Re: [PATCH 10/15] KVM: selftests: Remove perf_test_args.host_page_size

[Ben Gardon <bgardon@google.com>]

On Wed, Feb 10, 2021 at 3:06 PM Sean Christopherson <seanjc@google.com> wrote:
>
> Remove perf_test_args.host_page_size and instead use getpagesize() so
> that it's somewhat obvious that, for tests that care about the host page
> size, they care about the system page size, not the hardware page size,
> e.g. that the logic is unchanged if hugepages are in play.
>
> No functional change intended.
>
> Signed-off-by: Sean Christopherson <seanjc@google.com>

Reviewed-by: Ben Gardon <bgardon@google.com>

> ---
>  tools/testing/selftests/kvm/demand_paging_test.c          | 8 ++++----
>  tools/testing/selftests/kvm/include/perf_test_util.h      | 1 -
>  tools/testing/selftests/kvm/lib/perf_test_util.c          | 6 ++----
>  .../selftests/kvm/memslot_modification_stress_test.c      | 2 +-
>  4 files changed, 7 insertions(+), 10 deletions(-)
>
> diff --git a/tools/testing/selftests/kvm/demand_paging_test.c b/tools/testing/selftests/kvm/demand_paging_test.c
> index 0cbf111e6c21..b937a65b0e6d 100644
> --- a/tools/testing/selftests/kvm/demand_paging_test.c
> +++ b/tools/testing/selftests/kvm/demand_paging_test.c
> @@ -83,7 +83,7 @@ static int handle_uffd_page_request(int uffd, uint64_t addr)
>
>         copy.src = (uint64_t)guest_data_prototype;
>         copy.dst = addr;
> -       copy.len = perf_test_args.host_page_size;
> +       copy.len = getpagesize();
>         copy.mode = 0;
>
>         clock_gettime(CLOCK_MONOTONIC, &start);
> @@ -100,7 +100,7 @@ static int handle_uffd_page_request(int uffd, uint64_t addr)
>         PER_PAGE_DEBUG("UFFDIO_COPY %d \t%ld ns\n", tid,
>                        timespec_to_ns(ts_diff));
>         PER_PAGE_DEBUG("Paged in %ld bytes at 0x%lx from thread %d\n",
> -                      perf_test_args.host_page_size, addr, tid);
> +                      getpagesize(), addr, tid);
>
>         return 0;
>  }
> @@ -271,10 +271,10 @@ static void run_test(enum vm_guest_mode mode, void *arg)
>
>         perf_test_args.wr_fract = 1;
>
> -       guest_data_prototype = malloc(perf_test_args.host_page_size);
> +       guest_data_prototype = malloc(getpagesize());
>         TEST_ASSERT(guest_data_prototype,
>                     "Failed to allocate buffer for guest data pattern");
> -       memset(guest_data_prototype, 0xAB, perf_test_args.host_page_size);
> +       memset(guest_data_prototype, 0xAB, getpagesize());
>
>         vcpu_threads = malloc(nr_vcpus * sizeof(*vcpu_threads));
>         TEST_ASSERT(vcpu_threads, "Memory allocation failed");
> diff --git a/tools/testing/selftests/kvm/include/perf_test_util.h b/tools/testing/selftests/kvm/include/perf_test_util.h
> index cccf1c44bddb..223fe6b79a04 100644
> --- a/tools/testing/selftests/kvm/include/perf_test_util.h
> +++ b/tools/testing/selftests/kvm/include/perf_test_util.h
> @@ -28,7 +28,6 @@ struct perf_test_vcpu_args {
>
>  struct perf_test_args {
>         struct kvm_vm *vm;
> -       uint64_t host_page_size;
>         uint64_t gpa;
>         uint64_t guest_page_size;
>         int wr_fract;
> diff --git a/tools/testing/selftests/kvm/lib/perf_test_util.c b/tools/testing/selftests/kvm/lib/perf_test_util.c
> index 03f125236021..982a86c8eeaa 100644
> --- a/tools/testing/selftests/kvm/lib/perf_test_util.c
> +++ b/tools/testing/selftests/kvm/lib/perf_test_util.c
> @@ -57,8 +57,6 @@ struct kvm_vm *perf_test_create_vm(enum vm_guest_mode mode, int vcpus,
>
>         pr_info("Testing guest mode: %s\n", vm_guest_mode_string(mode));
>
> -       pta->host_page_size = getpagesize();
> -
>         /*
>          * Snapshot the non-huge page size.  This is used by the guest code to
>          * access/dirty pages at the logging granularity.
> @@ -68,7 +66,7 @@ struct kvm_vm *perf_test_create_vm(enum vm_guest_mode mode, int vcpus,
>         guest_num_pages = vm_adjust_num_guest_pages(mode,
>                                 (vcpus * vcpu_memory_bytes) / pta->guest_page_size);
>
> -       TEST_ASSERT(vcpu_memory_bytes % pta->host_page_size == 0,
> +       TEST_ASSERT(vcpu_memory_bytes % getpagesize() == 0,
>                     "Guest memory size is not host page size aligned.");
>         TEST_ASSERT(vcpu_memory_bytes % pta->guest_page_size == 0,
>                     "Guest memory size is not guest page size aligned.");
> @@ -88,7 +86,7 @@ struct kvm_vm *perf_test_create_vm(enum vm_guest_mode mode, int vcpus,
>                     guest_num_pages, vm_get_max_gfn(vm), vcpus, vcpu_memory_bytes);
>
>         pta->gpa = (vm_get_max_gfn(vm) - guest_num_pages) * pta->guest_page_size;
> -       pta->gpa &= ~(pta->host_page_size - 1);
> +       pta->gpa &= ~(getpagesize() - 1);
>         if (backing_src == VM_MEM_SRC_ANONYMOUS_THP ||
>             backing_src == VM_MEM_SRC_ANONYMOUS_HUGETLB)
>                 pta->gpa &= ~(KVM_UTIL_HUGEPAGE_ALIGNMENT - 1);
> diff --git a/tools/testing/selftests/kvm/memslot_modification_stress_test.c b/tools/testing/selftests/kvm/memslot_modification_stress_test.c
> index 569bb1f55bdf..b3b8f08e91ad 100644
> --- a/tools/testing/selftests/kvm/memslot_modification_stress_test.c
> +++ b/tools/testing/selftests/kvm/memslot_modification_stress_test.c
> @@ -123,7 +123,7 @@ static void run_test(enum vm_guest_mode mode, void *arg)
>                            p->nr_memslot_modifications,
>                            perf_test_args.gpa +
>                            (guest_percpu_mem_size * nr_vcpus) +
> -                          perf_test_args.host_page_size +
> +                          getpagesize() +
>                            perf_test_args.guest_page_size);
>
>         run_vcpus = false;
> --
> 2.30.0.478.g8a0d178c01-goog
>