arch_timer_edge_cases tries to migrate itself across host cpus. Before the first test it migrates to cpu 0 by setting up an affinity mask with only bit 0 set. After that it looks for the next possible cpu in the current affinity mask which still has only bit 0 set. So there is no migration at all.

Fix this by reading the default mask at start and use this to find the next cpu in each iteration.

Signed-off-by: Sebastian Ott sebott@redhat.com --- tools/testing/selftests/kvm/arm64/arch_timer_edge_cases.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/kvm/arm64/arch_timer_edge_cases.c b/tools/testing/selftests/kvm/arm64/arch_timer_edge_cases.c index c4716e0c1438..a813b4c6c817 100644 --- a/tools/testing/selftests/kvm/arm64/arch_timer_edge_cases.c +++ b/tools/testing/selftests/kvm/arm64/arch_timer_edge_cases.c @@ -849,17 +849,17 @@ static void guest_code(enum arch_timer timer) GUEST_DONE(); }

+static cpu_set_t default_cpuset; + static uint32_t next_pcpu(void) { uint32_t max = get_nprocs(); uint32_t cur = sched_getcpu(); uint32_t next = cur; - cpu_set_t cpuset; + cpu_set_t cpuset = default_cpuset;

TEST_ASSERT(max > 1, "Need at least two physical cpus");

- sched_getaffinity(0, sizeof(cpuset), &cpuset); - do { next = (next + 1) % CPU_SETSIZE; } while (!CPU_ISSET(next, &cpuset)); @@ -1046,6 +1046,8 @@ int main(int argc, char *argv[]) if (!parse_args(argc, argv)) exit(KSFT_SKIP);

+ sched_getaffinity(0, sizeof(default_cpuset), &default_cpuset); + if (test_args.test_virtual) { test_vm_create(&vm, &vcpu, VIRTUAL); test_run(vm, vcpu);

arch_timer_edge_cases uses ~0 as the maximum counter value, however there's no architectural guarantee that this is valid.

Figure out the effective counter width based on the effective frequency like it's done by the kernel.

This also serves as a workaround for AC03_CPU_14 that led to the following assertion failure on ampere-one machines:

==== Test Assertion Failure ==== arm64/arch_timer_edge_cases.c:169: timer_condition == istatus pid=11236 tid=11236 errno=4 - Interrupted system call 1 0x0000000000404ce7: test_run at arch_timer_edge_cases.c:938 2 0x0000000000401ebb: main at arch_timer_edge_cases.c:1053 3 0x0000ffff9fa8625b: ?? ??:0 4 0x0000ffff9fa8633b: ?? ??:0 5 0x0000000000401fef: _start at ??:? 0x1 != 0x0 (timer_condition != istatus)

Note that the following subtest only worked since the counter initialized with CVAL_MAX would instantly overflow (which is no longer the case):

test_set_cnt_after_cval_no_irq(timer, 0, DEF_CNT, CVAL_MAX, sm);

To fix this we could swap CVAL_MAX for 0 here but since that is already done by test_move_counters_behind_timers() let's remove that subtest.

Link: https://lore.kernel.org/kvmarm/ac1de1d2-ef2b-d439-dc48-8615e121b07b@redhat.c... Link: https://amperecomputing.com/assets/AmpereOne_Developer_ER_v0_80_20240823_289... Signed-off-by: Sebastian Ott sebott@redhat.com --- .../kvm/arm64/arch_timer_edge_cases.c | 27 ++++++++++++------- 1 file changed, 18 insertions(+), 9 deletions(-)

diff --git a/tools/testing/selftests/kvm/arm64/arch_timer_edge_cases.c b/tools/testing/selftests/kvm/arm64/arch_timer_edge_cases.c index be8bbedc933b..b4d22b3ab7cc 100644 --- a/tools/testing/selftests/kvm/arm64/arch_timer_edge_cases.c +++ b/tools/testing/selftests/kvm/arm64/arch_timer_edge_cases.c @@ -22,7 +22,8 @@ #include "gic.h" #include "vgic.h"

-static const uint64_t CVAL_MAX = ~0ULL; +/* Depends on counter width. */ +static uint64_t CVAL_MAX; /* tval is a signed 32-bit int. */ static const int32_t TVAL_MAX = INT32_MAX; static const int32_t TVAL_MIN = INT32_MIN; @@ -30,8 +31,8 @@ static const int32_t TVAL_MIN = INT32_MIN; /* After how much time we say there is no IRQ. */ static const uint32_t TIMEOUT_NO_IRQ_US = 50000;

-/* A nice counter value to use as the starting one for most tests. */ -static const uint64_t DEF_CNT = (CVAL_MAX / 2); +/* Counter value to use as the starting one for most tests. Set to CVAL_MAX/2 */ +static uint64_t DEF_CNT;

/* Number of runs. */ static const uint32_t NR_TEST_ITERS_DEF = 5; @@ -732,12 +733,6 @@ static void test_move_counters_ahead_of_timers(enum arch_timer timer) test_set_cnt_after_tval(timer, 0, tval, (uint64_t) tval + 1, wm); } - - for (i = 0; i < ARRAY_SIZE(sleep_method); i++) { - sleep_method_t sm = sleep_method[i]; - - test_set_cnt_after_cval_no_irq(timer, 0, DEF_CNT, CVAL_MAX, sm); - } }

/* @@ -975,6 +970,8 @@ static void test_vm_create(struct kvm_vm **vm, struct kvm_vcpu **vcpu, test_init_timer_irq(*vm, *vcpu); vgic_v3_setup(*vm, 1, 64); sync_global_to_guest(*vm, test_args); + sync_global_to_guest(*vm, CVAL_MAX); + sync_global_to_guest(*vm, DEF_CNT); }

static void test_print_help(char *name) @@ -1035,6 +1032,17 @@ static bool parse_args(int argc, char *argv[]) return false; }

+static void set_counter_defaults(void) +{ + const uint64_t MIN_ROLLOVER_SECS = 40ULL * 365 * 24 * 3600; + uint64_t freq = read_sysreg(CNTFRQ_EL0); + uint64_t width = ilog2(MIN_ROLLOVER_SECS * freq); + + width = clamp(width, 56, 64); + CVAL_MAX = GENMASK_ULL(width - 1, 0); + DEF_CNT = CVAL_MAX / 2; +} + int main(int argc, char *argv[]) { struct kvm_vcpu *vcpu; @@ -1047,6 +1055,7 @@ int main(int argc, char *argv[]) exit(KSFT_SKIP);

sched_getaffinity(0, sizeof(default_cpuset), &default_cpuset); + set_counter_defaults();

if (test_args.test_virtual) { test_vm_create(&vm, &vcpu, VIRTUAL);