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-rw-r--r--tools/testing/selftests/kvm/access_tracking_perf_test.c115
1 files changed, 59 insertions, 56 deletions
diff --git a/tools/testing/selftests/kvm/access_tracking_perf_test.c b/tools/testing/selftests/kvm/access_tracking_perf_test.c
index d8909032317a..76c583a07ea2 100644
--- a/tools/testing/selftests/kvm/access_tracking_perf_test.c
+++ b/tools/testing/selftests/kvm/access_tracking_perf_test.c
@@ -31,8 +31,9 @@
* These limitations are worked around in this test by using a large enough
* region of memory for each vCPU such that the number of translations cached in
* the TLB and the number of pages held in pagevecs are a small fraction of the
- * overall workload. And if either of those conditions are not true this test
- * will fail rather than silently passing.
+ * overall workload. And if either of those conditions are not true (for example
+ * in nesting, where TLB size is unlimited) this test will print a warning
+ * rather than silently passing.
*/
#include <inttypes.h>
#include <limits.h>
@@ -74,7 +75,7 @@ struct test_params {
uint64_t vcpu_memory_bytes;
/* The number of vCPUs to create in the VM. */
- int vcpus;
+ int nr_vcpus;
};
static uint64_t pread_uint64(int fd, const char *filename, uint64_t index)
@@ -104,10 +105,7 @@ static uint64_t lookup_pfn(int pagemap_fd, struct kvm_vm *vm, uint64_t gva)
return 0;
pfn = entry & PAGEMAP_PFN_MASK;
- if (!pfn) {
- print_skip("Looking up PFNs requires CAP_SYS_ADMIN");
- exit(KSFT_SKIP);
- }
+ __TEST_REQUIRE(pfn, "Looking up PFNs requires CAP_SYS_ADMIN");
return pfn;
}
@@ -127,10 +125,12 @@ static void mark_page_idle(int page_idle_fd, uint64_t pfn)
"Set page_idle bits for PFN 0x%" PRIx64, pfn);
}
-static void mark_vcpu_memory_idle(struct kvm_vm *vm, int vcpu_id)
+static void mark_vcpu_memory_idle(struct kvm_vm *vm,
+ struct perf_test_vcpu_args *vcpu_args)
{
- uint64_t base_gva = perf_test_args.vcpu_args[vcpu_id].gva;
- uint64_t pages = perf_test_args.vcpu_args[vcpu_id].pages;
+ int vcpu_idx = vcpu_args->vcpu_idx;
+ uint64_t base_gva = vcpu_args->gva;
+ uint64_t pages = vcpu_args->pages;
uint64_t page;
uint64_t still_idle = 0;
uint64_t no_pfn = 0;
@@ -138,7 +138,7 @@ static void mark_vcpu_memory_idle(struct kvm_vm *vm, int vcpu_id)
int pagemap_fd;
/* If vCPUs are using an overlapping region, let vCPU 0 mark it idle. */
- if (overlap_memory_access && vcpu_id)
+ if (overlap_memory_access && vcpu_idx)
return;
page_idle_fd = open("/sys/kernel/mm/page_idle/bitmap", O_RDWR);
@@ -170,30 +170,35 @@ static void mark_vcpu_memory_idle(struct kvm_vm *vm, int vcpu_id)
*/
TEST_ASSERT(no_pfn < pages / 100,
"vCPU %d: No PFN for %" PRIu64 " out of %" PRIu64 " pages.",
- vcpu_id, no_pfn, pages);
+ vcpu_idx, no_pfn, pages);
/*
- * Test that at least 90% of memory has been marked idle (the rest might
- * not be marked idle because the pages have not yet made it to an LRU
- * list or the translations are still cached in the TLB). 90% is
+ * Check that at least 90% of memory has been marked idle (the rest
+ * might not be marked idle because the pages have not yet made it to an
+ * LRU list or the translations are still cached in the TLB). 90% is
* arbitrary; high enough that we ensure most memory access went through
* access tracking but low enough as to not make the test too brittle
* over time and across architectures.
+ *
+ * Note that when run in nested virtualization, this check will trigger
+ * much more frequently because TLB size is unlimited and since no flush
+ * happens, much more pages are cached there and guest won't see the
+ * "idle" bit cleared.
