[Qemu-devel] [PATCH qom-cpu-next 0/3] X86CPU: "feature-words"/"filtered-features" properties (v12)

[Qemu-devel] [PATCH qom-cpu-next 0/3] X86CPU: "feature-words"/"filtered-features" properties (v12)

[Eduardo Habkost]

Resubmitting after a rebase and a few trivial changes.

Changes v11 -> v12:
 * Remove unnecessary entries from .gitignore
 * Fix indentation of x86_cpu_get_feature_words() declaration
 * Rebase on top of qom-cpu-next
   (commit bd87d2a - target-i386: Use FeatureWord loop on filter_features_for_kvm())

Git tree for reference:

    git://github.com/ehabkost/qemu-hacks.git work/cpu-raw-features.v12

Eduardo Habkost (3):
  target-i386: Add "feature-words" property
  target-i386: Introduce X86CPU.filtered_features field
  target-i386: Add "filtered-features" property to X86CPU

 Makefile.objs         |  7 ++++-
 qapi-schema.json      | 32 ++++++++++++++++++++
 target-i386/cpu-qom.h |  3 ++
 target-i386/cpu.c     | 82 +++++++++++++++++++++++++++++++++++++++++----------
 4 files changed, 108 insertions(+), 16 deletions(-)

-- 
1.8.1.4

[Qemu-devel] [PATCH qom-cpu-next 1/3] target-i386: Add "feature-words" property

[Eduardo Habkost]

This property will be useful for libvirt, as libvirt already has logic
based on low-level feature bits (not feature names), so it will be
really easy to convert the current libvirt logic to something using the
"feature-words" property.

The property will have two main use cases:
 - Checking host capabilities, by checking the features of the "host"
   CPU model
 - Checking which features are enabled on each CPU model

Example output:

  $ ./QMP/qmp --path=/tmp/m qom-get --path=/machine/unattached/device[1] --property=feature-words
  item[0].cpuid-register: EDX
  item[0].cpuid-input-eax: 2147483658
  item[0].features: 0
  item[1].cpuid-register: EAX
  item[1].cpuid-input-eax: 1073741825
  item[1].features: 0
  item[2].cpuid-register: EDX
  item[2].cpuid-input-eax: 3221225473
  item[2].features: 0
  item[3].cpuid-register: ECX
  item[3].cpuid-input-eax: 2147483649
  item[3].features: 101
  item[4].cpuid-register: EDX
  item[4].cpuid-input-eax: 2147483649
  item[4].features: 563346425
  item[5].cpuid-register: EBX
  item[5].cpuid-input-eax: 7
  item[5].features: 0
  item[5].cpuid-input-ecx: 0
  item[6].cpuid-register: ECX
  item[6].cpuid-input-eax: 1
  item[6].features: 2155880449
  item[7].cpuid-register: EDX
  item[7].cpuid-input-eax: 1
  item[7].features: 126614521

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
Changes v11 -> v12:
 * Remove unnecessary entries from .gitignore
 * Fix indentation of x86_cpu_get_feature_words() declaration
 * Rebase on top of qom-cpu-next
   (commit bd87d2a - target-i386: Use FeatureWord loop on filter_features_for_kvm())

Changes v1 -> v2 (series marked as v11):
 * Merge the non-qapi and qapi patches, to keep series simpler
 * Use the feature word array series as base, so we don't have
   to set the feature word values one-by-one in the code
 * Change type name of property from "x86-cpu-feature-words" to
   "X86CPUFeatureWordInfo"
 * Remove cpu-qapi-schema.json and simply add the type definitions
   to qapi-schema.json, to keep the changes simpler
   * This required compiling qapi-types.o and qapi-visit.o into
     *-user as well
---
 Makefile.objs     |  7 +++++-
 qapi-schema.json  | 32 +++++++++++++++++++++++++
 target-i386/cpu.c | 70 +++++++++++++++++++++++++++++++++++++++++++++----------
 3 files changed, 96 insertions(+), 13 deletions(-)

diff --git a/Makefile.objs b/Makefile.objs
index fcb303a..286ce06 100644
--- a/Makefile.objs
+++ b/Makefile.objs
@@ -79,10 +79,15 @@ common-obj-$(CONFIG_SMARTCARD_NSS) += $(libcacard-y)
 ######################################################################
 # qapi
 
