Hi Krish,

On Wed, May 26, 2021 at 5:34 PM Krish Sadhukhan
[off-list ref] wrote:

On 5/24/21 8:18 AM, Jing Zhang wrote:

quoted

Add selftest to check KVM stats descriptors validity.

Reviewed-by: David Matlack <dmatlack@google.com>
Reviewed-by: Ricardo Koller <redacted>
Signed-off-by: Jing Zhang <redacted>
---
  tools/testing/selftests/kvm/.gitignore        |   1 +
  tools/testing/selftests/kvm/Makefile          |   3 +
  .../testing/selftests/kvm/include/kvm_util.h  |   3 +
  .../selftests/kvm/kvm_bin_form_stats.c        | 216 ++++++++++++++++++
  tools/testing/selftests/kvm/lib/kvm_util.c    |  12 +
  5 files changed, 235 insertions(+)
  create mode 100644 tools/testing/selftests/kvm/kvm_bin_form_stats.c

We should probably follow the naming convention for the majority of the
files in the kvm directory and name it kvm_stats_read_test.c or
kvm_stats_test.c or something like that.

Sure. Will change the name.

quoted

diff --git a/tools/testing/selftests/kvm/.gitignore b/tools/testing/selftests/kvm/.gitignore
index bd83158e0e0b..35796667c944 100644
--- a/tools/testing/selftests/kvm/.gitignore
+++ b/tools/testing/selftests/kvm/.gitignore

@@ -43,3 +43,4 @@
  /memslot_modification_stress_test
  /set_memory_region_test
  /steal_time
+/kvm_bin_form_stats

diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
index e439d027939d..2984c86c848a 100644
--- a/tools/testing/selftests/kvm/Makefile
+++ b/tools/testing/selftests/kvm/Makefile

@@ -76,6 +76,7 @@ TEST_GEN_PROGS_x86_64 += kvm_page_table_test
  TEST_GEN_PROGS_x86_64 += memslot_modification_stress_test
  TEST_GEN_PROGS_x86_64 += set_memory_region_test
  TEST_GEN_PROGS_x86_64 += steal_time
+TEST_GEN_PROGS_x86_64 += kvm_bin_form_stats

  TEST_GEN_PROGS_aarch64 += aarch64/get-reg-list
  TEST_GEN_PROGS_aarch64 += aarch64/get-reg-list-sve

@@ -87,6 +88,7 @@ TEST_GEN_PROGS_aarch64 += kvm_create_max_vcpus
  TEST_GEN_PROGS_aarch64 += kvm_page_table_test
  TEST_GEN_PROGS_aarch64 += set_memory_region_test
  TEST_GEN_PROGS_aarch64 += steal_time
+TEST_GEN_PROGS_aarch64 += kvm_bin_form_stats

  TEST_GEN_PROGS_s390x = s390x/memop
  TEST_GEN_PROGS_s390x += s390x/resets

@@ -96,6 +98,7 @@ TEST_GEN_PROGS_s390x += dirty_log_test
  TEST_GEN_PROGS_s390x += kvm_create_max_vcpus
  TEST_GEN_PROGS_s390x += kvm_page_table_test
  TEST_GEN_PROGS_s390x += set_memory_region_test
+TEST_GEN_PROGS_s390x += kvm_bin_form_stats

  TEST_GEN_PROGS += $(TEST_GEN_PROGS_$(UNAME_M))
  LIBKVM += $(LIBKVM_$(UNAME_M))

diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h
index a8f022794ce3..ee01a67022d9 100644
--- a/tools/testing/selftests/kvm/include/kvm_util.h
+++ b/tools/testing/selftests/kvm/include/kvm_util.h

@@ -387,4 +387,7 @@ uint64_t get_ucall(struct kvm_vm *vm, uint32_t vcpu_id, struct ucall *uc);
  #define GUEST_ASSERT_4(_condition, arg1, arg2, arg3, arg4) \
      __GUEST_ASSERT((_condition), 4, (arg1), (arg2), (arg3), (arg4))

+int vm_get_statsfd(struct kvm_vm *vm);
+int vcpu_get_statsfd(struct kvm_vm *vm, uint32_t vcpuid);
+
  #endif /* SELFTEST_KVM_UTIL_H */

diff --git a/tools/testing/selftests/kvm/kvm_bin_form_stats.c b/tools/testing/selftests/kvm/kvm_bin_form_stats.c
new file mode 100644
index 000000000000..09e12c5838af
--- /dev/null
+++ b/tools/testing/selftests/kvm/kvm_bin_form_stats.c

@@ -0,0 +1,216 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * kvm_bin_form_stats
+ *
+ * Copyright (C) 2021, Google LLC.
+ *
+ * Test the fd-based interface for KVM statistics.
+ */
+
+#define _GNU_SOURCE /* for program_invocation_short_name */
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+
+#include "test_util.h"
+
+#include "kvm_util.h"
+#include "asm/kvm.h"
+#include "linux/kvm.h"
+
+int stats_test(int stats_fd, int size_stat)

The return value is not used by the caller. Perhaps make it a void ?

