On 7/26/2023 6:13 AM, isaku.yamahata@xxxxxxxxx wrote:
...
+static int tdx_get_capabilities(struct kvm_tdx_cmd *cmd)
+{
+ struct kvm_tdx_capabilities __user *user_caps;
+ const struct tdsysinfo_struct *tdsysinfo;
+ struct kvm_tdx_capabilities *caps = NULL;
+ int ret;
needs to initialize ret to 0; otherwise it returns random value on success.
+
+ BUILD_BUG_ON(sizeof(struct kvm_tdx_cpuid_config) !=
+ sizeof(struct tdx_cpuid_config));
+
+ if (cmd->flags)
+ return -EINVAL;
+
+ tdsysinfo = tdx_get_sysinfo();
+ if (!tdsysinfo)
+ return -EOPNOTSUPP;
+
+ caps = kmalloc(sizeof(*caps), GFP_KERNEL);
+ if (!caps)
+ return -ENOMEM;
+
+ user_caps = (void __user *)cmd->data;
+ if (copy_from_user(caps, user_caps, sizeof(*caps))) {
+ ret = -EFAULT;
+ goto out;
+ }
+
+ if (caps->nr_cpuid_configs < tdsysinfo->num_cpuid_config) {
+ ret = -E2BIG;
+ goto out;
+ }
+
+ *caps = (struct kvm_tdx_capabilities) {
+ .attrs_fixed0 = tdsysinfo->attributes_fixed0,
+ .attrs_fixed1 = tdsysinfo->attributes_fixed1,
+ .xfam_fixed0 = tdsysinfo->xfam_fixed0,
+ .xfam_fixed1 = tdsysinfo->xfam_fixed1,
+ .supported_gpaw = TDX_CAP_GPAW_48 |
+ (kvm_get_shadow_phys_bits() >= 52 &&
+ cpu_has_vmx_ept_5levels()) ? TDX_CAP_GPAW_52 : 0,
+ .nr_cpuid_configs = tdsysinfo->num_cpuid_config,
+ .padding = 0,
+ };
+
+ if (copy_to_user(user_caps, caps, sizeof(*caps))) {
+ ret = -EFAULT;
+ goto out;
+ }
+ if (copy_to_user(user_caps->cpuid_configs, &tdsysinfo->cpuid_configs,
+ tdsysinfo->num_cpuid_config *
+ sizeof(struct tdx_cpuid_config))) {
+ ret = -EFAULT;
+ }
+
+out:
+ /* kfree() accepts NULL. */
+ kfree(caps);
+ return ret;
+}
