On Thu, 2022-04-14 at 15:20 +0200, Vitaly Kuznetsov wrote:
> Introduce a selftest for Hyper-V PV IPI hypercalls
> (HvCallSendSyntheticClusterIpi, HvCallSendSyntheticClusterIpiEx).
>
> The test creates one 'sender' vCPU and two 'receiver' vCPU and then
> issues various combinations of send IPI hypercalls in both 'normal'
> and 'fast' (with XMM input where necessary) mode. Later, the test
> checks whether IPIs were delivered to the expected destination vCPU[s].
>
> Signed-off-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
> ---
> tools/testing/selftests/kvm/.gitignore | 1 +
> tools/testing/selftests/kvm/Makefile | 1 +
> .../selftests/kvm/include/x86_64/hyperv.h | 3 +
> .../selftests/kvm/x86_64/hyperv_features.c | 5 +-
> .../testing/selftests/kvm/x86_64/hyperv_ipi.c | 374 ++++++++++++++++++
> 5 files changed, 381 insertions(+), 3 deletions(-)
> create mode 100644 tools/testing/selftests/kvm/x86_64/hyperv_ipi.c
>
> diff --git a/tools/testing/selftests/kvm/.gitignore b/tools/testing/selftests/kvm/.gitignore
> index 56140068b763..5d5fbb161d56 100644
> --- a/tools/testing/selftests/kvm/.gitignore
> +++ b/tools/testing/selftests/kvm/.gitignore
> @@ -23,6 +23,7 @@
> /x86_64/hyperv_clock
> /x86_64/hyperv_cpuid
> /x86_64/hyperv_features
> +/x86_64/hyperv_ipi
> /x86_64/hyperv_svm_test
> /x86_64/mmio_warning_test
> /x86_64/mmu_role_test
> diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
> index af582d168621..44889f897fe7 100644
> --- a/tools/testing/selftests/kvm/Makefile
> +++ b/tools/testing/selftests/kvm/Makefile
> @@ -52,6 +52,7 @@ TEST_GEN_PROGS_x86_64 += x86_64/fix_hypercall_test
> TEST_GEN_PROGS_x86_64 += x86_64/hyperv_clock
> TEST_GEN_PROGS_x86_64 += x86_64/hyperv_cpuid
> TEST_GEN_PROGS_x86_64 += x86_64/hyperv_features
> +TEST_GEN_PROGS_x86_64 += x86_64/hyperv_ipi
> TEST_GEN_PROGS_x86_64 += x86_64/hyperv_svm_test
> TEST_GEN_PROGS_x86_64 += x86_64/kvm_clock_test
> TEST_GEN_PROGS_x86_64 += x86_64/kvm_pv_test
> diff --git a/tools/testing/selftests/kvm/include/x86_64/hyperv.h b/tools/testing/selftests/kvm/include/x86_64/hyperv.h
> index b66910702c0a..f51d6fab8e93 100644
> --- a/tools/testing/selftests/kvm/include/x86_64/hyperv.h
> +++ b/tools/testing/selftests/kvm/include/x86_64/hyperv.h
> @@ -184,5 +184,8 @@
>
> /* hypercall options */
> #define HV_HYPERCALL_FAST_BIT BIT(16)
> +#define HV_HYPERCALL_VARHEAD_OFFSET 17
> +
> +#define HYPERV_LINUX_OS_ID ((u64)0x8100 << 48)
>
> #endif /* !SELFTEST_KVM_HYPERV_H */
> diff --git a/tools/testing/selftests/kvm/x86_64/hyperv_features.c b/tools/testing/selftests/kvm/x86_64/hyperv_features.c
> index 672915ce73d8..98c020356925 100644
> --- a/tools/testing/selftests/kvm/x86_64/hyperv_features.c
> +++ b/tools/testing/selftests/kvm/x86_64/hyperv_features.c
> @@ -14,7 +14,6 @@
> #include "hyperv.h"
>
> #define VCPU_ID 0
> -#define LINUX_OS_ID ((u64)0x8100 << 48)
>
> extern unsigned char rdmsr_start;
> extern unsigned char rdmsr_end;
> @@ -127,7 +126,7 @@ static void guest_hcall(vm_vaddr_t pgs_gpa, struct hcall_data *hcall)
> int i = 0;
> u64 res, input, output;
>
> - wrmsr(HV_X64_MSR_GUEST_OS_ID, LINUX_OS_ID);
> + wrmsr(HV_X64_MSR_GUEST_OS_ID, HYPERV_LINUX_OS_ID);
> wrmsr(HV_X64_MSR_HYPERCALL, pgs_gpa);
>
> while (hcall->control) {
> @@ -230,7 +229,7 @@ static void guest_test_msrs_access(void)
> */
> msr->idx = HV_X64_MSR_GUEST_OS_ID;
> msr->write = 1;
> - msr->write_val = LINUX_OS_ID;
> + msr->write_val = HYPERV_LINUX_OS_ID;
> msr->available = 1;
> break;
> case 3:
Nitpick: I think that the HYPERV_LINUX_OS_ID change should be in a separate patch.