Will do.

quoted

+{
+     ssize_t ret;
+     int i;
+     size_t size_desc, size_data = 0;
+     struct kvm_stats_header header;
+     struct kvm_stats_desc *stats_desc, *pdesc;
+     void *stats_data;
+
+     /* Read kvm stats header */
+     ret = read(stats_fd, &header, sizeof(header));
+     TEST_ASSERT(ret == sizeof(header), "Read stats header");
+     size_desc = sizeof(*stats_desc) + header.name_size;
+
+     /* Check id string in header, that should start with "kvm" */
+     TEST_ASSERT(!strncmp(header.id, "kvm", 3) &&
+                     strlen(header.id) < KVM_STATS_ID_MAXLEN,
+                     "Invalid KVM stats type");
+
+     /* Sanity check for other fields in header */
+     if (header.count == 0)

Does this need a message as to why count is zero ?

Will add a warning message here.

quoted

+             return 0;
+     /* Check overlap */
+     TEST_ASSERT(header.desc_offset > 0 && header.data_offset > 0
+                     && header.desc_offset >= sizeof(header)
+                     && header.data_offset >= sizeof(header),
+                     "Invalid offset fields in header");
+     TEST_ASSERT(header.desc_offset > header.data_offset
+                     || (header.desc_offset + size_desc * header.count <=
+                             header.data_offset),
+                     "Descriptor block is overlapped with data block");
+
+     /* Allocate memory for stats descriptors */
+     stats_desc = calloc(header.count, size_desc);
+     TEST_ASSERT(stats_desc, "Allocate memory for stats descriptors");
+     /* Read kvm stats descriptors */
+     ret = pread(stats_fd, stats_desc,
+                     size_desc * header.count, header.desc_offset);
+     TEST_ASSERT(ret == size_desc * header.count,
+                     "Read KVM stats descriptors");
+
+     /* Sanity check for fields in descriptors */
+     for (i = 0; i < header.count; ++i) {
+             pdesc = (void *)stats_desc + i * size_desc;
+             /* Check type,unit,base boundaries */
+             TEST_ASSERT((pdesc->flags & KVM_STATS_TYPE_MASK)
+                             <= KVM_STATS_TYPE_MAX, "Unknown KVM stats type");
+             TEST_ASSERT((pdesc->flags & KVM_STATS_UNIT_MASK)
+                             <= KVM_STATS_UNIT_MAX, "Unknown KVM stats unit");
+             TEST_ASSERT((pdesc->flags & KVM_STATS_BASE_MASK)
+                             <= KVM_STATS_BASE_MAX, "Unknown KVM stats base");
+             /* Check exponent for stats unit
+              * Exponent for counter should be greater than or equal to 0
+              * Exponent for unit bytes should be greater than or equal to 0
+              * Exponent for unit seconds should be less than or equal to 0
+              * Exponent for unit clock cycles should be greater than or
+              * equal to 0
+              */
+             switch (pdesc->flags & KVM_STATS_UNIT_MASK) {
+             case KVM_STATS_UNIT_NONE:
+             case KVM_STATS_UNIT_BYTES:
+             case KVM_STATS_UNIT_CYCLES:
+                     TEST_ASSERT(pdesc->exponent >= 0,
+                                     "Unsupported KVM stats unit");
+                     break;
+             case KVM_STATS_UNIT_SECONDS:
+                     TEST_ASSERT(pdesc->exponent <= 0,
+                                     "Unsupported KVM stats unit");
+                     break;
+             }
+             /* Check name string */
+             TEST_ASSERT(strlen(pdesc->name) < header.name_size,
+                             "KVM stats name(%s) too long", pdesc->name);
+             /* Check size field, which should not be zero */
+             TEST_ASSERT(pdesc->size, "KVM descriptor(%s) with size of 0",
+                             pdesc->name);
+             size_data += pdesc->size * size_stat;
+     }
+     /* Check overlap */
+     TEST_ASSERT(header.data_offset >= header.desc_offset
+                     || header.data_offset + size_data <= header.desc_offset,
+                     "Data block is overlapped with Descriptor block");
+     /* Check validity of all stats data size */
+     TEST_ASSERT(size_data >= header.count * size_stat,
+                     "Data size is not correct");
+
+     /* Allocate memory for stats data */
+     stats_data = malloc(size_data);
+     TEST_ASSERT(stats_data, "Allocate memory for stats data");
+     /* Read kvm stats data as a bulk */
+     ret = pread(stats_fd, stats_data, size_data, header.data_offset);
+     TEST_ASSERT(ret == size_data, "Read KVM stats data");
+     /* Read kvm stats data one by one */
+     size_data = 0;
+     for (i = 0; i < header.count; ++i) {
+             pdesc = (void *)stats_desc + i * size_desc;
+             ret = pread(stats_fd, stats_data, pdesc->size * size_stat,
+                             header.data_offset + size_data);
+             TEST_ASSERT(ret == pdesc->size * size_stat,
+                             "Read data of KVM stats: %s", pdesc->name);
+             size_data += pdesc->size * size_stat;
+     }
+
+     free(stats_data);
+     free(stats_desc);
+     return 0;
+}
+
+
+int vm_stats_test(struct kvm_vm *vm)
+{
+     int stats_fd;
+     struct kvm_vm_stats_data *stats_data;
+
+     /* Get fd for VM stats */
+     stats_fd = vm_get_statsfd(vm);
+     TEST_ASSERT(stats_fd >= 0, "Get VM stats fd");
+
+     stats_test(stats_fd, sizeof(stats_data->value[0]));
+     close(stats_fd);
+
+     return 0;
+}
+
+int vcpu_stats_test(struct kvm_vm *vm, int vcpu_id)
+{
+     int stats_fd;
+     struct kvm_vcpu_stats_data *stats_data;
+
+     /* Get fd for VCPU stats */
+     stats_fd = vcpu_get_statsfd(vm, vcpu_id);
+     TEST_ASSERT(stats_fd >= 0, "Get VCPU stats fd");
+
+     stats_test(stats_fd, sizeof(stats_data->value[0]));
+     close(stats_fd);
+
+     return 0;
+}
+
+#define DEFAULT_NUM_VM               4
+#define DEFAULT_NUM_VCPU     4
+
+/*
+ * Usage: kvm_bin_form_stats [#vm] [#vcpu]
+ * The first parameter #vm set the number of VMs being created.
+ * The second parameter #vcpu set the number of VCPUs being created.
+ * By default, DEFAULT_NUM_VM VM and DEFAULT_NUM_VCPU VCPU for the VM would be
+ * created for testing.
+ */
+
+int main(int argc, char *argv[])
+{
+     int max_vm = DEFAULT_NUM_VM, max_vcpu = DEFAULT_NUM_VCPU, ret, i, j;
+     struct kvm_vm **vms;
+
+     /* Get the number of VMs and VCPUs that would be created for testing. */
+     if (argc > 1) {
+             max_vm = strtol(argv[1], NULL, 0);
+             if (max_vm <= 0)
+                     max_vm = DEFAULT_NUM_VM;
+     }
+     if (argc > 2) {
+             max_vcpu = strtol(argv[2], NULL, 0);
+             if (max_vcpu <= 0)
+                     max_vcpu = DEFAULT_NUM_VCPU;
+     }
+
+     /* Check the extension for binary stats */
+     ret = kvm_check_cap(KVM_CAP_STATS_BINARY_FD);
+     TEST_ASSERT(ret >= 0,
+                     "Binary form statistics interface is not supported");
+
+     /* Create VMs and VCPUs */
+     vms = malloc(sizeof(vms[0]) * max_vm);
+     TEST_ASSERT(vms, "Allocate memory for storing VM pointers");
+     for (i = 0; i < max_vm; ++i) {
+             vms[i] = vm_create(VM_MODE_DEFAULT,
+                             DEFAULT_GUEST_PHY_PAGES, O_RDWR);
+             for (j = 0; j < max_vcpu; ++j)
+                     vm_vcpu_add(vms[i], j);
+     }
+
+     /* Check stats read for every VM and VCPU */
+     for (i = 0; i < max_vm; ++i) {
+             vm_stats_test(vms[i]);
+             for (j = 0; j < max_vcpu; ++j)
+                     vcpu_stats_test(vms[i], j);
+     }
+

