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-rw-r--r--tools/testing/selftests/kvm/Makefile1
-rw-r--r--tools/testing/selftests/kvm/aarch64/smccc_filter.c268
-rw-r--r--tools/testing/selftests/kvm/include/aarch64/processor.h13
-rw-r--r--tools/testing/selftests/kvm/lib/aarch64/processor.c52
4 files changed, 315 insertions, 19 deletions
diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
index 84a627c43795..d66a0642cffd 100644
--- a/tools/testing/selftests/kvm/Makefile
+++ b/tools/testing/selftests/kvm/Makefile
@@ -141,6 +141,7 @@ TEST_GEN_PROGS_aarch64 += aarch64/get-reg-list
TEST_GEN_PROGS_aarch64 += aarch64/hypercalls
TEST_GEN_PROGS_aarch64 += aarch64/page_fault_test
TEST_GEN_PROGS_aarch64 += aarch64/psci_test
+TEST_GEN_PROGS_aarch64 += aarch64/smccc_filter
TEST_GEN_PROGS_aarch64 += aarch64/vcpu_width_config
TEST_GEN_PROGS_aarch64 += aarch64/vgic_init
TEST_GEN_PROGS_aarch64 += aarch64/vgic_irq
diff --git a/tools/testing/selftests/kvm/aarch64/smccc_filter.c b/tools/testing/selftests/kvm/aarch64/smccc_filter.c
new file mode 100644
index 000000000000..f4ceae9c8925
--- /dev/null
+++ b/tools/testing/selftests/kvm/aarch64/smccc_filter.c
@@ -0,0 +1,268 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * smccc_filter - Tests for the SMCCC filter UAPI.
+ *
+ * Copyright (c) 2023 Google LLC
+ *
+ * This test includes:
+ * - Tests that the UAPI constraints are upheld by KVM. For example, userspace
+ * is prevented from filtering the architecture range of SMCCC calls.
+ * - Test that the filter actions (DENIED, FWD_TO_USER) work as intended.
+ */
+
+#include <linux/arm-smccc.h>
+#include <linux/psci.h>
+#include <stdint.h>
+
+#include "processor.h"
+#include "test_util.h"
+
+enum smccc_conduit {
+ HVC_INSN,
+ SMC_INSN,
+};
+
+#define for_each_conduit(conduit) \
+ for (conduit = HVC_INSN; conduit <= SMC_INSN; conduit++)
+
+static void guest_main(uint32_t func_id, enum smccc_conduit conduit)
+{
+ struct arm_smccc_res res;
+
+ if (conduit == SMC_INSN)
+ smccc_smc(func_id, 0, 0, 0, 0, 0, 0, 0, &res);
+ else
+ smccc_hvc(func_id, 0, 0, 0, 0, 0, 0, 0, &res);
+
+ GUEST_SYNC(res.a0);
+}
+
+static int __set_smccc_filter(struct kvm_vm *vm, uint32_t start, uint32_t nr_functions,
+ enum kvm_smccc_filter_action action)
+{
+ struct kvm_smccc_filter filter = {
+ .base = start,
+ .nr_functions = nr_functions,
+ .action = action,
+ };
+
+ return __kvm_device_attr_set(vm->fd, KVM_ARM_VM_SMCCC_CTRL,
+ KVM_ARM_VM_SMCCC_FILTER, &filter);
+}
+
+static void set_smccc_filter(struct kvm_vm *vm, uint32_t start, uint32_t nr_functions,
+ enum kvm_smccc_filter_action action)
+{
+ int ret = __set_smccc_filter(vm, start, nr_functions, action);
+
+ TEST_ASSERT(!ret, "failed to configure SMCCC filter: %d", ret);
+}
+
+static struct kvm_vm *setup_vm(struct kvm_vcpu **vcpu)
+{
+ struct kvm_vcpu_init init;
+ struct kvm_vm *vm;
+
+ vm = vm_create(1);
+ vm_ioctl(vm, KVM_ARM_PREFERRED_TARGET, &init);
+
+ /*
+ * Enable in-kernel emulation of PSCI to ensure that calls are denied
+ * due to the SMCCC filter, not because of KVM.
