[PATCH v2 2/5] KVM: selftests: memstress: Add option to enable dirty-ring on VM creation

[Leonardo Bras]

Dirty-ring should be enabled after the VM is created, but before the
creation of any cpu. To to so, add an option on memstress_create_vm() that
takes dirty-ring size, and enables it at the correct moment.

This required a new function memstress_vm_create_with_vcpus() to be
created based on the previously used __vm_create_with_vcpus();

Signed-off-by: Leonardo Bras <leo.bras@xxxxxxx>
---
 .../testing/selftests/kvm/include/memstress.h |  1 +
 tools/testing/selftests/kvm/lib/memstress.c   | 27 +++++++++++++++----
 2 files changed, 23 insertions(+), 5 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/memstress.h b/tools/testing/selftests/kvm/include/memstress.h
index cea2062e1dcb..465edf0da8f3 100644
--- a/tools/testing/selftests/kvm/include/memstress.h
+++ b/tools/testing/selftests/kvm/include/memstress.h
@@ -53,20 +53,21 @@ struct memstress_args {
 	struct memstress_vcpu_args vcpu_args[KVM_MAX_VCPUS];
 };
 
 struct memstress_params {
 	enum vm_guest_mode mode;
 	int nr_vcpus;
 	u64 vcpu_memory_bytes;
 	int slots;
 	enum vm_mem_backing_src_type backing_src;
 	bool partition_vcpu_memory_access;
+	u32 dirty_ring_size;
 };
 
 extern struct memstress_args memstress_args;
 
 struct kvm_vm *memstress_create_vm(struct memstress_params *params);
 void memstress_destroy_vm(struct kvm_vm *vm);
 
 void memstress_set_write_percent(struct kvm_vm *vm, u32 write_percent);
 void memstress_set_random_access(struct kvm_vm *vm, bool random_access);
 
diff --git a/tools/testing/selftests/kvm/lib/memstress.c b/tools/testing/selftests/kvm/lib/memstress.c
index 880657df65e9..b1f13499e85f 100644
--- a/tools/testing/selftests/kvm/lib/memstress.c
+++ b/tools/testing/selftests/kvm/lib/memstress.c
@@ -114,20 +114,41 @@ void memstress_setup_vcpus(struct kvm_vm *vm, int nr_vcpus,
 		}
 
 		vcpu_args_set(vcpus[i], 1, i);
 
 		pr_debug("Added VCPU %d with test mem gpa [%lx, %lx)\n",
 			 i, vcpu_args->gpa, vcpu_args->gpa +
 			 (vcpu_args->pages * args->guest_page_size));
 	}
 }
 
+static struct kvm_vm *memstress_vm_create_with_vcpus(struct memstress_params *params,
+						     u64 extra_mem_pages)
+{
+	struct kvm_vm *vm;
+	int i;
+
+	TEST_ASSERT(params->nr_vcpus > 0, "Invalid number of vCPUs (%d)",
+		    params->nr_vcpus);
+
+	vm = __vm_create(VM_SHAPE(params->mode), params->nr_vcpus, extra_mem_pages);
+
+	if (params->dirty_ring_size)
+		vm_enable_dirty_ring(vm, params->dirty_ring_size);
+
+	for (i = 0; i < params->nr_vcpus; ++i)
+		vcpus[i] = vm_vcpu_add(vm, i, memstress_guest_code);
+
+	kvm_arch_vm_finalize_vcpus(vm);
+	return vm;
+}
+
 struct kvm_vm *memstress_create_vm(struct memstress_params *params)
 {
 	struct memstress_args *args = &memstress_args;
 	struct kvm_vm *vm;
 	u64 guest_num_pages, slot0_pages = 0;
 	u64 backing_src_pagesz = get_backing_src_pagesz(params->backing_src);
 	u64 region_end_gfn;
 	int i;
 
 	pr_info("Testing guest mode: %s\n", vm_guest_mode_string(params->mode));
@@ -158,25 +179,21 @@ struct kvm_vm *memstress_create_vm(struct memstress_params *params)
 	 * in-memory data structures.
 	 */
 	if (args->nested)
 		slot0_pages += memstress_nested_pages(params->nr_vcpus);
 
 	/*
 	 * Pass guest_num_pages to populate the page tables for test memory.
 	 * The memory is also added to memslot 0, but that's a benign side
 	 * effect as KVM allows aliasing HVAs in meslots.
 	 */
-	vm = __vm_create_with_vcpus(VM_SHAPE(params->mode),
-				    params->nr_vcpus,
-				    slot0_pages + guest_num_pages,
-				    memstress_guest_code, vcpus);
-
+	vm = memstress_vm_create_with_vcpus(params, slot0_pages + guest_num_pages);
 	args->vm = vm;
 
 	/* Put the test region at the top guest physical memory. */
 	region_end_gfn = vm->max_gfn + 1;
 
 #ifdef __x86_64__
 	/*
 	 * When running vCPUs in L2, restrict the test region to 48 bits to
 	 * avoid needing 5-level page tables to identity map L2.
 	 */
-- 
2.55.0