// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2020, Google LLC.
*/
#include <inttypes.h>
#include <linux/bitmap.h>
#include "kvm_util.h"
#include "memstress.h"
#include "processor.h"
#include "ucall_common.h"
struct memstress_args memstress_args;
/*
* Guest virtual memory offset of the testing memory slot.
* Must not conflict with identity mapped test code.
*/
static uint64_t guest_test_virt_mem = DEFAULT_GUEST_TEST_MEM;
struct vcpu_thread {
/* The index of the vCPU. */
int vcpu_idx;
/* The pthread backing the vCPU. */
pthread_t thread;
/* Set to true once the vCPU thread is up and running. */
bool running;
};
/* The vCPU threads involved in this test. */
static struct vcpu_thread vcpu_threads[KVM_MAX_VCPUS];
/* The function run by each vCPU thread, as provided by the test. */
static void (*vcpu_thread_fn)(struct memstress_vcpu_args *);
/* Set to true once all vCPU threads are up and running. */
static bool all_vcpu_threads_running;
static struct kvm_vcpu *vcpus[KVM_MAX_VCPUS];
/*
* Continuously write to the first 8 bytes of each page in the
* specified region.
*/
void memstress_guest_code(uint32_t vcpu_idx)
{
struct memstress_args *args = &memstress_args;
struct memstress_vcpu_args *vcpu_args = &args->vcpu_args[vcpu_idx];
struct guest_random_state rand_state;
uint64_t gva;
uint64_t pages;
uint64_t addr;
uint64_t page;
int i;
rand_state = new_guest_random_state(guest_random_seed + vcpu_idx);
gva = vcpu_args->gva;
pages = vcpu_args->pages;
/* Make sure vCPU args data structure is not corrupt. */
GUEST_ASSERT(vcpu_args->vcpu_idx == vcpu_idx);
while (true) {
for (i = 0; i < sizeof(memstress_args); i += args->guest_page_size)
(void) *((volatile char *)args + i);
for (i = 0; i < pages; i++) {
if (args->random_access)
page = guest_random_u32(&rand_state) % pages;
else
page = i;
addr = gva + (page * args->guest_page_size);
if (__guest_random_bool(&rand_state, args->write_percent))
*(uint64_t *)addr = 0x0123456789ABCDEF;
else
READ_ONCE(*(uint64_t *)addr);
}
GUEST_SYNC(1);
}
}
void memstress_setup_vcpus(struct kvm_vm *vm, int nr_vcpus,
struct kvm_vcpu *vcpus[],
uint64_t vcpu_memory_bytes,
bool partition_vcpu_memory_access)
{
struct memstress_args *args = &memstress_args;
struct memstress_vcpu_args *vcpu_args;
int i;
for (i = 0; i < nr_vcpus; i++) {
vcpu_args = &args->vcpu_args[i];
vcpu_args->vcpu = vcpus[i];
vcpu_args->vcpu_idx = i;
if (partition_vcpu_memory_access) {
vcpu_args->gva = guest_test_virt_mem +
(i * vcpu_memory_bytes);
vcpu_args->pages = vcpu_memory_bytes /
args->guest_page_size;
vcpu_args->gpa = args->gpa + (i * vcpu_memory_bytes);
} else {
vcpu_args->gva = guest_test_virt_mem;
vcpu_args->pages = (nr_vcpus * vcpu_memory_bytes) /
args->guest_page_size;
vcpu_args->gpa = args->gpa;
}
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));
}
}
struct kvm_vm *memstress_create_vm(enum vm_guest_mode mode, int nr_vcpus,
uint64_t vcpu_memory_bytes, int slots,
enum vm_mem_backing_src_type backing_src,
bool partition_vcpu_memory_access)
{
struct memstress_args *args = &memstress_args;
struct kvm_vm *vm;
uint64_t guest_num_pages, slot0_pages = 0;
uint64_t backing_src_pagesz = get_backing_src_pagesz(backing_src);
uint64_t region_end_gfn;
int i;
pr_info("Testing guest mode: %s\n", vm_guest_mode_string(mode));
/* By default vCPUs will write to memory. */
args->write_percent = 100;
/*
* Snapshot the non-huge page size. This is used by the guest code to
* access/dirty pages at the logging granularity.
