[PATCH 126/128] KVM: selftests: Move per-VM/per-vCPU nr pages calculation to __vm_create()

Sean Christopherson
2022-05-04T23:07:42Z

Handle all memslot0 size adjustments in __vm_create(). Currently, the
adjustments reside in __vm_create_with_vcpus(), which means tests that
call vm_create() or __vm_create() directly are left to their own devices.
Some tests just pass DEFAULT_GUEST_PHY_PAGES and don't bother with any
adjustments, while others mimic the per-vCPU calculations.

For vm_create(), and thus __vm_create(), take the number of vCPUs that
will be runnable to calculate that number of per-vCPU pages needed for
memslot0. To give readers a hint that neither vm_create() nor
__vm_create() create vCPUs, name the parameter @nr_runnable_vcpus instead
of @nr_vcpus. That also gives readers a hint as to why tests that create
larger numbers of vCPUs but never actually run those vCPUs can skip
straight to the vm_create_barebones() variant.

Signed-off-by: Sean Christopherson <seanjc@google.com>
---
.../selftests/kvm/aarch64/psci_cpu_on_test.c | 2 +-
.../testing/selftests/kvm/aarch64/vgic_init.c | 4 +-
tools/testing/selftests/kvm/dirty_log_test.c | 3 +-
.../selftests/kvm/hardware_disable_test.c | 2 +-
.../selftests/kvm/include/kvm_util_base.h | 9 ++-
tools/testing/selftests/kvm/lib/kvm_util.c | 56 ++++++++++++-------
tools/testing/selftests/kvm/s390x/resets.c | 2 +-
.../kvm/x86_64/pmu_event_filter_test.c | 2 +-
.../selftests/kvm/x86_64/set_boot_cpu_id.c | 5 +-
.../selftests/kvm/x86_64/tsc_scaling_sync.c | 2 +-
10 files changed, 52 insertions(+), 35 deletions(-)

diff --git a/tools/testing/selftests/kvm/aarch64/psci_cpu_on_test.c b/tools/testing/selftests/kvm/aarch64/psci_cpu_on_test.c
index 3ed8dcbd4227..844268d5deab 100644
--- a/tools/testing/selftests/kvm/aarch64/psci_cpu_on_test.c
+++ b/tools/testing/selftests/kvm/aarch64/psci_cpu_on_test.c
@@ -74,7 +74,7 @@ int main(void)
struct kvm_vm *vm;
struct ucall uc;

- vm = vm_create(DEFAULT_GUEST_PHY_PAGES);
+ vm = vm_create(2);
ucall_init(vm, NULL);

vm_ioctl(vm, KVM_ARM_PREFERRED_TARGET, &init);
diff --git a/tools/testing/selftests/kvm/aarch64/vgic_init.c b/tools/testing/selftests/kvm/aarch64/vgic_init.c
index 7ee10f02d4bf..56b76fbfffea 100644
--- a/tools/testing/selftests/kvm/aarch64/vgic_init.c
+++ b/tools/testing/selftests/kvm/aarch64/vgic_init.c
@@ -403,7 +403,7 @@ static void test_v3_typer_accesses(void)
uint32_t val;
int ret, i;

- v.vm = vm_create(DEFAULT_GUEST_PHY_PAGES);
+ v.vm = vm_create(NR_VCPUS);
(void)vm_vcpu_add(v.vm, 0, guest_code);

v.gic_fd = kvm_create_device(v.vm, KVM_DEV_TYPE_ARM_VGIC_V3);
@@ -472,7 +472,7 @@ static struct vm_gic vm_gic_v3_create_with_vcpuids(int nr_vcpus,
struct vm_gic v;
int i;

- v.vm = vm_create(DEFAULT_GUEST_PHY_PAGES);
+ v.vm = vm_create(nr_vcpus);
for (i = 0; i < nr_vcpus; i++)
vm_vcpu_add(v.vm, vcpuids[i], guest_code);

diff --git a/tools/testing/selftests/kvm/dirty_log_test.c b/tools/testing/selftests/kvm/dirty_log_test.c
index 64d05fe8157b..e13cb007007b 100644
--- a/tools/testing/selftests/kvm/dirty_log_test.c
+++ b/tools/testing/selftests/kvm/dirty_log_test.c
@@ -672,11 +672,10 @@ static struct kvm_vm *create_vm(enum vm_guest_mode mode, struct kvm_vcpu **vcpu,
uint64_t extra_mem_pages, void *guest_code)
{
struct kvm_vm *vm;
- uint64_t extra_pg_pages = extra_mem_pages / 512 * 2;

pr_info("Testing guest mode: %s\n", vm_guest_mode_string(mode));

- vm = __vm_create(mode, DEFAULT_GUEST_PHY_PAGES + extra_pg_pages);
+ vm = __vm_create(mode, 1, extra_mem_pages);

log_mode_create_vm_done(vm);
*vcpu = vm_vcpu_add(vm, 0, guest_code);
diff --git a/tools/testing/selftests/kvm/hardware_disable_test.c b/tools/testing/selftests/kvm/hardware_disable_test.c
index f5eecd51fe70..5d58e52dc382 100644
--- a/tools/testing/selftests/kvm/hardware_disable_test.c
+++ b/tools/testing/selftests/kvm/hardware_disable_test.c
@@ -98,7 +98,7 @@ static void run_test(uint32_t run)
for (i = 0; i < VCPU_NUM; i++)
CPU_SET(i, &cpu_set);

