Minki/linux
1
0
Fork 1
mirror of https://github.com/torvalds/linux.git synced 2024-11-23 04:31:50 +00:00
Code Issues Packages Projects Releases Wiki Activity

KVM: selftests: Support multiple vCPUs in demand paging test

Browse Source 
Most VMs have multiple vCPUs, the concurrent execution of which has a
substantial impact on demand paging performance. Add an option to create
multiple vCPUs to each access disjoint regions of memory.

Signed-off-by: Ben Gardon <bgardon@google.com>
[guest_code() can't return, use GUEST_ASSERT(). Ensure the number
 of guests pages is compatible with the host.]
Signed-off-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Ben Gardon 2020-01-23 10:04:33 -08:00 committed by Paolo Bonzini
parent 9bbf24744e
commit 018494e6d8
1 changed files with 171 additions and 82 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

253
tools/testing/selftests/kvm/demand_paging_test.c
View File

@ -26,7 +26,6 @@
#include "processor.h"
#ifdef __NR_userfaultfd
#define VCPU_ID 1
/* The memory slot index demand page */
#define TEST_MEM_SLOT_INDEX 1
@ -36,6 +35,14 @@
#define DEFAULT_GUEST_TEST_MEM_SIZE (1 << 30) /* 1G */
#ifdef PRINT_PER_VCPU_UPDATES
#define PER_VCPU_DEBUG(...) DEBUG(__VA_ARGS__)
#else
#define PER_VCPU_DEBUG(...)
#endif
#define MAX_VCPUS 512
/*
* Guest/Host shared variables. Ensure addr_gva2hva() and/or
* sync_global_to/from_guest() are used when accessing from
@ -69,18 +76,24 @@ struct vcpu_args {
struct kvm_vm *vm;
};
static struct vcpu_args vcpu_args;
static struct vcpu_args vcpu_args[MAX_VCPUS];
/*
* Continuously write to the first 8 bytes of each page in the demand paging
* memory region.
*/
static void guest_code(void)
static void guest_code(uint32_t vcpu_id)
{
uint64_t gva = vcpu_args.gva;
uint64_t pages = vcpu_args.pages;
uint64_t gva;
uint64_t pages;
int i;
/* Make sure vCPU args data structure is not corrupt. */
GUEST_ASSERT(vcpu_args[vcpu_id].vcpu_id == vcpu_id);
gva = vcpu_args[vcpu_id].gva;
pages = vcpu_args[vcpu_id].pages;
for (i = 0; i < pages; i++) {
uint64_t addr = gva + (i * guest_page_size);
@ -91,17 +104,15 @@ static void guest_code(void)
GUEST_SYNC(1);
}
/* Points to the test VM memory region on which we are doing demand paging */
static void *host_test_mem;
static uint64_t host_num_pages;
static void *vcpu_worker(void *data)
{
int ret;
struct kvm_vm *vm = vcpu_args.vm;
int vcpu_id = vcpu_args.vcpu_id;
struct vcpu_args *args = (struct vcpu_args *)data;
struct kvm_vm *vm = args->vm;
int vcpu_id = args->vcpu_id;
struct kvm_run *run;
vcpu_args_set(vm, vcpu_id, 1, vcpu_id);
run = vcpu_state(vm, vcpu_id);
/* Let the guest access its memory */
@ -116,18 +127,34 @@ static void *vcpu_worker(void *data)
return NULL;
}
static struct kvm_vm *create_vm(enum vm_guest_mode mode, uint32_t vcpuid,
uint64_t extra_mem_pages, void *guest_code)
#define PAGE_SHIFT_4K 12
#define PTES_PER_4K_PT 512
static struct kvm_vm *create_vm(enum vm_guest_mode mode, int vcpus,
uint64_t vcpu_memory_bytes)
{
struct kvm_vm *vm;
uint64_t extra_pg_pages = extra_mem_pages / 512 * 2;
uint64_t pages = DEFAULT_GUEST_PHY_PAGES;
vm = _vm_create(mode, DEFAULT_GUEST_PHY_PAGES + extra_pg_pages, O_RDWR);
/* Account for a few pages per-vCPU for stacks */
pages += DEFAULT_STACK_PGS * vcpus;
/*
* Reserve twice the ammount of memory needed to map the test region and
* the page table / stacks region, at 4k, for page tables. Do the
* calculation with 4K page size: the smallest of all archs. (e.g., 64K
* page size guest will need even less memory for page tables).