> diff --git a/tools/testing/selftests/kvm/x86_64/hyperv_ipi.c b/tools/testing/selftests/kvm/x86_64/hyperv_ipi.c
> new file mode 100644
> index 000000000000..075963c32d45
> --- /dev/null
> +++ b/tools/testing/selftests/kvm/x86_64/hyperv_ipi.c
> @@ -0,0 +1,374 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Hyper-V HvCallSendSyntheticClusterIpi{,Ex} tests
> + *
> + * Copyright (C) 2022, Red Hat, Inc.
> + *
> + */
> +
> +#define _GNU_SOURCE /* for program_invocation_short_name */
> +#include <pthread.h>
> +#include <inttypes.h>
> +
> +#include "kvm_util.h"
> +#include "hyperv.h"
> +#include "processor.h"
> +#include "test_util.h"
> +#include "vmx.h"
> +
> +#define SENDER_VCPU_ID 1
> +#define RECEIVER_VCPU_ID_1 2
> +#define RECEIVER_VCPU_ID_2 65
> +
> +#define IPI_VECTOR 0xfe
> +
> +static volatile uint64_t ipis_rcvd[RECEIVER_VCPU_ID_2 + 1];
> +
> +struct thread_params {
> + struct kvm_vm *vm;
> + uint32_t vcpu_id;
> +};
> +
> +struct hv_vpset {
> + u64 format;
> + u64 valid_bank_mask;
> + u64 bank_contents[2];
> +};
> +
> +enum HV_GENERIC_SET_FORMAT {
> + HV_GENERIC_SET_SPARSE_4K,
> + HV_GENERIC_SET_ALL,
> +};
> +
> +/* HvCallSendSyntheticClusterIpi hypercall */
> +struct hv_send_ipi {
> + u32 vector;
> + u32 reserved;
> + u64 cpu_mask;
> +};
> +
> +/* HvCallSendSyntheticClusterIpiEx hypercall */
> +struct hv_send_ipi_ex {
> + u32 vector;
> + u32 reserved;
> + struct hv_vpset vp_set;
> +};
> +
> +static inline void hv_init(vm_vaddr_t pgs_gpa)
> +{
> + wrmsr(HV_X64_MSR_GUEST_OS_ID, HYPERV_LINUX_OS_ID);
> + wrmsr(HV_X64_MSR_HYPERCALL, pgs_gpa);
> +}
> +
> +static void receiver_code(void *hcall_page, vm_vaddr_t pgs_gpa)
> +{
> + u32 vcpu_id;
> +
> + x2apic_enable();
> + hv_init(pgs_gpa);
> +
> + vcpu_id = rdmsr(HV_X64_MSR_VP_INDEX);
> +
> + /* Signal sender vCPU we're ready */
> + ipis_rcvd[vcpu_id] = (u64)-1;
> +
> + for (;;)
> + asm volatile("sti; hlt; cli");
> +}
> +
> +static void guest_ipi_handler(struct ex_regs *regs)
> +{
> + u32 vcpu_id = rdmsr(HV_X64_MSR_VP_INDEX);
> +
> + ipis_rcvd[vcpu_id]++;
> + wrmsr(HV_X64_MSR_EOI, 1);
> +}
> +
> +static inline u64 hypercall(u64 control, vm_vaddr_t arg1, vm_vaddr_t arg2)
> +{
> + u64 hv_status;
> +
> + asm volatile("mov %3, %%r8\n"
> + "vmcall"
> + : "=a" (hv_status),
> + "+c" (control), "+d" (arg1)
> + : "r" (arg2)
> + : "cc", "memory", "r8", "r9", "r10", "r11");
> +
> + return hv_status;
> +}
> +
> +static inline void nop_loop(void)
> +{
> + int i;
> +
> + for (i = 0; i < 100000000; i++)
> + asm volatile("nop");
> +}
> +
