Hi Drew,
On 9/16/20 11:26 AM, Andrew Jones wrote:
> We add the kvm-steal-time CPU property and implement it for machvirt.
> A tiny bit of refactoring was also done to allow pmu and pvtime to
> use the same vcpu device helper functions.
This needs a rebase. Besides this still looks good to me
Reviewed-by: Eric Auger <eric.au...@redhat.com>
Thanks
Eric
>
> Signed-off-by: Andrew Jones <drjo...@redhat.com>
> ---
> docs/system/arm/cpu-features.rst | 11 ++++++
> hw/arm/virt.c | 43 +++++++++++++++++++--
> include/hw/arm/virt.h | 5 +++
> target/arm/cpu.c | 8 ++++
> target/arm/cpu.h | 4 ++
> target/arm/kvm.c | 16 ++++++++
> target/arm/kvm64.c | 64 +++++++++++++++++++++++++++++---
> target/arm/kvm_arm.h | 43 +++++++++++++++++++++
> target/arm/monitor.c | 2 +-
> tests/qtest/arm-cpu-features.c | 25 +++++++++++--
> 10 files changed, 208 insertions(+), 13 deletions(-)
>
> diff --git a/docs/system/arm/cpu-features.rst
> b/docs/system/arm/cpu-features.rst
> index 2d5c06cd016b..35196a6b759d 100644
> --- a/docs/system/arm/cpu-features.rst
> +++ b/docs/system/arm/cpu-features.rst
> @@ -200,6 +200,17 @@ the list of KVM VCPU features and their descriptions.
> adjustment, also restoring the legacy (pre-5.0)
> behavior.
>
> + kvm-steal-time Since v5.2, kvm-steal-time is enabled by
> + default when KVM is enabled, the feature is
> + supported, and the guest is 64-bit.
> +
> + When kvm-steal-time is enabled a 64-bit guest
> + can account for time its CPUs were not running
> + due to the host not scheduling the corresponding
> + VCPU threads. The accounting statistics may
> + influence the guest scheduler behavior and/or be
> + exposed to the guest userspace.
> +
> SVE CPU Properties
> ==================
>
> diff --git a/hw/arm/virt.c b/hw/arm/virt.c
> index 6797eb397a7a..12efc2f095cb 100644
> --- a/hw/arm/virt.c
> +++ b/hw/arm/virt.c
> @@ -151,6 +151,7 @@ static const MemMapEntry base_memmap[] = {
> [VIRT_PCDIMM_ACPI] = { 0x09070000, MEMORY_HOTPLUG_IO_LEN },
> [VIRT_ACPI_GED] = { 0x09080000, ACPI_GED_EVT_SEL_LEN },
> [VIRT_NVDIMM_ACPI] = { 0x09090000, NVDIMM_ACPI_IO_LEN},
> + [VIRT_PVTIME] = { 0x090a0000, 0x00010000 },
> [VIRT_MMIO] = { 0x0a000000, 0x00000200 },
> /* ...repeating for a total of NUM_VIRTIO_TRANSPORTS, each of that size
> */
> [VIRT_PLATFORM_BUS] = { 0x0c000000, 0x02000000 },
> @@ -1666,15 +1667,39 @@ static void finalize_gic_version(VirtMachineState
> *vms)
> * virt_cpu_post_init() must be called after the CPUs have
> * been realized and the GIC has been created.
> */
> -static void virt_cpu_post_init(VirtMachineState *vms)
> +static void virt_cpu_post_init(VirtMachineState *vms, int max_cpus,
> + MemoryRegion *sysmem)
> {
> - bool aarch64, pmu;
> + bool aarch64, pmu, steal_time;
> CPUState *cpu;
>
> aarch64 = object_property_get_bool(OBJECT(first_cpu), "aarch64", NULL);
> pmu = object_property_get_bool(OBJECT(first_cpu), "pmu", NULL);
> + steal_time = object_property_get_bool(OBJECT(first_cpu),
> + "kvm-steal-time", NULL);
>
> if (kvm_enabled()) {
> + hwaddr pvtime_reg_base = vms->memmap[VIRT_PVTIME].base;
> + hwaddr pvtime_reg_size = vms->memmap[VIRT_PVTIME].size;
> +
> + if (steal_time) {
> + MemoryRegion *pvtime = g_new(MemoryRegion, 1);
> + hwaddr pvtime_size = max_cpus * PVTIME_SIZE_PER_CPU;
> +
> + /* The memory region size must be a multiple of host page size.