-common-obj-y += qmp-marshal.o qapi-visit.o qapi-types.o
+common-obj-y += qmp-marshal.o
 common-obj-y += qmp.o hmp.o
 endif
 
+######################################################################
+# some qapi visitors are used by both system and user emulation:
+
+common-obj-y += qapi-visit.o qapi-types.o
+
 #######################################################################
 # Target-independent parts used in system and user emulation
 common-obj-y += qemu-log.o
diff --git a/qapi-schema.json b/qapi-schema.json
index 7797400..199744a 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -3587,3 +3587,35 @@
 ##
 {'command': 'query-command-line-options', 'data': { '*option': 'str' },
  'returns': ['CommandLineOptionInfo'] }
+
+##
+# @X86CPURegister32
+#
+# A X86 32-bit register
+#
+# Since: 1.5
+##
+{ 'enum': 'X86CPURegister32',
+  'data': [ 'EAX', 'EBX', 'ECX', 'EDX', 'ESP', 'EBP', 'ESI', 'EDI' ] }
+
+##
+# @X86CPUFeatureWordInfo
+#
+# Information about a X86 CPU feature word
+#
+# @cpuid-input-eax: Input EAX value for CPUID instruction for that feature word
+#
+# @cpuid-input-ecx: #optional Input ECX value for CPUID instruction for that
+#                   feature word
+#
+# @cpuid-register: Output register containing the feature bits
+#
+# @features: value of output register, containing the feature bits
+#
+# Since: 1.5
+##
+{ 'type': 'X86CPUFeatureWordInfo',
+  'data': { 'cpuid-input-eax': 'int',
+            '*cpuid-input-ecx': 'int',
+            'cpuid-register': 'X86CPURegister32',
+            'features': 'int' } }
diff --git a/target-i386/cpu.c b/target-i386/cpu.c
index a39b364..3857514 100644
--- a/target-i386/cpu.c
+++ b/target-i386/cpu.c
@@ -30,6 +30,8 @@
 #include "qemu/config-file.h"
 #include "qapi/qmp/qerror.h"
 
+#include "qapi-types.h"
+#include "qapi-visit.h"
 #include "qapi/visitor.h"
 #include "sysemu/arch_init.h"
 
@@ -195,23 +197,34 @@ static FeatureWordInfo feature_word_info[FEATURE_WORDS] = {
     },
 };
 
+typedef struct X86RegisterInfo32 {
+    /* Name of register */
+    const char *name;
+    /* QAPI enum value register */
+    X86CPURegister32 qapi_enum;
+} X86RegisterInfo32;
+
+#define REGISTER(reg) \
+    [R_##reg] = { .name = #reg, .qapi_enum = X86_C_P_U_REGISTER32_##reg }
+X86RegisterInfo32 x86_reg_info_32[CPU_NB_REGS32] = {
+    REGISTER(EAX),
+    REGISTER(ECX),
+    REGISTER(EDX),
+    REGISTER(EBX),
+    REGISTER(ESP),
+    REGISTER(EBP),
+    REGISTER(ESI),
+    REGISTER(EDI),
+};
+#undef REGISTER
+
+
 const char *get_register_name_32(unsigned int reg)
 {
-    static const char *reg_names[CPU_NB_REGS32] = {
-        [R_EAX] = "EAX",
-        [R_ECX] = "ECX",
-        [R_EDX] = "EDX",
-        [R_EBX] = "EBX",
-        [R_ESP] = "ESP",
-        [R_EBP] = "EBP",
-        [R_ESI] = "ESI",
-        [R_EDI] = "EDI",
-    };
-
     if (reg > CPU_NB_REGS32) {
         return NULL;
     }
-    return reg_names[reg];
+    return x86_reg_info_32[reg].name;
 }
 
 /* collects per-function cpuid data
@@ -1405,6 +1418,36 @@ static void x86_cpuid_set_apic_id(Object *obj, Visitor *v, void *opaque,
     cpu->env.cpuid_apic_id = value;
 }
 
