[Qemu-devel] [PATCH 0/6] i386: Add "max" CPU model to TCG and KVM

[Qemu-devel] [PATCH 0/6] i386: Add "max" CPU model to TCG and KVM

[Eduardo Habkost]

This is v2 of the previous series that enabled the "host" CPU
model on TCG. Now a new "max" CPU is being added, while keeping
"host" KVM-specific.

In addition to simply adding "max" as a copy of the existing
"host" CPU model, additional patches change it to not use any
host CPUID information when in TCG mode.

---
Cc: "Richard W.M. Jones" <rjones@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
Cc: "Daniel P. Berrange" <berrange@redhat.com>
Cc: Peter Maydell <peter.maydell@linaro.org>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Jiri Denemark <jdenemar@redhat.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: "Jason J. Herne" <jjherne@linux.vnet.ibm.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>

Eduardo Habkost (6):
  i386: Unset cannot_destroy_with_object_finalize_yet on "host" model
  i386: Add ordering field to CPUClass
  i386: Rename X86CPU::host_features to X86CPU::max_features
  i386: Create "max" CPU model
  i386: Make "max" model not use any host CPUID info on TCG
  i386: Don't set CPUClass::cpu_def on "max" model

 target/i386/cpu-qom.h |   6 ++-
 target/i386/cpu.h     |   2 +-
 target/i386/cpu.c     | 110 +++++++++++++++++++++++++++++---------------------
 3 files changed, 71 insertions(+), 47 deletions(-)

-- 
2.11.0.259.g40922b1

[Qemu-devel] [PATCH 1/6] i386: Unset cannot_destroy_with_object_finalize_yet on "host" model

[Eduardo Habkost]

The class is now safe because the assert(kvm_enabled()) line was
removed by commit e435601058e656e6d24e3e87b187e5518f7bf16a.

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
---
 target/i386/cpu.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index cff23e129d..7947c8737c 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -1571,8 +1571,6 @@ static void host_x86_cpu_class_init(ObjectClass *oc, void *data)
      */
 
     dc->props = host_x86_cpu_properties;
-    /* Reason: host_x86_cpu_initfn() dies when !kvm_enabled() */
-    dc->cannot_destroy_with_object_finalize_yet = true;
 }
 
 static void host_x86_cpu_initfn(Object *obj)
-- 
2.11.0.259.g40922b1

Re: [Qemu-devel] [PATCH 1/6] i386: Unset cannot_destroy_with_object_finalize_yet on "host" model

[Eduardo Habkost]

On Thu, Jan 19, 2017 at 07:04:44PM -0200, Eduardo Habkost wrote:
> The class is now safe because the assert(kvm_enabled()) line was
> removed by commit e435601058e656e6d24e3e87b187e5518f7bf16a.
> 
> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>

Applied to x86-next.

-- 
Eduardo

[Qemu-devel] [PATCH 2/6] i386: Add ordering field to CPUClass

[Eduardo Habkost]

Instead of using kvm_enabled to order the "-cpu help" list, use a
new "ordering" field for that.

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
---
 target/i386/cpu-qom.h | 2 ++
 target/i386/cpu.c     | 8 ++++----
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/target/i386/cpu-qom.h b/target/i386/cpu-qom.h
index 8cd607e9a2..14abd0a8c1 100644
--- a/target/i386/cpu-qom.h
+++ b/target/i386/cpu-qom.h
@@ -48,6 +48,7 @@ typedef struct X86CPUDefinition X86CPUDefinition;
  * X86CPUClass:
  * @cpu_def: CPU model definition
  * @kvm_required: Whether CPU model requires KVM to be enabled.
+ * @ordering: Ordering on the "-cpu help" CPU model list.
  * @migration_safe: See CpuDefinitionInfo::migration_safe
  * @parent_realize: The parent class' realize handler.
  * @parent_reset: The parent class' reset handler.
@@ -63,6 +64,7 @@ typedef struct X86CPUClass {
     X86CPUDefinition *cpu_def;
 
     bool kvm_required;
+    int ordering;
     bool migration_safe;
 