> */
> + pvtime_size = REAL_HOST_PAGE_ALIGN(pvtime_size);
> +
> + if (pvtime_size > pvtime_reg_size) {
> + error_report("pvtime requires a %ld byte memory region for "
> + "%d CPUs, but only %ld has been reserved",
> + pvtime_size, max_cpus, pvtime_reg_size);
> + exit(1);
> + }
> +
> + memory_region_init_ram(pvtime, NULL, "pvtime", pvtime_size,
> NULL);
> + memory_region_add_subregion(sysmem, pvtime_reg_base, pvtime);
> + }
> +
> CPU_FOREACH(cpu) {
> if (pmu) {
> assert(arm_feature(&ARM_CPU(cpu)->env, ARM_FEATURE_PMU));
> @@ -1683,6 +1708,10 @@ static void virt_cpu_post_init(VirtMachineState *vms)
> }
> kvm_arm_pmu_init(cpu);
> }
> + if (steal_time) {
> + kvm_arm_pvtime_init(cpu, pvtime_reg_base +
> + cpu->cpu_index *
> PVTIME_SIZE_PER_CPU);
> + }
> }
> } else {
> if (aarch64 && vms->highmem) {
> @@ -1853,6 +1882,11 @@ static void machvirt_init(MachineState *machine)
> object_property_set_bool(cpuobj, "kvm-no-adjvtime", true, NULL);
> }
>
> + if (vmc->no_kvm_steal_time &&
> + object_property_find(cpuobj, "kvm-steal-time", NULL)) {
> + object_property_set_bool(cpuobj, "kvm-steal-time", false, NULL);
> + }
> +
> if (vmc->no_pmu && object_property_find(cpuobj, "pmu", NULL)) {
> object_property_set_bool(cpuobj, "pmu", false, NULL);
> }
> @@ -1924,7 +1958,7 @@ static void machvirt_init(MachineState *machine)
>
> create_gic(vms);
>
> - virt_cpu_post_init(vms);
> + virt_cpu_post_init(vms, possible_cpus->len, sysmem);
>
> fdt_add_pmu_nodes(vms);
>
> @@ -2566,8 +2600,11 @@ DEFINE_VIRT_MACHINE_AS_LATEST(5, 2)
>
> static void virt_machine_5_1_options(MachineClass *mc)
> {
> + VirtMachineClass *vmc = VIRT_MACHINE_CLASS(OBJECT_CLASS(mc));
> +
> virt_machine_5_2_options(mc);
> compat_props_add(mc->compat_props, hw_compat_5_1, hw_compat_5_1_len);
> + vmc->no_kvm_steal_time = true;
> }
> DEFINE_VIRT_MACHINE(5, 1)
>
> diff --git a/include/hw/arm/virt.h b/include/hw/arm/virt.h
> index 392b0bd57188..e0c59cc2aa75 100644
> --- a/include/hw/arm/virt.h
> +++ b/include/hw/arm/virt.h
> @@ -54,6 +54,9 @@
>
> #define PPI(irq) ((irq) + 16)
>
> +/* See Linux kernel arch/arm64/include/asm/pvclock-abi.h */
> +#define PVTIME_SIZE_PER_CPU 64
> +
> enum {
> VIRT_FLASH,
> VIRT_MEM,
> @@ -81,6 +84,7 @@ enum {
> VIRT_PCDIMM_ACPI,
> VIRT_ACPI_GED,
> VIRT_NVDIMM_ACPI,
> + VIRT_PVTIME,
> VIRT_LOWMEMMAP_LAST,
> };
>
> @@ -126,6 +130,7 @@ struct VirtMachineClass {
> bool no_highmem_ecam;
> bool no_ged; /* Machines < 4.2 has no support for ACPI GED device */
> bool kvm_no_adjvtime;
> + bool no_kvm_steal_time;
> bool acpi_expose_flash;
> };
> typedef struct VirtMachineClass VirtMachineClass;
> diff --git a/target/arm/cpu.c b/target/arm/cpu.c