> +static inline void sync_to_xmm(void *data)
> +{
> + int i;
> +
> + for (i = 0; i < 8; i++)
> + write_sse_reg(i, (sse128_t *)(data + sizeof(sse128_t) * i));
> +}
> +
> +static void sender_guest_code(void *hcall_page, vm_vaddr_t pgs_gpa)
> +{
> + struct hv_send_ipi *ipi = (struct hv_send_ipi *)hcall_page;
> + struct hv_send_ipi_ex *ipi_ex = (struct hv_send_ipi_ex *)hcall_page;
> + int stage = 1, ipis_expected[2] = {0};
> + u64 res;
> +
> + hv_init(pgs_gpa);
> + GUEST_SYNC(stage++);
> +
> + /* Wait for receiver vCPUs to come up */
> + while (!ipis_rcvd[RECEIVER_VCPU_ID_1] || !ipis_rcvd[RECEIVER_VCPU_ID_2])
> + nop_loop();
> + ipis_rcvd[RECEIVER_VCPU_ID_1] = ipis_rcvd[RECEIVER_VCPU_ID_2] = 0;
> +
> + /* 'Slow' HvCallSendSyntheticClusterIpi to RECEIVER_VCPU_ID_1 */
> + ipi->vector = IPI_VECTOR;
> + ipi->cpu_mask = 1 << RECEIVER_VCPU_ID_1;
> + res = hypercall(HVCALL_SEND_IPI, pgs_gpa, pgs_gpa + 4096);
> + GUEST_ASSERT((res & 0xffff) == 0);
> + nop_loop();
> + GUEST_ASSERT(ipis_rcvd[RECEIVER_VCPU_ID_1] == ++ipis_expected[0]);
> + GUEST_ASSERT(ipis_rcvd[RECEIVER_VCPU_ID_2] == ipis_expected[1]);
> + GUEST_SYNC(stage++);
> + /* 'Fast' HvCallSendSyntheticClusterIpi to RECEIVER_VCPU_ID_1 */
> + res = hypercall(HVCALL_SEND_IPI | HV_HYPERCALL_FAST_BIT,
> + IPI_VECTOR, 1 << RECEIVER_VCPU_ID_1);
> + GUEST_ASSERT((res & 0xffff) == 0);
> + nop_loop();
> + GUEST_ASSERT(ipis_rcvd[RECEIVER_VCPU_ID_1] == ++ipis_expected[0]);
> + GUEST_ASSERT(ipis_rcvd[RECEIVER_VCPU_ID_2] == ipis_expected[1]);
> + GUEST_SYNC(stage++);
> +
> + /* 'Slow' HvCallSendSyntheticClusterIpiEx to RECEIVER_VCPU_ID_1 */
> + memset(hcall_page, 0, 4096);
> + ipi_ex->vector = IPI_VECTOR;
> + ipi_ex->vp_set.format = HV_GENERIC_SET_SPARSE_4K;
> + ipi_ex->vp_set.valid_bank_mask = 1 << 0;
> + ipi_ex->vp_set.bank_contents[0] = BIT(RECEIVER_VCPU_ID_1);
> + res = hypercall(HVCALL_SEND_IPI_EX | (1 << HV_HYPERCALL_VARHEAD_OFFSET),
> + pgs_gpa, pgs_gpa + 4096);
> + GUEST_ASSERT((res & 0xffff) == 0);
> + nop_loop();
> + GUEST_ASSERT(ipis_rcvd[RECEIVER_VCPU_ID_1] == ++ipis_expected[0]);
> + GUEST_ASSERT(ipis_rcvd[RECEIVER_VCPU_ID_2] == ipis_expected[1]);
> + GUEST_SYNC(stage++);
> + /* 'XMM Fast' HvCallSendSyntheticClusterIpiEx to RECEIVER_VCPU_ID_1 */
> + sync_to_xmm(&ipi_ex->vp_set.valid_bank_mask);
> + res = hypercall(HVCALL_SEND_IPI_EX | HV_HYPERCALL_FAST_BIT |
> + (1 << HV_HYPERCALL_VARHEAD_OFFSET),
> + IPI_VECTOR, HV_GENERIC_SET_SPARSE_4K);
> + GUEST_ASSERT((res & 0xffff) == 0);
> + nop_loop();
> + GUEST_ASSERT(ipis_rcvd[RECEIVER_VCPU_ID_1] == ++ipis_expected[0]);