+ */
+ init.features[0] |= (1 << KVM_ARM_VCPU_PSCI_0_2);
+
+ *vcpu = aarch64_vcpu_add(vm, 0, &init, guest_main);
+ return vm;
+}
+
+static void test_pad_must_be_zero(void)
+{
+ struct kvm_vcpu *vcpu;
+ struct kvm_vm *vm = setup_vm(&vcpu);
+ struct kvm_smccc_filter filter = {
+ .base = PSCI_0_2_FN_PSCI_VERSION,
+ .nr_functions = 1,
+ .action = KVM_SMCCC_FILTER_DENY,
+ .pad = { -1 },
+ };
+ int r;
+
+ r = __kvm_device_attr_set(vm->fd, KVM_ARM_VM_SMCCC_CTRL,
+ KVM_ARM_VM_SMCCC_FILTER, &filter);
+ TEST_ASSERT(r < 0 && errno == EINVAL,
+ "Setting filter with nonzero padding should return EINVAL");
+}
+
+/* Ensure that userspace cannot filter the Arm Architecture SMCCC range */
+static void test_filter_reserved_range(void)
+{
+ struct kvm_vcpu *vcpu;
+ struct kvm_vm *vm = setup_vm(&vcpu);
+ uint32_t smc64_fn;
+ int r;
+
+ r = __set_smccc_filter(vm, ARM_SMCCC_ARCH_WORKAROUND_1,
+ 1, KVM_SMCCC_FILTER_DENY);
+ TEST_ASSERT(r < 0 && errno == EEXIST,
+ "Attempt to filter reserved range should return EEXIST");
+
+ smc64_fn = ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, ARM_SMCCC_SMC_64,
+ 0, 0);
+
+ r = __set_smccc_filter(vm, smc64_fn, 1, KVM_SMCCC_FILTER_DENY);
+ TEST_ASSERT(r < 0 && errno == EEXIST,
+ "Attempt to filter reserved range should return EEXIST");
+
+ kvm_vm_free(vm);
+}
+
+static void test_invalid_nr_functions(void)
+{
+ struct kvm_vcpu *vcpu;
+ struct kvm_vm *vm = setup_vm(&vcpu);
+ int r;
+
+ r = __set_smccc_filter(vm, PSCI_0_2_FN64_CPU_ON, 0, KVM_SMCCC_FILTER_DENY);
+ TEST_ASSERT(r < 0 && errno == EINVAL,
+ "Attempt to filter 0 functions should return EINVAL");
+
+ kvm_vm_free(vm);
+}
+
+static void test_overflow_nr_functions(void)
+{
+ struct kvm_vcpu *vcpu;
+ struct kvm_vm *vm = setup_vm(&vcpu);
+ int r;
+
+ r = __set_smccc_filter(vm, ~0, ~0, KVM_SMCCC_FILTER_DENY);
+ TEST_ASSERT(r < 0 && errno == EINVAL,
+ "Attempt to overflow filter range should return EINVAL");
+
+ kvm_vm_free(vm);
+}
+
+static void test_reserved_action(void)
+{
+ struct kvm_vcpu *vcpu;
+ struct kvm_vm *vm = setup_vm(&vcpu);
+ int r;
+
+ r = __set_smccc_filter(vm, PSCI_0_2_FN64_CPU_ON, 1, -1);
+ TEST_ASSERT(r < 0 && errno == EINVAL,
+ "Attempt to use reserved filter action should return EINVAL");
+
+ kvm_vm_free(vm);
+}
+
+
+/* Test that overlapping configurations of the SMCCC filter are rejected */
+static void test_filter_overlap(void)
+{
+ struct kvm_vcpu *vcpu;
+ struct kvm_vm *vm = setup_vm(&vcpu);
+ int r;
+
+ set_smccc_filter(vm, PSCI_0_2_FN64_CPU_ON, 1, KVM_SMCCC_FILTER_DENY);
+
+ r = __set_smccc_filter(vm, PSCI_0_2_FN64_CPU_ON, 1, KVM_SMCCC_FILTER_DENY);
+ TEST_ASSERT(r < 0 && errno == EEXIST,
+ "Attempt to filter already configured range should return EEXIST");
+
+ kvm_vm_free(vm);
+}
+
+static void expect_call_denied(struct kvm_vcpu *vcpu)
+{
+ struct ucall uc;
+