Does it make sense to add one more test case here to test this fd
interface on a VM or on a VCPU that has been deleted ? For example, how
does this fd interface behave if we delete the 4th VM and the 4th VCPU
in the 3rd VM ?

If you meant to test the behavior when we are trying to access a
invalid fd which belongs
to a VM or VCPU that doesn't exist, that's a good idea. I will add a
test for that. thanks.

quoted

+     for (i = 0; i < max_vm; ++i)
+             kvm_vm_free(vms[i]);
+     free(vms);
+     return 0;
+}

diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index fc83f6c5902d..d9e0b2c8b906 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c

@@ -2090,3 +2090,15 @@ unsigned int vm_calc_num_guest_pages(enum vm_guest_mode mode, size_t size)
      n = DIV_ROUND_UP(size, vm_guest_mode_params[mode].page_size);
      return vm_adjust_num_guest_pages(mode, n);
  }
+
+int vm_get_statsfd(struct kvm_vm *vm)
+{
+     return ioctl(vm->fd, KVM_STATS_GETFD, NULL);
+}
+
+int vcpu_get_statsfd(struct kvm_vm *vm, uint32_t vcpuid)
+{
+     struct vcpu *vcpu = vcpu_find(vm, vcpuid);
+
+     return ioctl(vcpu->fd, KVM_STATS_GETFD, NULL);
+}

Do we need separate functions if they are called just once ?  Or perhaps
have a single function for the ioctl call, like ?

      int get_stats_fd(int fd, int type)

      {

             return ioctl(fd, type, NULL);

      }

I guess two separate functions are more clear, one function does one thing.

Thanks,
Jing