> + GUEST_ASSERT(ipis_rcvd[RECEIVER_VCPU_ID_2] == ipis_expected[1]);
> + GUEST_SYNC(stage++);
> +
> + /* 'Slow' HvCallSendSyntheticClusterIpiEx to RECEIVER_VCPU_ID_2 */
> + memset(hcall_page, 0, 4096);
> + ipi_ex->vector = IPI_VECTOR;
> + ipi_ex->vp_set.format = HV_GENERIC_SET_SPARSE_4K;
> + ipi_ex->vp_set.valid_bank_mask = 1 << 1;
> + ipi_ex->vp_set.bank_contents[0] = BIT(RECEIVER_VCPU_ID_2 - 64);
> + res = hypercall(HVCALL_SEND_IPI_EX | (1 << HV_HYPERCALL_VARHEAD_OFFSET),
> + pgs_gpa, pgs_gpa + 4096);
> + GUEST_ASSERT((res & 0xffff) == 0);
> + nop_loop();
> + GUEST_ASSERT(ipis_rcvd[RECEIVER_VCPU_ID_1] == ipis_expected[0]);
> + GUEST_ASSERT(ipis_rcvd[RECEIVER_VCPU_ID_2] == ++ipis_expected[1]);
> + GUEST_SYNC(stage++);
> + /* 'XMM Fast' HvCallSendSyntheticClusterIpiEx to RECEIVER_VCPU_ID_2 */
> + sync_to_xmm(&ipi_ex->vp_set.valid_bank_mask);
> + res = hypercall(HVCALL_SEND_IPI_EX | HV_HYPERCALL_FAST_BIT |
> + (1 << HV_HYPERCALL_VARHEAD_OFFSET),
> + IPI_VECTOR, HV_GENERIC_SET_SPARSE_4K);
> + GUEST_ASSERT((res & 0xffff) == 0);
> + nop_loop();
> + GUEST_ASSERT(ipis_rcvd[RECEIVER_VCPU_ID_1] == ipis_expected[0]);
> + GUEST_ASSERT(ipis_rcvd[RECEIVER_VCPU_ID_2] == ++ipis_expected[1]);
> + GUEST_SYNC(stage++);
> +
> + /* 'Slow' HvCallSendSyntheticClusterIpiEx to both RECEIVER_VCPU_ID_{1,2} */
> + memset(hcall_page, 0, 4096);
> + ipi_ex->vector = IPI_VECTOR;
> + ipi_ex->vp_set.format = HV_GENERIC_SET_SPARSE_4K;
> + ipi_ex->vp_set.valid_bank_mask = 1 << 1 | 1;
> + ipi_ex->vp_set.bank_contents[0] = BIT(RECEIVER_VCPU_ID_1);
> + ipi_ex->vp_set.bank_contents[1] = BIT(RECEIVER_VCPU_ID_2 - 64);
> + res = hypercall(HVCALL_SEND_IPI_EX | (2 << HV_HYPERCALL_VARHEAD_OFFSET),
> + pgs_gpa, pgs_gpa + 4096);
> + GUEST_ASSERT((res & 0xffff) == 0);
> + nop_loop();
> + GUEST_ASSERT(ipis_rcvd[RECEIVER_VCPU_ID_1] == ++ipis_expected[0]);
> + GUEST_ASSERT(ipis_rcvd[RECEIVER_VCPU_ID_2] == ++ipis_expected[1]);
> + GUEST_SYNC(stage++);
> + /* 'XMM Fast' HvCallSendSyntheticClusterIpiEx to both RECEIVER_VCPU_ID_{1, 2} */
> + sync_to_xmm(&ipi_ex->vp_set.valid_bank_mask);
> + res = hypercall(HVCALL_SEND_IPI_EX | HV_HYPERCALL_FAST_BIT |
> + (2 << HV_HYPERCALL_VARHEAD_OFFSET),
> + IPI_VECTOR, HV_GENERIC_SET_SPARSE_4K);
> + GUEST_ASSERT((res & 0xffff) == 0);
> + nop_loop();
> + GUEST_ASSERT(ipis_rcvd[RECEIVER_VCPU_ID_1] == ++ipis_expected[0]);
> + GUEST_ASSERT(ipis_rcvd[RECEIVER_VCPU_ID_2] == ++ipis_expected[1]);
> + GUEST_SYNC(stage++);
> +
> + /* 'Slow' HvCallSendSyntheticClusterIpiEx to HV_GENERIC_SET_ALL */
