[v4,4/4] KVM: PPC: selftests: powerpc enable kvm_create_max_vcpus test

Commit Message

Nicholas Piggin Nov. 20, 2023, 12:29 p.m. UTC

powerpc's maximum permitted vCPU ID depends on the VM's SMT mode, and
the maximum reported by KVM_CAP_MAX_VCPU_ID exceeds a simple non-SMT
VM's limit.

The powerpc KVM selftest port uses non-SMT VMs, so add a workaround
to the kvm_create_max_vcpus test case to limit vCPU IDs to
KVM_CAP_MAX_VCPUS on powerpc. And enable the test case.

Signed-off-by: Nicholas Piggin <[e-mail]>
---
 tools/testing/selftests/kvm/Makefile               | 1 +
 tools/testing/selftests/kvm/kvm_create_max_vcpus.c | 9 +++++++++
 2 files changed, 10 insertions(+)

Patch

diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
index a198fe6136c8..1e904d8871d7 100644
--- a/tools/testing/selftests/kvm/Makefile
+++ b/tools/testing/selftests/kvm/Makefile
@@ -211,6 +211,7 @@  TEST_GEN_PROGS_powerpc += dirty_log_test
 TEST_GEN_PROGS_powerpc += dirty_log_perf_test
 TEST_GEN_PROGS_powerpc += guest_print_test
 TEST_GEN_PROGS_powerpc += hardware_disable_test
+TEST_GEN_PROGS_powerpc += kvm_create_max_vcpus
 TEST_GEN_PROGS_powerpc += kvm_page_table_test
 TEST_GEN_PROGS_powerpc += max_guest_memory_test
 TEST_GEN_PROGS_powerpc += memslot_modification_stress_test
diff --git a/tools/testing/selftests/kvm/kvm_create_max_vcpus.c b/tools/testing/selftests/kvm/kvm_create_max_vcpus.c
index 31b3cb24b9a7..330ede73c147 100644
--- a/tools/testing/selftests/kvm/kvm_create_max_vcpus.c
+++ b/tools/testing/selftests/kvm/kvm_create_max_vcpus.c
@@ -51,6 +51,15 @@  int main(int argc, char *argv[])
 	pr_info("KVM_CAP_MAX_VCPU_ID: %d\n", kvm_max_vcpu_id);
 	pr_info("KVM_CAP_MAX_VCPUS: %d\n", kvm_max_vcpus);
 
+#ifdef __powerpc64__
+	/*
+	 * powerpc has a particular format for the vcpu ID that depends on
+	 * the guest SMT mode, and the max ID cap is too large for non-SMT
+	 * modes, where the maximum ID is the same as the maximum vCPUs.
+	 */
+	kvm_max_vcpu_id = kvm_max_vcpus;
+#endif
+
 	/*
 	 * Check that we're allowed to open nr_fds_wanted file descriptors and
 	 * try raising the limits if needed.