*/
- TEST_ASSERT(still_idle < pages / 10,
- "vCPU%d: Too many pages still idle (%"PRIu64 " out of %"
- PRIu64 ").\n",
- vcpu_id, still_idle, pages);
+ if (still_idle < pages / 10)
+ printf("WARNING: vCPU%d: Too many pages still idle (%" PRIu64
+ "out of %" PRIu64 "), this will affect performance results"
+ ".\n",
+ vcpu_idx, still_idle, pages);
close(page_idle_fd);
close(pagemap_fd);
}
-static void assert_ucall(struct kvm_vm *vm, uint32_t vcpu_id,
- uint64_t expected_ucall)
+static void assert_ucall(struct kvm_vcpu *vcpu, uint64_t expected_ucall)
{
struct ucall uc;
- uint64_t actual_ucall = get_ucall(vm, vcpu_id, &uc);
+ uint64_t actual_ucall = get_ucall(vcpu, &uc);
TEST_ASSERT(expected_ucall == actual_ucall,
"Guest exited unexpectedly (expected ucall %" PRIu64
@@ -217,28 +222,29 @@ static bool spin_wait_for_next_iteration(int *current_iteration)
static void vcpu_thread_main(struct perf_test_vcpu_args *vcpu_args)
{
+ struct kvm_vcpu *vcpu = vcpu_args->vcpu;
struct kvm_vm *vm = perf_test_args.vm;
- int vcpu_id = vcpu_args->vcpu_id;
+ int vcpu_idx = vcpu_args->vcpu_idx;
int current_iteration = 0;
while (spin_wait_for_next_iteration(&current_iteration)) {
switch (READ_ONCE(iteration_work)) {
case ITERATION_ACCESS_MEMORY:
- vcpu_run(vm, vcpu_id);
- assert_ucall(vm, vcpu_id, UCALL_SYNC);
+ vcpu_run(vcpu);
+ assert_ucall(vcpu, UCALL_SYNC);
break;
case ITERATION_MARK_IDLE:
- mark_vcpu_memory_idle(vm, vcpu_id);
+ mark_vcpu_memory_idle(vm, vcpu_args);
break;
};
- vcpu_last_completed_iteration[vcpu_id] = current_iteration;
+ vcpu_last_completed_iteration[vcpu_idx] = current_iteration;
}
}
-static void spin_wait_for_vcpu(int vcpu_id, int target_iteration)
+static void spin_wait_for_vcpu(int vcpu_idx, int target_iteration)
{
- while (READ_ONCE(vcpu_last_completed_iteration[vcpu_id]) !=
+ while (READ_ONCE(vcpu_last_completed_iteration[vcpu_idx]) !=
target_iteration) {
continue;
}
@@ -250,12 +256,11 @@ enum access_type {
ACCESS_WRITE,
};
-static void run_iteration(struct kvm_vm *vm, int vcpus, const char *description)
+static void run_iteration(struct kvm_vm *vm, int nr_vcpus, const char *description)
{
struct timespec ts_start;
struct timespec ts_elapsed;
- int next_iteration;
- int vcpu_id;
+ int next_iteration, i;
/* Kick off the vCPUs by incrementing iteration. */
next_iteration = ++iteration;
@@ -263,23 +268,23 @@ static void run_iteration(struct kvm_vm *vm, int vcpus, const char *description)
clock_gettime(CLOCK_MONOTONIC, &ts_start);
/* Wait for all vCPUs to finish the iteration. */
- for (vcpu_id = 0; vcpu_id < vcpus; vcpu_id++)
- spin_wait_for_vcpu(vcpu_id, next_iteration);
+ for (i = 0; i < nr_vcpus; i++)
+ spin_wait_for_vcpu(i, next_iteration);
ts_elapsed = timespec_elapsed(ts_start);
pr_info("%-30s: %ld.%09lds\n",
description, ts_elapsed.tv_sec, ts_elapsed.tv_nsec);
}
-static void access_memory(struct kvm_vm *vm, int vcpus, enum access_type access,
- const char *description)
+static void access_memory(struct kvm_vm *vm, int nr_vcpus,
+ enum access_type access, const char *description)
{
perf_test_set_wr_fract(vm, (access == ACCESS_READ) ? INT_MAX : 1);