> index 7b5ea65fab95..972768a7ee9d 100644
> --- a/target/arm/cpu.c
> +++ b/target/arm/cpu.c
> @@ -1310,6 +1310,14 @@ void arm_cpu_finalize_features(ARMCPU *cpu, Error
> **errp)
> return;
> }
> }
> +
> + if (kvm_enabled()) {
> + kvm_arm_steal_time_finalize(cpu, &local_err);
> + if (local_err != NULL) {
> + error_propagate(errp, local_err);
> + return;
> + }
> + }
> }
>
> static void arm_cpu_realizefn(DeviceState *dev, Error **errp)
> diff --git a/target/arm/cpu.h b/target/arm/cpu.h
> index 6036f61d60b3..dcabd6ce2d97 100644
> --- a/target/arm/cpu.h
> +++ b/target/arm/cpu.h
> @@ -24,6 +24,7 @@
> #include "hw/registerfields.h"
> #include "cpu-qom.h"
> #include "exec/cpu-defs.h"
> +#include "qapi/qapi-types-common.h"
>
> /* ARM processors have a weak memory model */
> #define TCG_GUEST_DEFAULT_MO (0)
> @@ -863,6 +864,9 @@ struct ARMCPU {
> bool kvm_vtime_dirty;
> uint64_t kvm_vtime;
>
> + /* KVM steal time */
> + OnOffAuto kvm_steal_time;
> +
> /* Uniprocessor system with MP extensions */
> bool mp_is_up;
>
> diff --git a/target/arm/kvm.c b/target/arm/kvm.c
> index 2eae73315d6e..f30c16f23d4a 100644
> --- a/target/arm/kvm.c
> +++ b/target/arm/kvm.c
> @@ -192,6 +192,16 @@ static void kvm_no_adjvtime_set(Object *obj, bool value,
> Error **errp)
> ARM_CPU(obj)->kvm_adjvtime = !value;
> }
>
> +static bool kvm_steal_time_get(Object *obj, Error **errp)
> +{
> + return ARM_CPU(obj)->kvm_steal_time != ON_OFF_AUTO_OFF;
> +}
> +
> +static void kvm_steal_time_set(Object *obj, bool value, Error **errp)
> +{
> + ARM_CPU(obj)->kvm_steal_time = value ? ON_OFF_AUTO_ON : ON_OFF_AUTO_OFF;
> +}
> +
> /* KVM VCPU properties should be prefixed with "kvm-". */
> void kvm_arm_add_vcpu_properties(Object *obj)
> {
> @@ -207,6 +217,12 @@ void kvm_arm_add_vcpu_properties(Object *obj)
> "the virtual counter. VM stopped
> time "
> "will be counted.");
> }
> +
> + cpu->kvm_steal_time = ON_OFF_AUTO_AUTO;
> + object_property_add_bool(obj, "kvm-steal-time", kvm_steal_time_get,
> + kvm_steal_time_set);
> + object_property_set_description(obj, "kvm-steal-time",
> + "Set off to disable KVM steal time.");
> }
>
> bool kvm_arm_pmu_supported(void)
> diff --git a/target/arm/kvm64.c b/target/arm/kvm64.c
> index 987b35e33fea..92768166809d 100644
> --- a/target/arm/kvm64.c
> +++ b/target/arm/kvm64.c
> @@ -17,6 +17,7 @@
> #include <linux/kvm.h>
>
> #include "qemu-common.h"
> +#include "qapi/error.h"
> #include "cpu.h"
> #include "qemu/timer.h"
> #include "qemu/error-report.h"
> @@ -397,19 +398,20 @@ static CPUWatchpoint *find_hw_watchpoint(CPUState *cpu,
> target_ulong addr)
> return NULL;
> }
>
> -static bool kvm_arm_pmu_set_attr(CPUState *cs, struct kvm_device_attr *attr)
