From 730f72105b478553c4f22555c29b0f64224ff914 Mon Sep 17 00:00:00 2001

From: Andrew Jones <drjones@redhat.com>

Date: Fri, 31 Jan 2020 14:23:14 +0000

Subject: [PATCH 12/15] target/arm/cpu: Add the kvm-no-adjvtime CPU property

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RH-Author: Andrew Jones <drjones@redhat.com>

Message-id: <20200131142314.13175-6-drjones@redhat.com>

Patchwork-id: 93623

O-Subject: [RHEL-AV-8.2.0 qemu-kvm PATCH 5/5] target/arm/cpu: Add the kvm-no-adjvtime CPU property

Bugzilla: 1647366

RH-Acked-by: Philippe Mathieu-Daudé <philmd@redhat.com>

RH-Acked-by: Auger Eric <eric.auger@redhat.com>

RH-Acked-by: Gavin Shan <gshan@redhat.com>

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1647366

Author: Andrew Jones <drjones@redhat.com>

Date:   Thu, 30 Jan 2020 16:02:06 +0000

    target/arm/cpu: Add the kvm-no-adjvtime CPU property

    kvm-no-adjvtime is a KVM specific CPU property and a first of its

    kind. To accommodate it we also add kvm_arm_add_vcpu_properties()

    and a KVM specific CPU properties description to the CPU features

    document.

    Signed-off-by: Andrew Jones <drjones@redhat.com>

    Message-id: 20200120101023.16030-7-drjones@redhat.com

    Reviewed-by: Peter Maydell <peter.maydell@linaro.org>

    Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

(cherry picked from commit dea101a1ae9968c9fec6ab0291489dad7c49f36f)

Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>

Conflicts:

	Dropped the second hunk of the hw/arm/virt.c changes

        as they would patch dead code.

Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>

---

 docs/arm-cpu-features.rst | 37 ++++++++++++++++++++++++++++++++++++-

 hw/arm/virt.c             |  5 +++++

 include/hw/arm/virt.h     |  1 +

 target/arm/cpu.c          |  2 ++

 target/arm/cpu64.c        |  1 +

 target/arm/kvm.c          | 28 ++++++++++++++++++++++++++++

 target/arm/kvm_arm.h      | 11 +++++++++++

 target/arm/monitor.c      |  1 +

 tests/arm-cpu-features.c  |  4 ++++

 9 files changed, 89 insertions(+), 1 deletion(-)

diff --git a/docs/arm-cpu-features.rst b/docs/arm-cpu-features.rst

index 1b367e2..45d1eb6 100644

--- a/docs/arm-cpu-features.rst

+++ b/docs/arm-cpu-features.rst

@@ -31,7 +31,9 @@ supporting the feature or only supporting the feature under certain

 configurations.  For example, the `aarch64` CPU feature, which, when

 disabled, enables the optional AArch32 CPU feature, is only supported

 when using the KVM accelerator and when running on a host CPU type that

-supports the feature.

+supports the feature.  While `aarch64` currently only works with KVM,

+it could work with TCG.  CPU features that are specific to KVM are

+prefixed with "kvm-" and are described in "KVM VCPU Features".

 CPU Feature Probing

 ===================

@@ -171,6 +173,39 @@ disabling many SVE vector lengths would be quite verbose, the `sve<N>` CPU

 properties have special semantics (see "SVE CPU Property Parsing

 Semantics").

+KVM VCPU Features

+=================

+

+KVM VCPU features are CPU features that are specific to KVM, such as

+paravirt features or features that enable CPU virtualization extensions.

+The features' CPU properties are only available when KVM is enabled and

+are named with the prefix "kvm-".  KVM VCPU features may be probed,

+enabled, and disabled in the same way as other CPU features.  Below is

+the list of KVM VCPU features and their descriptions.

+

+  kvm-no-adjvtime          By default kvm-no-adjvtime is disabled.  This

+                           means that by default the virtual time

+                           adjustment is enabled (vtime is *not not*

+                           adjusted).