+static void x86_cpu_get_feature_words(Object *obj, Visitor *v, void *opaque,
+                                      const char *name, Error **errp)
+{
+    X86CPU *cpu = X86_CPU(obj);
+    CPUX86State *env = &cpu->env;
+    FeatureWord w;
+    Error *err = NULL;
+    X86CPUFeatureWordInfo word_infos[FEATURE_WORDS] = { };
+    X86CPUFeatureWordInfoList list_entries[FEATURE_WORDS] = { };
+    X86CPUFeatureWordInfoList *list = NULL;
+
+    for (w = 0; w < FEATURE_WORDS; w++) {
+        FeatureWordInfo *wi = &feature_word_info[w];
+        X86CPUFeatureWordInfo *qwi = &word_infos[w];
+        qwi->cpuid_input_eax = wi->cpuid_eax;
+        qwi->has_cpuid_input_ecx = wi->cpuid_needs_ecx;
+        qwi->cpuid_input_ecx = wi->cpuid_ecx;
+        qwi->cpuid_register = x86_reg_info_32[wi->cpuid_reg].qapi_enum;
+        qwi->features = env->features[w];
+
+        /* List will be in reverse order, but order shouldn't matter */
+        list_entries[w].next = list;
+        list_entries[w].value = &word_infos[w];
+        list = &list_entries[w];
+    }
+
+    visit_type_X86CPUFeatureWordInfoList(v, &list, "feature-words", &err);
+    error_propagate(errp, err);
+}
+
 static int cpu_x86_find_by_name(x86_def_t *x86_cpu_def, const char *name)
 {
     x86_def_t *def;
@@ -2396,6 +2439,9 @@ static void x86_cpu_initfn(Object *obj)
     object_property_add(obj, "apic-id", "int",
                         x86_cpuid_get_apic_id,
                         x86_cpuid_set_apic_id, NULL, NULL, NULL);
+    object_property_add(obj, "feature-words", "X86CPUFeatureWordInfo",
+                        x86_cpu_get_feature_words,
+                        NULL, NULL, NULL, NULL);
 
     env->cpuid_apic_id = x86_cpu_apic_id_from_index(cs->cpu_index);
 
-- 
1.8.1.4

[Qemu-devel] [PATCH qom-cpu-next 2/3] target-i386: Introduce X86CPU.filtered_features field

[Eduardo Habkost]

This field will contain the feature bits that were filtered out because
of missing host support.

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
Changes v11 -> v12:
 * Rebase on top of qom-cpu-next
   (commit bd87d2a - target-i386: Use FeatureWord loop on filter_features_for_kvm())
---
 target-i386/cpu-qom.h | 3 +++
 target-i386/cpu.c     | 9 ++++++---
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/target-i386/cpu-qom.h b/target-i386/cpu-qom.h
index f890f1c..849cedf 100644
--- a/target-i386/cpu-qom.h
+++ b/target-i386/cpu-qom.h
@@ -65,6 +65,9 @@ typedef struct X86CPU {
     /*< public >*/
 
     CPUX86State env;
+
+    /* Features that were filtered out because of missing host capabilities */
+    uint32_t filtered_features[FEATURE_WORDS];
 } X86CPU;
 
 static inline X86CPU *x86_env_get_cpu(CPUX86State *env)
diff --git a/target-i386/cpu.c b/target-i386/cpu.c
index 3857514..38793bc 100644
--- a/target-i386/cpu.c
+++ b/target-i386/cpu.c
@@ -1698,9 +1698,12 @@ static void filter_features_for_kvm(X86CPU *cpu)
 
     for (w = 0; w < FEATURE_WORDS; w++) {
         FeatureWordInfo *wi = &feature_word_info[w];
-        env->features[w] &= kvm_arch_get_supported_cpuid(s, wi->cpuid_eax,
-                                                            wi->cpuid_ecx,
-                                                            wi->cpuid_reg);
+        uint32_t host_feat = kvm_arch_get_supported_cpuid(s, wi->cpuid_eax,
+                                                             wi->cpuid_ecx,
+                                                             wi->cpuid_reg);
+        uint32_t requested_features = env->features[w];
+        env->features[w] &= host_feat;
+        cpu->filtered_features[w] = requested_features & ~env->features[w];
     }
 }
 #endif
-- 
1.8.1.4

[Qemu-devel] [PATCH qom-cpu-next 3/3] target-i386: Add "filtered-features" property to X86CPU

[Eduardo Habkost]

This property will contain all the features that were removed from the
CPU because they are not supported by the host.