> +static bool kvm_arm_set_device_attr(CPUState *cs, struct kvm_device_attr
> *attr,
> + const char *name)
> {
> int err;
>
> err = kvm_vcpu_ioctl(cs, KVM_HAS_DEVICE_ATTR, attr);
> if (err != 0) {
> - error_report("PMU: KVM_HAS_DEVICE_ATTR: %s", strerror(-err));
> + error_report("%s: KVM_HAS_DEVICE_ATTR: %s", name, strerror(-err));
> return false;
> }
>
> err = kvm_vcpu_ioctl(cs, KVM_SET_DEVICE_ATTR, attr);
> if (err != 0) {
> - error_report("PMU: KVM_SET_DEVICE_ATTR: %s", strerror(-err));
> + error_report("%s: KVM_SET_DEVICE_ATTR: %s", name, strerror(-err));
> return false;
> }
>
> @@ -426,7 +428,7 @@ void kvm_arm_pmu_init(CPUState *cs)
> if (!ARM_CPU(cs)->has_pmu) {
> return;
> }
> - if (!kvm_arm_pmu_set_attr(cs, &attr)) {
> + if (!kvm_arm_set_device_attr(cs, &attr, "PMU")) {
> error_report("failed to init PMU");
> abort();
> }
> @@ -443,12 +445,29 @@ void kvm_arm_pmu_set_irq(CPUState *cs, int irq)
> if (!ARM_CPU(cs)->has_pmu) {
> return;
> }
> - if (!kvm_arm_pmu_set_attr(cs, &attr)) {
> + if (!kvm_arm_set_device_attr(cs, &attr, "PMU")) {
> error_report("failed to set irq for PMU");
> abort();
> }> }
>
> +void kvm_arm_pvtime_init(CPUState *cs, uint64_t ipa)
> +{
> + struct kvm_device_attr attr = {
> + .group = KVM_ARM_VCPU_PVTIME_CTRL,
> + .attr = KVM_ARM_VCPU_PVTIME_IPA,
> + .addr = (uint64_t)&ipa,
> + };
> +
> + if (ARM_CPU(cs)->kvm_steal_time == ON_OFF_AUTO_OFF) {
> + return;
> + }
> + if (!kvm_arm_set_device_attr(cs, &attr, "PVTIME IPA")) {
> + error_report("failed to init PVTIME IPA");
> + abort();
> + }
> +}
> +
> static int read_sys_reg32(int fd, uint32_t *pret, uint64_t id)
> {
> uint64_t ret;
> @@ -651,6 +670,36 @@ bool kvm_arm_get_host_cpu_features(ARMHostCPUFeatures
> *ahcf)
> return true;
> }
>
> +void kvm_arm_steal_time_finalize(ARMCPU *cpu, Error **errp)
> +{
> + bool has_steal_time = kvm_arm_steal_time_supported();
> +
> + if (cpu->kvm_steal_time == ON_OFF_AUTO_AUTO) {
> + if (!has_steal_time || !arm_feature(&cpu->env, ARM_FEATURE_AARCH64))
> {
> + cpu->kvm_steal_time = ON_OFF_AUTO_OFF;
> + } else {
> + cpu->kvm_steal_time = ON_OFF_AUTO_ON;
> + }
> + } else if (cpu->kvm_steal_time == ON_OFF_AUTO_ON) {
> + if (!has_steal_time) {
> + error_setg(errp, "'kvm-steal-time' cannot be enabled "
> + "on this host");
> + return;
> + } else if (!arm_feature(&cpu->env, ARM_FEATURE_AARCH64)) {
> + /*
> + * DEN0057A chapter 2 says "This specification only covers
> + * systems in which the Execution state of the hypervisor
> + * as well as EL1 of virtual machines is AArch64.". And,
> + * to ensure that, the smc/hvc calls are only specified as
> + * smc64/hvc64.
