From 59d5c1ed6df222791ab7263e5a0c95eea9d83363 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Thu, 30 Oct 2025 13:09:45 -0700 Subject: [PATCH] KVM: TDX: Add tdx_get_cmd() helper to get and validate sub-ioctl command 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 Reviewed-by: Kai Huang Reviewed-by: Binbin Wu Reviewed-by: Yan Zhao Tested-by: Yan Zhao Tested-by: Kai Huang Link: https://patch.msgid.link/20251030200951.3402865-23-seanjc@google.com Signed-off-by: Sean Christopherson --- arch/x86/kvm/vmx/tdx.c | 33 ++++++++++++++++++++------------- 1 file changed, 20 insertions(+), 13 deletions(-) diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c index 88c85fd82a0ee..f42cc955d49c9 100644 --- a/arch/x86/kvm/vmx/tdx.c +++ b/arch/x86/kvm/vmx/tdx.c @@ -2792,21 +2792,30 @@ static int tdx_td_finalize(struct kvm *kvm, struct kvm_tdx_cmd *cmd) return 0; } -int tdx_vm_ioctl(struct kvm *kvm, void __user *argp) +static int tdx_get_cmd(void __user *argp, struct kvm_tdx_cmd *cmd) { - struct kvm_tdx_cmd tdx_cmd; - int r; - - if (copy_from_user(&tdx_cmd, argp, sizeof(struct kvm_tdx_cmd))) + if (copy_from_user(cmd, argp, sizeof(*cmd))) return -EFAULT; /* - * Userspace should never set hw_error. It is used to fill - * hardware-defined error by the kernel. + * Userspace should never set hw_error. KVM writes hw_error to report + * hardware-defined error back to userspace. */ - if (tdx_cmd.hw_error) + 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; + + r = tdx_get_cmd(argp, &tdx_cmd); + if (r) + return r; + mutex_lock(&kvm->lock); switch (tdx_cmd.id) { @@ -3181,11 +3190,9 @@ 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: -- 2.47.3