This way, libvirt or other management tools can emulate the
check/enforce behavior by checking if filtered-properties is all zeroes,
before starting the guest.

Example output where some features were missing:

  $ ./install/bin/qemu-system-x86_64 -enable-kvm -cpu Haswell,check -S -qmp unix:/tmp/m,server,nowait
  warning: host doesn't support requested feature: CPUID.01H:ECX.fma [bit 12]
  warning: host doesn't support requested feature: CPUID.01H:ECX.movbe [bit 22]
  warning: host doesn't support requested feature: CPUID.01H:ECX.tsc-deadline [bit 24]
  warning: host doesn't support requested feature: CPUID.01H:ECX.xsave [bit 26]
  warning: host doesn't support requested feature: CPUID.01H:ECX.avx [bit 28]
  warning: host doesn't support requested feature: CPUID.07H:EBX.fsgsbase [bit 0]
  warning: host doesn't support requested feature: CPUID.07H:EBX.bmi1 [bit 3]
  warning: host doesn't support requested feature: CPUID.07H:EBX.hle [bit 4]
  warning: host doesn't support requested feature: CPUID.07H:EBX.avx2 [bit 5]
  warning: host doesn't support requested feature: CPUID.07H:EBX.smep [bit 7]
  warning: host doesn't support requested feature: CPUID.07H:EBX.bmi2 [bit 8]
  warning: host doesn't support requested feature: CPUID.07H:EBX.erms [bit 9]
  warning: host doesn't support requested feature: CPUID.07H:EBX.invpcid [bit 10]
  warning: host doesn't support requested feature: CPUID.07H:EBX.rtm [bit 11]
  [...]
  $ ./QMP/qmp --path=/tmp/m qom-get --path=/machine/unattached/device[1] --property=filtered-features
  item[0].cpuid-register: EDX
  item[0].cpuid-input-eax: 2147483658
  item[0].features: 0
  item[1].cpuid-register: EAX
  item[1].cpuid-input-eax: 1073741825
  item[1].features: 0
  item[2].cpuid-register: EDX
  item[2].cpuid-input-eax: 3221225473
  item[2].features: 0
  item[3].cpuid-register: ECX
  item[3].cpuid-input-eax: 2147483649
  item[3].features: 0
  item[4].cpuid-register: EDX
  item[4].cpuid-input-eax: 2147483649
  item[4].features: 0
  item[5].cpuid-register: EBX
  item[5].cpuid-input-eax: 7
  item[5].features: 4025
  item[5].cpuid-input-ecx: 0
  item[6].cpuid-register: ECX
  item[6].cpuid-input-eax: 1
  item[6].features: 356519936
  item[7].cpuid-register: EDX
  item[7].cpuid-input-eax: 1
  item[7].features: 0

Example output when no feature is missing:

  $ ./install/bin/qemu-system-x86_64 -enable-kvm -cpu Nehalem,enforce -S -qmp unix:/tmp/m,server,nowait
  [...]
  $ ./QMP/qmp --path=/tmp/m qom-get --path=/machine/unattached/device[1]
  --property=filtered-features
  item[0].cpuid-register: EDX
  item[0].cpuid-input-eax: 2147483658
  item[0].features: 0
  item[1].cpuid-register: EAX
  item[1].cpuid-input-eax: 1073741825
  item[1].features: 0
  item[2].cpuid-register: EDX
  item[2].cpuid-input-eax: 3221225473
  item[2].features: 0
  item[3].cpuid-register: ECX
  item[3].cpuid-input-eax: 2147483649
  item[3].features: 0
  item[4].cpuid-register: EDX
  item[4].cpuid-input-eax: 2147483649
  item[4].features: 0
  item[5].cpuid-register: EBX
  item[5].cpuid-input-eax: 7
  item[5].features: 0
  item[5].cpuid-input-ecx: 0
  item[6].cpuid-register: ECX
  item[6].cpuid-input-eax: 1
  item[6].features: 0
  item[7].cpuid-register: EDX
  item[7].cpuid-input-eax: 1
  item[7].features: 0