iteration_work = ITERATION_ACCESS_MEMORY;
- run_iteration(vm, vcpus, description);
+ run_iteration(vm, nr_vcpus, description);
}
-static void mark_memory_idle(struct kvm_vm *vm, int vcpus)
+static void mark_memory_idle(struct kvm_vm *vm, int nr_vcpus)
{
/*
* Even though this parallelizes the work across vCPUs, this is still a
@@ -289,37 +294,37 @@ static void mark_memory_idle(struct kvm_vm *vm, int vcpus)
*/
pr_debug("Marking VM memory idle (slow)...\n");
iteration_work = ITERATION_MARK_IDLE;
- run_iteration(vm, vcpus, "Mark memory idle");
+ run_iteration(vm, nr_vcpus, "Mark memory idle");
}
static void run_test(enum vm_guest_mode mode, void *arg)
{
struct test_params *params = arg;
struct kvm_vm *vm;
- int vcpus = params->vcpus;
+ int nr_vcpus = params->nr_vcpus;
- vm = perf_test_create_vm(mode, vcpus, params->vcpu_memory_bytes, 1,
+ vm = perf_test_create_vm(mode, nr_vcpus, params->vcpu_memory_bytes, 1,
params->backing_src, !overlap_memory_access);
- perf_test_start_vcpu_threads(vcpus, vcpu_thread_main);
+ perf_test_start_vcpu_threads(nr_vcpus, vcpu_thread_main);
pr_info("\n");
- access_memory(vm, vcpus, ACCESS_WRITE, "Populating memory");
+ access_memory(vm, nr_vcpus, ACCESS_WRITE, "Populating memory");
/* As a control, read and write to the populated memory first. */
- access_memory(vm, vcpus, ACCESS_WRITE, "Writing to populated memory");
- access_memory(vm, vcpus, ACCESS_READ, "Reading from populated memory");
+ access_memory(vm, nr_vcpus, ACCESS_WRITE, "Writing to populated memory");
+ access_memory(vm, nr_vcpus, ACCESS_READ, "Reading from populated memory");
/* Repeat on memory that has been marked as idle. */
- mark_memory_idle(vm, vcpus);
- access_memory(vm, vcpus, ACCESS_WRITE, "Writing to idle memory");
- mark_memory_idle(vm, vcpus);
- access_memory(vm, vcpus, ACCESS_READ, "Reading from idle memory");
+ mark_memory_idle(vm, nr_vcpus);
+ access_memory(vm, nr_vcpus, ACCESS_WRITE, "Writing to idle memory");
+ mark_memory_idle(vm, nr_vcpus);
+ access_memory(vm, nr_vcpus, ACCESS_READ, "Reading from idle memory");
/* Set done to signal the vCPU threads to exit */
done = true;
- perf_test_join_vcpu_threads(vcpus);
+ perf_test_join_vcpu_threads(nr_vcpus);
perf_test_destroy_vm(vm);
}
@@ -347,7 +352,7 @@ int main(int argc, char *argv[])
struct test_params params = {
.backing_src = DEFAULT_VM_MEM_SRC,
.vcpu_memory_bytes = DEFAULT_PER_VCPU_MEM_SIZE,
- .vcpus = 1,
+ .nr_vcpus = 1,
};
int page_idle_fd;
int opt;
@@ -363,7 +368,7 @@ int main(int argc, char *argv[])
params.vcpu_memory_bytes = parse_size(optarg);
break;
case 'v':
- params.vcpus = atoi(optarg);
+ params.nr_vcpus = atoi(optarg);
break;
case 'o':
overlap_memory_access = true;
@@ -379,10 +384,8 @@ int main(int argc, char *argv[])
}
page_idle_fd = open("/sys/kernel/mm/page_idle/bitmap", O_RDWR);
- if (page_idle_fd < 0) {
- print_skip("CONFIG_IDLE_PAGE_TRACKING is not enabled");
- exit(KSFT_SKIP);
- }
+ __TEST_REQUIRE(page_idle_fd >= 0,
+ "CONFIG_IDLE_PAGE_TRACKING is not enabled");
close(page_idle_fd);
for_each_guest_mode(run_test, &params);
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.