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[Qemu-arm] [PATCH V5 1/2] arm64: Add an option to turn on/off vPMU suppo


From: Wei Huang
Subject: [Qemu-arm] [PATCH V5 1/2] arm64: Add an option to turn on/off vPMU support
Date: Thu, 22 Sep 2016 11:13:22 -0400

This patch adds a pmu=[on/off] option to enable/disable vPMU support
in guest vCPU. This option is only available for cortex-a57/cortex-53/
host under both TCG and KVM modes, but unavailable on ARMv7 and other
processors. It allows virt tools, such as libvirt, to determine the
exsitence of vPMU and configure it. Note that, if nothing specified,
the pmu option is set to AUTO as default, allowing machine-level PMU
property to override it. Also when pmu is turned on under non-KVM mode,
a warning message will be printed.

Signed-off-by: Wei Huang <address@hidden>
---
 hw/arm/virt-acpi-build.c |  2 +-
 hw/arm/virt.c            |  2 +-
 target-arm/cpu.c         | 23 +++++++++++++++++++++++
 target-arm/cpu.h         |  3 ++-
 target-arm/cpu64.c       |  2 ++
 target-arm/kvm64.c       | 17 ++++++++++++++---
 6 files changed, 43 insertions(+), 6 deletions(-)

diff --git a/hw/arm/virt-acpi-build.c b/hw/arm/virt-acpi-build.c
index 295ec86..8b3083e 100644
--- a/hw/arm/virt-acpi-build.c
+++ b/hw/arm/virt-acpi-build.c
@@ -540,7 +540,7 @@ build_madt(GArray *table_data, BIOSLinker *linker, 
VirtGuestInfo *guest_info)
         gicc->uid = i;
         gicc->flags = cpu_to_le32(ACPI_GICC_ENABLED);
 
-        if (armcpu->has_pmu) {
+        if (arm_feature(&armcpu->env, ARM_FEATURE_PMU)) {
             gicc->performance_interrupt = cpu_to_le32(PPI(VIRTUAL_PMU_IRQ));
         }
     }
diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index a193b5a..a781ad0 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -477,7 +477,7 @@ static void fdt_add_pmu_nodes(const VirtBoardInfo *vbi, int 
gictype)
 
     CPU_FOREACH(cpu) {
         armcpu = ARM_CPU(cpu);
-        if (!armcpu->has_pmu ||
+        if (!arm_feature(&armcpu->env, ARM_FEATURE_PMU) ||
             !kvm_arm_pmu_create(cpu, PPI(VIRTUAL_PMU_IRQ))) {
             return;
         }
diff --git a/target-arm/cpu.c b/target-arm/cpu.c
index ce8b8f4..ed7b884 100644
--- a/target-arm/cpu.c
+++ b/target-arm/cpu.c
@@ -19,6 +19,7 @@
  */
 
 #include "qemu/osdep.h"
+#include "qemu/error-report.h"
 #include "qapi/error.h"
 #include "cpu.h"
 #include "internals.h"
@@ -31,6 +32,7 @@
 #include "hw/arm/arm.h"
 #include "sysemu/sysemu.h"
 #include "sysemu/kvm.h"
+#include "sysemu/qtest.h"
 #include "kvm_arm.h"
 
 static void arm_cpu_set_pc(CPUState *cs, vaddr value)
@@ -509,6 +511,10 @@ static Property arm_cpu_rvbar_property =
 static Property arm_cpu_has_el3_property =
             DEFINE_PROP_BOOL("has_el3", ARMCPU, has_el3, true);
 
+/* use property name "pmu" to match other archs and virt tools */
+static Property arm_cpu_has_pmu_property =
+    DEFINE_PROP_ON_OFF_AUTO("pmu", ARMCPU, has_pmu, ON_OFF_AUTO_AUTO);
+
 static Property arm_cpu_has_mpu_property =
             DEFINE_PROP_BOOL("has-mpu", ARMCPU, has_mpu, true);
 
@@ -552,6 +558,11 @@ static void arm_cpu_post_init(Object *obj)
 #endif
     }
 
+    if (arm_feature(&cpu->env, ARM_FEATURE_PMU)) {
+        qdev_property_add_static(DEVICE(obj), &arm_cpu_has_pmu_property,
+                                 &error_abort);
+    }
+
     if (arm_feature(&cpu->env, ARM_FEATURE_MPU)) {
         qdev_property_add_static(DEVICE(obj), &arm_cpu_has_mpu_property,
                                  &error_abort);
@@ -576,6 +587,7 @@ static void arm_cpu_realizefn(DeviceState *dev, Error 
**errp)
     ARMCPU *cpu = ARM_CPU(dev);
     ARMCPUClass *acc = ARM_CPU_GET_CLASS(dev);
     CPUARMState *env = &cpu->env;
+    static bool pmu_warned;
 
     /* Some features automatically imply others: */
     if (arm_feature(env, ARM_FEATURE_V8)) {
@@ -648,6 +660,17 @@ static void arm_cpu_realizefn(DeviceState *dev, Error 
**errp)
         cpu->id_aa64pfr0 &= ~0xf000;
     }
 
