[PATCH 2/2] KVM: arm64: selftests: Add KVM_CAP_ARM_DISABLE_EXITS UAPI test

[David Woodhouse]

From: David Woodhouse <dwmw at amazon.co.uk>

Test the KVM_CAP_ARM_DISABLE_EXITS capability interface:
 - KVM_CHECK_EXTENSION reports KVM_ARM_DISABLE_EXITS_WFI
 - KVM_ENABLE_CAP succeeds with valid flags (WFI, zero)
 - KVM_ENABLE_CAP fails with EINVAL for unknown flags

Signed-off-by: David Woodhouse <dwmw at amazon.co.uk>
---
 tools/testing/selftests/kvm/Makefile.kvm      |  1 +
 .../selftests/kvm/arm64/disable_exits.c       | 48 +++++++++++++++++++
 2 files changed, 49 insertions(+)
 create mode 100644 tools/testing/selftests/kvm/arm64/disable_exits.c

diff --git a/tools/testing/selftests/kvm/Makefile.kvm b/tools/testing/selftests/kvm/Makefile.kvm
index 878d7cb92555..d8e7ff122445 100644
--- a/tools/testing/selftests/kvm/Makefile.kvm
+++ b/tools/testing/selftests/kvm/Makefile.kvm
@@ -179,6 +179,7 @@ TEST_GEN_PROGS_arm64 += arm64/vgic_irq
 TEST_GEN_PROGS_arm64 += arm64/vgic_lpi_stress
 TEST_GEN_PROGS_arm64 += arm64/vgic_group_iidr
 TEST_GEN_PROGS_arm64 += arm64/vgic_group_v2
+TEST_GEN_PROGS_arm64 += arm64/disable_exits
 TEST_GEN_PROGS_arm64 += arm64/vpmu_counter_access
 TEST_GEN_PROGS_arm64 += arm64/no-vgic-v3
 TEST_GEN_PROGS_arm64 += arm64/idreg-idst
diff --git a/tools/testing/selftests/kvm/arm64/disable_exits.c b/tools/testing/selftests/kvm/arm64/disable_exits.c
new file mode 100644
index 000000000000..27fe6c9297b2
--- /dev/null
+++ b/tools/testing/selftests/kvm/arm64/disable_exits.c
@@ -0,0 +1,48 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * disable_exits.c - Test KVM_CAP_ARM_DISABLE_EXITS UAPI
+ *
+ * Verify that KVM_CHECK_EXTENSION reports the valid exit disable mask
+ * and that KVM_ENABLE_CAP accepts valid flags and rejects invalid ones.
+ */
+#include "test_util.h"
+#include "kvm_util.h"
+#include "processor.h"
+
+int main(int argc, char *argv[])
+{
+	struct kvm_vm *vm;
+	int r;
+
+	TEST_REQUIRE(kvm_has_cap(KVM_CAP_ARM_DISABLE_EXITS));
+
+	r = kvm_check_cap(KVM_CAP_ARM_DISABLE_EXITS);
+	TEST_ASSERT(r & KVM_ARM_DISABLE_EXITS_WFI,
+		    "KVM_CHECK_EXTENSION should report WFI: got 0x%x", r);
+	TEST_ASSERT(r & KVM_ARM_DISABLE_EXITS_WFE,
+		    "KVM_CHECK_EXTENSION should report WFE: got 0x%x", r);
+
+	vm = vm_create(1);
+
+	/* Valid: disable WFI trapping */
+	vm_enable_cap(vm, KVM_CAP_ARM_DISABLE_EXITS, KVM_ARM_DISABLE_EXITS_WFI);
+
+	/* Valid: disable WFE trapping */
+	vm_enable_cap(vm, KVM_CAP_ARM_DISABLE_EXITS, KVM_ARM_DISABLE_EXITS_WFE);
+
+	/* Valid: disable both */
+	vm_enable_cap(vm, KVM_CAP_ARM_DISABLE_EXITS,
+		      KVM_ARM_DISABLE_EXITS_WFI | KVM_ARM_DISABLE_EXITS_WFE);
+
+	/* Valid: no exits disabled (no-op) */
+	vm_enable_cap(vm, KVM_CAP_ARM_DISABLE_EXITS, 0);
+
+	/* Invalid: unknown bit set */
+	r = __vm_enable_cap(vm, KVM_CAP_ARM_DISABLE_EXITS, 1ULL << 31);
+	TEST_ASSERT(r == -1 && errno == EINVAL,
+		    "Unknown flags should fail with EINVAL: got %d errno %d",
+		    r, errno);
+
+	kvm_vm_free(vm);
+	return 0;
+}
-- 
2.51.0