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Blame SOURCES/kvm-target-arm-cpu-Add-the-kvm-no-adjvtime-CPU-property.patch

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From 730f72105b478553c4f22555c29b0f64224ff914 Mon Sep 17 00:00:00 2001
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From: Andrew Jones <drjones@redhat.com>
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Date: Fri, 31 Jan 2020 14:23:14 +0000
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Subject: [PATCH 12/15] target/arm/cpu: Add the kvm-no-adjvtime CPU property
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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RH-Author: Andrew Jones <drjones@redhat.com>
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Message-id: <20200131142314.13175-6-drjones@redhat.com>
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Patchwork-id: 93623
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O-Subject: [RHEL-AV-8.2.0 qemu-kvm PATCH 5/5] target/arm/cpu: Add the kvm-no-adjvtime CPU property
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Bugzilla: 1647366
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RH-Acked-by: Philippe Mathieu-Daudé <philmd@redhat.com>
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RH-Acked-by: Auger Eric <eric.auger@redhat.com>
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RH-Acked-by: Gavin Shan <gshan@redhat.com>
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Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1647366
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Author: Andrew Jones <drjones@redhat.com>
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Date:   Thu, 30 Jan 2020 16:02:06 +0000
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    target/arm/cpu: Add the kvm-no-adjvtime CPU property
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    kvm-no-adjvtime is a KVM specific CPU property and a first of its
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    kind. To accommodate it we also add kvm_arm_add_vcpu_properties()
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    and a KVM specific CPU properties description to the CPU features
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    document.
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    Signed-off-by: Andrew Jones <drjones@redhat.com>
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    Message-id: 20200120101023.16030-7-drjones@redhat.com
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    Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
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    Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
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(cherry picked from commit dea101a1ae9968c9fec6ab0291489dad7c49f36f)
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Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>
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Conflicts:
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	Dropped the second hunk of the hw/arm/virt.c changes
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        as they would patch dead code.
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Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>
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---
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 docs/arm-cpu-features.rst | 37 ++++++++++++++++++++++++++++++++++++-
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 hw/arm/virt.c             |  5 +++++
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 include/hw/arm/virt.h     |  1 +
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 target/arm/cpu.c          |  2 ++
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 target/arm/cpu64.c        |  1 +
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 target/arm/kvm.c          | 28 ++++++++++++++++++++++++++++
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 target/arm/kvm_arm.h      | 11 +++++++++++
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 target/arm/monitor.c      |  1 +
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 tests/arm-cpu-features.c  |  4 ++++
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 9 files changed, 89 insertions(+), 1 deletion(-)
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diff --git a/docs/arm-cpu-features.rst b/docs/arm-cpu-features.rst
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index 1b367e2..45d1eb6 100644
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--- a/docs/arm-cpu-features.rst
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+++ b/docs/arm-cpu-features.rst
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@@ -31,7 +31,9 @@ supporting the feature or only supporting the feature under certain
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 configurations.  For example, the `aarch64` CPU feature, which, when
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 disabled, enables the optional AArch32 CPU feature, is only supported
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 when using the KVM accelerator and when running on a host CPU type that
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-supports the feature.
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+supports the feature.  While `aarch64` currently only works with KVM,
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+it could work with TCG.  CPU features that are specific to KVM are
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+prefixed with "kvm-" and are described in "KVM VCPU Features".
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 CPU Feature Probing
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 ===================
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@@ -171,6 +173,39 @@ disabling many SVE vector lengths would be quite verbose, the `sve<N>` CPU
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 properties have special semantics (see "SVE CPU Property Parsing
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 Semantics").
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+KVM VCPU Features
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+=================
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+
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+KVM VCPU features are CPU features that are specific to KVM, such as
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+paravirt features or features that enable CPU virtualization extensions.
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+The features' CPU properties are only available when KVM is enabled and
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+are named with the prefix "kvm-".  KVM VCPU features may be probed,
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+enabled, and disabled in the same way as other CPU features.  Below is
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+the list of KVM VCPU features and their descriptions.
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+
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+  kvm-no-adjvtime          By default kvm-no-adjvtime is disabled.  This
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+                           means that by default the virtual time
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+                           adjustment is enabled (vtime is *not not*
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+                           adjusted).
