On 2/26/2024 4:25 PM, isaku.yamahata@xxxxxxxxx wrote:
...
+static int setup_tdparams_xfam(struct kvm_cpuid2 *cpuid, struct td_params *td_params)
+{
+ const struct kvm_cpuid_entry2 *entry;
+ u64 guest_supported_xcr0;
+ u64 guest_supported_xss;
+
+ /* Setup td_params.xfam */
+ entry = kvm_find_cpuid_entry2(cpuid->entries, cpuid->nent, 0xd, 0);
+ if (entry)
+ guest_supported_xcr0 = (entry->eax | ((u64)entry->edx << 32));
+ else
+ guest_supported_xcr0 = 0;
+ guest_supported_xcr0 &= kvm_caps.supported_xcr0;
+
+ entry = kvm_find_cpuid_entry2(cpuid->entries, cpuid->nent, 0xd, 1);
+ if (entry)
+ guest_supported_xss = (entry->ecx | ((u64)entry->edx << 32));
+ else
+ guest_supported_xss = 0;
+
+ /*
+ * PT and CET can be exposed to TD guest regardless of KVM's XSS, PT
+ * and, CET support.
+ */
+ guest_supported_xss &=
+ (kvm_caps.supported_xss | XFEATURE_MASK_PT | TDX_TD_XFAM_CET);
+
+ td_params->xfam = guest_supported_xcr0 | guest_supported_xss;
+ if (td_params->xfam & XFEATURE_MASK_LBR) {
+ /*
+ * TODO: once KVM supports LBR(save/restore LBR related
+ * registers around TDENTER), remove this guard.
+ */
+#define MSG_LBR "TD doesn't support LBR yet. KVM needs to save/restore IA32_LBR_DEPTH properly.\n"
+ pr_warn(MSG_LBR);
+ return -EOPNOTSUPP;
This unsupported behavior is totally decided by KVM even if TDX module
supports it. I think we need to reflect it in tdx_info->xfam_fixed0,
which gets reported to userspace via KVM_TDX_CAPABILITIES. So userspace
will aware that LBR is not supported for TDs.
+ }
+
+ return 0;
+}
+
+static int setup_tdparams(struct kvm *kvm, struct td_params *td_params,
+ struct kvm_tdx_init_vm *init_vm)
+{
+ struct kvm_cpuid2 *cpuid = &init_vm->cpuid;
+ int ret;
+
+ if (kvm->created_vcpus)
+ return -EBUSY;
+
+ if (init_vm->attributes & TDX_TD_ATTRIBUTE_PERFMON) {
+ /*
+ * TODO: save/restore PMU related registers around TDENTER.
+ * Once it's done, remove this guard.
+ */
+#define MSG_PERFMON "TD doesn't support perfmon yet. KVM needs to save/restore host perf registers properly.\n"
+ pr_warn(MSG_PERFMON);
+ return -EOPNOTSUPP;
similar as above, we need reflect it in tdx_info->attributes_fixed0
+ }
+
