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[82.30.61.225]) by smtp.gmail.com with ESMTPSA id g1-20020a7bc4c1000000b0039736892653sm12259wmk.27.2022.05.24.11.44.43 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 24 May 2022 11:44:44 -0700 (PDT) Date: Tue, 24 May 2022 19:44:41 +0100 From: "Dr. David Alan Gilbert" To: Paolo Bonzini Cc: qemu-devel@nongnu.org, armbru@redhat.com, berrange@redhat.com, Mark Kanda Subject: Re: [PATCH v3 2/8] kvm: Support for querying fd-based stats Message-ID: References: <20220516090058.1195767-1-pbonzini@redhat.com> <20220516090058.1195767-3-pbonzini@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220516090058.1195767-3-pbonzini@redhat.com> User-Agent: Mutt/2.2.1 (2022-02-19) Received-SPF: pass client-ip=170.10.133.124; envelope-from=dgilbert@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -28 X-Spam_score: -2.9 X-Spam_bar: -- X-Spam_report: (-2.9 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.082, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * Paolo Bonzini (pbonzini@redhat.com) wrote: > From: Mark Kanda > > Add support for querying fd-based KVM stats - as introduced by Linux kernel > commit: > > cb082bfab59a ("KVM: stats: Add fd-based API to read binary stats data") > > This allows the user to analyze the behavior of the VM without access > to debugfs. > > Signed-off-by: Mark Kanda > Signed-off-by: Paolo Bonzini > --- > accel/kvm/kvm-all.c | 403 ++++++++++++++++++++++++++++++++++++++++++++ > qapi/stats.json | 2 +- > 2 files changed, 404 insertions(+), 1 deletion(-) > > diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c > index 32e177bd26..6a6bbe2994 100644 > --- a/accel/kvm/kvm-all.c > +++ b/accel/kvm/kvm-all.c > @@ -47,6 +47,7 @@ > #include "kvm-cpus.h" > > #include "hw/boards.h" > +#include "monitor/stats.h" > > /* This check must be after config-host.h is included */ > #ifdef CONFIG_EVENTFD > @@ -2310,6 +2311,9 @@ bool kvm_dirty_ring_enabled(void) > return kvm_state->kvm_dirty_ring_size ? true : false; > } > > +static void query_stats_cb(StatsResultList **result, StatsTarget target, Error **errp); > +static void query_stats_schemas_cb(StatsSchemaList **result, Error **errp); > + > static int kvm_init(MachineState *ms) > { > MachineClass *mc = MACHINE_GET_CLASS(ms); > @@ -2638,6 +2642,10 @@ static int kvm_init(MachineState *ms) > } > } > > + if (kvm_check_extension(kvm_state, KVM_CAP_BINARY_STATS_FD)) { > + add_stats_callbacks(query_stats_cb, query_stats_schemas_cb); > + } > + > return 0; > > err: > @@ -3697,3 +3705,398 @@ static void kvm_type_init(void) > } > > type_init(kvm_type_init); > + > +typedef struct StatsArgs { > + union StatsResultsType { > + StatsResultList **stats; > + StatsSchemaList **schema; > + } result; > + Error **errp; > +} StatsArgs; > + > +static StatsList *add_kvmstat_entry(struct kvm_stats_desc *pdesc, > + uint64_t *stats_data, > + StatsList *stats_list, > + Error **errp) > +{ > + > + StatsList *stats_entry; > + Stats *stats; > + uint64List *val_list = NULL; A comment here something like: /* Only add stats that we understand */ ? > + switch (pdesc->flags & KVM_STATS_TYPE_MASK) { > + case KVM_STATS_TYPE_CUMULATIVE: > + case KVM_STATS_TYPE_INSTANT: > + case KVM_STATS_TYPE_PEAK: > + case KVM_STATS_TYPE_LINEAR_HIST: > + case KVM_STATS_TYPE_LOG_HIST: > + break; > + default: > + return stats_list; > + } > + > + switch (pdesc->flags & KVM_STATS_UNIT_MASK) { > + case KVM_STATS_UNIT_NONE: > + case KVM_STATS_UNIT_BYTES: > + case KVM_STATS_UNIT_CYCLES: > + case KVM_STATS_UNIT_SECONDS: > + break; > + default: > + return stats_list; > + } > + > + switch (pdesc->flags & KVM_STATS_BASE_MASK) { > + case