KVM: arm64: selftests: Add a test for FEAT_IDST

Add a very basic test checking that FEAT_IDST actually works for
the {GMID,SMIDR,CSSIDR2}_EL1 registers.

Link: https://patch.msgid.link/20260108173233.2911955-10-maz@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>

diff --git a/tools/testing/selftests/kvm/Makefile.kvm b/tools/testing/selftests/kvm/Makefile.kvm
index ba5c2b643efaa263f90185b72fe59ecb0fcd6dbc..bfa2fad0aba121903352c2931ea3e697c3621291 100644 (file)
--- a/tools/testing/selftests/kvm/Makefile.kvm
+++ b/tools/testing/selftests/kvm/Makefile.kvm
@@ -175,6 +175,7 @@ TEST_GEN_PROGS_arm64 += arm64/vgic_irq
 TEST_GEN_PROGS_arm64 += arm64/vgic_lpi_stress
 TEST_GEN_PROGS_arm64 += arm64/vpmu_counter_access
 TEST_GEN_PROGS_arm64 += arm64/no-vgic-v3
+TEST_GEN_PROGS_arm64 += arm64/idreg-idst
 TEST_GEN_PROGS_arm64 += arm64/kvm-uuid
 TEST_GEN_PROGS_arm64 += access_tracking_perf_test
 TEST_GEN_PROGS_arm64 += arch_timer

diff --git a/tools/testing/selftests/kvm/arm64/idreg-idst.c b/tools/testing/selftests/kvm/arm64/idreg-idst.c
new file mode 100644 (file)
index 0000000..9ca9f12
--- /dev/null
+++ b/tools/testing/selftests/kvm/arm64/idreg-idst.c
@@ -0,0 +1,117 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Access all FEAT_IDST-handled registers that depend on more than
+ * just FEAT_AA64, and fail if we don't get an a trap with an 0x18 EC.
+ */
+
+#include <test_util.h>
+#include <kvm_util.h>
+#include <processor.h>
+
+static volatile bool sys64, undef;
+
+#define __check_sr_read(r)                                     \
+       ({                                                      \
+               uint64_t val;                                   \
+                                                               \
+               sys64 = false;                                  \
+               undef = false;                                  \
+               dsb(sy);                                        \
+               val = read_sysreg_s(SYS_ ## r);                 \
+               val;                                            \
+       })
+
+/* Fatal checks */
+#define check_sr_read(r)                                       \
+       do {                                                    \
+               __check_sr_read(r);                             \
+               __GUEST_ASSERT(!undef, #r " unexpected UNDEF"); \
+               __GUEST_ASSERT(sys64, #r " didn't trap");       \
+       } while(0)
+
+
+static void guest_code(void)
+{
+       check_sr_read(CCSIDR2_EL1);
+       check_sr_read(SMIDR_EL1);
+       check_sr_read(GMID_EL1);
+
+       GUEST_DONE();
+}
+
+static void guest_sys64_handler(struct ex_regs *regs)
+{
+       sys64 = true;
+       undef = false;
+       regs->pc += 4;
+}
+
+static void guest_undef_handler(struct ex_regs *regs)
+{
+       sys64 = false;
+       undef = true;
+       regs->pc += 4;
+}
+
+static void test_run_vcpu(struct kvm_vcpu *vcpu)
+{
+       struct ucall uc;
+
+       do {
+               vcpu_run(vcpu);
+
+               switch (get_ucall(vcpu, &uc)) {
+               case UCALL_ABORT:
+                       REPORT_GUEST_ASSERT(uc);
+                       break;
+               case UCALL_PRINTF:
+                       printf("%s", uc.buffer);
+                       break;
+               case UCALL_DONE:
+                       break;
+               default:
+                       TEST_FAIL("Unknown ucall %lu", uc.cmd);
+               }
+       } while (uc.cmd != UCALL_DONE);
+}
+
+static void test_guest_feat_idst(void)
+{
+       struct kvm_vcpu *vcpu;
+       struct kvm_vm *vm;
+
+       /* This VM has no MTE, no SME, no CCIDX */
+       vm = vm_create_with_one_vcpu(&vcpu, guest_code);
+
+       vm_init_descriptor_tables(vm);
+       vcpu_init_descriptor_tables(vcpu);
+
+       vm_install_sync_handler(vm, VECTOR_SYNC_CURRENT,
+                               ESR_ELx_EC_SYS64, guest_sys64_handler);
+       vm_install_sync_handler(vm, VECTOR_SYNC_CURRENT,
+                               ESR_ELx_EC_UNKNOWN, guest_undef_handler);
+
+       test_run_vcpu(vcpu);
+
+       kvm_vm_free(vm);
+}
+
+int main(int argc, char *argv[])
+{
+       struct kvm_vcpu *vcpu;
+       struct kvm_vm *vm;
+       uint64_t mmfr2;
+
+       test_disable_default_vgic();
+
+       vm = vm_create_with_one_vcpu(&vcpu, NULL);
+       mmfr2 = vcpu_get_reg(vcpu, KVM_ARM64_SYS_REG(SYS_ID_AA64MMFR2_EL1));
+       __TEST_REQUIRE(FIELD_GET(ID_AA64MMFR2_EL1_IDS, mmfr2) > 0,
+                      "FEAT_IDST not supported");
+       kvm_vm_free(vm);
+
+       test_guest_feat_idst();
+
+       return 0;
+}