     /* Optional description of CPU model.
diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index 7947c8737c..0c6d8d605e 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -1550,6 +1550,7 @@ static void host_x86_cpu_class_init(ObjectClass *oc, void *data)
     uint32_t eax = 0, ebx = 0, ecx = 0, edx = 0;
 
     xcc->kvm_required = true;
+    xcc->ordering = 9;
 
     host_cpuid(0x0, 0, &eax, &ebx, &ecx, &edx);
     x86_cpu_vendor_words2str(host_cpudef.vendor, ebx, edx, ecx);
@@ -2127,7 +2128,7 @@ static void listflags(FILE *f, fprintf_function print, const char **featureset)
     }
 }
 
-/* Sort alphabetically by type name, listing kvm_required models last. */
+/* Sort alphabetically by type name, respecting X86CPUClass::ordering. */
 static gint x86_cpu_list_compare(gconstpointer a, gconstpointer b)
 {
     ObjectClass *class_a = (ObjectClass *)a;
@@ -2136,9 +2137,8 @@ static gint x86_cpu_list_compare(gconstpointer a, gconstpointer b)
     X86CPUClass *cc_b = X86_CPU_CLASS(class_b);
     const char *name_a, *name_b;
 
-    if (cc_a->kvm_required != cc_b->kvm_required) {
-        /* kvm_required items go last */
-        return cc_a->kvm_required ? 1 : -1;
+    if (cc_a->ordering != cc_b->ordering) {
+        return cc_a->ordering - cc_b->ordering;
     } else {
         name_a = object_class_get_name(class_a);
         name_b = object_class_get_name(class_b);
-- 
2.11.0.259.g40922b1

Re: [Qemu-devel] [PATCH 2/6] i386: Add ordering field to CPUClass

[Eduardo Habkost]

On Thu, Jan 19, 2017 at 07:04:45PM -0200, Eduardo Habkost wrote:
> Instead of using kvm_enabled to order the "-cpu help" list, use a
> new "ordering" field for that.
> 
> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>

Applied to x86-next.

-- 
Eduardo

[Qemu-devel] [PATCH 3/6] i386: Rename X86CPU::host_features to X86CPU::max_features

[Eduardo Habkost]

Rename the field and add a small comment to make its purpose
clearer.

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
---
 target/i386/cpu.h | 2 +-
 target/i386/cpu.c | 6 +++---
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/target/i386/cpu.h b/target/i386/cpu.h
index 10c5a3538d..889363e120 100644
--- a/target/i386/cpu.h
+++ b/target/i386/cpu.h
@@ -1211,7 +1211,7 @@ struct X86CPU {
     bool enforce_cpuid;
     bool expose_kvm;
     bool migratable;
-    bool host_features;
+    bool max_features; /* Enable all supported features automatically */
     uint32_t apic_id;
 
     /* if true the CPUID code directly forward host cache leaves to the guest */
diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index 0c6d8d605e..006d0a8b70 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -1583,7 +1583,7 @@ static void host_x86_cpu_initfn(Object *obj)
     /* We can't fill the features array here because we don't know yet if
      * "migratable" is true or false.
      */
-    cpu->host_features = true;
+    cpu->max_features = true;
 
     /* If KVM is disabled, x86_cpu_realizefn() will report an error later */
     if (kvm_enabled()) {
@@ -3102,12 +3102,12 @@ static void x86_cpu_load_features(X86CPU *cpu, Error **errp)
     GList *l;
     Error *local_err = NULL;
 
-    /*TODO: cpu->host_features incorrectly overwrites features
+    /*TODO: cpu->max_features incorrectly overwrites features
      * set using "feat=on|off". Once we fix this, we can convert
      * plus_features & minus_features to global properties
      * inside x86_cpu_parse_featurestr() too.
      */
-    if (cpu->host_features) {
+    if (cpu->max_features) {
         for (w = 0; w < FEATURE_WORDS; w++) {
             env->features[w] =
                 x86_cpu_get_supported_feature_word(w, cpu->migratable);
-- 
2.11.0.259.g40922b1

Re: [Qemu-devel] [PATCH 3/6] i386: Rename X86CPU::host_features to X86CPU::max_features

[Eduardo Habkost]

On Thu, Jan 19, 2017 at 07:04:46PM -0200, Eduardo Habkost wrote:
> Rename the field and add a small comment to make its purpose
> clearer.
> 
> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>

Applied to x86-next.