+ if (get_ucall(vcpu, &uc) != UCALL_SYNC)
+ TEST_FAIL("Unexpected ucall: %lu\n", uc.cmd);
+
+ TEST_ASSERT(uc.args[1] == SMCCC_RET_NOT_SUPPORTED,
+ "Unexpected SMCCC return code: %lu", uc.args[1]);
+}
+
+/* Denied SMCCC calls have a return code of SMCCC_RET_NOT_SUPPORTED */
+static void test_filter_denied(void)
+{
+ enum smccc_conduit conduit;
+ struct kvm_vcpu *vcpu;
+ struct kvm_vm *vm;
+
+ for_each_conduit(conduit) {
+ vm = setup_vm(&vcpu);
+
+ set_smccc_filter(vm, PSCI_0_2_FN_PSCI_VERSION, 1, KVM_SMCCC_FILTER_DENY);
+ vcpu_args_set(vcpu, 2, PSCI_0_2_FN_PSCI_VERSION, conduit);
+
+ vcpu_run(vcpu);
+ expect_call_denied(vcpu);
+
+ kvm_vm_free(vm);
+ }
+}
+
+static void expect_call_fwd_to_user(struct kvm_vcpu *vcpu, uint32_t func_id,
+ enum smccc_conduit conduit)
+{
+ struct kvm_run *run = vcpu->run;
+
+ TEST_ASSERT(run->exit_reason == KVM_EXIT_HYPERCALL,
+ "Unexpected exit reason: %u", run->exit_reason);
+ TEST_ASSERT(run->hypercall.nr == func_id,
+ "Unexpected SMCCC function: %llu", run->hypercall.nr);
+
+ if (conduit == SMC_INSN)
+ TEST_ASSERT(run->hypercall.flags & KVM_HYPERCALL_EXIT_SMC,
+ "KVM_HYPERCALL_EXIT_SMC is not set");
+ else
+ TEST_ASSERT(!(run->hypercall.flags & KVM_HYPERCALL_EXIT_SMC),
+ "KVM_HYPERCALL_EXIT_SMC is set");
+}
+
+/* SMCCC calls forwarded to userspace cause KVM_EXIT_HYPERCALL exits */
+static void test_filter_fwd_to_user(void)
+{
+ enum smccc_conduit conduit;
+ struct kvm_vcpu *vcpu;
+ struct kvm_vm *vm;
+
+ for_each_conduit(conduit) {
+ vm = setup_vm(&vcpu);
+
+ set_smccc_filter(vm, PSCI_0_2_FN_PSCI_VERSION, 1, KVM_SMCCC_FILTER_FWD_TO_USER);
+ vcpu_args_set(vcpu, 2, PSCI_0_2_FN_PSCI_VERSION, conduit);
+
+ vcpu_run(vcpu);
+ expect_call_fwd_to_user(vcpu, PSCI_0_2_FN_PSCI_VERSION, conduit);
+
+ kvm_vm_free(vm);
+ }
+}
+
+static bool kvm_supports_smccc_filter(void)
+{
+ struct kvm_vm *vm = vm_create_barebones();
+ int r;
+
+ r = __kvm_has_device_attr(vm->fd, KVM_ARM_VM_SMCCC_CTRL, KVM_ARM_VM_SMCCC_FILTER);
+
+ kvm_vm_free(vm);
+ return !r;
+}
+
+int main(void)
+{
+ TEST_REQUIRE(kvm_supports_smccc_filter());
+
+ test_pad_must_be_zero();
+ test_invalid_nr_functions();
+ test_overflow_nr_functions();
+ test_reserved_action();
+ test_filter_reserved_range();
+ test_filter_overlap();
+ test_filter_denied();
+ test_filter_fwd_to_user();
+}
diff --git a/tools/testing/selftests/kvm/include/aarch64/processor.h b/tools/testing/selftests/kvm/include/aarch64/processor.h
index 5f977528e09c..cb537253a6b9 100644
--- a/tools/testing/selftests/kvm/include/aarch64/processor.h
+++ b/tools/testing/selftests/kvm/include/aarch64/processor.h
@@ -214,6 +214,19 @@ void smccc_hvc(uint32_t function_id, uint64_t arg0, uint64_t arg1,
uint64_t arg2, uint64_t arg3, uint64_t arg4, uint64_t arg5,
uint64_t arg6, struct arm_smccc_res *res);
+/**