KVM_STATS_BASE_POW10: > + case KVM_STATS_BASE_POW2: > + break; > + default: > + return stats_list; > + } > + > + /* Alloc and populate data list */ > + stats_entry = g_new0(StatsList, 1); > + stats = g_new0(Stats, 1); > + stats->name = g_strdup(pdesc->name); > + stats->value = g_new0(StatsValue, 1);; > + > + if (pdesc->size == 1) { > + stats->value->u.scalar = *stats_data; > + stats->value->type = QTYPE_QNUM; > + } else { > + int i; > + for (i = 0; i < pdesc->size; i++) { > + uint64List *val_entry = g_new0(uint64List, 1); > + val_entry->value = stats_data[i]; > + val_entry->next = val_list; > + val_list = val_entry; > + } > + stats->value->u.list = val_list; > + stats->value->type = QTYPE_QLIST; > + } > + > + stats_entry->value = stats; > + stats_entry->next = stats_list; Can all that use QAPI_LIST_PREPEND? > + return stats_entry; > +} > + > +static StatsSchemaValueList *add_kvmschema_entry(struct kvm_stats_desc *pdesc, > + StatsSchemaValueList *list, > + Error **errp) > +{ > + StatsSchemaValueList *schema_entry = g_new0(StatsSchemaValueList, 1); > + schema_entry->value = g_new0(StatsSchemaValue, 1); > + > + switch (pdesc->flags & KVM_STATS_TYPE_MASK) { > + case KVM_STATS_TYPE_CUMULATIVE: > + schema_entry->value->type = STATS_TYPE_CUMULATIVE; > + break; > + case KVM_STATS_TYPE_INSTANT: > + schema_entry->value->type = STATS_TYPE_INSTANT; > + break; > + case KVM_STATS_TYPE_PEAK: > + schema_entry->value->type = STATS_TYPE_PEAK; > + break; > + case KVM_STATS_TYPE_LINEAR_HIST: > + schema_entry->value->type = STATS_TYPE_LINEAR_HISTOGRAM; > + schema_entry->value->bucket_size = pdesc->bucket_size; > + schema_entry->value->has_bucket_size = true; > + break; > + case KVM_STATS_TYPE_LOG_HIST: > + schema_entry->value->type = STATS_TYPE_LOG2_HISTOGRAM; > + break; > + default: > + goto exit; > + } > + > + switch (pdesc->flags & KVM_STATS_UNIT_MASK) { > + case KVM_STATS_UNIT_NONE: > + break; > + case KVM_STATS_UNIT_BYTES: > + schema_entry->value->has_unit = true; > + schema_entry->value->unit = STATS_UNIT_BYTES; > + break; > + case KVM_STATS_UNIT_CYCLES: > + schema_entry->value->has_unit = true; > + schema_entry->value->unit = STATS_UNIT_CYCLES; > + break; > + case KVM_STATS_UNIT_SECONDS: > + schema_entry->value->has_unit = true; > + schema_entry->value->unit = STATS_UNIT_SECONDS; Had you considered making these UNIT_SECONDS, I'm just thinking there are probably other interfaces that parse things with units. > + break; > + default: > + goto exit; > + } > + > + schema_entry->value->exponent = pdesc->exponent; > + if (pdesc->exponent) { > + switch (pdesc->flags & KVM_STATS_BASE_MASK) { > + case KVM_STATS_BASE_POW10: > + schema_entry->value->has_base = true; > + schema_entry->value->base = 10; > + break; > + case KVM_STATS_BASE_POW2: > + schema_entry->value->has_base = true; > + schema_entry->value->base = 2; > + break; > + default: > + goto exit; > + } > + } > + > + schema_entry->value->name = g_strdup(pdesc->name); > + schema_entry->next = list; > + return schema_entry; > +exit: > + g_free(schema_entry->value); > + g_free(schema_entry); > + return list; > +} > + > +/* Cached stats descriptors */ > +typedef struct StatsDescriptors { > + char *ident; /* 'vm' or vCPU qom path */ > + struct kvm_stats_desc *kvm_stats_desc; > + struct kvm_stats_header *kvm_stats_header; > + QTAILQ_ENTRY(StatsDescriptors) next; > +} StatsDescriptors; > + > +static QTAILQ_HEAD(, StatsDescriptors) stats_descriptors = > + QTAILQ_HEAD_INITIALIZER(stats_descriptors); > + > +static StatsDescriptors *find_stats_descriptors(StatsTarget target, int stats_fd, > + Error **errp) > +{ > + StatsDescriptors *descriptors; > + const char *ident; > + struct kvm_stats_desc *kvm_stats_desc; > + struct kvm_stats_header *kvm_stats_header; > + size_t size_desc; > + ssize_t ret; > + > + switch (target) { > + case STATS_TARGET_VM: > + ident = StatsTarget_str(STATS_TARGET_VM); > + break; > + case STATS_TARGET_VCPU: > + ident = current_cpu->parent_obj.canonical_path; > + break; > + default: > + abort(); > + } > + > + QTAILQ_FOREACH(descriptors, &stats_descriptors, next) { > + if (g_str_equal(descriptors->ident, ident)) { > + return descriptors; > + } > + } > + > + descriptors = g_new0(StatsDescriptors, 1); > + > + /* Read stats header */ > + kvm_stats_header = g_malloc(sizeof(*kvm_stats_header)); > + ret = read(stats_fd, kvm_stats_header, sizeof(*kvm_stats_header)); > + if (ret != sizeof(*kvm_stats_header)) { > + error_setg(errp, "KVM stats: failed to read stats header: " > + "expected %zu actual %zu", > + sizeof(*kvm_stats_header), ret); > + return NULL; > + } > + size_desc = sizeof(*kvm_stats_desc) + kvm_stats_header->name_size; > + > + /* Read stats descriptors */ > + kvm_stats_desc = g_malloc0_n(kvm_stats_header->num_desc, size_desc); > + ret = pread(stats_fd, kvm_stats_desc, > + size_desc * kvm_stats_header->num_desc, > + kvm_stats_header->desc_offset); > + > + if (ret != size_desc * kvm_stats_header->num_desc) { > + error_setg(errp, "KVM stats: failed to read stats descriptors: " > + "expected %zu actual %zu", > + size_desc * kvm_stats_header->num_desc, ret); > + g_free(descriptors); > + return NULL; > + } > + descriptors->kvm_stats_header = kvm_stats_header; > + descriptors->kvm_stats_desc = kvm_stats_desc; > + descriptors->ident = g_strdup(ident); > + QTAILQ_INSERT_TAIL(&stats_descriptors, descriptors, next); > + return descriptors; > +} > + > +static void query_stats(StatsResultList **result, StatsTarget target, > + int stats_fd, Error **errp) > +{ > + struct kvm_stats_desc *kvm_stats_desc; > + struct kvm_stats_header *kvm_stats_header; > + StatsDescriptors *descriptors; > + g_autofree uint64_t *stats_data = NULL; > + struct kvm_stats_desc *pdesc; > + StatsList *stats_list = NULL; > + size_t size_desc, size_data = 0; > + ssize_t ret; > + int i; > + > + descriptors = find_stats_descriptors(target, stats_fd, errp); > + if (!descriptors) { > + return; > + } > + > + kvm_stats_header = descriptors->kvm_stats_header; > + kvm_stats_desc = descriptors->kvm_stats_desc; > + size_desc = sizeof(*kvm_stats_desc) + kvm_stats_header->name_size; > + > + /* Tally the total data size; read schema data */ > + for (i = 0; i < kvm_stats_header->num_desc; ++i) { > + pdesc = (void *)kvm_stats_desc + i * size_desc; > + size_data += pdesc->size * sizeof(*stats_data); > + } > + > + stats_data = g_malloc0(size_data); > + ret = pread(stats_fd, stats_data, size_data, kvm_stats_header->data_offset); > + > + if (ret != size_data) { > + error_setg(errp, "KVM stats: failed to read data: " > + "expected %zu actual %zu", size_data, ret); > + return; > + } > + > + for (i = 0; i < kvm_stats_header->num_desc; ++i) { > + uint64_t *stats; > + pdesc = (void *)kvm_stats_desc + i * size_desc; > + > + /* Add entry to the list */ > + stats = (void *)stats_data + pdesc->offset; > + stats_list = add_kvmstat_entry(pdesc, stats, stats_list, errp); > + } > + > + if (!stats_list) { > + return; > + } > + > + switch (target) { > + case STATS_TARGET_VM: > + add_stats_entry(result, STATS_PROVIDER_KVM, NULL, stats_list); > + break; > + case STATS_TARGET_VCPU: > + add_stats_entry(result, STATS_PROVIDER_KVM, > + current_cpu->parent_obj.canonical_path, > + stats_list); > + break; > + default: > + break; > + } > +} > + > +static void