-- 
Eduardo

[Qemu-devel] [PATCH 4/6] i386: Create "max" CPU model

[Eduardo Habkost]

Rename the existing "host" CPU model to "max, and set it to
kvm_enabled=false. The new "max" CPU model will be able to enable
all features supported by TCG out of the box, because its logic
is based on x86_cpu_get_supported_feature_word(), which already
works with TCG.

A new KVM-specific "host" class was added, that simply inherits
everything from "max" except the 'ordering' and 'description'
fields.

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
---
 target/i386/cpu.c | 42 +++++++++++++++++++++++++++++-------------
 1 file changed, 29 insertions(+), 13 deletions(-)

diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index 006d0a8b70..6f3a62840f 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -1503,8 +1503,6 @@ void x86_cpu_change_kvm_default(const char *prop, const char *value)
 static uint32_t x86_cpu_get_supported_feature_word(FeatureWord w,
                                                    bool migratable_only);
 
-#ifdef CONFIG_KVM
-
 static bool lmce_supported(void)
 {
     uint64_t mce_cap;
@@ -1533,23 +1531,22 @@ static int cpu_x86_fill_model_id(char *str)
 
 static X86CPUDefinition host_cpudef;
 
-static Property host_x86_cpu_properties[] = {
+static Property max_x86_cpu_properties[] = {
     DEFINE_PROP_BOOL("migratable", X86CPU, migratable, true),
     DEFINE_PROP_BOOL("host-cache-info", X86CPU, cache_info_passthrough, false),
     DEFINE_PROP_END_OF_LIST()
 };
 
-/* class_init for the "host" CPU model
+/* class_init for the "max" CPU model
  *
  * This function may be called before KVM is initialized.
  */
-static void host_x86_cpu_class_init(ObjectClass *oc, void *data)
+static void max_x86_cpu_class_init(ObjectClass *oc, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(oc);
     X86CPUClass *xcc = X86_CPU_CLASS(oc);
     uint32_t eax = 0, ebx = 0, ecx = 0, edx = 0;
 
-    xcc->kvm_required = true;
     xcc->ordering = 9;
 
     host_cpuid(0x0, 0, &eax, &ebx, &ecx, &edx);
@@ -1564,17 +1561,16 @@ static void host_x86_cpu_class_init(ObjectClass *oc, void *data)
 
     xcc->cpu_def = &host_cpudef;
     xcc->model_description =
-        "KVM processor with all supported host features "
-        "(only available in KVM mode)";
+        "Enables all features supported by the accelerator in the current host";
 
     /* level, xlevel, xlevel2, and the feature words are initialized on
      * instance_init, because they require KVM to be initialized.
      */
 
-    dc->props = host_x86_cpu_properties;
+    dc->props = max_x86_cpu_properties;
 }
 
-static void host_x86_cpu_initfn(Object *obj)
+static void max_x86_cpu_initfn(Object *obj)
 {
     X86CPU *cpu = X86_CPU(obj);
     CPUX86State *env = &cpu->env;
@@ -1585,7 +1581,6 @@ static void host_x86_cpu_initfn(Object *obj)
      */
     cpu->max_features = true;
 
-    /* If KVM is disabled, x86_cpu_realizefn() will report an error later */
     if (kvm_enabled()) {
         env->cpuid_min_level =
             kvm_arch_get_supported_cpuid(s, 0x0, 0, R_EAX);
@@ -1602,10 +1597,30 @@ static void host_x86_cpu_initfn(Object *obj)
     object_property_set_bool(OBJECT(cpu), true, "pmu", &error_abort);
 }
 