> + */
> + error_setg(errp, "'kvm-steal-time' cannot be enabled "
> + "for AArch32 guests");
> + return;
> + }
> + }
> +}
> +
> bool kvm_arm_aarch32_supported(void)
> {
> return kvm_check_extension(kvm_state, KVM_CAP_ARM_EL1_32BIT);
> @@ -661,6 +710,11 @@ bool kvm_arm_sve_supported(void)
> return kvm_check_extension(kvm_state, KVM_CAP_ARM_SVE);
> }
>
> +bool kvm_arm_steal_time_supported(void)
> +{
> + return kvm_check_extension(kvm_state, KVM_CAP_STEAL_TIME);
> +}
> +
> QEMU_BUILD_BUG_ON(KVM_ARM64_SVE_VQ_MIN != 1);
>
> void kvm_arm_sve_get_vls(CPUState *cs, unsigned long *map)
> diff --git a/target/arm/kvm_arm.h b/target/arm/kvm_arm.h
> index f513702176a7..eb81b7059eb1 100644
> --- a/target/arm/kvm_arm.h
> +++ b/target/arm/kvm_arm.h
> @@ -267,6 +267,24 @@ void kvm_arm_set_cpu_features_from_host(ARMCPU *cpu);
> */
> void kvm_arm_add_vcpu_properties(Object *obj);
>
> +/**
> + * kvm_arm_steal_time_finalize:
> + * @cpu: ARMCPU for which to finalize kvm-steal-time
> + * @errp: Pointer to Error* for error propagation
> + *
> + * Validate the kvm-steal-time property selection and set its default
> + * based on KVM support and guest configuration.
> + */
> +void kvm_arm_steal_time_finalize(ARMCPU *cpu, Error **errp);
> +
> +/**
> + * kvm_arm_steal_time_supported:
> + *
> + * Returns: true if KVM can enable steal time reporting
> + * and false otherwise.
> + */
> +bool kvm_arm_steal_time_supported(void);
> +
> /**
> * kvm_arm_aarch32_supported:
> *
> @@ -340,6 +358,16 @@ int kvm_arm_vgic_probe(void);
>
> void kvm_arm_pmu_set_irq(CPUState *cs, int irq);
> void kvm_arm_pmu_init(CPUState *cs);
> +
> +/**
> + * kvm_arm_pvtime_init:
> + * @cs: CPUState
> + * @ipa: Per-vcpu guest physical base address of the pvtime structures
> + *
> + * Initializes PVTIME for the VCPU, setting the PVTIME IPA to @ipa.
> + */
> +void kvm_arm_pvtime_init(CPUState *cs, uint64_t ipa);
> +
> int kvm_arm_set_irq(int cpu, int irqtype, int irq, int level);
>
> #else
> @@ -363,6 +391,11 @@ static inline bool kvm_arm_sve_supported(void)
> return false;
> }
>
> +static inline bool kvm_arm_steal_time_supported(void)
> +{
> + return false;
> +}
> +
> /*
> * These functions should never actually be called without KVM support.
