* [kvm-unit-tests PATCH v5 1/1] s390x: add parallel skey migration test
2022-12-20 8:30 [kvm-unit-tests PATCH v5 0/1] s390x: test storage keys during migration Nico Boehr
@ 2022-12-20 8:30 ` Nico Boehr
0 siblings, 0 replies; 2+ messages in thread
From: Nico Boehr @ 2022-12-20 8:30 UTC (permalink / raw)
To: kvm; +Cc: frankja, imbrenda, thuth, nsg
Right now, we have a test which sets storage keys, then migrates the VM
and - after migration finished - verifies the skeys are still there.
Add a new version of the test which changes storage keys while the
migration is in progress. This is achieved by adding a command line
argument to the existing migration-skey test.
Signed-off-by: Nico Boehr <nrb@linux.ibm.com>
Reviewed-by: Nina Schoetterl-Glausch <nsg@linux.ibm.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
---
s390x/migration-skey.c | 218 +++++++++++++++++++++++++++++++++++++----
s390x/unittests.cfg | 15 ++-
2 files changed, 210 insertions(+), 23 deletions(-)
diff --git a/s390x/migration-skey.c b/s390x/migration-skey.c
index a91eb6b5a63e..8d6d8ecfe61c 100644
--- a/s390x/migration-skey.c
+++ b/s390x/migration-skey.c
@@ -2,6 +2,12 @@
/*
* Storage Key migration tests
*
+ * There are two variants of this test:
+ * - sequential: set storage keys on some pages, migrates the VM and then
+ * verifies that the storage keys are still as we expect.
+ * - parallel: start migration and set and check storage keys on some
+ * pages while migration is in process.
+ *
* Copyright IBM Corp. 2022
*
* Authors:
@@ -13,16 +19,45 @@
#include <asm/facility.h>
#include <asm/page.h>
#include <asm/mem.h>
-#include <asm/interrupt.h>
+#include <asm/barrier.h>
#include <hardware.h>
+#include <smp.h>
+
+struct verify_result {
+ bool verify_failed;
+ union skey expected_key;
+ union skey actual_key;
+ unsigned long page_mismatch_idx;
+ unsigned long page_mismatch_addr;
+};
#define NUM_PAGES 128
-static uint8_t pagebuf[NUM_PAGES][PAGE_SIZE] __attribute__((aligned(PAGE_SIZE)));
+static uint8_t pagebuf[NUM_PAGES * PAGE_SIZE] __attribute__((aligned(PAGE_SIZE)));
+
+static struct verify_result result;
+
+static unsigned int thread_iters;
+static bool thread_should_exit;
+static bool thread_exited;
+
+static enum {
+ TEST_INVALID,
+ TEST_SEQUENTIAL,
+ TEST_PARALLEL
+} arg_test_to_run;
-static void test_migration(void)
+/*
+ * Set storage key test pattern on pagebuf with a seed for the storage keys.
+ *
+ * Each page's storage key is generated by taking the page's index in pagebuf,
+ * XOR-ing that with the given seed and then multipling the result with two.
+ *
+ * Only the lower seven bits of the seed are considered.
+ */
+static void set_test_pattern(unsigned char seed)
{
- union skey expected_key, actual_key;
- int i, key_to_set, key_mismatches = 0;
+ unsigned char key_to_set;
+ unsigned long i;
for (i = 0; i < NUM_PAGES; i++) {
/*
@@ -32,15 +67,34 @@ static void test_migration(void)
* protection as well as reference and change indication for
* some keys.
*/
- key_to_set = i * 2;
- set_storage_key(pagebuf[i], key_to_set, 1);
+ key_to_set = (i ^ seed) * 2;
+ set_storage_key(pagebuf + i * PAGE_SIZE, key_to_set, 1);
}
+}
- migrate_once();
+/*
+ * Verify storage keys on pagebuf.
+ * Storage keys must have been set by set_test_pattern on pagebuf before.
+ * set_test_pattern must have been called with the same seed value.
+ *
+ * If storage keys match the expected result, will return a verify_result
+ * with verify_failed false. All other fields are then invalid.
+ * If there is a mismatch, returned struct will have verify_failed true and will
+ * be filled with the details on the first mismatch encountered.