+static const TypeInfo max_x86_cpu_type_info = {
+    .name = X86_CPU_TYPE_NAME("max"),
+    .parent = TYPE_X86_CPU,
+    .instance_init = max_x86_cpu_initfn,
+    .class_init = max_x86_cpu_class_init,
+};
+
+#ifdef CONFIG_KVM
+
+static void host_x86_cpu_class_init(ObjectClass *oc, void *data)
+{
+    X86CPUClass *xcc = X86_CPU_CLASS(oc);
+
+    xcc->kvm_required = true;
+    xcc->ordering = 8;
+
+    xcc->model_description =
+        "KVM processor with all supported host features "
+        "(only available in KVM mode)";
+}
+
 static const TypeInfo host_x86_cpu_type_info = {
     .name = X86_CPU_TYPE_NAME("host"),
-    .parent = TYPE_X86_CPU,
-    .instance_init = host_x86_cpu_initfn,
+    .parent = X86_CPU_TYPE_NAME("max"),
     .class_init = host_x86_cpu_class_init,
 };
 
@@ -3729,6 +3744,7 @@ static void x86_cpu_register_types(void)
     for (i = 0; i < ARRAY_SIZE(builtin_x86_defs); i++) {
         x86_register_cpudef_type(&builtin_x86_defs[i]);
     }
+    type_register_static(&max_x86_cpu_type_info);
 #ifdef CONFIG_KVM
     type_register_static(&host_x86_cpu_type_info);
 #endif
-- 
2.11.0.259.g40922b1

[Qemu-devel] [PATCH 5/6] i386: Make "max" model not use any host CPUID info on TCG

[Eduardo Habkost]

Instead of reporting host CPUID data on "max", use the qemu64 CPU
model as reference to initialize CPUID
vendor/family/model/stepping/model-id.

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
---
 target/i386/cpu.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index 6f3a62840f..ea4e1ae519 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -1592,6 +1592,15 @@ static void max_x86_cpu_initfn(Object *obj)
         if (lmce_supported()) {
             object_property_set_bool(OBJECT(cpu), true, "lmce", &error_abort);
         }
+    } else {
+        object_property_set_str(OBJECT(cpu), CPUID_VENDOR_AMD,
+                                "vendor", &error_abort);
+        object_property_set_int(OBJECT(cpu), 6, "family", &error_abort);
+        object_property_set_int(OBJECT(cpu), 6, "model", &error_abort);
+        object_property_set_int(OBJECT(cpu), 3, "stepping", &error_abort);
+        object_property_set_str(OBJECT(cpu),
+                                "QEMU TCG CPU version " QEMU_HW_VERSION,
+                                "model-id", &error_abort);
     }
 
     object_property_set_bool(OBJECT(cpu), true, "pmu", &error_abort);
-- 
2.11.0.259.g40922b1

[Qemu-devel] [PATCH 6/6] i386: Don't set CPUClass::cpu_def on "max" model

[Eduardo Habkost]

Host CPUID info is used by the "max" CPU model only in KVM mode.
Move the initialization of CPUID data for "max" from class_init
to instance_init, and don't set CPUClass::cpu_def for "max".

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
---
 target/i386/cpu-qom.h |  4 +++-
 target/i386/cpu.c     | 45 +++++++++++++++++++++------------------------
 2 files changed, 24 insertions(+), 25 deletions(-)

diff --git a/target/i386/cpu-qom.h b/target/i386/cpu-qom.h
index 14abd0a8c1..f6c704c3a9 100644
--- a/target/i386/cpu-qom.h
+++ b/target/i386/cpu-qom.h
@@ -60,7 +60,9 @@ typedef struct X86CPUClass {
     CPUClass parent_class;
     /*< public >*/
 