*/
pages += (2 * pages) / PTES_PER_4K_PT;
pages += ((2 * vcpus * vcpu_memory_bytes) >> PAGE_SHIFT_4K) /
PTES_PER_4K_PT;
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);
#ifdef __x86_64__
vm_create_irqchip(vm);
#endif
vm_vcpu_add_default(vm, vcpuid, guest_code);
return vm;
}
@ -242,17 +269,13 @@ static void *uffd_handler_thread_fn(void *arg)
static int setup_demand_paging(struct kvm_vm *vm,
pthread_t *uffd_handler_thread, int pipefd,
useconds_t uffd_delay)
useconds_t uffd_delay,
struct uffd_handler_args *uffd_args,
void *hva, uint64_t len)
{
int uffd;
struct uffdio_api uffdio_api;
struct uffdio_register uffdio_register;
struct uffd_handler_args uffd_args;
guest_data_prototype = malloc(host_page_size);
TEST_ASSERT(guest_data_prototype,
"Failed to allocate buffer for guest data pattern");
memset(guest_data_prototype, 0xAB, host_page_size);
uffd = syscall(__NR_userfaultfd, O_CLOEXEC | O_NONBLOCK);
if (uffd == -1) {
@ -267,8 +290,8 @@ static int setup_demand_paging(struct kvm_vm *vm,
return -1;
}
uffdio_register.range.start = (uint64_t)host_test_mem;
uffdio_register.range.len = host_num_pages * host_page_size;
uffdio_register.range.start = (uint64_t)hva;
uffdio_register.range.len = len;
uffdio_register.mode = UFFDIO_REGISTER_MODE_MISSING;
if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register) == -1) {
DEBUG("ioctl uffdio_register failed\n");
@ -281,44 +304,40 @@ static int setup_demand_paging(struct kvm_vm *vm,
return -1;
}
uffd_args.uffd = uffd;
uffd_args.pipefd = pipefd;
uffd_args.delay = uffd_delay;
uffd_args->uffd = uffd;
uffd_args->pipefd = pipefd;
uffd_args->delay = uffd_delay;
pthread_create(uffd_handler_thread, NULL, uffd_handler_thread_fn,
&uffd_args);
uffd_args);
PER_VCPU_DEBUG("Created uffd thread for HVA range [%p, %p)\n",
hva, hva + len);
return 0;
}
#define PAGE_SHIFT_4K 12
static void run_test(enum vm_guest_mode mode, bool use_uffd,
useconds_t uffd_delay, uint64_t guest_memory_bytes)
useconds_t uffd_delay, int vcpus,
uint64_t vcpu_memory_bytes)
{
pthread_t vcpu_thread;
pthread_t uffd_handler_thread;
int pipefd[2];
pthread_t *vcpu_threads;
pthread_t *uffd_handler_threads = NULL;
struct uffd_handler_args *uffd_args = NULL;
int *pipefds = NULL;
struct kvm_vm *vm;
uint64_t guest_num_pages;
int vcpu_id;
int r;
/*
* We reserve page table for twice the ammount of memory we intend
* to use in the test region for demand paging. Here we do the
* calculation with 4K page size which is the smallest so the page
* number will be enough for all archs. (e.g., 64K page size guest
* will need even less memory for page tables).