> + memset(hcall_page, 0, 4096);
> + ipi_ex->vector = IPI_VECTOR;
> + ipi_ex->vp_set.format = HV_GENERIC_SET_ALL;
> + res = hypercall(HVCALL_SEND_IPI_EX,
> + pgs_gpa, pgs_gpa + 4096);
> + GUEST_ASSERT((res & 0xffff) == 0);
> + nop_loop();
> + GUEST_ASSERT(ipis_rcvd[RECEIVER_VCPU_ID_1] == ++ipis_expected[0]);
> + GUEST_ASSERT(ipis_rcvd[RECEIVER_VCPU_ID_2] == ++ipis_expected[1]);
> + GUEST_SYNC(stage++);
> + /* 'XMM Fast' HvCallSendSyntheticClusterIpiEx to HV_GENERIC_SET_ALL */
> + sync_to_xmm(&ipi_ex->vp_set.valid_bank_mask);
> + res = hypercall(HVCALL_SEND_IPI_EX | HV_HYPERCALL_FAST_BIT,
> + IPI_VECTOR, HV_GENERIC_SET_ALL);
> + GUEST_ASSERT((res & 0xffff) == 0);
> + nop_loop();
> + GUEST_ASSERT(ipis_rcvd[RECEIVER_VCPU_ID_1] == ++ipis_expected[0]);
> + GUEST_ASSERT(ipis_rcvd[RECEIVER_VCPU_ID_2] == ++ipis_expected[1]);
> + GUEST_SYNC(stage++);
> +
> + GUEST_DONE();
> +}
> +
> +static void *vcpu_thread(void *arg)
> +{
> + struct thread_params *params = (struct thread_params *)arg;
> + struct ucall uc;
> + int old;
> + int r;
> + unsigned int exit_reason;
> +
> + r = pthread_setcanceltype(PTHREAD_CANCEL_ASYNCHRONOUS, &old);
> + TEST_ASSERT(r == 0,
> + "pthread_setcanceltype failed on vcpu_id=%u with errno=%d",
> + params->vcpu_id, r);
> +
> + vcpu_run(params->vm, params->vcpu_id);
> + exit_reason = vcpu_state(params->vm, params->vcpu_id)->exit_reason;
> +
> + TEST_ASSERT(exit_reason == KVM_EXIT_IO,
> + "vCPU %u exited with unexpected exit reason %u-%s, expected KVM_EXIT_IO",
> + params->vcpu_id, exit_reason, exit_reason_str(exit_reason));
> +
> + if (get_ucall(params->vm, params->vcpu_id, &uc) == UCALL_ABORT) {
> + TEST_ASSERT(false,
> + "vCPU %u exited with error: %s.\n",
> + params->vcpu_id, (const char *)uc.args[0]);
> + }
> +
> + return NULL;
> +}
> +
> +static void cancel_join_vcpu_thread(pthread_t thread, uint32_t vcpu_id)
> +{
> + void *retval;
> + int r;
> +
> + r = pthread_cancel(thread);
> + TEST_ASSERT(r == 0,
> + "pthread_cancel on vcpu_id=%d failed with errno=%d",
> + vcpu_id, r);
> +
> + r = pthread_join(thread, &retval);
> + TEST_ASSERT(r == 0,
> + "pthread_join on vcpu_id=%d failed with errno=%d",
> + vcpu_id, r);
> + TEST_ASSERT(retval == PTHREAD_CANCELED,
> + "expected retval=%p, got %p", PTHREAD_CANCELED,
> + retval);
> +}
> +
> +int main(int argc, char *argv[])
> +{
> + int r;
> + pthread_t threads[2];
> + struct thread_params params[2];
> + struct kvm_vm *vm;
> + struct kvm_run *run;
> + vm_vaddr_t hcall_page;
> + struct ucall uc;
> + int stage = 1;
> +