-    /* Should be eventually replaced by subclass-specific property defaults. */
+    /* CPU definition, automatically loaded by instance_init if not NULL.
+     * Should be eventually replaced by subclass-specific property defaults.
+     */
     X86CPUDefinition *cpu_def;
 
     bool kvm_required;
diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index ea4e1ae519..f959eaa2a5 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -1529,47 +1529,27 @@ static int cpu_x86_fill_model_id(char *str)
     return 0;
 }
 
-static X86CPUDefinition host_cpudef;
-
 static Property max_x86_cpu_properties[] = {
     DEFINE_PROP_BOOL("migratable", X86CPU, migratable, true),
     DEFINE_PROP_BOOL("host-cache-info", X86CPU, cache_info_passthrough, false),
     DEFINE_PROP_END_OF_LIST()
 };
 
-/* class_init for the "max" CPU model
- *
- * This function may be called before KVM is initialized.
- */
 static void max_x86_cpu_class_init(ObjectClass *oc, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(oc);
     X86CPUClass *xcc = X86_CPU_CLASS(oc);
-    uint32_t eax = 0, ebx = 0, ecx = 0, edx = 0;
 
     xcc->ordering = 9;
 
-    host_cpuid(0x0, 0, &eax, &ebx, &ecx, &edx);
-    x86_cpu_vendor_words2str(host_cpudef.vendor, ebx, edx, ecx);
-
-    host_cpuid(0x1, 0, &eax, &ebx, &ecx, &edx);
-    host_cpudef.family = ((eax >> 8) & 0x0F) + ((eax >> 20) & 0xFF);
-    host_cpudef.model = ((eax >> 4) & 0x0F) | ((eax & 0xF0000) >> 12);
-    host_cpudef.stepping = eax & 0x0F;
-
-    cpu_x86_fill_model_id(host_cpudef.model_id);
-
-    xcc->cpu_def = &host_cpudef;
     xcc->model_description =
         "Enables all features supported by the accelerator in the current host";
 
-    /* level, xlevel, xlevel2, and the feature words are initialized on
-     * instance_init, because they require KVM to be initialized.
-     */
-
     dc->props = max_x86_cpu_properties;
 }
 
+static void x86_cpu_load_def(X86CPU *cpu, X86CPUDefinition *def, Error **errp);
+
 static void max_x86_cpu_initfn(Object *obj)
 {
     X86CPU *cpu = X86_CPU(obj);
@@ -1582,6 +1562,21 @@ static void max_x86_cpu_initfn(Object *obj)
     cpu->max_features = true;
 
     if (kvm_enabled()) {
+        X86CPUDefinition host_cpudef = { };
+        uint32_t eax = 0, ebx = 0, ecx = 0, edx = 0;
+
+        host_cpuid(0x0, 0, &eax, &ebx, &ecx, &edx);
+        x86_cpu_vendor_words2str(host_cpudef.vendor, ebx, edx, ecx);
+
+        host_cpuid(0x1, 0, &eax, &ebx, &ecx, &edx);
+        host_cpudef.family = ((eax >> 8) & 0x0F) + ((eax >> 20) & 0xFF);
+        host_cpudef.model = ((eax >> 4) & 0x0F) | ((eax & 0xF0000) >> 12);
+        host_cpudef.stepping = eax & 0x0F;
+
+        cpu_x86_fill_model_id(host_cpudef.model_id);
+
+        x86_cpu_load_def(cpu, &host_cpudef, &error_abort);
+
         env->cpuid_min_level =
             kvm_arch_get_supported_cpuid(s, 0x0, 0, R_EAX);
         env->cpuid_min_xlevel =
@@ -2184,7 +2179,7 @@ static void x86_cpu_list_entry(gpointer data, gpointer user_data)
     CPUListState *s = user_data;
     char *name = x86_cpu_class_get_model_name(cc);
     const char *desc = cc->model_description;
-    if (!desc) {
+    if (!desc && cc->cpu_def) {
         desc = cc->cpu_def->model_id;
     }
 
