KVM: TDX: Use guard() to acquire kvm->lock in tdx_vm_ioctl()

Use guard() in tdx_vm_ioctl() to tidy up the code a small amount, but more
importantly to minimize the diff of a future change, which will use
guard-like semantics to acquire and release multiple locks.

No functional change intended.

Reviewed-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Reviewed-by: Kai Huang <kai.huang@intel.com>
Reviewed-by: Binbin Wu <binbin.wu@linux.intel.com>
Reviewed-by: Yan Zhao <yan.y.zhao@intel.com>
Tested-by: Yan Zhao <yan.y.zhao@intel.com>
Tested-by: Kai Huang <kai.huang@intel.com>
Link: https://patch.msgid.link/20251030200951.3402865-25-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
index 3b4d62a3bf314e9d39d1e425d289b02db2c45c02..a4818d9acbd5bb5ced0943d48df68722705c9a2c 100644 (file)
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -2816,7 +2816,7 @@ int tdx_vm_ioctl(struct kvm *kvm, void __user *argp)
        if (r)
                return r;
 
-       mutex_lock(&kvm->lock);
+       guard(mutex)(&kvm->lock);
 
        switch (tdx_cmd.id) {
        case KVM_TDX_CAPABILITIES:
@@ -2829,15 +2829,12 @@ int tdx_vm_ioctl(struct kvm *kvm, void __user *argp)
                r = tdx_td_finalize(kvm, &tdx_cmd);
                break;
        default:
-               r = -EINVAL;
-               goto out;
+               return -EINVAL;
        }
 
        if (copy_to_user(argp, &tdx_cmd, sizeof(struct kvm_tdx_cmd)))
-               r = -EFAULT;
+               return -EFAULT;
 
-out:
-       mutex_unlock(&kvm->lock);
        return r;
 }