From a5bde5d8fde8a8cb28e59a672d5ddc5b9c1e7656 Mon Sep 17 00:00:00 2001 From: Breno Leitao Date: Wed, 5 Aug 2026 07:52:36 -0700 Subject: workqueue: skip the node_nr_active update for non-unbound workqueues apply_wqattrs_commit() updates node_nr_active->max unconditionally. wq->node_nr_active[] is only allocated for unbound workqueues, so guard the call before per-cpu workqueues start using this path. No functional change: only unbound workqueues reach apply_wqattrs_*() today. Signed-off-by: Breno Leitao Signed-off-by: Tejun Heo --- arch/arm64/hyperv/mshyperv.c | 136 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 136 insertions(+) create mode 100644 arch/arm64/hyperv/mshyperv.c (limited to 'arch/arm64/hyperv/mshyperv.c') diff --git a/arch/arm64/hyperv/mshyperv.c b/arch/arm64/hyperv/mshyperv.c new file mode 100644 index 000000000..4fdc26ade --- /dev/null +++ b/arch/arm64/hyperv/mshyperv.c @@ -0,0 +1,136 @@ +// SPDX-License-Identifier: GPL-2.0 + +/* + * Core routines for interacting with Microsoft's Hyper-V hypervisor, + * including hypervisor initialization. + * + * Copyright (C) 2021, Microsoft, Inc. + * + * Author : Michael Kelley + */ + +#include +#include +#include +#include +#include +#include +#include + +static bool hyperv_initialized; + +int hv_get_hypervisor_version(union hv_hypervisor_version_info *info) +{ + hv_get_vpreg_128(HV_REGISTER_HYPERVISOR_VERSION, + (struct hv_get_vp_registers_output *)info); + + return 0; +} +EXPORT_SYMBOL_GPL(hv_get_hypervisor_version); + +#ifdef CONFIG_ACPI + +static bool __init hyperv_detect_via_acpi(void) +{ + if (acpi_disabled) + return false; + /* + * Hypervisor ID is only available in ACPI v6+, and the + * structure layout was extended in v6 to accommodate that + * new field. + * + * At the very minimum, this check makes sure not to read + * past the FADT structure. + * + * It is also needed to catch running in some unknown + * non-Hyper-V environment that has ACPI 5.x or less. + * In such a case, it can't be Hyper-V. + */ + if (acpi_gbl_FADT.header.revision < 6) + return false; + return strncmp((char *)&acpi_gbl_FADT.hypervisor_id, "MsHyperV", 8) == 0; +} + +#else + +static bool __init hyperv_detect_via_acpi(void) +{ + return false; +} + +#endif + +static bool __init hyperv_detect_via_smccc(void) +{ + uuid_t hyperv_uuid = UUID_INIT( + 0x58ba324d, 0x6447, 0x24cd, + 0x75, 0x6c, 0xef, 0x8e, + 0x24, 0x70, 0x59, 0x16); + + return arm_smccc_hypervisor_has_uuid(&hyperv_uuid); +} + +static int __init hyperv_init(void) +{ + struct hv_get_vp_registers_output result; + u64 guest_id; + int ret; + + /* + * Allow for a kernel built with CONFIG_HYPERV to be running in + * a non-Hyper-V environment. + * + * In such cases, do nothing and return success. + */ + if (!hyperv_detect_via_acpi() && !hyperv_detect_via_smccc()) + return 0; + + /* Setup the guest ID */ + guest_id = hv_generate_guest_id(LINUX_VERSION_CODE); + hv_set_vpreg(HV_REGISTER_GUEST_OS_ID, guest_id); + + /* Get the features and hints from Hyper-V */ + hv_get_vpreg_128(HV_REGISTER_PRIVILEGES_AND_FEATURES_INFO, &result); + ms_hyperv.features = result.as32.a; + ms_hyperv.priv_high = result.as32.b; + ms_hyperv.misc_features = result.as32.c; + + hv_get_vpreg_128(HV_REGISTER_FEATURES_INFO, &result); + ms_hyperv.hints = result.as32.a; + + pr_info("Hyper-V: privilege flags low 0x%x, high 0x%x, hints 0x%x, misc 0x%x\n", + ms_hyperv.features, ms_hyperv.priv_high, ms_hyperv.hints, + ms_hyperv.misc_features); + + hv_identify_partition_type(); + + ret = hv_common_init(); + if (ret) + return ret; + + ret = cpuhp_setup_state(CPUHP_AP_HYPERV_ONLINE, "arm64/hyperv_init:online", + hv_common_cpu_init, hv_common_cpu_die); + if (ret < 0) { + hv_common_free(); + return ret; + } + + if (ms_hyperv.priv_high & HV_ACCESS_PARTITION_ID) + hv_get_partition_id(); + ms_hyperv.vtl = get_vtl(); + if (ms_hyperv.vtl > 0) /* non default VTL */ + pr_info("Linux runs in Hyper-V Virtual Trust Level %d\n", ms_hyperv.vtl); + + ms_hyperv_late_init(); + + hyperv_initialized = true; + return 0; +} + +early_initcall(hyperv_init); + +bool hv_is_hyperv_initialized(void) +{ + return hyperv_initialized; +} +EXPORT_SYMBOL_GPL(hv_is_hyperv_initialized); -- cgit v1.3.1