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    Subject[PATCH v7 8/9] selftests: KVM: aarch64: Introduce hypercall ABI test
    From
    Introduce a KVM selftest to check the hypercall interface
    for arm64 platforms. The test validates the user-space'
    [GET|SET]_ONE_REG interface to read/write the psuedo-firmware
    registers as well as its effects on the guest upon certain
    configurations.

    Signed-off-by: Raghavendra Rao Ananta <rananta@google.com>
    Reviewed-by: Gavin Shan <gshan@redhat.com>
    ---
    tools/testing/selftests/kvm/.gitignore | 1 +
    tools/testing/selftests/kvm/Makefile | 1 +
    .../selftests/kvm/aarch64/hypercalls.c | 336 ++++++++++++++++++
    3 files changed, 338 insertions(+)
    create mode 100644 tools/testing/selftests/kvm/aarch64/hypercalls.c

    diff --git a/tools/testing/selftests/kvm/.gitignore b/tools/testing/selftests/kvm/.gitignore
    index 1bb575dfc42e..b17e464ec661 100644
    --- a/tools/testing/selftests/kvm/.gitignore
    +++ b/tools/testing/selftests/kvm/.gitignore
    @@ -2,6 +2,7 @@
    /aarch64/arch_timer
    /aarch64/debug-exceptions
    /aarch64/get-reg-list
    +/aarch64/hypercalls
    /aarch64/psci_test
    /aarch64/vcpu_width_config
    /aarch64/vgic_init
    diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
    index c2cf4d318296..97eef0c03d3b 100644
    --- a/tools/testing/selftests/kvm/Makefile
    +++ b/tools/testing/selftests/kvm/Makefile
    @@ -105,6 +105,7 @@ TEST_GEN_PROGS_x86_64 += system_counter_offset_test
    TEST_GEN_PROGS_aarch64 += aarch64/arch_timer
    TEST_GEN_PROGS_aarch64 += aarch64/debug-exceptions
    TEST_GEN_PROGS_aarch64 += aarch64/get-reg-list
    +TEST_GEN_PROGS_aarch64 += aarch64/hypercalls
    TEST_GEN_PROGS_aarch64 += aarch64/psci_test
    TEST_GEN_PROGS_aarch64 += aarch64/vcpu_width_config
    TEST_GEN_PROGS_aarch64 += aarch64/vgic_init
    diff --git a/tools/testing/selftests/kvm/aarch64/hypercalls.c b/tools/testing/selftests/kvm/aarch64/hypercalls.c
    new file mode 100644
    index 000000000000..41e0210b7a5e
    --- /dev/null
    +++ b/tools/testing/selftests/kvm/aarch64/hypercalls.c
    @@ -0,0 +1,336 @@
    +// SPDX-License-Identifier: GPL-2.0-only
    +
    +/* hypercalls: Check the ARM64's psuedo-firmware bitmap register interface.
    + *
    + * The test validates the basic hypercall functionalities that are exposed
    + * via the psuedo-firmware bitmap register. This includes the registers'
    + * read/write behavior before and after the VM has started, and if the
    + * hypercalls are properly masked or unmasked to the guest when disabled or
    + * enabled from the KVM userspace, respectively.
