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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
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
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
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