ne_donated_cpu(9)

💅 ne_donated_cpu(9) — a Kernel API Manual moment

Okay bestie, so this whole page is about ne_donated_cpu(9) — yes, that's the manual section 9, kernel API vibes only — and it's literally just one little function that answers a very specific question: is this CPU already being used by the enclave or not? That's it. That's the whole gig. And honestly? Iconic. 🎀

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🌸 NAME 🌸

ne_donated_cpu — check if the provided CPU is already used by the enclave.

Like, it's a vibe check for CPUs. Is this core taken? Yes or no. Go. ✨

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🦋 SYNOPSIS 🦋

bool ne_donated_cpu (struct ne_enclave *ne_enclave , unsigned int cpu );

No cap, that's the whole signature. It returns a bool and takes two things. We'll get into them right now. 👑

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💖 ARGUMENTS 💖

• ne_enclave — the private data associated with the current enclave. Basically the enclave's little personal diary of state, and you're handing over the pointer to it. 🫶
• cpu — the CPU you want to check, i.e. the one you're asking "hey, are you already used?" about.

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✨ CONTEXT ✨

Process context, bestie. And listen — this function is called with the ne_enclave mutex held. So like, don't go calling it wherever, the mutex has to already be in your hands. That's the whole rule. 🔒

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🔥 RETURN 🔥

• True if the provided CPU is already used by the enclave.
• False otherwise.

Two outcomes. Binary. Main character energy. ✅❌

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🌈 SEE ALSO 🌈

Buckle up, because this list is long and we're keeping every single one, no skipping, fr fr. 💀

• Kernel file ./drivers/virt/nitro_enclaves/ne_misc_dev.c Enclave lifetime management driver for Nitro Enclaves (NE).(9)
• NE_CPUS_SIZE(9)
• NE_EIF_LOAD_OFFSET(9)
• NE_MIN_ENCLAVE_MEM_SIZE(9)
• NE_MIN_MEM_REGION_SIZE(9)
• NE_PARENT_VM_CID(9)
• struct ne_cpu_pool(9)
• struct ne_phys_contig_mem_regions(9)
• ne_check_enclaves_created(9)
• ne_setup_cpu_pool(9)
• ne_teardown_cpu_pool(9)
• ne_set_kernel_param(9)
• ne_get_unused_core_from_cpu_pool(9)
• ne_set_enclave_threads_per_core(9)
• ne_get_cpu_from_cpu_pool(9)
• ne_get_vcpu_core_from_cpu_pool(9)
• ne_check_cpu_in_cpu_pool(9)
• ne_add_vcpu_ioctl(9)
• ne_sanity_check_user_mem_region(9)
• ne_sanity_check_user_mem_region_page(9)
• ne_sanity_check_phys_mem_region(9)
• ne_merge_phys_contig_memory_regions(9)
• ne_set_user_memory_region_ioctl(9)
• ne_start_enclave_ioctl(9)
• ne_enclave_ioctl(9)
• ne_enclave_remove_all_mem_region_entries(9)
• ne_enclave_remove_all_vcpu_id_entries(9)
• ne_pci_dev_remove_enclave_entry(9)
• ne_enclave_release(9)
• ne_enclave_poll(9)
• ne_create_vm_ioctl(9)
• ne_ioctl(9)

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Okay so real talk: this function is only meaningful in process context and while holding the ne_enclave mutex. Not optional, bestie. Don't come for me if you skip that. 🙈

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And that's the page! 🧚 This little love letter lives over at ./drivers/virt/nitro_enclaves, dated October 2026 — go check the source if you want the full lore, iykyk. Byeee 💜🦋