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
Changes v11 -> v12:
 * Rebase on top of qom-cpu-next
   (commit bd87d2a - target-i386: Use FeatureWord loop on filter_features_for_kvm())
---
 target-i386/cpu.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/target-i386/cpu.c b/target-i386/cpu.c
index 38793bc..eb1825b 100644
--- a/target-i386/cpu.c
+++ b/target-i386/cpu.c
@@ -1418,11 +1418,11 @@ static void x86_cpuid_set_apic_id(Object *obj, Visitor *v, void *opaque,
     cpu->env.cpuid_apic_id = value;
 }
 
+/* Generic getter for "feature-words" and "filtered-features" properties */
 static void x86_cpu_get_feature_words(Object *obj, Visitor *v, void *opaque,
                                       const char *name, Error **errp)
 {
-    X86CPU *cpu = X86_CPU(obj);
-    CPUX86State *env = &cpu->env;
+    uint32_t *array = (uint32_t *)opaque;
     FeatureWord w;
     Error *err = NULL;
     X86CPUFeatureWordInfo word_infos[FEATURE_WORDS] = { };
@@ -1436,7 +1436,7 @@ static void x86_cpu_get_feature_words(Object *obj, Visitor *v, void *opaque,
         qwi->has_cpuid_input_ecx = wi->cpuid_needs_ecx;
         qwi->cpuid_input_ecx = wi->cpuid_ecx;
         qwi->cpuid_register = x86_reg_info_32[wi->cpuid_reg].qapi_enum;
-        qwi->features = env->features[w];
+        qwi->features = array[w];
 
         /* List will be in reverse order, but order shouldn't matter */
         list_entries[w].next = list;
@@ -2444,7 +2444,10 @@ static void x86_cpu_initfn(Object *obj)
                         x86_cpuid_set_apic_id, NULL, NULL, NULL);
     object_property_add(obj, "feature-words", "X86CPUFeatureWordInfo",
                         x86_cpu_get_feature_words,
-                        NULL, NULL, NULL, NULL);
+                        NULL, NULL, (void *)env->features, NULL);
+    object_property_add(obj, "filtered-features", "X86CPUFeatureWordInfo",
+                        x86_cpu_get_feature_words,
+                        NULL, NULL, (void *)cpu->filtered_features, NULL);
 
     env->cpuid_apic_id = x86_cpu_apic_id_from_index(cs->cpu_index);
 
-- 
1.8.1.4

Re: [Qemu-devel] [PATCH qom-cpu-next 0/3] X86CPU: "feature-words"/"filtered-features" properties (v12)

[Andreas Färber]

Am 06.05.2013 18:20, schrieb Eduardo Habkost:
> Resubmitting after a rebase and a few trivial changes.
> 
> Changes v11 -> v12:
>  * Remove unnecessary entries from .gitignore
>  * Fix indentation of x86_cpu_get_feature_words() declaration
>  * Rebase on top of qom-cpu-next
>    (commit bd87d2a - target-i386: Use FeatureWord loop on filter_features_for_kvm())
> 
> Git tree for reference:
> 
>     git://github.com/ehabkost/qemu-hacks.git work/cpu-raw-features.v12
> 
> Eduardo Habkost (3):
>   target-i386: Add "feature-words" property
>   target-i386: Introduce X86CPU.filtered_features field
>   target-i386: Add "filtered-features" property to X86CPU

Thanks, applied all to qom-cpu (tweaking some commit messages):
https://github.com/afaerber/qemu-cpu/commits/qom-cpu

In particular I have edited the QOM paths to not rely on
/machine/unassigned (since those may change, e.g., with QOM realize) and
consistently line-broken commands within 76 chars.

Andreas

>  Makefile.objs         |  7 ++++-
>  qapi-schema.json      | 32 ++++++++++++++++++++
>  target-i386/cpu-qom.h |  3 ++
>  target-i386/cpu.c     | 82 +++++++++++++++++++++++++++++++++++++++++----------
>  4 files changed, 108 insertions(+), 16 deletions(-)

-- 
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg, Germany
GF: Jeff Hawn, Jennifer Guild, Felix Imendörffer; HRB 16746 AG Nürnberg