> */
> @@ -396,6 +429,16 @@ static inline void kvm_arm_pmu_init(CPUState *cs)
> g_assert_not_reached();
> }
>
> +static inline void kvm_arm_pvtime_init(CPUState *cs, uint64_t ipa)
> +{
> + g_assert_not_reached();
> +}
> +
> +static inline void kvm_arm_steal_time_finalize(ARMCPU *cpu, Error **errp)
> +{
> + g_assert_not_reached();
> +}
> +
> static inline void kvm_arm_sve_get_vls(CPUState *cs, unsigned long *map)
> {
> g_assert_not_reached();
> diff --git a/target/arm/monitor.c b/target/arm/monitor.c
> index ba6e01abd037..bd3590604a71 100644
> --- a/target/arm/monitor.c
> +++ b/target/arm/monitor.c
> @@ -103,7 +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",
> + "kvm-no-adjvtime", "kvm-steal-time",
> NULL
> };
>
> diff --git a/tests/qtest/arm-cpu-features.c b/tests/qtest/arm-cpu-features.c
> index 77b5e30a9cf5..d20094d5a709 100644
> --- a/tests/qtest/arm-cpu-features.c
> +++ b/tests/qtest/arm-cpu-features.c
> @@ -452,6 +452,7 @@ static void test_query_cpu_model_expansion(const void
> *data)
> assert_set_feature(qts, "max", "pmu", true);
>
> assert_has_not_feature(qts, "max", "kvm-no-adjvtime");
> + assert_has_not_feature(qts, "max", "kvm-steal-time");
>
> if (g_str_equal(qtest_get_arch(), "aarch64")) {
> assert_has_feature_enabled(qts, "max", "aarch64");
> @@ -493,6 +494,7 @@ static void test_query_cpu_model_expansion_kvm(const void
> *data)
> assert_set_feature(qts, "host", "kvm-no-adjvtime", false);
>
> if (g_str_equal(qtest_get_arch(), "aarch64")) {
> + bool kvm_supports_steal_time;
> bool kvm_supports_sve;
> char max_name[8], name[8];
> uint32_t max_vq, vq;
> @@ -500,6 +502,10 @@ static void test_query_cpu_model_expansion_kvm(const
> void *data)
> QDict *resp;
> char *error;
>
> + assert_error(qts, "cortex-a15",
> + "We cannot guarantee the CPU type 'cortex-a15' works "
> + "with KVM on this host", NULL);
> +
> assert_has_feature_enabled(qts, "host", "aarch64");
>
> /* Enabling and disabling pmu should always work. */
> @@ -507,16 +513,26 @@ static void test_query_cpu_model_expansion_kvm(const
> void *data)
> assert_set_feature(qts, "host", "pmu", false);
> assert_set_feature(qts, "host", "pmu", true);
>
> - assert_error(qts, "cortex-a15",
> - "We cannot guarantee the CPU type 'cortex-a15' works "
> - "with KVM on this host", NULL);
> -
> + /*
> + * Some features would be enabled by default, but they're disabled
> + * because this instance of KVM doesn't support them. Test that the
> + * features are present, and, when enabled, issue further tests.
> + */
> + assert_has_feature(qts, "host", "kvm-steal-time");
> assert_has_feature(qts, "host", "sve");
> +
> resp = do_query_no_props(qts, "host");
> + kvm_supports_steal_time = resp_get_feature(resp, "kvm-steal-time");
> kvm_supports_sve = resp_get_feature(resp, "sve");
> vls = resp_get_sve_vls(resp);
> qobject_unref(resp);
>
> + if (kvm_supports_steal_time) {
> + /* If we have steal-time then we should be able to toggle it. */
> + assert_set_feature(qts, "host", "kvm-steal-time", false);
> + assert_set_feature(qts, "host", "kvm-steal-time", true);
> + }
> +
> if (kvm_supports_sve) {
> g_assert(vls != 0);
> max_vq = 64 - __builtin_clzll(vls);
> @@ -577,6 +593,7 @@ static void test_query_cpu_model_expansion_kvm(const void
> *data)
> assert_has_not_feature(qts, "host", "aarch64");
> assert_has_not_feature(qts, "host", "pmu");
> assert_has_not_feature(qts, "host", "sve");
> + assert_has_not_feature(qts, "host", "kvm-steal-time");
> }
>
> qtest_quit(qts);
>