+

+                           When virtual time adjustment is enabled each

+                           time the VM transitions back to running state

+                           the VCPU's virtual counter is updated to ensure

+                           stopped time is not counted.  This avoids time

+                           jumps surprising guest OSes and applications,

+                           as long as they use the virtual counter for

+                           timekeeping.  However it has the side effect of

+                           the virtual and physical counters diverging.

+                           All timekeeping based on the virtual counter

+                           will appear to lag behind any timekeeping that

+                           does not subtract VM stopped time.  The guest

+                           may resynchronize its virtual counter with

+                           other time sources as needed.

+

+                           Enable kvm-no-adjvtime to disable virtual time

+                           adjustment, also restoring the legacy (pre-5.0)

+                           behavior.

+

 SVE CPU Properties

 ==================

diff --git a/hw/arm/virt.c b/hw/arm/virt.c

index e108391..d30d38c 100644

--- a/hw/arm/virt.c

+++ b/hw/arm/virt.c

@@ -1707,6 +1707,11 @@ static void machvirt_init(MachineState *machine)

             }

         }

+        if (vmc->kvm_no_adjvtime &&

+            object_property_find(cpuobj, "kvm-no-adjvtime", NULL)) {

+            object_property_set_bool(cpuobj, true, "kvm-no-adjvtime", NULL);

+        }

+

         if (vmc->no_pmu && object_property_find(cpuobj, "pmu", NULL)) {

             object_property_set_bool(cpuobj, false, "pmu", NULL);

         }

diff --git a/include/hw/arm/virt.h b/include/hw/arm/virt.h

index 53fdf16..77828ce 100644

--- a/include/hw/arm/virt.h

+++ b/include/hw/arm/virt.h

@@ -109,6 +109,7 @@ typedef struct {

     bool smbios_old_sys_ver;

     bool no_highmem_ecam;

     bool no_ged;   /* Machines < 4.2 has no support for ACPI GED device */

+    bool kvm_no_adjvtime;

 } VirtMachineClass;

 typedef struct {

diff --git a/target/arm/cpu.c b/target/arm/cpu.c

index 3788fc3..e46efe9 100644

--- a/target/arm/cpu.c

+++ b/target/arm/cpu.c

@@ -2482,6 +2482,7 @@ static void arm_max_initfn(Object *obj)

     if (kvm_enabled()) {

         kvm_arm_set_cpu_features_from_host(cpu);

+        kvm_arm_add_vcpu_properties(obj);

     } else {

         cortex_a15_initfn(obj);

@@ -2673,6 +2674,7 @@ static void arm_host_initfn(Object *obj)

     if (arm_feature(&cpu->env, ARM_FEATURE_AARCH64)) {

         aarch64_add_sve_properties(obj);

     }

+    kvm_arm_add_vcpu_properties(obj);

     arm_cpu_post_init(obj);

 }

diff --git a/target/arm/cpu64.c b/target/arm/cpu64.c

index a39d6fc..3cd416d 100644

--- a/target/arm/cpu64.c

+++ b/target/arm/cpu64.c

@@ -605,6 +605,7 @@ static void aarch64_max_initfn(Object *obj)

     if (kvm_enabled()) {

         kvm_arm_set_cpu_features_from_host(cpu);

+        kvm_arm_add_vcpu_properties(obj);

     } else {

         uint64_t t;

         uint32_t u;

diff --git a/target/arm/kvm.c b/target/arm/kvm.c

index 26d7f8b..4be9497 100644

--- a/target/arm/kvm.c

+++ b/target/arm/kvm.c

@@ -17,6 +17,8 @@

 #include "qemu/timer.h"

 #include "qemu/error-report.h"

 #include "qemu/main-loop.h"

+#include "qom/object.h"

+#include "qapi/error.h"

 #include "sysemu/sysemu.h"

 #include "sysemu/kvm.h"

 #include "sysemu/kvm_int.h"

@@ -179,6 +181,32 @@ void kvm_arm_set_cpu_features_from_host(ARMCPU *cpu)

     env->features = arm_host_cpu_features.features;

