -EFAULT; - - if (cmd.hw_error) - return -EINVAL; + ret = tdx_get_cmd(argp, &cmd); + if (ret) + return ret; switch (cmd.id) { case KVM_TDX_INIT_VCPU: -- 2.51.1.930.gacf6e81ea2-goog