    + */
    +
    +#include <errno.h>
    +#include <linux/arm-smccc.h>
    +#include <asm/kvm.h>
    +#include <kvm_util.h>
    +
    +#include "processor.h"
    +
    +#define FW_REG_ULIMIT_VAL(max_feat_bit) (GENMASK(max_feat_bit, 0))
    +
    +/* Last valid bits of the bitmapped firmware registers */
    +#define KVM_REG_ARM_STD_BMAP_BIT_MAX 0
    +#define KVM_REG_ARM_STD_HYP_BMAP_BIT_MAX 0
    +#define KVM_REG_ARM_VENDOR_HYP_BMAP_BIT_MAX 1
    +
    +struct kvm_fw_reg_info {
    + uint64_t reg; /* Register definition */
    + uint64_t max_feat_bit; /* Bit that represents the upper limit of the feature-map */
    +};
    +
    +#define FW_REG_INFO(r) \
    + { \
    + .reg = r, \
    + .max_feat_bit = r##_BIT_MAX, \
    + }
    +
    +static const struct kvm_fw_reg_info fw_reg_info[] = {
    + FW_REG_INFO(KVM_REG_ARM_STD_BMAP),
    + FW_REG_INFO(KVM_REG_ARM_STD_HYP_BMAP),
    + FW_REG_INFO(KVM_REG_ARM_VENDOR_HYP_BMAP),
    +};
    +
    +enum test_stage {
    + TEST_STAGE_REG_IFACE,
    + TEST_STAGE_HVC_IFACE_FEAT_DISABLED,
    + TEST_STAGE_HVC_IFACE_FEAT_ENABLED,
    + TEST_STAGE_HVC_IFACE_FALSE_INFO,
    + TEST_STAGE_END,
    +};
    +
    +static int stage = TEST_STAGE_REG_IFACE;
    +
    +struct test_hvc_info {
    + uint32_t func_id;
    + uint64_t arg1;
    +};
    +
    +#define TEST_HVC_INFO(f, a1) \
    + { \
    + .func_id = f, \
    + .arg1 = a1, \
    + }
    +
    +static const struct test_hvc_info hvc_info[] = {
    + /* KVM_REG_ARM_STD_BMAP */
    + TEST_HVC_INFO(ARM_SMCCC_TRNG_VERSION, 0),
    + TEST_HVC_INFO(ARM_SMCCC_TRNG_FEATURES, ARM_SMCCC_TRNG_RND64),
    + TEST_HVC_INFO(ARM_SMCCC_TRNG_GET_UUID, 0),
    + TEST_HVC_INFO(ARM_SMCCC_TRNG_RND32, 0),
    + TEST_HVC_INFO(ARM_SMCCC_TRNG_RND64, 0),
    +
    + /* KVM_REG_ARM_STD_HYP_BMAP */
    + TEST_HVC_INFO(ARM_SMCCC_ARCH_FEATURES_FUNC_ID, ARM_SMCCC_HV_PV_TIME_FEATURES),
    + TEST_HVC_INFO(ARM_SMCCC_HV_PV_TIME_FEATURES, ARM_SMCCC_HV_PV_TIME_ST),
    + TEST_HVC_INFO(ARM_SMCCC_HV_PV_TIME_ST, 0),
    +
    + /* KVM_REG_ARM_VENDOR_HYP_BMAP */
    + TEST_HVC_INFO(ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID,
    + ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID),
    + TEST_HVC_INFO(ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID, 0),
    + TEST_HVC_INFO(ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID, KVM_PTP_VIRT_COUNTER),
    +};
    +
    +/* Feed false hypercall info to test the KVM behavior */
    +static const struct test_hvc_info false_hvc_info[] = {
    + /* Feature support check against a different family of hypercalls */
    + TEST_HVC_INFO(ARM_SMCCC_TRNG_FEATURES, ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID),
    + TEST_HVC_INFO(ARM_SMCCC_ARCH_FEATURES_FUNC_ID, ARM_SMCCC_TRNG_RND64),
    + TEST_HVC_INFO(ARM_SMCCC_HV_PV_TIME_FEATURES, ARM_SMCCC_TRNG_RND64),
    +};
    +
    +static void guest_test_hvc(const struct test_hvc_info *hc_info)
    +{
    + unsigned int i;
    + struct arm_smccc_res res;
    + unsigned int hvc_info_arr_sz;
    +
    + hvc_info_arr_sz =
    + hc_info == hvc_info ? ARRAY_SIZE(hvc_info) : ARRAY_SIZE(false_hvc_info);
    +
    + for (i = 0; i < hvc_info_arr_sz; i++, hc_info++) {
    + memset(&res, 0, sizeof(res));
    + smccc_hvc(hc_info->func_id, hc_info->arg1, 0, 0, 0, 0, 0, 0, &res);
    +
    + switch (stage) {
    + case TEST_STAGE_HVC_IFACE_FEAT_DISABLED:
    + case TEST_STAGE_HVC_IFACE_FALSE_INFO:
    + GUEST_ASSERT_3(res.a0 == SMCCC_RET_NOT_SUPPORTED,
    + res.a0, hc_info->func_id, hc_info->arg1);
    + break;
    + case TEST_STAGE_HVC_IFACE_FEAT_ENABLED:
    + GUEST_ASSERT_3(res.a0 != SMCCC_RET_NOT_SUPPORTED,
    + res.a0, hc_info->func_id, hc_info->arg1);
    + break;
    + default:
    + GUEST_ASSERT_1(0, stage);
    + }
    + }
    +}
    +
    +static void guest_code(void)
    +{
    + while (stage != TEST_STAGE_END) {
    + switch (stage) {
    + case TEST_STAGE_REG_IFACE:
    + break;
    + case TEST_STAGE_HVC_IFACE_FEAT_DISABLED:
    + case TEST_STAGE_HVC_IFACE_FEAT_ENABLED:
    + guest_test_hvc(hvc_info);
    + break;
    + case TEST_STAGE_HVC_IFACE_FALSE_INFO:
    + guest_test_hvc(false_hvc_info);
    + break;
    + default:
    + GUEST_ASSERT_1(0, stage);
    + }
    +
    + GUEST_SYNC(stage);
    + }
    +
    + GUEST_DONE();
    +}
    +
    +static int set_fw_reg(struct kvm_vm *vm, uint64_t id, uint64_t val)
    +{
    + struct kvm_one_reg reg = {
    + .id = id,
    + .addr = (uint64_t)&val,
    + };
    +
    + return _vcpu_ioctl(vm, 0, KVM_SET_ONE_REG, &reg);
    +}
    +
    +static void get_fw_reg(struct kvm_vm *vm, uint64_t id, uint64_t *addr)
    +{
    + struct kvm_one_reg reg = {
    + .id = id,
    + .addr = (uint64_t)addr,
    + };
    +
    + vcpu_ioctl(vm, 0, KVM_GET_ONE_REG, &reg);
    +}
    +
    +struct st_time {
    + uint32_t rev;
    + uint32_t attr;
    + uint64_t st_time;
    +};
    +
    +#define STEAL_TIME_SIZE ((sizeof(struct st_time) + 63) & ~63)
    +#define ST_GPA_BASE (1 << 30)
    +
    +static void steal_time_init(struct kvm_vm *vm)
    +{
    + uint64_t st_ipa = (ulong)ST_GPA_BASE;
    + unsigned int gpages;
    + struct kvm_device_attr dev = {
    + .group = KVM_ARM_VCPU_PVTIME_CTRL,
    + .attr = KVM_ARM_VCPU_PVTIME_IPA,
    + .addr = (uint64_t)&st_ipa,
    + };
    +
    + gpages = vm_calc_num_guest_pages(VM_MODE_DEFAULT, STEAL_TIME_SIZE);
    + vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS, ST_GPA_BASE, 1, gpages, 0);
    +
    + vcpu_ioctl(vm, 0, KVM_SET_DEVICE_ATTR, &dev);
    +}
    +
    +static void test_fw_regs_before_vm_start(struct kvm_vm *vm)
    +{
    + uint64_t val;
    + unsigned int i;
    + int ret;
    +
    + for (i = 0; i < ARRAY_SIZE(fw_reg_info); i++) {
    + const struct kvm_fw_reg_info *reg_info = &fw_reg_info[i];
    +
    + /* First 'read' should be an upper limit of the features supported */
    + get_fw_reg(vm, reg_info->reg, &val);
    + TEST_ASSERT(val == FW_REG_ULIMIT_VAL(reg_info->max_feat_bit),
    + "Expected all the features to be set for reg: 0x%lx; expected: 0x%lx; read: 0x%lx\n",
    + reg_info->reg, FW_REG_ULIMIT_VAL(reg_info->max_feat_bit), val);
    +
    + /* Test a 'write' by disabling all the features of the register map */
    + ret = set_fw_reg(vm, reg_info->reg, 0);
    + TEST_ASSERT(ret == 0,
    + "Failed to clear all the features of reg: 0x%lx; ret: %d\n",
    + reg_info->reg, errno);
    +
    + get_fw_reg(vm, reg_info->reg, &val);
    + TEST_ASSERT(val == 0,
    + "Expected all the features to be cleared for reg: 0x%lx\n", reg_info->reg);
    +
    + /*
    + * Test enabling a feature that's not supported.
    + * Avoid this check if all the bits are occupied.
    + */
    + if (reg_info->max_feat_bit < 63) {
    + ret = set_fw_reg(vm, reg_info->reg, BIT(reg_info->max_feat_bit + 1));
    + TEST_ASSERT(ret != 0 && errno == EINVAL,
    + "Unexpected behavior or return value (%d) while setting an unsupported feature for reg: 0x%lx\n",
    + errno, reg_info->reg);
    + }
    + }
    +}
    +
    +static void test_fw_regs_after_vm_start(struct kvm_vm *vm)
    +{
    + uint64_t val;
    + unsigned int i;
    + int ret;
    +
    + for (i = 0; i < ARRAY_SIZE(fw_reg_info); i++) {
    + const struct kvm_fw_reg_info *reg_info = &fw_reg_info[i];
    +
    + /*
    + * Before starting the VM, the test clears all the bits.
    + * Check if that's still the case.
    + */
    + get_fw_reg(vm, reg_info->reg, &val);
    + TEST_ASSERT(val == 0,
    + "Expected all the features to be cleared for reg: 0x%lx\n",
    + reg_info->reg);
    +
    + /*
    + * Since the VM has run at least once, KVM shouldn't allow modification of
    + * the registers and should return EBUSY. Set the registers and check for
    + * the expected errno.
    + */
    + ret = set_fw_reg(vm, reg_info->reg, FW_REG_ULIMIT_VAL(reg_info->max_feat_bit));
    + TEST_ASSERT(ret != 0 && errno == EBUSY,
    + "Unexpected behavior or return value (%d) while setting a feature while VM is running for reg: 0x%lx\n",
    + errno, reg_info->reg);
    + }
    +}
    +
    +static struct kvm_vm *test_vm_create(void)
    +{
    + struct kvm_vm *vm;
    +
    + vm = vm_create_default(0, 0, guest_code);
    +
    + ucall_init(vm, NULL);
    + steal_time_init(vm);
    +
    + return vm;
    +}
    +
    +static struct kvm_vm *test_guest_stage(struct kvm_vm *vm)
    +{
    + struct kvm_vm *ret_vm = vm;
    +
    + pr_debug("Stage: %d\n", stage);
    +
    + switch (stage) {
    + case TEST_STAGE_REG_IFACE:
    + test_fw_regs_after_vm_start(vm);
    + break;
    + case TEST_STAGE_HVC_IFACE_FEAT_DISABLED:
    + /* Start a new VM so that all the features are now enabled by default */
    + kvm_vm_free(vm);
    + ret_vm = test_vm_create();
    + break;
    + case TEST_STAGE_HVC_IFACE_FEAT_ENABLED:
    + case TEST_STAGE_HVC_IFACE_FALSE_INFO:
    + break;
    + default:
    + TEST_FAIL("Unknown test stage: %d\n", stage);
    + }
    +
    + stage++;
    + sync_global_to_guest(vm, stage);
    +
    + return ret_vm;
    +}
    +
    +static void test_run(void)
    +{
    + struct kvm_vm *vm;
    + struct ucall uc;
    + bool guest_done = false;
    +
    + vm = test_vm_create();
    +
    + test_fw_regs_before_vm_start(vm);
    +
    + while (!guest_done) {
    + vcpu_run(vm, 0);
    +
    + switch (get_ucall(vm, 0, &uc)) {
    + case UCALL_SYNC:
    + vm = test_guest_stage(vm);
    + break;
    + case UCALL_DONE:
    + guest_done = true;
    + break;
    + case UCALL_ABORT:
    + TEST_FAIL("%s at %s:%ld\n\tvalues: 0x%lx, 0x%lx; 0x%lx, stage: %u",
    + (const char *)uc.args[0], __FILE__, uc.args[1],
    + uc.args[2], uc.args[3], uc.args[4], stage);
    + break;
    + default:
    + TEST_FAIL("Unexpected guest exit\n");
    + }
    + }
    +
    + kvm_vm_free(vm);
    +}
    +
    +int main(void)
    +{
    + setbuf(stdout, NULL);
    +
    + test_run();
    + return 0;
    +}
    --
    2.36.0.464.gb9c8b46e94-goog
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