*/
args->guest_page_size = vm_guest_mode_params[mode].page_size;
guest_num_pages = vm_adjust_num_guest_pages(mode,
(nr_vcpus * vcpu_memory_bytes) / args->guest_page_size);
TEST_ASSERT(vcpu_memory_bytes % getpagesize() == 0,
"Guest memory size is not host page size aligned.");
TEST_ASSERT(vcpu_memory_bytes % args->guest_page_size == 0,
"Guest memory size is not guest page size aligned.");
TEST_ASSERT(guest_num_pages % slots == 0,
"Guest memory cannot be evenly divided into %d slots.",
slots);
/*
* If using nested, allocate extra pages for the nested page tables and
* in-memory data structures.
*/
if (args->nested)
slot0_pages += memstress_nested_pages(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(mode), nr_vcpus,
slot0_pages + guest_num_pages,
memstress_guest_code, vcpus);
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.
*/
if (args->nested)
region_end_gfn = min(region_end_gfn, (1UL << 48) / args->guest_page_size);
#endif
/*
* If there should be more memory in the guest test region than there
* can be pages in the guest, it will definitely cause problems.
*/
TEST_ASSERT(guest_num_pages < region_end_gfn,
"Requested more guest memory than address space allows.\n"
" guest pages: %" PRIx64 " max gfn: %" PRIx64
" nr_vcpus: %d wss: %" PRIx64 "]",
guest_num_pages, region_end_gfn - 1, nr_vcpus, vcpu_memory_bytes);
args->gpa = (region_end_gfn - guest_num_pages - 1) * args->guest_page_size;
args->gpa = align_down(args->gpa, backing_src_pagesz);
#ifdef __s390x__
/* Align to 1M (segment size) */
args->gpa = align_down(args->gpa, 1 << 20);
#endif
args->size = guest_num_pages * args->guest_page_size;
pr_info("guest physical test memory: [0x%lx, 0x%lx)\n",
args->gpa, args->gpa + args->size);
/* Add extra memory slots for testing */
for (i = 0; i < slots; i++) {
uint64_t region_pages = guest_num_pages / slots;
vm_paddr_t region_start = args->gpa + region_pages * args->guest_page_size * i;
vm_userspace_mem_region_add(vm, backing_src, region_start,
MEMSTRESS_MEM_SLOT_INDEX + i,
region_pages, 0);
}
/* Do mapping for the demand paging memory slot */
virt_map(vm, guest_test_virt_mem, args->gpa, guest_num_pages);
memstress_setup_vcpus(vm, nr_vcpus, vcpus, vcpu_memory_bytes,
partition_vcpu_memory_access);
if (args->nested) {
pr_info("Configuring vCPUs to run in L2 (nested).\n");
memstress_setup_nested(vm, nr_vcpus, vcpus);
}
/* Export the shared variables to the guest. */
sync_global_to_guest(vm, memstress_args);
return vm;
}
void memstress_destroy_vm(struct kvm_vm *vm)
{
kvm_vm_free(vm);
}
void memstress_set_write_percent(struct kvm_vm *vm, uint32_t write_percent)
{
memstress_args.write_percent = write_percent;
sync_global_to_guest(vm, memstress_args.write_percent);
}
void memstress_set_random_access(struct kvm_vm *vm, bool random_access)
{
memstress_args.random_access = random_access;
sync_global_to_guest(vm, memstress_args.random_access);
}
uint64_t __weak memstress_nested_pages(int nr_vcpus)
{
return 0;
}
void __weak memstress_setup_nested(struct kvm_vm *vm, int nr_vcpus, struct kvm_vcpu **vcpus)
{
pr_info("%s() not support on this architecture, skipping.\n", __func__);
exit(KSFT_SKIP);
}
static void *vcpu_thread_main(void *data)
{
struct vcpu_thread *vcpu = data;
int vcpu_idx = vcpu->vcpu_idx;
if (memstress_args.pin_vcpus)
kvm_pin_this_task_to_pcpu(memstress_args.vcpu_to_pcpu[vcpu_idx]);
WRITE_ONCE(vcpu->running, true);
/*
* Wait for all vCPU threads to be up and running before calling the test-
* provided vCPU thread function. This prevents thread creation (which
* requires taking the mmap_sem in write mode) from interfering with the
* guest faulting in its memory.