- vm = vm_create(DEFAULT_GUEST_PHY_PAGES);
+ vm = vm_create(VCPU_NUM);

pr_debug("%s: [%d] start vcpus\n", __func__, run);
for (i = 0; i < VCPU_NUM; ++i) {
diff --git a/tools/testing/selftests/kvm/include/kvm_util_base.h b/tools/testing/selftests/kvm/include/kvm_util_base.h
index b9c806982dbd..527f63a30668 100644
--- a/tools/testing/selftests/kvm/include/kvm_util_base.h
+++ b/tools/testing/selftests/kvm/include/kvm_util_base.h
@@ -528,18 +528,21 @@ vm_paddr_t vm_alloc_page_table(struct kvm_vm *vm);
/*
* ____vm_create() does KVM_CREATE_VM and little else. __vm_create() also
* loads the test binary into guest memory and creates an IRQ chip (x86 only).
+ * __vm_create() does NOT create vCPUs, @nr_runnable_vcpus is used purely to
+ * calculate the amount of memory needed for per-vCPU data, e.g. stacks.
*/
struct kvm_vm *____vm_create(enum vm_guest_mode mode, uint64_t nr_pages);
-struct kvm_vm *__vm_create(enum vm_guest_mode mode, uint64_t nr_pages);
+struct kvm_vm *__vm_create(enum vm_guest_mode mode, uint32_t nr_runnable_vcpus,
+ uint64_t nr_extra_pages);

static inline struct kvm_vm *vm_create_barebones(void)
{
return ____vm_create(VM_MODE_DEFAULT, 0);
}

-static inline struct kvm_vm *vm_create(uint64_t nr_pages)
+static inline struct kvm_vm *vm_create(uint32_t nr_runnable_vcpus)
{
- return __vm_create(VM_MODE_DEFAULT, nr_pages);
+ return __vm_create(VM_MODE_DEFAULT, nr_runnable_vcpus, 0);
}

struct kvm_vm *__vm_create_with_vcpus(enum vm_guest_mode mode, uint32_t nr_vcpus,
diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index a8bbafc67d97..f4bd4d7559b9 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -262,12 +262,45 @@ struct kvm_vm *____vm_create(enum vm_guest_mode mode, uint64_t nr_pages)
return vm;
}

-struct kvm_vm *__vm_create(enum vm_guest_mode mode, uint64_t nr_pages)
+static uint64_t vm_nr_pages_required(uint32_t nr_runnable_vcpus,
+ uint64_t extra_mem_pages)
{
+ uint64_t nr_pages;
+
+ TEST_ASSERT(nr_runnable_vcpus,
+ "Use vm_create_barebones() for VMs that _never_ have vCPUs\n");
+
+ TEST_ASSERT(nr_runnable_vcpus <= kvm_check_cap(KVM_CAP_MAX_VCPUS),
+ "nr_vcpus = %d too large for host, max-vcpus = %d",
+ nr_runnable_vcpus, kvm_check_cap(KVM_CAP_MAX_VCPUS));
+
+ nr_pages = DEFAULT_GUEST_PHY_PAGES;
+ nr_pages += nr_runnable_vcpus * DEFAULT_STACK_PGS;
+
+ /*
+ * Account for the number of pages needed for the page tables. The
+ * maximum page table size for a memory region will be when the
+ * smallest page size is used. Considering each page contains x page
+ * table descriptors, the total extra size for page tables (for extra
+ * N pages) will be: N/x+N/x^2+N/x^3+... which is definitely smaller
+ * than N/x*2.
+ */
+ nr_pages += (nr_pages + extra_mem_pages) / PTES_PER_MIN_PAGE * 2;
+
+ TEST_ASSERT(nr_runnable_vcpus <= kvm_check_cap(KVM_CAP_MAX_VCPUS),
+ "Host doesn't support %d vCPUs, max-vcpus = %d",
+ nr_runnable_vcpus, kvm_check_cap(KVM_CAP_MAX_VCPUS));
+
+ return vm_adjust_num_guest_pages(VM_MODE_DEFAULT, nr_pages);
+}
+
+struct kvm_vm *__vm_create(enum vm_guest_mode mode, uint32_t nr_runnable_vcpus,
+ uint64_t nr_extra_pages)
+{
+ uint64_t nr_pages = vm_nr_pages_required(nr_runnable_vcpus,
+ nr_extra_pages);
struct kvm_vm *vm;

- nr_pages = vm_adjust_num_guest_pages(VM_MODE_DEFAULT, nr_pages);
-
vm = ____vm_create(mode, nr_pages);

kvm_vm_elf_load(vm, program_invocation_name);
@@ -301,27 +334,12 @@ struct kvm_vm *__vm_create_with_vcpus(enum vm_guest_mode mode, uint32_t nr_vcpus
uint64_t extra_mem_pages,
void *guest_code, struct kvm_vcpu *vcpus[])
{
- uint64_t vcpu_pages, extra_pg_pages, pages;
struct kvm_vm *vm;
int i;