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+
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+                           When virtual time adjustment is enabled each
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+                           time the VM transitions back to running state
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+                           the VCPU's virtual counter is updated to ensure
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+                           stopped time is not counted.  This avoids time
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+                           jumps surprising guest OSes and applications,
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+                           as long as they use the virtual counter for
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+                           timekeeping.  However it has the side effect of
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+                           the virtual and physical counters diverging.
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+                           All timekeeping based on the virtual counter
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+                           will appear to lag behind any timekeeping that
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+                           does not subtract VM stopped time.  The guest
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+                           may resynchronize its virtual counter with
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+                           other time sources as needed.
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+
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+                           Enable kvm-no-adjvtime to disable virtual time
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+                           adjustment, also restoring the legacy (pre-5.0)
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+                           behavior.
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+
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 SVE CPU Properties
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 ==================
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diff --git a/hw/arm/virt.c b/hw/arm/virt.c
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index e108391..d30d38c 100644
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--- a/hw/arm/virt.c
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+++ b/hw/arm/virt.c
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@@ -1707,6 +1707,11 @@ static void machvirt_init(MachineState *machine)
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             }
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         }
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+        if (vmc->kvm_no_adjvtime &&
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+            object_property_find(cpuobj, "kvm-no-adjvtime", NULL)) {
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+            object_property_set_bool(cpuobj, true, "kvm-no-adjvtime", NULL);
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+        }
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+
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         if (vmc->no_pmu && object_property_find(cpuobj, "pmu", NULL)) {
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             object_property_set_bool(cpuobj, false, "pmu", NULL);
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         }
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diff --git a/include/hw/arm/virt.h b/include/hw/arm/virt.h
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index 53fdf16..77828ce 100644
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--- a/include/hw/arm/virt.h
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+++ b/include/hw/arm/virt.h
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@@ -109,6 +109,7 @@ typedef struct {
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     bool smbios_old_sys_ver;
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     bool no_highmem_ecam;
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     bool no_ged;   /* Machines < 4.2 has no support for ACPI GED device */
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+    bool kvm_no_adjvtime;
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 } VirtMachineClass;
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 typedef struct {
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diff --git a/target/arm/cpu.c b/target/arm/cpu.c
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index 3788fc3..e46efe9 100644
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--- a/target/arm/cpu.c
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+++ b/target/arm/cpu.c
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@@ -2482,6 +2482,7 @@ static void arm_max_initfn(Object *obj)
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     if (kvm_enabled()) {
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         kvm_arm_set_cpu_features_from_host(cpu);
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+        kvm_arm_add_vcpu_properties(obj);
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     } else {
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         cortex_a15_initfn(obj);
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@@ -2673,6 +2674,7 @@ static void arm_host_initfn(Object *obj)
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     if (arm_feature(&cpu->env, ARM_FEATURE_AARCH64)) {
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         aarch64_add_sve_properties(obj);
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     }
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+    kvm_arm_add_vcpu_properties(obj);
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     arm_cpu_post_init(obj);
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 }
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diff --git a/target/arm/cpu64.c b/target/arm/cpu64.c
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index a39d6fc..3cd416d 100644
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--- a/target/arm/cpu64.c
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+++ b/target/arm/cpu64.c
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@@ -605,6 +605,7 @@ static void aarch64_max_initfn(Object *obj)
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     if (kvm_enabled()) {
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         kvm_arm_set_cpu_features_from_host(cpu);
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+        kvm_arm_add_vcpu_properties(obj);
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     } else {
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         uint64_t t;
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         uint32_t u;
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diff --git a/target/arm/kvm.c b/target/arm/kvm.c
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index 26d7f8b..4be9497 100644
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--- a/target/arm/kvm.c
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+++ b/target/arm/kvm.c
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@@ -17,6 +17,8 @@
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 #include "qemu/timer.h"
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 #include "qemu/error-report.h"
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 #include "qemu/main-loop.h"
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+#include "qom/object.h"
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+#include "qapi/error.h"
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 #include "sysemu/sysemu.h"
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 #include "sysemu/kvm.h"
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 #include "sysemu/kvm_int.h"
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@@ -179,6 +181,32 @@ void kvm_arm_set_cpu_features_from_host(ARMCPU *cpu)