*/
while (!READ_ONCE(all_vcpu_threads_running))
;
vcpu_thread_fn(&memstress_args.vcpu_args[vcpu_idx]);
return NULL;
}
void memstress_start_vcpu_threads(int nr_vcpus,
void (*vcpu_fn)(struct memstress_vcpu_args *))
{
int i;
vcpu_thread_fn = vcpu_fn;
WRITE_ONCE(all_vcpu_threads_running, false);
WRITE_ONCE(memstress_args.stop_vcpus, false);
for (i = 0; i < nr_vcpus; i++) {
struct vcpu_thread *vcpu = &vcpu_threads[i];
vcpu->vcpu_idx = i;
WRITE_ONCE(vcpu->running, false);
pthread_create(&vcpu->thread, NULL, vcpu_thread_main, vcpu);
}
for (i = 0; i < nr_vcpus; i++) {
while (!READ_ONCE(vcpu_threads[i].running))
;
}
WRITE_ONCE(all_vcpu_threads_running, true);
}
void memstress_join_vcpu_threads(int nr_vcpus)
{
int i;
WRITE_ONCE(memstress_args.stop_vcpus, true);
for (i = 0; i < nr_vcpus; i++)
pthread_join(vcpu_threads[i].thread, NULL);
}
static void toggle_dirty_logging(struct kvm_vm *vm, int slots, bool enable)
{
int i;
for (i = 0; i < slots; i++) {
int slot = MEMSTRESS_MEM_SLOT_INDEX + i;
int flags = enable ? KVM_MEM_LOG_DIRTY_PAGES : 0;
vm_mem_region_set_flags(vm, slot, flags);
}
}
void memstress_enable_dirty_logging(struct kvm_vm *vm, int slots)
{
toggle_dirty_logging(vm, slots, true);
}
void memstress_disable_dirty_logging(struct kvm_vm *vm, int slots)
{
toggle_dirty_logging(vm, slots, false);
}
void memstress_get_dirty_log(struct kvm_vm *vm, unsigned long *bitmaps[], int slots)
{
int i;
for (i = 0; i < slots; i++) {
int slot = MEMSTRESS_MEM_SLOT_INDEX + i;
kvm_vm_get_dirty_log(vm, slot, bitmaps[i]);
}
}
void memstress_clear_dirty_log(struct kvm_vm *vm, unsigned long *bitmaps[],
int slots, uint64_t pages_per_slot)
{
int i;
for (i = 0; i < slots; i++) {
int slot = MEMSTRESS_MEM_SLOT_INDEX + i;
kvm_vm_clear_dirty_log(vm, slot, bitmaps[i], 0, pages_per_slot);
}
}
unsigned long **memstress_alloc_bitmaps(int slots, uint64_t pages_per_slot)
{
unsigned long **bitmaps;
int i;
bitmaps = malloc(slots * sizeof(bitmaps[0]));
TEST_ASSERT(bitmaps, "Failed to allocate bitmaps array.");
for (i = 0; i < slots; i++) {
bitmaps[i] = bitmap_zalloc(pages_per_slot);
TEST_ASSERT(bitmaps[i], "Failed to allocate slot bitmap.");
}
return bitmaps;
}
void memstress_free_bitmaps(unsigned long *bitmaps[], int slots)
{
int i;
for (i = 0; i < slots; i++)
free(bitmaps[i]);
free(bitmaps);
}
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