[PATCH 13/15] KVM: selftests: Sync perf_test_args to guest during VM creation

[Sean Christopherson]

Copy perf_test_args to the guest during VM creation instead of relying on
the caller to do so at their leisure.  Ideally, tests wouldn't even be
able to modify perf_test_args, i.e. they would have no motivation to do
the sync, but enforcing that is arguably a net negative for readability.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
 tools/testing/selftests/kvm/demand_paging_test.c           | 7 +------
 tools/testing/selftests/kvm/dirty_log_perf_test.c          | 6 +-----
 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       | 7 +------
 5 files changed, 10 insertions(+), 17 deletions(-)

diff --git a/tools/testing/selftests/kvm/demand_paging_test.c b/tools/testing/selftests/kvm/demand_paging_test.c
index 00f2c795b68d..d06ff8f37c53 100644
--- a/tools/testing/selftests/kvm/demand_paging_test.c
+++ b/tools/testing/selftests/kvm/demand_paging_test.c
@@ -267,11 +267,9 @@ static void run_test(enum vm_guest_mode mode, void *arg)
 	int r;
 
 	vm = perf_test_create_vm(mode, nr_vcpus, guest_percpu_mem_size,
-				 VM_MEM_SRC_ANONYMOUS,
+				 VM_MEM_SRC_ANONYMOUS, 1,
 				 p->partition_vcpu_memory_access);
 
-	perf_test_args.wr_fract = 1;
-
 	guest_data_prototype = malloc(getpagesize());
 	TEST_ASSERT(guest_data_prototype,
 		    "Failed to allocate buffer for guest data pattern");
@@ -319,9 +317,6 @@ static void run_test(enum vm_guest_mode mode, void *arg)
 		}
 	}
 
-	/* Export the shared variables to the guest */
-	sync_global_to_guest(vm, perf_test_args);
-
 	pr_info("Finished creating vCPUs and starting uffd threads\n");
 
 	clock_gettime(CLOCK_MONOTONIC, &start);
diff --git a/tools/testing/selftests/kvm/dirty_log_perf_test.c b/tools/testing/selftests/kvm/dirty_log_perf_test.c
index 2c809452eac1..9ab24bf50c60 100644
--- a/tools/testing/selftests/kvm/dirty_log_perf_test.c
+++ b/tools/testing/selftests/kvm/dirty_log_perf_test.c
@@ -114,11 +114,9 @@ static void run_test(enum vm_guest_mode mode, void *arg)
 	struct timespec clear_dirty_log_total = (struct timespec){0};
 
 	vm = perf_test_create_vm(mode, nr_vcpus, guest_percpu_mem_size,
-				 p->backing_src,
+				 p->backing_src, p->wr_fract,
 				 p->partition_vcpu_memory_access);
 
-	perf_test_args.wr_fract = p->wr_fract;
-
 	guest_num_pages = (nr_vcpus * guest_percpu_mem_size) >> vm_get_page_shift(vm);
 	guest_num_pages = vm_adjust_num_guest_pages(mode, guest_num_pages);
 	host_num_pages = vm_num_host_pages(mode, guest_num_pages);
@@ -133,8 +131,6 @@ static void run_test(enum vm_guest_mode mode, void *arg)
 	vcpu_threads = malloc(nr_vcpus * sizeof(*vcpu_threads));
 	TEST_ASSERT(vcpu_threads, "Memory allocation failed");
 
-	sync_global_to_guest(vm, perf_test_args);
-
 	/* Start the iterations */
 	iteration = 0;
 	host_quit = false;
diff --git a/tools/testing/selftests/kvm/include/perf_test_util.h b/tools/testing/selftests/kvm/include/perf_test_util.h
index 3a21e82a0173..330e528f206f 100644
--- a/tools/testing/selftests/kvm/include/perf_test_util.h
+++ b/tools/testing/selftests/kvm/include/perf_test_util.h
@@ -40,6 +40,7 @@ extern struct perf_test_args perf_test_args;
 struct kvm_vm *perf_test_create_vm(enum vm_guest_mode mode, int vcpus,
 				   uint64_t vcpu_memory_bytes,
 				   enum vm_mem_backing_src_type backing_src,
+				   int wr_fract,
 				   bool partition_vcpu_memory_access);
 void perf_test_destroy_vm(struct kvm_vm *vm);
 
diff --git a/tools/testing/selftests/kvm/lib/perf_test_util.c b/tools/testing/selftests/kvm/lib/perf_test_util.c
index 3aa99365726b..6f41fe2685cb 100644
--- a/tools/testing/selftests/kvm/lib/perf_test_util.c
+++ b/tools/testing/selftests/kvm/lib/perf_test_util.c
@@ -85,6 +85,7 @@ static void perf_test_setup_vcpus(struct kvm_vm *vm, int vcpus,
 struct kvm_vm *perf_test_create_vm(enum vm_guest_mode mode, int vcpus,
 				   uint64_t vcpu_memory_bytes,
 				   enum vm_mem_backing_src_type backing_src,
+				   int wr_fract,
 				   bool partition_vcpu_memory_access)
 {
 	struct perf_test_args *pta = &perf_test_args;
@@ -93,6 +94,8 @@ 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->wr_fract = wr_fract;
+
 	/*
 	 * Snapshot the non-huge page size.  This is used by the guest code to
 	 * access/dirty pages at the logging granularity.
@@ -148,6 +151,9 @@ struct kvm_vm *perf_test_create_vm(enum vm_guest_mode mode, int vcpus,
 
 	ucall_init(vm, NULL);
 
+	/* Export the shared variables to the guest */
+	sync_global_to_guest(vm, perf_test_args);
+
 	return vm;
 }
 
diff --git a/tools/testing/selftests/kvm/memslot_modification_stress_test.c b/tools/testing/selftests/kvm/memslot_modification_stress_test.c
index 949822833b6b..5ea9d7ef248e 100644
--- a/tools/testing/selftests/kvm/memslot_modification_stress_test.c
+++ b/tools/testing/selftests/kvm/memslot_modification_stress_test.c
@@ -98,17 +98,12 @@ static void run_test(enum vm_guest_mode mode, void *arg)
 	int vcpu_id;
 
 	vm = perf_test_create_vm(mode, nr_vcpus, guest_percpu_mem_size,
-				 VM_MEM_SRC_ANONYMOUS,
+				 VM_MEM_SRC_ANONYMOUS, 1,
 				 p->partition_vcpu_memory_access);
 
-	perf_test_args.wr_fract = 1;
-
 	vcpu_threads = malloc(nr_vcpus * sizeof(*vcpu_threads));
 	TEST_ASSERT(vcpu_threads, "Memory allocation failed");
 
-	/* Export the shared variables to the guest */
-	sync_global_to_guest(vm, perf_test_args);
-
 	pr_info("Finished creating vCPUs\n");
 
 	for (vcpu_id = 0; vcpu_id < nr_vcpus; vcpu_id++)
-- 
2.30.0.478.g8a0d178c01-goog