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     env->features = arm_host_cpu_features.features;
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 }
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+static bool kvm_no_adjvtime_get(Object *obj, Error **errp)
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+{
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+    return !ARM_CPU(obj)->kvm_adjvtime;
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+}
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+
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+static void kvm_no_adjvtime_set(Object *obj, bool value, Error **errp)
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+{
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+    ARM_CPU(obj)->kvm_adjvtime = !value;
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+}
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+
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+/* KVM VCPU properties should be prefixed with "kvm-". */
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+void kvm_arm_add_vcpu_properties(Object *obj)
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+{
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+    if (!kvm_enabled()) {
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+        return;
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+    }
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+
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+    ARM_CPU(obj)->kvm_adjvtime = true;
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+    object_property_add_bool(obj, "kvm-no-adjvtime", kvm_no_adjvtime_get,
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+                             kvm_no_adjvtime_set, &error_abort);
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+    object_property_set_description(obj, "kvm-no-adjvtime",
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+                                    "Set on to disable the adjustment of "
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+                                    "the virtual counter. VM stopped time "
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+                                    "will be counted.", &error_abort);
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+}
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+
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 bool kvm_arm_pmu_supported(CPUState *cpu)
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 {
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     KVMState *s = KVM_STATE(current_machine->accelerator);
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diff --git a/target/arm/kvm_arm.h b/target/arm/kvm_arm.h
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index 01a9a18..ae9e075 100644
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--- a/target/arm/kvm_arm.h
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+++ b/target/arm/kvm_arm.h
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@@ -256,6 +256,15 @@ void kvm_arm_sve_get_vls(CPUState *cs, unsigned long *map);
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 void kvm_arm_set_cpu_features_from_host(ARMCPU *cpu);
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 /**
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+ * kvm_arm_add_vcpu_properties:
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+ * @obj: The CPU object to add the properties to
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+ *
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+ * Add all KVM specific CPU properties to the CPU object. These
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+ * are the CPU properties with "kvm-" prefixed names.
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+ */
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+void kvm_arm_add_vcpu_properties(Object *obj);
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+
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+/**
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  * kvm_arm_aarch32_supported:
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  * @cs: CPUState
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  *
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@@ -345,6 +354,8 @@ static inline void kvm_arm_set_cpu_features_from_host(ARMCPU *cpu)
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     cpu->host_cpu_probe_failed = true;
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 }
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+static inline void kvm_arm_add_vcpu_properties(Object *obj) {}
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+
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 static inline bool kvm_arm_aarch32_supported(CPUState *cs)
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 {
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     return false;
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diff --git a/target/arm/monitor.c b/target/arm/monitor.c
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index fa054f8..9725dff 100644
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--- a/target/arm/monitor.c
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+++ b/target/arm/monitor.c
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@@ -103,6 +103,7 @@ static const char *cpu_model_advertised_features[] = {
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     "sve128", "sve256", "sve384", "sve512",
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     "sve640", "sve768", "sve896", "sve1024", "sve1152", "sve1280",
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     "sve1408", "sve1536", "sve1664", "sve1792", "sve1920", "sve2048",
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+    "kvm-no-adjvtime",
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     NULL
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 };
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diff --git a/tests/arm-cpu-features.c b/tests/arm-cpu-features.c
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index 89285ca..ba1a6fe 100644
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--- a/tests/arm-cpu-features.c
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+++ b/tests/arm-cpu-features.c
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@@ -428,6 +428,8 @@ static void test_query_cpu_model_expansion(const void *data)
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     assert_has_feature_enabled(qts, "cortex-a15", "pmu");
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     assert_has_not_feature(qts, "cortex-a15", "aarch64");
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+    assert_has_not_feature(qts, "max", "kvm-no-adjvtime");
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+
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     if (g_str_equal(qtest_get_arch(), "aarch64")) {
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         assert_has_feature_enabled(qts, "max", "aarch64");
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         assert_has_feature_enabled(qts, "max", "sve");
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@@ -462,6 +464,8 @@ static void test_query_cpu_model_expansion_kvm(const void *data)
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         return;
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     }
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+    assert_has_feature_disabled(qts, "host", "kvm-no-adjvtime");
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+
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     if (g_str_equal(qtest_get_arch(), "aarch64")) {
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         bool kvm_supports_sve;
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         char max_name[8], name[8];
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-- 
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1.8.3.1
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