i386: Make Hyper-V version id configurable

Currently, we hardcode Hyper-V version id (CPUID 0x40000002) to
WS2008R2 and it is known that certain tools in Windows check this. It
seems useful to provide some flexibility by making it possible to change
this info at will. CPUID information is defined in TLFS as:

EAX: Build Number
EBX Bits 31-16: Major Version
    Bits 15-0: Minor Version
ECX Service Pack
EDX Bits 31-24: Service Branch
    Bits 23-0: Service Number

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20210902093530.345756-8-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

docs/hyperv.txt

@@ -211,6 +211,20 @@ When the option is set to 'on' QEMU will always enable the feature, regardless
 of host setup. To keep guests secure, this can only be used in conjunction with
 exposing correct vCPU topology and vCPU pinning.
 
+3.20. hv-version-id-{build,major,minor,spack,sbranch,snumber}
+=============================================================
+This changes Hyper-V version identification in CPUID 0x40000002.EAX-EDX from the
+default (WS2008R2).
+- hv-version-id-build sets 'Build Number' (32 bits)
+- hv-version-id-major sets 'Major Version' (16 bits)
+- hv-version-id-minor sets 'Minor Version' (16 bits)
+- hv-version-id-spack sets 'Service Pack' (32 bits)
+- hv-version-id-sbranch sets 'Service Branch' (8 bits)
+- hv-version-id-snumber sets 'Service Number' (24 bits)
+
+Note: hv-version-id-* are not enlightenments and thus don't enable Hyper-V
+identification when specified without any other enlightenments.
+
 4. Supplementary features
 =========================
 

target/i386/cpu.c

@@ -6258,10 +6258,6 @@ static void x86_cpu_hyperv_realize(X86CPU *cpu)
     cpu->hyperv_interface_id[2] = 0;
     cpu->hyperv_interface_id[3] = 0;
 
-    /* Hypervisor system identity */
-    cpu->hyperv_version_id[0] = 0x00001bbc;
-    cpu->hyperv_version_id[1] = 0x00060001;
-
     /* Hypervisor implementation limits */
     cpu->hyperv_limits[0] = 64;
     cpu->hyperv_limits[1] = 0;
@@ -6840,6 +6836,17 @@ static Property x86_cpu_properties[] = {
     DEFINE_PROP_BOOL("hv-passthrough", X86CPU, hyperv_passthrough, false),
     DEFINE_PROP_BOOL("hv-enforce-cpuid", X86CPU, hyperv_enforce_cpuid, false),
 
+    /* WS2008R2 identify by default */
+    DEFINE_PROP_UINT32("hv-version-id-build", X86CPU, hyperv_ver_id_build,
+                       0x1bbc),
+    DEFINE_PROP_UINT16("hv-version-id-major", X86CPU, hyperv_ver_id_major,
+                       0x0006),
+    DEFINE_PROP_UINT16("hv-version-id-minor", X86CPU, hyperv_ver_id_minor,
+                       0x0001),
+    DEFINE_PROP_UINT32("hv-version-id-spack", X86CPU, hyperv_ver_id_sp, 0),
+    DEFINE_PROP_UINT8("hv-version-id-sbranch", X86CPU, hyperv_ver_id_sb, 0),
+    DEFINE_PROP_UINT32("hv-version-id-snumber", X86CPU, hyperv_ver_id_sn, 0),
+
     DEFINE_PROP_BOOL("check", X86CPU, check_cpuid, true),
     DEFINE_PROP_BOOL("enforce", X86CPU, enforce_cpuid, false),
     DEFINE_PROP_BOOL("x-force-features", X86CPU, force_features, false),

target/i386/cpu.h

@@ -1717,10 +1717,15 @@ struct X86CPU {
     OnOffAuto hyperv_no_nonarch_cs;
     uint32_t hyperv_vendor_id[3];
     uint32_t hyperv_interface_id[4];
-    uint32_t hyperv_version_id[4];
     uint32_t hyperv_limits[3];
     uint32_t hyperv_nested[4];
     bool hyperv_enforce_cpuid;
+    uint32_t hyperv_ver_id_build;
+    uint16_t hyperv_ver_id_major;
+    uint16_t hyperv_ver_id_minor;
+    uint32_t hyperv_ver_id_sp;
+    uint8_t hyperv_ver_id_sb;
+    uint32_t hyperv_ver_id_sn;
 
     bool check_cpuid;
     bool enforce_cpuid;

target/i386/kvm/kvm.c

@@ -1258,14 +1258,18 @@ bool kvm_hyperv_expand_features(X86CPU *cpu, Error **errp)
         cpu->hyperv_interface_id[3] =
             hv_cpuid_get_host(cs, HV_CPUID_INTERFACE, R_EDX);
 
-        cpu->hyperv_version_id[0] =
+        cpu->hyperv_ver_id_build =
             hv_cpuid_get_host(cs, HV_CPUID_VERSION, R_EAX);
-        cpu->hyperv_version_id[1] =
-            hv_cpuid_get_host(cs, HV_CPUID_VERSION, R_EBX);
-        cpu->hyperv_version_id[2] =
+        cpu->hyperv_ver_id_major =
+            hv_cpuid_get_host(cs, HV_CPUID_VERSION, R_EBX) >> 16;
+        cpu->hyperv_ver_id_minor =
+            hv_cpuid_get_host(cs, HV_CPUID_VERSION, R_EBX) & 0xffff;
+        cpu->hyperv_ver_id_sp =
             hv_cpuid_get_host(cs, HV_CPUID_VERSION, R_ECX);
-        cpu->hyperv_version_id[3] =
-            hv_cpuid_get_host(cs, HV_CPUID_VERSION, R_EDX);
+        cpu->hyperv_ver_id_sb =
+            hv_cpuid_get_host(cs, HV_CPUID_VERSION, R_EDX) >> 24;
+        cpu->hyperv_ver_id_sn =
+            hv_cpuid_get_host(cs, HV_CPUID_VERSION, R_EDX) & 0xffffff;
 
         cpu->hv_max_vps = hv_cpuid_get_host(cs, HV_CPUID_IMPLEMENT_LIMITS,
                                             R_EAX);
@@ -1351,10 +1355,12 @@ static int hyperv_fill_cpuids(CPUState *cs,
 
     c = &cpuid_ent[cpuid_i++];
     c->function = HV_CPUID_VERSION;
-    c->eax = cpu->hyperv_version_id[0];
-    c->ebx = cpu->hyperv_version_id[1];
-    c->ecx = cpu->hyperv_version_id[2];
-    c->edx = cpu->hyperv_version_id[3];
+    c->eax = cpu->hyperv_ver_id_build;
+    c->ebx = (uint32_t)cpu->hyperv_ver_id_major << 16 |
+        cpu->hyperv_ver_id_minor;
+    c->ecx = cpu->hyperv_ver_id_sp;
+    c->edx = (uint32_t)cpu->hyperv_ver_id_sb << 24 |
+        (cpu->hyperv_ver_id_sn & 0xffffff);
 
     c = &cpuid_ent[cpuid_i++];
     c->function = HV_CPUID_FEATURES;