*/
vm = create_vm(mode, VCPU_ID,
(2 * guest_memory_bytes) >> PAGE_SHIFT_4K,
guest_code);
vm = create_vm(mode, vcpus, vcpu_memory_bytes);
guest_page_size = vm_get_page_size(vm);
TEST_ASSERT(guest_memory_bytes % guest_page_size == 0,
TEST_ASSERT(vcpu_memory_bytes % guest_page_size == 0,
"Guest memory size is not guest page size aligned.");
guest_num_pages = guest_memory_bytes / guest_page_size;
guest_num_pages = (vcpus * vcpu_memory_bytes) / guest_page_size;
guest_num_pages = vm_adjust_num_guest_pages(mode, guest_num_pages);
#ifdef __s390x__
/* Round up to multiple of 1M (segment size) */
@ -330,13 +349,13 @@ static void run_test(enum vm_guest_mode mode, bool use_uffd,
*/
TEST_ASSERT(guest_num_pages < vm_get_max_gfn(vm),
"Requested more guest memory than address space allows.\n"
" guest pages: %lx max gfn: %lx\n",
guest_num_pages, vm_get_max_gfn(vm));
" guest pages: %lx max gfn: %lx vcpus: %d wss: %lx]\n",
guest_num_pages, vm_get_max_gfn(vm), vcpus,
vcpu_memory_bytes);
host_page_size = getpagesize();
TEST_ASSERT(guest_memory_bytes % host_page_size == 0,
TEST_ASSERT(vcpu_memory_bytes % host_page_size == 0,
"Guest memory size is not host page size aligned.");
host_num_pages = guest_memory_bytes / host_page_size;
guest_test_phys_mem = (vm_get_max_gfn(vm) - guest_num_pages) *
guest_page_size;
@ -361,55 +380,114 @@ static void run_test(enum vm_guest_mode mode, bool use_uffd,
virt_map(vm, guest_test_virt_mem, guest_test_phys_mem,
guest_num_pages * guest_page_size, 0);
/* Cache the HVA pointer of the region */
host_test_mem = addr_gpa2hva(vm, (vm_paddr_t)guest_test_phys_mem);
ucall_init(vm, NULL);
guest_data_prototype = malloc(host_page_size);
TEST_ASSERT(guest_data_prototype,
"Failed to allocate buffer for guest data pattern");
memset(guest_data_prototype, 0xAB, host_page_size);
vcpu_threads = malloc(vcpus * sizeof(*vcpu_threads));
TEST_ASSERT(vcpu_threads, "Memory allocation failed");
if (use_uffd) {
/* Set up user fault fd to handle demand paging requests. */
r = pipe2(pipefd, O_CLOEXEC | O_NONBLOCK);
TEST_ASSERT(!r, "Failed to set up pipefd");
uffd_handler_threads =
malloc(vcpus * sizeof(*uffd_handler_threads));
TEST_ASSERT(uffd_handler_threads, "Memory allocation failed");
r = setup_demand_paging(vm, &uffd_handler_thread, pipefd[0],
uffd_delay);
if (r < 0)
exit(-r);
uffd_args = malloc(vcpus * sizeof(*uffd_args));
TEST_ASSERT(uffd_args, "Memory allocation failed");
pipefds = malloc(sizeof(int) * vcpus * 2);
TEST_ASSERT(pipefds, "Unable to allocate memory for pipefd");
}
for (vcpu_id = 0; vcpu_id < vcpus; vcpu_id++) {
vm_paddr_t vcpu_gpa;
void *vcpu_hva;
vm_vcpu_add_default(vm, vcpu_id, guest_code);
vcpu_gpa = guest_test_phys_mem + (vcpu_id * vcpu_memory_bytes);
PER_VCPU_DEBUG("Added VCPU %d with test mem gpa [%lx, %lx)\n",
vcpu_id, vcpu_gpa, vcpu_gpa + vcpu_memory_bytes);
/* Cache the HVA pointer of the region */
vcpu_hva = addr_gpa2hva(vm, vcpu_gpa);
if (use_uffd) {
/*
* Set up user fault fd to handle demand paging
* requests.
*/
r = pipe2(&pipefds[vcpu_id * 2],
O_CLOEXEC | O_NONBLOCK);
TEST_ASSERT(!r, "Failed to set up pipefd");
r = setup_demand_paging(vm,
&uffd_handler_threads[vcpu_id],
pipefds[vcpu_id * 2],
uffd_delay, &uffd_args[vcpu_id],
vcpu_hva, vcpu_memory_bytes);
if (r < 0)
exit(-r);
}
#ifdef __x86_64__
vcpu_set_cpuid(vm, VCPU_ID, kvm_get_supported_cpuid());
#endif
#ifdef __aarch64__
ucall_init(vm, NULL);
vcpu_set_cpuid(vm, vcpu_id, kvm_get_supported_cpuid());
#endif
vcpu_args[vcpu_id].vm = vm;
vcpu_args[vcpu_id].vcpu_id = vcpu_id;
vcpu_args[vcpu_id].gva = guest_test_virt_mem +
(vcpu_id * vcpu_memory_bytes);
