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[34.82.80.254]) by smtp.gmail.com with ESMTPSA id y13-20020a17090a390d00b001c995e0a481sm3446636pjb.30.2022.04.05.15.24.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 05 Apr 2022 15:24:16 -0700 (PDT) Date: Tue, 5 Apr 2022 22:24:12 +0000 From: David Matlack To: Ben Gardon Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Paolo Bonzini , Peter Xu , Sean Christopherson , Jim Mattson , David Dunn , Jing Zhang , Junaid Shahid Subject: Re: [PATCH v3 03/11] KVM: selftests: Test reading a single stat Message-ID: References: <20220330174621.1567317-1-bgardon@google.com> <20220330174621.1567317-4-bgardon@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220330174621.1567317-4-bgardon@google.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Mar 30, 2022 at 10:46:13AM -0700, Ben Gardon wrote: > Retrieve the value of a single stat by name in the binary stats test to > ensure the kvm_util library functions work. > > CC: Jing Zhang > Signed-off-by: Ben Gardon > --- > .../selftests/kvm/include/kvm_util_base.h | 1 + > .../selftests/kvm/kvm_binary_stats_test.c | 3 ++ > tools/testing/selftests/kvm/lib/kvm_util.c | 53 +++++++++++++++++++ > 3 files changed, 57 insertions(+) > > diff --git a/tools/testing/selftests/kvm/include/kvm_util_base.h b/tools/testing/selftests/kvm/include/kvm_util_base.h > index 4783fd1cd4cf..78c4407f36b4 100644 > --- a/tools/testing/selftests/kvm/include/kvm_util_base.h > +++ b/tools/testing/selftests/kvm/include/kvm_util_base.h > @@ -402,6 +402,7 @@ void assert_on_unhandled_exception(struct kvm_vm *vm, uint32_t vcpuid); > int vm_get_stats_fd(struct kvm_vm *vm); > int vcpu_get_stats_fd(struct kvm_vm *vm, uint32_t vcpuid); > void dump_vm_stats(struct kvm_vm *vm); > +uint64_t vm_get_single_stat(struct kvm_vm *vm, const char *stat_name); > > uint32_t guest_get_vcpuid(void); > > diff --git a/tools/testing/selftests/kvm/kvm_binary_stats_test.c b/tools/testing/selftests/kvm/kvm_binary_stats_test.c > index afc4701ce8dd..97bde355f105 100644 > --- a/tools/testing/selftests/kvm/kvm_binary_stats_test.c > +++ b/tools/testing/selftests/kvm/kvm_binary_stats_test.c > @@ -177,6 +177,9 @@ static void vm_stats_test(struct kvm_vm *vm) > > /* Dump VM stats */ > dump_vm_stats(vm); > + > + /* Read a single stat. */ > + printf("remote_tlb_flush: %lu\n", vm_get_single_stat(vm, "remote_tlb_flush")); > } > > static void vcpu_stats_test(struct kvm_vm *vm, int vcpu_id) > diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c > index f87df68b150d..9c4574381daa 100644 > --- a/tools/testing/selftests/kvm/lib/kvm_util.c > +++ b/tools/testing/selftests/kvm/lib/kvm_util.c > @@ -2705,3 +2705,56 @@ void dump_vm_stats(struct kvm_vm *vm) > close(stats_fd); > } > > +static int vm_get_stat_data(struct kvm_vm *vm, const char *stat_name, > + uint64_t **data) > +{ > + struct kvm_stats_desc *stats_desc; > + struct kvm_stats_header *header; > + struct kvm_stats_desc *desc; > + size_t size_desc; > + int stats_fd; > + int ret = -EINVAL; > + int i; > + > + *data = NULL; > + > + stats_fd = vm_get_stats_fd(vm); > + > + header = read_vm_stats_header(stats_fd); > + > + stats_desc = read_vm_stats_desc(stats_fd, header); > + > + size_desc = stats_desc_size(header); > + > + /* Read kvm stats data one by one */ > + for (i = 0; i < header->num_desc; ++i) { > + desc = (void *)stats_desc + (i * size_desc); > + > + if (strcmp(desc->name, stat_name)) > + continue; > + > + ret = read_stat_data(stats_fd, header, desc, data); > + } > + > + free(stats_desc); > + free(header); > + > + close(stats_fd); > + > + return ret; > +} > + > +uint64_t vm_get_single_stat(struct kvm_vm *vm, const char *stat_name) > +{ > + uint64_t *data; > + uint64_t value; > + int ret; > + > + ret = vm_get_stat_data(vm, stat_name, &data); > + TEST_ASSERT(ret == 1, "Stat %s expected to have 1 element, but has %d", > + stat_name, ret); > + value = *data; > + free(data); Allocating temporary storage for the data is unnecessary. Just read the stat directly into &value. You'll need to change read_stat_data() to accept another parameter that defines the number of elements the caller wants to read. Otherwise botched stats could trigger a buffer overflow. > + return value; > +} > + > -- > 2.35.1.1021.g381101b075-goog >