KVM: selftests: Introduce vm_create_[default_]_with_vcpus

Introduce new vm_create variants that also takes a number of vcpus,
an amount of per-vcpu pages, and optionally a list of vcpuids. These
variants will create default VMs with enough additional pages to
cover the vcpu stacks, per-vcpu pages, and pagetable pages for all.
The new 'default' variant uses VM_MODE_DEFAULT, whereas the other
new variant accepts the mode as a parameter.
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Ben Gardon <bgardon@google.com>
Signed-off-by: Andrew Jones <drjones@redhat.com>
Message-Id: <20201111122636.73346-6-drjones@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

tools/testing/selftests/kvm/include/kvm_util.h

@@ -266,6 +266,16 @@ vm_paddr_t vm_phy_pages_alloc(struct kvm_vm *vm, size_t num,
 struct kvm_vm *vm_create_default(uint32_t vcpuid, uint64_t extra_mem_pages,
 				 void *guest_code);
 
+/* Same as vm_create_default, but can be used for more than one vcpu */
+struct kvm_vm *vm_create_default_with_vcpus(uint32_t nr_vcpus, uint64_t extra_mem_pages,
+					    uint32_t num_percpu_pages, void *guest_code,
+					    uint32_t vcpuids[]);
+
+/* Like vm_create_default_with_vcpus, but accepts mode as a parameter */
+struct kvm_vm *vm_create_with_vcpus(enum vm_guest_mode mode, uint32_t nr_vcpus,
+				    uint64_t extra_mem_pages, uint32_t num_percpu_pages,
+				    void *guest_code, uint32_t vcpuids[]);
+
 /*
  * Adds a vCPU with reasonable defaults (e.g. a stack)
  *

tools/testing/selftests/kvm/lib/kvm_util.c

@@ -282,8 +282,9 @@ struct kvm_vm *vm_create(enum vm_guest_mode mode, uint64_t phy_pages, int perm)
 	return vm;
 }
 
-struct kvm_vm *vm_create_default(uint32_t vcpuid, uint64_t extra_mem_pages,
-				 void *guest_code)
+struct kvm_vm *vm_create_with_vcpus(enum vm_guest_mode mode, uint32_t nr_vcpus,
+				    uint64_t extra_mem_pages, uint32_t num_percpu_pages,
+				    void *guest_code, uint32_t vcpuids[])
 {
 	/* The maximum page table size for a memory region will be when the
 	 * smallest pages are used. Considering each page contains x page
@@ -291,10 +292,18 @@ struct kvm_vm *vm_create_default(uint32_t vcpuid, uint64_t extra_mem_pages,
 	 * N pages) will be: N/x+N/x^2+N/x^3+... which is definitely smaller
 	 * than N/x*2.
 	 */
-	uint64_t extra_pg_pages = (extra_mem_pages / PTES_PER_MIN_PAGE) * 2;
+	uint64_t vcpu_pages = (DEFAULT_STACK_PGS + num_percpu_pages) * nr_vcpus;
+	uint64_t extra_pg_pages = (extra_mem_pages + vcpu_pages) / PTES_PER_MIN_PAGE * 2;
+	uint64_t pages = DEFAULT_GUEST_PHY_PAGES + vcpu_pages + extra_pg_pages;
 	struct kvm_vm *vm;
+	int i;
+
+	TEST_ASSERT(nr_vcpus <= kvm_check_cap(KVM_CAP_MAX_VCPUS),
+		    "nr_vcpus = %d too large for host, max-vcpus = %d",
+		    nr_vcpus, kvm_check_cap(KVM_CAP_MAX_VCPUS));
 
-	vm = vm_create(VM_MODE_DEFAULT, DEFAULT_GUEST_PHY_PAGES + extra_pg_pages, O_RDWR);
+	pages = vm_adjust_num_guest_pages(mode, pages);
+	vm = vm_create(mode, pages, O_RDWR);
 
 	kvm_vm_elf_load(vm, program_invocation_name, 0, 0);
 
@@ -302,11 +311,27 @@ struct kvm_vm *vm_create_default(uint32_t vcpuid, uint64_t extra_mem_pages,
 	vm_create_irqchip(vm);
 #endif
 
-	vm_vcpu_add_default(vm, vcpuid, guest_code);
+	for (i = 0; i < nr_vcpus; ++i)
+		vm_vcpu_add_default(vm, vcpuids ? vcpuids[i] : i, guest_code);
 
 	return vm;
 }
 
+struct kvm_vm *vm_create_default_with_vcpus(uint32_t nr_vcpus, uint64_t extra_mem_pages,
+					    uint32_t num_percpu_pages, void *guest_code,
+					    uint32_t vcpuids[])
+{
+	return vm_create_with_vcpus(VM_MODE_DEFAULT, nr_vcpus, extra_mem_pages,
+				    num_percpu_pages, guest_code, vcpuids);
+}
+
+struct kvm_vm *vm_create_default(uint32_t vcpuid, uint64_t extra_mem_pages,
+				 void *guest_code)
+{
+	return vm_create_default_with_vcpus(1, extra_mem_pages, 0, guest_code,
+					    (uint32_t []){ vcpuid });
+}
+
 /*
  * VM Restart
  *