+ * smccc_smc - Invoke a SMCCC function using the smc conduit
+ * @function_id: the SMCCC function to be called
+ * @arg0-arg6: SMCCC function arguments, corresponding to registers x1-x7
+ * @res: pointer to write the return values from registers x0-x3
+ *
+ */
+void smccc_smc(uint32_t function_id, uint64_t arg0, uint64_t arg1,
+ uint64_t arg2, uint64_t arg3, uint64_t arg4, uint64_t arg5,
+ uint64_t arg6, struct arm_smccc_res *res);
+
+
+
uint32_t guest_get_vcpuid(void);
#endif /* SELFTEST_KVM_PROCESSOR_H */
diff --git a/tools/testing/selftests/kvm/lib/aarch64/processor.c b/tools/testing/selftests/kvm/lib/aarch64/processor.c
index 233357d2f1cc..3a0259e25335 100644
--- a/tools/testing/selftests/kvm/lib/aarch64/processor.c
+++ b/tools/testing/selftests/kvm/lib/aarch64/processor.c
@@ -527,29 +527,43 @@ void aarch64_get_supported_page_sizes(uint32_t ipa,
close(kvm_fd);
}
+#define __smccc_call(insn, function_id, arg0, arg1, arg2, arg3, arg4, arg5, \
+ arg6, res) \
+ asm volatile("mov w0, %w[function_id]\n" \
+ "mov x1, %[arg0]\n" \
+ "mov x2, %[arg1]\n" \
+ "mov x3, %[arg2]\n" \
+ "mov x4, %[arg3]\n" \
+ "mov x5, %[arg4]\n" \
+ "mov x6, %[arg5]\n" \
+ "mov x7, %[arg6]\n" \
+ #insn "#0\n" \
+ "mov %[res0], x0\n" \
+ "mov %[res1], x1\n" \
+ "mov %[res2], x2\n" \
+ "mov %[res3], x3\n" \
+ : [res0] "=r"(res->a0), [res1] "=r"(res->a1), \
+ [res2] "=r"(res->a2), [res3] "=r"(res->a3) \
+ : [function_id] "r"(function_id), [arg0] "r"(arg0), \
+ [arg1] "r"(arg1), [arg2] "r"(arg2), [arg3] "r"(arg3), \
+ [arg4] "r"(arg4), [arg5] "r"(arg5), [arg6] "r"(arg6) \
+ : "x0", "x1", "x2", "x3", "x4", "x5", "x6", "x7")
+
+
void smccc_hvc(uint32_t function_id, uint64_t arg0, uint64_t arg1,
uint64_t arg2, uint64_t arg3, uint64_t arg4, uint64_t arg5,
uint64_t arg6, struct arm_smccc_res *res)
{
- asm volatile("mov w0, %w[function_id]\n"
- "mov x1, %[arg0]\n"
- "mov x2, %[arg1]\n"
- "mov x3, %[arg2]\n"
- "mov x4, %[arg3]\n"
- "mov x5, %[arg4]\n"
- "mov x6, %[arg5]\n"
- "mov x7, %[arg6]\n"
- "hvc #0\n"
- "mov %[res0], x0\n"
- "mov %[res1], x1\n"
- "mov %[res2], x2\n"
- "mov %[res3], x3\n"
- : [res0] "=r"(res->a0), [res1] "=r"(res->a1),
- [res2] "=r"(res->a2), [res3] "=r"(res->a3)
- : [function_id] "r"(function_id), [arg0] "r"(arg0),
- [arg1] "r"(arg1), [arg2] "r"(arg2), [arg3] "r"(arg3),
- [arg4] "r"(arg4), [arg5] "r"(arg5), [arg6] "r"(arg6)
- : "x0", "x1", "x2", "x3", "x4", "x5", "x6", "x7");
+ __smccc_call(hvc, function_id, arg0, arg1, arg2, arg3, arg4, arg5,
+ arg6, res);
+}
+
+void smccc_smc(uint32_t function_id, uint64_t arg0, uint64_t arg1,
+ uint64_t arg2, uint64_t arg3, uint64_t arg4, uint64_t arg5,
+ uint64_t arg6, struct arm_smccc_res *res)
+{
+ __smccc_call(smc, function_id, arg0, arg1, arg2, arg3, arg4, arg5,
+ arg6, res);
}
void kvm_selftest_arch_init(void)
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.