+ */
+static struct verify_result verify_test_pattern(unsigned char seed)
+{
+ union skey expected_key, actual_key;
+ struct verify_result result = {
+ .verify_failed = true
+ };
+ uint8_t *cur_page;
+ unsigned long i;
for (i = 0; i < NUM_PAGES; i++) {
- actual_key.val = get_storage_key(pagebuf[i]);
- expected_key.val = i * 2;
+ cur_page = pagebuf + i * PAGE_SIZE;
+ actual_key.val = get_storage_key(cur_page);
+ expected_key.val = (i ^ seed) * 2;
/*
* The PoP neither gives a guarantee that the reference bit is
@@ -51,27 +105,153 @@ static void test_migration(void)
actual_key.str.rf = 0;
expected_key.str.rf = 0;
- /* don't log anything when key matches to avoid spamming the log */
if (actual_key.val != expected_key.val) {
- key_mismatches++;
- report_fail("page %d expected_key=0x%x actual_key=0x%x", i, expected_key.val, actual_key.val);
+ result.expected_key.val = expected_key.val;
+ result.actual_key.val = actual_key.val;
+ result.page_mismatch_idx = i;
+ result.page_mismatch_addr = (unsigned long)cur_page;
+ return result;
}
}
- report(!key_mismatches, "skeys after migration match");
+ result.verify_failed = false;
+ return result;
+}
+
+static void report_verify_result(const struct verify_result * result)
+{
+ if (result->verify_failed)
+ report_fail("page skey mismatch: first page idx = %lu, addr = 0x%lx, "
+ "expected_key = 0x%02x, actual_key = 0x%02x",
+ result->page_mismatch_idx, result->page_mismatch_addr,
+ result->expected_key.val, result->actual_key.val);
+ else
+ report_pass("skeys match");
+}
+
+static void test_skey_migration_sequential(void)
+{
+ report_prefix_push("sequential");
+
+ set_test_pattern(0);
+
+ migrate_once();
+
+ result = verify_test_pattern(0);
+ report_verify_result(&result);
+
+ report_prefix_pop();
+}
+
+static void set_skeys_thread(void)
+{
+ while (!READ_ONCE(thread_should_exit)) {
+ set_test_pattern(thread_iters);
+
+ result = verify_test_pattern(thread_iters);
+
+ /*
+ * Always increment even if the verify fails. This ensures primary CPU knows where
+ * we left off and can do an additional verify round after migration finished.
+ */
+ thread_iters++;
+
+ if (result.verify_failed)
+ break;
+ }
+
+ WRITE_ONCE(thread_exited, 1);
+}
+
+static void test_skey_migration_parallel(void)
+{
+ report_prefix_push("parallel");
+
+ if (smp_query_num_cpus() == 1) {
+ report_skip("need at least 2 cpus for this test");
+ goto error;
+ }
+
+ smp_cpu_setup(1, PSW_WITH_CUR_MASK(set_skeys_thread));
+
+ migrate_once();
+
+ WRITE_ONCE(thread_should_exit, 1);
+
+ while (!READ_ONCE(thread_exited))
+ ;
+
+ /* Ensure we read result and thread_iters below from memory after thread exited */
+ mb();
+ report_info("thread completed %u iterations", thread_iters);
+
+ report_prefix_push("during migration");
+ report_verify_result(&result);
+ report_prefix_pop();
+
+ /*
+ * Verification of skeys occurs on the thread. We don't know if we
+ * were still migrating during the verification.
+ * To be sure, make another verification round after the migration
+ * finished to catch skeys which might not have been migrated
+ * correctly.
+ */
+ report_prefix_push("after migration");
+ assert(thread_iters > 0);
+ result = verify_test_pattern(thread_iters - 1);
+ report_verify_result(&result);
+ report_prefix_pop();
+
+error:
+ report_prefix_pop();
+}
+
+static void print_usage(void)
+{
+ report_info("Usage: migration-skey [--parallel|--sequential]");
+}
+
+static void parse_args(int argc, char **argv)
+{
+ if (argc < 2) {
+ /* default to sequential since it only needs one cpu */
+ arg_test_to_run = TEST_SEQUENTIAL;
+ return;
+ }
+
+ if (!strcmp("--parallel", argv[1]))
+ arg_test_to_run = TEST_PARALLEL;
+ else if (!strcmp("--sequential", argv[1]))
+ arg_test_to_run = TEST_SEQUENTIAL;
+ else
+ arg_test_to_run = TEST_INVALID;
}
-int main(void)
+int main(int argc, char **argv)
{
report_prefix_push("migration-skey");
- if (test_facility(169))
+ if (test_facility(169)) {
report_skip("storage key removal facility is active");
- else
- test_migration();
+ goto error;
+ }
- migrate_once();
+ parse_args(argc, argv);
+
+ switch (arg_test_to_run) {
+ case TEST_SEQUENTIAL:
+ test_skey_migration_sequential();
+ break;
+ case TEST_PARALLEL:
+ test_skey_migration_parallel();
+ break;
+ default:
+ print_usage();
+ break;
+ }
+error:
+ migrate_once();
report_prefix_pop();
return report_summary();
}
diff --git a/s390x/unittests.cfg b/s390x/unittests.cfg
index 3caf81eda396..d97eb5e943c8 100644
--- a/s390x/unittests.cfg
+++ b/s390x/unittests.cfg
@@ -185,10 +185,6 @@ smp = 2
file = migration-cmm.elf
groups = migration
-[migration-skey]
-file = migration-skey.elf
-groups = migration
-
[panic-loop-extint]
file = panic-loop-extint.elf
groups = panic
@@ -208,3 +204,14 @@ groups = migration
[exittime]
file = exittime.elf
smp = 2
+
+[migration-skey-sequential]
+file = migration-skey.elf
+groups = migration
+extra_params = -append '--sequential'
+
+[migration-skey-parallel]
+file = migration-skey.elf
+smp = 2
+groups = migration
+extra_params = -append '--parallel'
--
2.36.1
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