linux-kernel - [PATCH] KVM: LoongArch: selftests: Add steal time test case

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Message-Id: <20260129021839.3674879-1-maobibo@loongson.cn>
Date: Thu, 29 Jan 2026 10:18:39 +0800
From: Bibo Mao <maobibo@...ngson.cn>
To: Huacai Chen <chenhuacai@...nel.org>,
	Paolo Bonzini <pbonzini@...hat.com>,
	Shuah Khan <shuah@...nel.org>
Cc: kvm@...r.kernel.org,
	linux-kselftest@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH] KVM: LoongArch: selftests: Add steal time test case

LoongArch KVM supports steal time accounting now, here add steal time
test case on LoongArch.

Signed-off-by: Bibo Mao <maobibo@...ngson.cn>
---
 tools/testing/selftests/kvm/Makefile.kvm |  1 +
 tools/testing/selftests/kvm/steal_time.c | 85 ++++++++++++++++++++++++
 2 files changed, 86 insertions(+)

diff --git a/tools/testing/selftests/kvm/Makefile.kvm b/tools/testing/selftests/kvm/Makefile.kvm
index ba5c2b643efa..a18c00f1a4fa 100644
--- a/tools/testing/selftests/kvm/Makefile.kvm
+++ b/tools/testing/selftests/kvm/Makefile.kvm
@@ -228,6 +228,7 @@ TEST_GEN_PROGS_loongarch += kvm_page_table_test
 TEST_GEN_PROGS_loongarch += memslot_modification_stress_test
 TEST_GEN_PROGS_loongarch += memslot_perf_test
 TEST_GEN_PROGS_loongarch += set_memory_region_test
+TEST_GEN_PROGS_loongarch += steal_time
 
 SPLIT_TESTS += arch_timer
 SPLIT_TESTS += get-reg-list
diff --git a/tools/testing/selftests/kvm/steal_time.c b/tools/testing/selftests/kvm/steal_time.c
index 8edc1fca345b..ee13e8973c45 100644
--- a/tools/testing/selftests/kvm/steal_time.c
+++ b/tools/testing/selftests/kvm/steal_time.c
@@ -301,6 +301,91 @@ static void steal_time_dump(struct kvm_vm *vm, uint32_t vcpu_idx)
 	pr_info("\n");
 }
 
+#elif defined(__loongarch__)
+/* steal_time must have 64-byte alignment */
+#define STEAL_TIME_SIZE		((sizeof(struct kvm_steal_time) + 63) & ~63)
+#define KVM_STEAL_PHYS_VALID	BIT_ULL(0)
+
+struct kvm_steal_time {
+	__u64 steal;
+	__u32 version;
+	__u32 flags;
+	__u32 pad[12];
+};
+
+static bool is_steal_time_supported(struct kvm_vcpu *vcpu)
+{
+	int err;
+	uint64_t val;
+	struct kvm_device_attr attr = {
+		.group = KVM_LOONGARCH_VCPU_CPUCFG,
+		.attr = CPUCFG_KVM_FEATURE,
+		.addr = (uint64_t)&val,
+	};
+
+	err = __vcpu_ioctl(vcpu, KVM_HAS_DEVICE_ATTR, &attr);
+	if (err)
+		return false;
+
+	err = __vcpu_ioctl(vcpu, KVM_GET_DEVICE_ATTR, &attr);
+	if (err)
+		return false;
+
+	return val & BIT(KVM_FEATURE_STEAL_TIME);
+}
+
+static void steal_time_init(struct kvm_vcpu *vcpu, uint32_t i)
+{
+	struct kvm_vm *vm = vcpu->vm;
+	uint64_t st_gpa;
+	int err;
+	struct kvm_device_attr attr = {
+		.group = KVM_LOONGARCH_VCPU_PVTIME_CTRL,
+		.attr = KVM_LOONGARCH_VCPU_PVTIME_GPA,
+		.addr = (uint64_t)&st_gpa,
+	};
+
+	/* ST_GPA_BASE is identity mapped */
+	st_gva[i] = (void *)(ST_GPA_BASE + i * STEAL_TIME_SIZE);
+	sync_global_to_guest(vm, st_gva[i]);
+
+	err = __vcpu_ioctl(vcpu, KVM_HAS_DEVICE_ATTR, &attr);
+	TEST_ASSERT(err == 0, "No PV stealtime Feature");
+
+	st_gpa = (unsigned long)st_gva[i] | KVM_STEAL_PHYS_VALID;
+	err = __vcpu_ioctl(vcpu, KVM_SET_DEVICE_ATTR, &attr);
+	TEST_ASSERT(err == 0, "Fail to set PV stealtime GPA");
+}
+
+static void guest_code(int cpu)
+{
+	struct kvm_steal_time *st = st_gva[cpu];
+	uint32_t version;
+
+	memset(st, 0, sizeof(*st));
+	GUEST_SYNC(0);
+
+	GUEST_ASSERT(!(READ_ONCE(st->version) & 1));
+	WRITE_ONCE(guest_stolen_time[cpu], st->steal);
+	version = READ_ONCE(st->version);
+	GUEST_ASSERT(!(READ_ONCE(st->version) & 1));
+	GUEST_SYNC(1);
+
+	GUEST_ASSERT(!(READ_ONCE(st->version) & 1));
+	GUEST_ASSERT(version < READ_ONCE(st->version));
+	WRITE_ONCE(guest_stolen_time[cpu], st->steal);
+	GUEST_ASSERT(!(READ_ONCE(st->version) & 1));
+	GUEST_DONE();
+}
+
+static void steal_time_dump(struct kvm_vm *vm, uint32_t vcpu_idx)
+{
+	struct kvm_steal_time *st = addr_gva2hva(vm, (ulong)st_gva[vcpu_idx]);
+
+	ksft_print_msg("VCPU%d:\n", vcpu_idx);
+	ksft_print_msg("    steal:     %lld\n", st->steal);
+	ksft_print_msg("    version:   %d\n", st->version);
+}
 #endif
 
 static void *do_steal_time(void *arg)

base-commit: 8dfce8991b95d8625d0a1d2896e42f93b9d7f68d
-- 
2.39.3