[RFC PATCH 08/10] KVM: selftests: Default private_mem_conversions_test to use 1 restrictedmem file for test data

[Ackerley Tng]

Default the private/shared memory conversion tests to use a single
file (when multiple memslots are requested), while executing on
multiple vCPUs in parallel, to stress-test the restrictedmem subsystem.

Also add a flag to allow multiple files to be used.

Signed-off-by: Ackerley Tng <ackerleytng@google.com>
---
 .../kvm/x86_64/private_mem_conversions_test.c | 52 ++++++++++++++-----
 1 file changed, 38 insertions(+), 14 deletions(-)

diff --git a/tools/testing/selftests/kvm/x86_64/private_mem_conversions_test.c 
b/tools/testing/selftests/kvm/x86_64/private_mem_conversions_test.c
index afaf8d0e52e6..ca30f0f05c39 100644
--- a/tools/testing/selftests/kvm/x86_64/private_mem_conversions_test.c
+++ b/tools/testing/selftests/kvm/x86_64/private_mem_conversions_test.c
@@ -324,7 +324,8 @@ void *thread_function(void *input)
 }
 
 static void add_memslot_for_vcpu(
-       struct kvm_vm *vm, enum vm_mem_backing_src_type src_type, uint8_t 
vcpu_id)
+       struct kvm_vm *vm, enum vm_mem_backing_src_type src_type, uint8_t 
vcpu_id,
+       int restrictedmem_fd, uint64_t restrictedmem_offset)
 {
        uint64_t gpa = data_gpa_base_for_vcpu_id(vcpu_id);
        uint32_t slot = DATA_SLOT_BASE + vcpu_id;
@@ -336,7 +337,8 @@ static void add_memslot_for_vcpu(
 
 static void test_mem_conversions(enum vm_mem_backing_src_type src_type,
                                 uint8_t nr_vcpus, uint32_t iterations,
-                                bool use_multiple_memslots)
+                                bool use_multiple_memslots,
+                                bool use_different_restrictedmem_files)
 {
        struct kvm_vcpu *vcpus[KVM_MAX_VCPUS];
        pthread_t threads[KVM_MAX_VCPUS];
@@ -356,21 +358,28 @@ static void test_mem_conversions(enum 
vm_mem_backing_src_type src_type,
        vm_enable_cap(vm, KVM_CAP_EXIT_HYPERCALL, (1 << KVM_HC_MAP_GPA_RANGE));
 
        npages_for_all_vcpus = DATA_SIZE / vm->page_size * nr_vcpus;
+       virt_map(vm, DATA_GPA_BASE, DATA_GPA_BASE, npages_for_all_vcpus);
 
        if (use_multiple_memslots) {
-               for (i = 0; i < nr_vcpus; i++)
-                       add_memslot_for_vcpu(vm, src_type, i);
+               int fd = memfd_restricted(0);
+               int offset = 0;
+
+               for (i = 0; i < nr_vcpus; i++) {
+                       if (use_different_restrictedmem_files) {
+                               if (i > 0)
+                                       fd = memfd_restricted(0);
+                       } else {
+                               offset = i * DATA_GPA_SPACING;
+                       }
+
+                       add_memslot_for_vcpu(vm, src_type, i, fd, offset);
+               }
        } else {
                vm_userspace_mem_region_add(
                        vm, src_type, DATA_GPA_BASE, DATA_SLOT_BASE,
                        npages_for_all_vcpus, KVM_MEM_PRIVATE);
        }
 
-       virt_map(vm, DATA_GPA_BASE, DATA_GPA_BASE, npages_for_all_vcpus);
-
-       for (i = 0; i < nr_vcpus; i++)
-               add_memslot_for_vcpu(vm, src_type, i);
-
        for (i = 0; i < nr_vcpus; i++) {
                args[i].vm = vm;
                args[i].vcpu = vcpus[i];
@@ -382,7 +391,7 @@ static void test_mem_conversions(enum 
vm_mem_backing_src_type src_type,
        for (i = 0; i < nr_vcpus; i++)
                pthread_join(threads[i], NULL);
 
-       if (!use_multiple_memslots)
+       if (!use_multiple_memslots || !use_different_restrictedmem_files)
                test_invalidation_code_unbound(vm, 1, DATA_SIZE * nr_vcpus);
        else
                test_invalidation_code_unbound(vm, nr_vcpus, DATA_SIZE);
@@ -391,8 +400,9 @@ static void test_mem_conversions(enum 
vm_mem_backing_src_type src_type,
 static void usage(const char *command)
 {
        puts("");
-       printf("usage: %s [-h] [-m] [-s mem-type] [-n number-of-vcpus] [-i 
number-of-iterations]\n",
-              command);
+       printf("usage: %s\n", command);
+       printf("       [-h] [-m] [-f] [-s mem-type]\n");
+       printf("       [-n number-of-vcpus] [-i number-of-iterations]\n");
        puts("");
        backing_src_help("-s");
        puts("");
@@ -404,6 +414,9 @@ static void usage(const char *command)
        puts("");
        puts(" -m: use multiple memslots (default: use 1 memslot)");
        puts("");
+       puts(" -f: use different restrictedmem files for each memslot");
+       puts("     (default: use 1 restrictedmem file for all memslots)");
+       puts("");
 }
 
 int main(int argc, char *argv[])
@@ -412,12 +425,13 @@ int main(int argc, char *argv[])
        uint8_t nr_vcpus = 2;
        uint32_t iterations = 10;
        bool use_multiple_memslots = false;
+       bool use_different_restrictedmem_files = false;
        int opt;
 
        TEST_REQUIRE(kvm_has_cap(KVM_CAP_EXIT_HYPERCALL));
        TEST_REQUIRE(kvm_check_cap(KVM_CAP_VM_TYPES) & 
BIT(KVM_X86_PROTECTED_VM));
 
-       while ((opt = getopt(argc, argv, "mhs:n:i:")) != -1) {
+       while ((opt = getopt(argc, argv, "fmhs:n:i:")) != -1) {
                switch (opt) {
                case 'n':
                        nr_vcpus = atoi_positive("nr_vcpus", optarg);
@@ -431,6 +445,9 @@ int main(int argc, char *argv[])
                case 'm':
                        use_multiple_memslots = true;
                        break;
+               case 'f':
+                       use_different_restrictedmem_files = true;
+                       break;
                case 'h':
                default:
                        usage(argv[0]);
@@ -438,6 +455,13 @@ int main(int argc, char *argv[])
                }
        }
 
-       test_mem_conversions(src_type, nr_vcpus, iterations, 
use_multiple_memslots);
+       if (!use_multiple_memslots && use_different_restrictedmem_files) {
+               printf("Overriding -f flag: ");
+               puts("Using just 1 restrictedmem file since only 1 memslot is 
to be used.");
+               use_different_restrictedmem_files = false;
+       }
+
+       test_mem_conversions(src_type, nr_vcpus, iterations, 
use_multiple_memslots,
+                            use_different_restrictedmem_files);
        return 0;
 }
-- 
2.40.0.rc2.332.ga46443480c-goog