vcpu_args[vcpu_id].pages = vcpu_memory_bytes / guest_page_size;
}
/* Export the shared variables to the guest */
sync_global_to_guest(vm, host_page_size);
sync_global_to_guest(vm, guest_page_size);
vcpu_args.vm = vm;
vcpu_args.vcpu_id = VCPU_ID;
vcpu_args.gva = guest_test_virt_mem;
vcpu_args.pages = guest_num_pages;
sync_global_to_guest(vm, vcpu_args);
pthread_create(&vcpu_thread, NULL, vcpu_worker, &vcpu_args);
/* Wait for the vcpu thread to quit */
pthread_join(vcpu_thread, NULL);
DEBUG("Finished creating vCPUs and starting uffd threads\n");
for (vcpu_id = 0; vcpu_id < vcpus; vcpu_id++) {
pthread_create(&vcpu_threads[vcpu_id], NULL, vcpu_worker,
&vcpu_args[vcpu_id]);
}
DEBUG("Started all vCPUs\n");
/* Wait for the vcpu threads to quit */
for (vcpu_id = 0; vcpu_id < vcpus; vcpu_id++) {
pthread_join(vcpu_threads[vcpu_id], NULL);
PER_VCPU_DEBUG("Joined thread for vCPU %d\n", vcpu_id);
}
DEBUG("All vCPU threads joined\n");
if (use_uffd) {
char c;
/* Tell the user fault fd handler thread to quit */
r = write(pipefd[1], &c, 1);
TEST_ASSERT(r == 1, "Unable to write to pipefd");
/* Tell the user fault fd handler threads to quit */
for (vcpu_id = 0; vcpu_id < vcpus; vcpu_id++) {
r = write(pipefds[vcpu_id * 2 + 1], &c, 1);
TEST_ASSERT(r == 1, "Unable to write to pipefd");
pthread_join(uffd_handler_thread, NULL);
pthread_join(uffd_handler_threads[vcpu_id], NULL);
}
}
ucall_uninit(vm);
kvm_vm_free(vm);
free(guest_data_prototype);
free(vcpu_threads);
if (use_uffd) {
free(uffd_handler_threads);
free(uffd_args);
free(pipefds);
}
}
struct guest_mode {
@ -428,7 +506,7 @@ static void help(char *name)
puts("");
printf("usage: %s [-h] [-m mode] [-u] [-d uffd_delay_usec]\n"
" [-b memory]\n", name);
" [-b memory] [-v vcpus]\n", name);
printf(" -m: specify the guest mode ID to test\n"
" (default: test all supported modes)\n"
" This option may be used multiple times.\n"
@ -443,7 +521,9 @@ static void help(char *name)
" FD handler to simulate demand paging\n"
" overheads. Ignored without -u.\n");
printf(" -b: specify the size of the memory region which should be\n"
" demand paged. e.g. 10M or 3G. Default: 1G\n");
" demand paged by each vCPU. e.g. 10M or 3G.\n"
" Default: 1G\n");
printf(" -v: specify the number of vCPUs to run.\n");
puts("");
exit(0);
}
@ -451,7 +531,8 @@ static void help(char *name)
int main(int argc, char *argv[])
{
bool mode_selected = false;
uint64_t guest_memory_bytes = DEFAULT_GUEST_TEST_MEM_SIZE;
uint64_t vcpu_memory_bytes = DEFAULT_GUEST_TEST_MEM_SIZE;
int vcpus = 1;
unsigned int mode;
int opt, i;
bool use_uffd = false;
@ -478,7 +559,7 @@ int main(int argc, char *argv[])
guest_mode_init(VM_MODE_P40V48_4K, true, true);
#endif
while ((opt = getopt(argc, argv, "hm:ud:b:")) != -1) {
while ((opt = getopt(argc, argv, "hm:ud:b:v:")) != -1) {
switch (opt) {
case 'm':
if (!mode_selected) {
@ -500,7 +581,15 @@ int main(int argc, char *argv[])
"A negative UFFD delay is not supported.");
break;
case 'b':
guest_memory_bytes = parse_size(optarg);
vcpu_memory_bytes = parse_size(optarg);
break;
case 'v':
vcpus = atoi(optarg);
TEST_ASSERT(vcpus > 0,
"Must have a positive number of vCPUs");
TEST_ASSERT(vcpus <= MAX_VCPUS,
"This test does not currently support\n"
"more than %d vCPUs.", MAX_VCPUS);
break;
case 'h':
default:
@ -515,7 +604,7 @@ int main(int argc, char *argv[])
TEST_ASSERT(guest_modes[i].supported,
"Guest mode ID %d (%s) not supported.",
i, vm_guest_mode_string(i));
run_test(i, use_uffd, uffd_delay, guest_memory_bytes);
run_test(i, use_uffd, uffd_delay, vcpus, vcpu_memory_bytes);
}
return 0;