query_stats_schema(StatsSchemaList **result, StatsTarget target, > + int stats_fd, Error **errp) > +{ > + struct kvm_stats_desc *kvm_stats_desc; > + struct kvm_stats_header *kvm_stats_header; > + StatsDescriptors *descriptors; > + struct kvm_stats_desc *pdesc; > + StatsSchemaValueList *stats_list = NULL; > + size_t size_desc; > + int i; > + > + descriptors = find_stats_descriptors(target, stats_fd, errp); > + if (!descriptors) { > + return; > + } > + > + kvm_stats_header = descriptors->kvm_stats_header; > + kvm_stats_desc = descriptors->kvm_stats_desc; > + size_desc = sizeof(*kvm_stats_desc) + kvm_stats_header->name_size; > + > + /* Tally the total data size; read schema data */ > + for (i = 0; i < kvm_stats_header->num_desc; ++i) { > + pdesc = (void *)kvm_stats_desc + i * size_desc; > + stats_list = add_kvmschema_entry(pdesc, stats_list, errp); > + } > + > + add_stats_schema(result, STATS_PROVIDER_KVM, target, stats_list); > +} > + > +static void query_stats_vcpu(CPUState *cpu, run_on_cpu_data data) > +{ > + StatsArgs *kvm_stats_args = (StatsArgs *) data.host_ptr; > + int stats_fd = kvm_vcpu_ioctl(cpu, KVM_GET_STATS_FD, NULL); > + Error *local_err = NULL; > + > + if (stats_fd == -1) { > + error_setg(&local_err, "KVM stats: ioctl failed"); > + error_propagate(kvm_stats_args->errp, local_err); > + return; > + } > + query_stats(kvm_stats_args->result.stats, STATS_TARGET_VCPU, stats_fd, > + kvm_stats_args->errp); > + close(stats_fd); > +} > + > +static void query_stats_schema_vcpu(CPUState *cpu, run_on_cpu_data data) > +{ > + StatsArgs *kvm_stats_args = (StatsArgs *) data.host_ptr; > + int stats_fd = kvm_vcpu_ioctl(cpu, KVM_GET_STATS_FD, NULL); > + Error *local_err = NULL; > + > + if (stats_fd == -1) { > + error_setg(&local_err, "KVM stats: ioctl failed"); Maybe error_setg_errno ? > + error_propagate(kvm_stats_args->errp, local_err); > + return; > + } > + query_stats_schema(kvm_stats_args->result.schema, STATS_TARGET_VCPU, stats_fd, > + kvm_stats_args->errp); > + close(stats_fd); > +} > + > +static void query_stats_cb(StatsResultList **result, StatsTarget target, Error **errp) > +{ > + KVMState *s = kvm_state; > + CPUState *cpu; > + int stats_fd; > + > + switch (target) { > + case STATS_TARGET_VM: > + { > + stats_fd = kvm_vm_ioctl(s, KVM_GET_STATS_FD, NULL); > + if (stats_fd == -1) { > + error_setg(errp, "KVM stats: ioctl failed"); > + return; > + } > + query_stats(result, target, stats_fd, errp); > + close(stats_fd); > + break; > + } > + case STATS_TARGET_VCPU: > + { > + StatsArgs stats_args; > + stats_args.result.stats = result; > + stats_args.errp = errp; > + CPU_FOREACH(cpu) { > + run_on_cpu(cpu, query_stats_vcpu, RUN_ON_CPU_HOST_PTR(&stats_args)); > + } > + break; > + } > + default: > + break; > + } > +} > + > +void query_stats_schemas_cb(StatsSchemaList **result, Error **errp) > +{ > + StatsArgs stats_args; > + KVMState *s = kvm_state; > + int stats_fd; > + > + stats_fd = kvm_vm_ioctl(s, KVM_GET_STATS_FD, NULL); > + if (stats_fd == -1) { > + error_setg(errp, "KVM stats: ioctl failed"); > + return; > + } > + query_stats_schema(result, STATS_TARGET_VM, stats_fd, errp); > + close(stats_fd); > + > + stats_args.result.schema = result; > + stats_args.errp = errp; > + run_on_cpu(first_cpu, query_stats_schema_vcpu, RUN_ON_CPU_HOST_PTR(&stats_args)); > +} > diff --git a/qapi/stats.json b/qapi/stats.json > index f0656a6435..382223e197 100644 > --- a/qapi/stats.json > +++ b/qapi/stats.json > @@ -51,7 +51,7 @@ > # Since: 7.1 > ## > { 'enum': 'StatsProvider', > - 'data': [ ] } > + 'data': [ 'kvm' ] } > > ## > # @StatsTarget: > -- > 2.36.0 > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK