[PATCH v6 8/9] selftests: KVM: aarch64: Introduce hypercall ABI test
Gavin Shan
gshan at redhat.com
Tue Apr 26 00:49:59 PDT 2022
Hi Raghavendra,
On 4/23/22 8:03 AM, Raghavendra Rao Ananta wrote:
> 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 at google.com>
> ---
> tools/testing/selftests/kvm/.gitignore | 1 +
> tools/testing/selftests/kvm/Makefile | 1 +
> .../selftests/kvm/aarch64/hypercalls.c | 335 ++++++++++++++++++
> 3 files changed, 337 insertions(+)
> create mode 100644 tools/testing/selftests/kvm/aarch64/hypercalls.c
>
There are comments about @false_hvc_info[] and some nits, as below.
Please evaluate and improve if it makes sense to you. Otherwise, it
looks good to me:
Reviewed-by: Gavin Shan <gshan at redhat.com>
> 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..f404343a0ae3
> --- /dev/null
> +++ b/tools/testing/selftests/kvm/aarch64/hypercalls.c
> @@ -0,0 +1,335 @@
> +// 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),
> +};
> +
I don't see too much benefits of @false_hvc_info[] because
NOT_SUPPORTED is always returned from its test case. I think
it and its test case can be removed if you agree. I'm not
sure if it was suggested by somebody else.
> +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, ®);
> +}
> +
> +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, ®);
> +}
> +
> +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);
> + }
> + }
> +}
Just in case :)
ret = set_fw_reg(vm, reg_info->reg, GENMASK(63, reg_info->max_feat_bit + 1));
> +
> +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);
> +
> + /*
> + * Set all the features for this register again. KVM shouldn't
> + * allow this as the VM is running.
> + */
> + 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);
> + }
> +}
> +
I guess you want to check -EBUSY is returned. In that case,
the comments here could be clearer, something like below
to emphasize '-EBUSY'.
/*
* After VM runs for once, -EBUSY should be returned on attempt
* to set features. Check if the correct errno is returned.
*/
> +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;
> +}
>
Thanks,
Gavin
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