+    if (cpu->has_pmu == ON_OFF_AUTO_ON && !kvm_enabled()) {
+        cpu->has_pmu = ON_OFF_AUTO_OFF;
+        if (!pmu_warned && !qtest_enabled()) {
+            error_report("warning: pmu can't be enabled without KVM 
acceleration");
+            pmu_warned = true;
+        }
+    }
+    if (cpu->has_pmu == ON_OFF_AUTO_OFF) {
+        unset_feature(env, ARM_FEATURE_PMU);
+    }
+
     if (!arm_feature(env, ARM_FEATURE_EL2)) {
         /* Disable the hypervisor feature bits in the processor feature
          * registers if we don't have EL2. These are id_pfr1[15:12] and
diff --git a/target-arm/cpu.h b/target-arm/cpu.h
index 76d824d..a2de272 100644
--- a/target-arm/cpu.h
+++ b/target-arm/cpu.h
@@ -580,7 +580,7 @@ struct ARMCPU {
     /* CPU has security extension */
     bool has_el3;
     /* CPU has PMU (Performance Monitor Unit) */
-    bool has_pmu;
+    OnOffAuto has_pmu;
 
     /* CPU has memory protection unit */
     bool has_mpu;
@@ -1129,6 +1129,7 @@ enum arm_features {
     ARM_FEATURE_V8_SHA256, /* implements SHA256 part of v8 Crypto Extensions */
     ARM_FEATURE_V8_PMULL, /* implements PMULL part of v8 Crypto Extensions */
     ARM_FEATURE_THUMB_DSP, /* DSP insns supported in the Thumb encodings */
+    ARM_FEATURE_PMU, /* has PMU support */
 };
 
 static inline int arm_feature(CPUARMState *env, int feature)
diff --git a/target-arm/cpu64.c b/target-arm/cpu64.c
index 1635deb..549cb1e 100644
--- a/target-arm/cpu64.c
+++ b/target-arm/cpu64.c
@@ -111,6 +111,7 @@ static void aarch64_a57_initfn(Object *obj)
     set_feature(&cpu->env, ARM_FEATURE_V8_PMULL);
     set_feature(&cpu->env, ARM_FEATURE_CRC);
     set_feature(&cpu->env, ARM_FEATURE_EL3);
+    set_feature(&cpu->env, ARM_FEATURE_PMU);
     cpu->kvm_target = QEMU_KVM_ARM_TARGET_CORTEX_A57;
     cpu->midr = 0x411fd070;
     cpu->revidr = 0x00000000;
@@ -166,6 +167,7 @@ static void aarch64_a53_initfn(Object *obj)
     set_feature(&cpu->env, ARM_FEATURE_V8_PMULL);
     set_feature(&cpu->env, ARM_FEATURE_CRC);
     set_feature(&cpu->env, ARM_FEATURE_EL3);
+    set_feature(&cpu->env, ARM_FEATURE_PMU);
     cpu->kvm_target = QEMU_KVM_ARM_TARGET_CORTEX_A53;
     cpu->midr = 0x410fd034;
     cpu->revidr = 0x00000000;
diff --git a/target-arm/kvm64.c b/target-arm/kvm64.c
index 5faa76c..ff86550 100644
--- a/target-arm/kvm64.c
+++ b/target-arm/kvm64.c
@@ -428,6 +428,11 @@ static inline void set_feature(uint64_t *features, int 
feature)
     *features |= 1ULL << feature;
 }
 
+static inline void unset_feature(uint64_t *features, int feature)
+{
+    *features &= ~(1ULL << feature);
+}
+
 bool kvm_arm_get_host_cpu_features(ARMHostCPUClass *ahcc)
 {
     /* Identify the feature bits corresponding to the host CPU, and
@@ -469,6 +474,7 @@ bool kvm_arm_get_host_cpu_features(ARMHostCPUClass *ahcc)
     set_feature(&features, ARM_FEATURE_VFP4);
     set_feature(&features, ARM_FEATURE_NEON);
     set_feature(&features, ARM_FEATURE_AARCH64);
+    set_feature(&features, ARM_FEATURE_PMU);
 
     ahcc->features = features;
 
@@ -482,6 +488,7 @@ int kvm_arch_init_vcpu(CPUState *cs)
     int ret;
     uint64_t mpidr;
     ARMCPU *cpu = ARM_CPU(cs);
+    CPUARMState *env = &cpu->env;
 
     if (cpu->kvm_target == QEMU_KVM_ARM_TARGET_NONE ||
         !object_dynamic_cast(OBJECT(cpu), TYPE_AARCH64_CPU)) {
@@ -501,10 +508,14 @@ int kvm_arch_init_vcpu(CPUState *cs)
     if (!arm_feature(&cpu->env, ARM_FEATURE_AARCH64)) {
         cpu->kvm_init_features[0] |= 1 << KVM_ARM_VCPU_EL1_32BIT;
     }
-    if (kvm_irqchip_in_kernel() &&
-        kvm_check_extension(cs->kvm_state, KVM_CAP_ARM_PMU_V3)) {
-        cpu->has_pmu = true;
+    if (!kvm_irqchip_in_kernel() ||
+        !kvm_check_extension(cs->kvm_state, KVM_CAP_ARM_PMU_V3)) {
+            cpu->has_pmu = ON_OFF_AUTO_OFF;
+    }
+    if (cpu->has_pmu == ON_OFF_AUTO_ON) {
         cpu->kvm_init_features[0] |= 1 << KVM_ARM_VCPU_PMU_V3;
+    } else {
+        unset_feature(&env->features, ARM_FEATURE_PMU);
     }
 
     /* Do KVM_ARM_VCPU_INIT ioctl */
-- 
1.8.3.1




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