[RFC 6/6] i386: Add a new property to set ITD related feature bits for Guest

[Zhao Liu <zhao1.liu@xxxxxxxxxxxxxxx>]

From: Zhao Liu <zhao1.liu@xxxxxxxxx>

The property enable-itd will be used to set ITD related feature bits
for Guest, which includes PTS, HFI, ITD and HRESET.

Now PTS, HFI, ITD and HRESET are marked as no_autoenable_flags, since
PTS, HFI and ITD have additional restrictions on CPU topology, and
HRESET is only used in ITD case. If user wants to enable ITD for Guest,
he need to specify PTS, HFI, ITD and HRESET explicitly in the -cpu
command.

Thus it's necessary to introduce "-cpu enable-itd" to help set these
feature bits.

Tested-by: Yanting Jiang <yanting.jiang@xxxxxxxxx>
Signed-off-by: Zhao Liu <zhao1.liu@xxxxxxxxx>
---
 target/i386/cpu.c | 20 +++++++++++++++-----
 target/i386/cpu.h |  3 +++
 2 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index 3b26b471b861..070f7ff43a1b 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -7304,6 +7304,12 @@ static void x86_cpu_realizefn(DeviceState *dev, Error **errp)
      */
     x86_cpu_hyperv_realize(cpu);
 
+    if (cpu->enable_itd) {
+        env->features[FEAT_6_EAX] |= CPUID_6_EAX_PTS | CPUID_6_EAX_HFI |
+                                     CPUID_6_EAX_ITD;
+        env->features[FEAT_7_1_EAX] |= CPUID_7_1_EAX_HRESET;
+    }
+
     x86_cpu_expand_features(cpu, &local_err);
     if (local_err) {
         goto out;
@@ -7494,22 +7500,25 @@ static void x86_cpu_realizefn(DeviceState *dev, Error **errp)
 
     if (env->features[FEAT_6_EAX] & CPUID_6_EAX_PTS && ms->smp.sockets > 1) {
         error_setg(errp,
-                   "PTS currently only supports 1 package, "
-                   "please set by \"-smp ...,sockets=1\"");
+                   "%s currently only supports 1 package, "
+                   "please set by \"-smp ...,sockets=1\"",
+                   cpu->enable_itd ? "enable-itd" : "PTS");
         return;
     }
 
     if (env->features[FEAT_6_EAX] & (CPUID_6_EAX_HFI | CPUID_6_EAX_ITD) &&
         (ms->smp.dies > 1 || ms->smp.sockets > 1)) {
         error_setg(errp,
-                   "HFI/ITD currently only supports die/package, "
-                   "please set by \"-smp ...,sockets=1,dies=1\"");
+                   "%s currently only supports 1 die/package, "
+                   "please set by \"-smp ...,sockets=1,dies=1\"",
+                   cpu->enable_itd ? "enable-itd" : "HFI/ITD");
         return;
     }
 
     if (env->features[FEAT_6_EAX] & (CPUID_6_EAX_PTS | CPUID_6_EAX_HFI) &&
         !(env->features[FEAT_6_EAX] & CPUID_6_EAX_ITD)) {
-        error_setg(errp,
+        error_setg(errp, "%s", cpu->enable_itd ?
+                   "Host doesn't support ITD" :
                    "In the absence of ITD, Guest does "
                    "not need PTS/HFI");
         return;
@@ -8003,6 +8012,7 @@ static Property x86_cpu_properties[] = {
                      false),
     DEFINE_PROP_BOOL("x-intel-pt-auto-level", X86CPU, intel_pt_auto_level,
                      true),
+    DEFINE_PROP_BOOL("enable-itd", X86CPU, enable_itd, false),
     DEFINE_PROP_END_OF_LIST()
 };
 
diff --git a/target/i386/cpu.h b/target/i386/cpu.h
index a68c9d8a8660..009ec66dead0 100644
--- a/target/i386/cpu.h
+++ b/target/i386/cpu.h
@@ -2071,6 +2071,9 @@ struct ArchCPU {
     int32_t hv_max_vps;
 
     bool xen_vapic;
+
+    /* Set ITD and related feature bits (PTS, HFI and HRESET) for Guest. */
+    bool enable_itd;
 };
 
 typedef struct X86CPUModel X86CPUModel;
-- 
2.34.1