TEST_ASSERT(!nr_vcpus || vcpus, "Must provide vCPU array");

- /* The maximum page table size for a memory region will be when the
- * smallest pages are used. Considering each page contains x page
- * table descriptors, the total extra size for page tables (for extra
- * N pages) will be: N/x+N/x^2+N/x^3+... which is definitely smaller
- * than N/x*2.
- */
- vcpu_pages = nr_vcpus * DEFAULT_STACK_PGS;
- extra_pg_pages = (DEFAULT_GUEST_PHY_PAGES + extra_mem_pages + vcpu_pages) / PTES_PER_MIN_PAGE * 2;
- pages = DEFAULT_GUEST_PHY_PAGES + vcpu_pages + extra_pg_pages;
-
- 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(mode, pages);
+ vm = __vm_create(mode, nr_vcpus, extra_mem_pages);

for (i = 0; i < nr_vcpus; ++i)
vcpus[i] = vm_vcpu_add(vm, i, guest_code);
diff --git a/tools/testing/selftests/kvm/s390x/resets.c b/tools/testing/selftests/kvm/s390x/resets.c
index a06ed20670fe..d95f57c46aad 100644
--- a/tools/testing/selftests/kvm/s390x/resets.c
+++ b/tools/testing/selftests/kvm/s390x/resets.c
@@ -208,7 +208,7 @@ static struct kvm_vm *create_vm(struct kvm_vcpu **vcpu)
{
struct kvm_vm *vm;

- vm = vm_create(DEFAULT_GUEST_PHY_PAGES);
+ vm = vm_create(1);

*vcpu = vm_vcpu_add(vm, ARBITRARY_NON_ZERO_VCPU_ID, guest_code_initial);

diff --git a/tools/testing/selftests/kvm/x86_64/pmu_event_filter_test.c b/tools/testing/selftests/kvm/x86_64/pmu_event_filter_test.c
index 592ff0304180..d438bcdf4378 100644
--- a/tools/testing/selftests/kvm/x86_64/pmu_event_filter_test.c
+++ b/tools/testing/selftests/kvm/x86_64/pmu_event_filter_test.c
@@ -340,7 +340,7 @@ static void test_pmu_config_disable(void (*guest_code)(void))
if (!(r & KVM_PMU_CAP_DISABLE))
return;

- vm = vm_create(DEFAULT_GUEST_PHY_PAGES);
+ vm = vm_create(1);

cap.cap = KVM_CAP_PMU_CAPABILITY;
cap.args[0] = KVM_PMU_CAP_DISABLE;
diff --git a/tools/testing/selftests/kvm/x86_64/set_boot_cpu_id.c b/tools/testing/selftests/kvm/x86_64/set_boot_cpu_id.c
index afc063178c6a..8bcaf4421dc5 100644
--- a/tools/testing/selftests/kvm/x86_64/set_boot_cpu_id.c
+++ b/tools/testing/selftests/kvm/x86_64/set_boot_cpu_id.c
@@ -78,13 +78,10 @@ static void run_vcpu(struct kvm_vcpu *vcpu)
static struct kvm_vm *create_vm(uint32_t nr_vcpus, uint32_t bsp_vcpu_id,
struct kvm_vcpu *vcpus[])
{
- uint64_t vcpu_pages = (DEFAULT_STACK_PGS) * nr_vcpus;
- uint64_t extra_pg_pages = vcpu_pages / PTES_PER_MIN_PAGE * nr_vcpus;
- uint64_t pages = DEFAULT_GUEST_PHY_PAGES + vcpu_pages + extra_pg_pages;
struct kvm_vm *vm;
uint32_t i;

- vm = vm_create(pages);
+ vm = vm_create(nr_vcpus);

vm_ioctl(vm, KVM_SET_BOOT_CPU_ID, (void *)(unsigned long)bsp_vcpu_id);

diff --git a/tools/testing/selftests/kvm/x86_64/tsc_scaling_sync.c b/tools/testing/selftests/kvm/x86_64/tsc_scaling_sync.c
index e416af887ca0..4a962952212e 100644
--- a/tools/testing/selftests/kvm/x86_64/tsc_scaling_sync.c
+++ b/tools/testing/selftests/kvm/x86_64/tsc_scaling_sync.c
@@ -98,7 +98,7 @@ int main(int argc, char *argv[])
exit(KSFT_SKIP);
}

- vm = vm_create(DEFAULT_GUEST_PHY_PAGES + DEFAULT_STACK_PGS * NR_TEST_VCPUS);
+ vm = vm_create(NR_TEST_VCPUS);
vm_ioctl(vm, KVM_SET_TSC_KHZ, (void *) TEST_TSC_KHZ);

pthread_spin_init(&create_lock, PTHREAD_PROCESS_PRIVATE);
--
2.36.0.464.gb9c8b46e94-goog