[PATCH v4 16/33] hw/i386/fw_cfg: Set SGX bits in feature control fw_cfg accordingly

[Yang Zhong]

From: Sean Christopherson <sean.j.christopherson@intel.com>

Request SGX an SGX Launch Control to be enabled in FEATURE_CONTROL
when the features are exposed to the guest. Our design is the SGX
Launch Control bit will be unconditionally set in FEATURE_CONTROL,
which is unlike host bios.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Yang Zhong <yang.zhong@intel.com>
---
 hw/i386/fw_cfg.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/hw/i386/fw_cfg.c b/hw/i386/fw_cfg.c
index 4e68d5dea4..f6d036dfbe 100644
--- a/hw/i386/fw_cfg.c
+++ b/hw/i386/fw_cfg.c
@@ -159,7 +159,7 @@ void fw_cfg_build_feature_control(MachineState *ms, 
FWCfgState *fw_cfg)
 {
     X86CPU *cpu = X86_CPU(ms->possible_cpus->cpus[0].cpu);
     CPUX86State *env = &cpu->env;
-    uint32_t unused, ecx, edx;
+    uint32_t unused, ebx, ecx, edx;
     uint64_t feature_control_bits = 0;
     uint64_t *val;
 
@@ -174,6 +174,14 @@ void fw_cfg_build_feature_control(MachineState *ms, 
FWCfgState *fw_cfg)
         feature_control_bits |= FEATURE_CONTROL_LMCE;
     }
 
+    cpu_x86_cpuid(env, 0x7, 0, &unused, &ebx, &ecx, &unused);
+    if (ebx & CPUID_7_0_EBX_SGX) {
+        feature_control_bits |= FEATURE_CONTROL_SGX;
+    }
+    if (ecx & CPUID_7_0_ECX_SGX_LC) {
+        feature_control_bits |= FEATURE_CONTROL_SGX_LC;
+    }
+
     if (!feature_control_bits) {
         return;
     }