 }

+static bool kvm_no_adjvtime_get(Object *obj, Error **errp)

+{

+    return !ARM_CPU(obj)->kvm_adjvtime;

+}

+

+static void kvm_no_adjvtime_set(Object *obj, bool value, Error **errp)

+{

+    ARM_CPU(obj)->kvm_adjvtime = !value;

+}

+

+/* KVM VCPU properties should be prefixed with "kvm-". */

+void kvm_arm_add_vcpu_properties(Object *obj)

+{

+    if (!kvm_enabled()) {

+        return;

+    }

+

+    ARM_CPU(obj)->kvm_adjvtime = true;

+    object_property_add_bool(obj, "kvm-no-adjvtime", kvm_no_adjvtime_get,

+                             kvm_no_adjvtime_set, &error_abort);

+    object_property_set_description(obj, "kvm-no-adjvtime",

+                                    "Set on to disable the adjustment of "

+                                    "the virtual counter. VM stopped time "

+                                    "will be counted.", &error_abort);

+}

+

 bool kvm_arm_pmu_supported(CPUState *cpu)

 {

     KVMState *s = KVM_STATE(current_machine->accelerator);

diff --git a/target/arm/kvm_arm.h b/target/arm/kvm_arm.h

index 01a9a18..ae9e075 100644

--- a/target/arm/kvm_arm.h

+++ b/target/arm/kvm_arm.h

@@ -256,6 +256,15 @@ void kvm_arm_sve_get_vls(CPUState *cs, unsigned long *map);

 void kvm_arm_set_cpu_features_from_host(ARMCPU *cpu);

 /**

+ * kvm_arm_add_vcpu_properties:

+ * @obj: The CPU object to add the properties to

+ *

+ * Add all KVM specific CPU properties to the CPU object. These

+ * are the CPU properties with "kvm-" prefixed names.

+ */

+void kvm_arm_add_vcpu_properties(Object *obj);

+

+/**

  * kvm_arm_aarch32_supported:

  * @cs: CPUState

  *

@@ -345,6 +354,8 @@ static inline void kvm_arm_set_cpu_features_from_host(ARMCPU *cpu)

     cpu->host_cpu_probe_failed = true;

 }

+static inline void kvm_arm_add_vcpu_properties(Object *obj) {}

+

 static inline bool kvm_arm_aarch32_supported(CPUState *cs)

 {

     return false;

diff --git a/target/arm/monitor.c b/target/arm/monitor.c

index fa054f8..9725dff 100644

--- a/target/arm/monitor.c

+++ b/target/arm/monitor.c

@@ -103,6 +103,7 @@ static const char *cpu_model_advertised_features[] = {

     "sve128", "sve256", "sve384", "sve512",

     "sve640", "sve768", "sve896", "sve1024", "sve1152", "sve1280",

     "sve1408", "sve1536", "sve1664", "sve1792", "sve1920", "sve2048",

+    "kvm-no-adjvtime",

     NULL

 };

diff --git a/tests/arm-cpu-features.c b/tests/arm-cpu-features.c

index 89285ca..ba1a6fe 100644

--- a/tests/arm-cpu-features.c

+++ b/tests/arm-cpu-features.c

@@ -428,6 +428,8 @@ static void test_query_cpu_model_expansion(const void *data)

     assert_has_feature_enabled(qts, "cortex-a15", "pmu");

     assert_has_not_feature(qts, "cortex-a15", "aarch64");

+    assert_has_not_feature(qts, "max", "kvm-no-adjvtime");

+

     if (g_str_equal(qtest_get_arch(), "aarch64")) {

         assert_has_feature_enabled(qts, "max", "aarch64");

         assert_has_feature_enabled(qts, "max", "sve");

@@ -462,6 +464,8 @@ static void test_query_cpu_model_expansion_kvm(const void *data)

         return;

     }

+    assert_has_feature_disabled(qts, "host", "kvm-no-adjvtime");

+

     if (g_str_equal(qtest_get_arch(), "aarch64")) {

         bool kvm_supports_sve;

         char max_name[8], name[8];

-- 

1.8.3.1