> + vm = vm_create_default(SENDER_VCPU_ID, 0, sender_guest_code);
> + params[0].vm = vm;
> + params[1].vm = vm;
> +
> + /* Hypercall input/output */
> + hcall_page = vm_vaddr_alloc_pages(vm, 2);
> + memset(addr_gva2hva(vm, hcall_page), 0x0, 2 * getpagesize());
> +
> + vm_init_descriptor_tables(vm);
> +
> + vm_vcpu_add_default(vm, RECEIVER_VCPU_ID_1, receiver_code);
> + vcpu_init_descriptor_tables(vm, RECEIVER_VCPU_ID_1);
> + vcpu_args_set(vm, RECEIVER_VCPU_ID_1, 2, hcall_page, addr_gva2gpa(vm, hcall_page));
> + vcpu_set_msr(vm, RECEIVER_VCPU_ID_1, HV_X64_MSR_VP_INDEX, RECEIVER_VCPU_ID_1);
> + vcpu_set_hv_cpuid(vm, RECEIVER_VCPU_ID_1);
> +
> + vm_vcpu_add_default(vm, RECEIVER_VCPU_ID_2, receiver_code);
> + vcpu_init_descriptor_tables(vm, RECEIVER_VCPU_ID_2);
> + vcpu_args_set(vm, RECEIVER_VCPU_ID_2, 2, hcall_page, addr_gva2gpa(vm, hcall_page));
> + vcpu_set_msr(vm, RECEIVER_VCPU_ID_2, HV_X64_MSR_VP_INDEX, RECEIVER_VCPU_ID_2);
> + vcpu_set_hv_cpuid(vm, RECEIVER_VCPU_ID_2);
> +
> + vm_install_exception_handler(vm, IPI_VECTOR, guest_ipi_handler);
> +
> + vcpu_args_set(vm, SENDER_VCPU_ID, 2, hcall_page, addr_gva2gpa(vm, hcall_page));
> + vcpu_set_hv_cpuid(vm, SENDER_VCPU_ID);
> +
> + params[0].vcpu_id = RECEIVER_VCPU_ID_1;
> + r = pthread_create(&threads[0], NULL, vcpu_thread, ¶ms[0]);
> + TEST_ASSERT(r == 0,
> + "pthread_create halter failed errno=%d", errno);
> +
> + params[1].vcpu_id = RECEIVER_VCPU_ID_2;
> + r = pthread_create(&threads[1], NULL, vcpu_thread, ¶ms[1]);
> + TEST_ASSERT(r == 0,
> + "pthread_create halter failed errno=%d", errno);
> +
> + run = vcpu_state(vm, SENDER_VCPU_ID);
> +
> + while (true) {
> + r = _vcpu_run(vm, SENDER_VCPU_ID);
> + TEST_ASSERT(!r, "vcpu_run failed: %d\n", r);
> + TEST_ASSERT(run->exit_reason == KVM_EXIT_IO,
> + "unexpected exit reason: %u (%s)",
> + run->exit_reason, exit_reason_str(run->exit_reason));
> +
> + switch (get_ucall(vm, SENDER_VCPU_ID, &uc)) {
> + case UCALL_SYNC:
> + TEST_ASSERT(uc.args[1] == stage,
> + "Unexpected stage: %ld (%d expected)\n",
> + uc.args[1], stage);
> + break;
> + case UCALL_ABORT:
> + TEST_FAIL("%s at %s:%ld", (const char *)uc.args[0],
> + __FILE__, uc.args[1]);
> + return 1;
> + case UCALL_DONE:
> + return 0;
> + }
> +
> + stage++;
> + }
> +
> + cancel_join_vcpu_thread(threads[0], RECEIVER_VCPU_ID_1);
> + cancel_join_vcpu_thread(threads[1], RECEIVER_VCPU_ID_2);
> + kvm_vm_free(vm);
> +
> + return 0;
> +}
Looks overall good to me, but I might have missed something.
Reviewed-by: Maxim Levitsky <mlevitsk@xxxxxxxxxx>
Best regards,
Maxim Levitsky