@@ -3592,7 +3587,9 @@ static void x86_cpu_initfn(Object *obj)
     object_property_add_alias(obj, "sse4_1", obj, "sse4.1", &error_abort);
     object_property_add_alias(obj, "sse4_2", obj, "sse4.2", &error_abort);
 
-    x86_cpu_load_def(cpu, xcc->cpu_def, &error_abort);
+    if (xcc->cpu_def) {
+        x86_cpu_load_def(cpu, xcc->cpu_def, &error_abort);
+    }
 }
 
 static int64_t x86_cpu_get_arch_id(CPUState *cs)
-- 
2.11.0.259.g40922b1

Re: [Qemu-devel] [PATCH 0/6] i386: Add "max" CPU model to TCG and KVM

[Peter Maydell]

On 19 January 2017 at 21:04, Eduardo Habkost <ehabkost@redhat.com> wrote:
> This is v2 of the previous series that enabled the "host" CPU
> model on TCG. Now a new "max" CPU is being added, while keeping
> "host" KVM-specific.
>
> In addition to simply adding "max" as a copy of the existing
> "host" CPU model, additional patches change it to not use any
> host CPUID information when in TCG mode.
>
> ---
> Cc: "Richard W.M. Jones" <rjones@redhat.com>
> Cc: David Hildenbrand <david@redhat.com>
> Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
> Cc: "Daniel P. Berrange" <berrange@redhat.com>
> Cc: Peter Maydell <peter.maydell@linaro.org>
> Cc: Igor Mammedov <imammedo@redhat.com>
> Cc: Jiri Denemark <jdenemar@redhat.com>
> Cc: Richard Henderson <rth@twiddle.net>
> Cc: Christian Borntraeger <borntraeger@de.ibm.com>
> Cc: "Jason J. Herne" <jjherne@linux.vnet.ibm.com>
> Cc: Paolo Bonzini <pbonzini@redhat.com>
>
> Eduardo Habkost (6):
>   i386: Unset cannot_destroy_with_object_finalize_yet on "host" model
>   i386: Add ordering field to CPUClass
>   i386: Rename X86CPU::host_features to X86CPU::max_features
>   i386: Create "max" CPU model
>   i386: Make "max" model not use any host CPUID info on TCG
>   i386: Don't set CPUClass::cpu_def on "max" model
>
>  target/i386/cpu-qom.h |   6 ++-
>  target/i386/cpu.h     |   2 +-
>  target/i386/cpu.c     | 110 +++++++++++++++++++++++++++++---------------------
>  3 files changed, 71 insertions(+), 47 deletions(-)

Should we be documenting this new -cpu max somewhere?

(If this series is OK I can send patches to add support to
ARM, and also to add "-machine gic-version=max" to allow
picking the best available interrupt controller type, by
analogy.)

thanks
-- PMM

Re: [Qemu-devel] [PATCH 0/6] i386: Add "max" CPU model to TCG and KVM

[David Hildenbrand]

Am 19.01.2017 um 22:04 schrieb Eduardo Habkost:
> This is v2 of the previous series that enabled the "host" CPU
> model on TCG. Now a new "max" CPU is being added, while keeping
> "host" KVM-specific.
> 
> In addition to simply adding "max" as a copy of the existing
> "host" CPU model, additional patches change it to not use any
> host CPUID information when in TCG mode.
> 

Concept looks good to me. Should also be fairly simple to implement for
s390x. Of course, the same restriction as for the "host" model applies
to "max" then. When running under KVM, and the CPU model KVM interface
is missing, the "max" model won't be able to be expanded.

-- 

David

Re: [Qemu-devel] [PATCH 0/6] i386: Add "max" CPU model to TCG and KVM

[Cornelia Huck]

On Thu, 19 Jan 2017 19:04:43 -0200
Eduardo Habkost <ehabkost@redhat.com> wrote:

> This is v2 of the previous series that enabled the "host" CPU
> model on TCG. Now a new "max" CPU is being added, while keeping
> "host" KVM-specific.

This looks like a good idea, and I think we'll do the same on s390.