__gaccess_shadow_fault(9)

💅 __gaccess_shadow_fault(9) 💅

okay so bestie, welcome to the Kernel API Manual page for __gaccess_shadow_fault(9) — this is the little kernel icon that handles a fault on a shadow page table, and we’re gonna read it together like a group chat ✨.

✨ NAME ✨

__gaccess_shadow_fault — Handle fault on a shadow page table. literally what it says on the tin, bestie 💅.

🌸 SYNOPSIS 🌸

       int __gaccess_shadow_fault (struct kvm_vcpu *vcpu , struct gmap *sg ,
       gpa_t saddr , union mvpg_pei *datptr , bool wr );

🎀 ARGUMENTS 🎀

this is the cast of characters, and every single one matters 🫶:

• vcpu — Virtual cpu that triggered the action. the main character who tripped the fault 😭.
• sg — The shadow guest address space structure. iconic shadow gmap energy.
• saddr — Faulting address in the shadow gmap. the exact spot where the drama is happening.
• datptr — Will contain the address of the faulting DAT table entry, or of the valid leaf, plus some flags. so it comes back holding the receipt 🧾✨.
• wr — Whether this is a write access. write or not, that’s the question 💅.

🔥 RETURN 🔥

the return values are the vibe check, no cap:

• 0 if the shadow fault was successfully resolved — slay, we fixed it 💖
• > 0 (pgm exception code) on exceptions while faulting — so greater than zero, and it comes with a pgm exception code.
• -EAGAIN if the caller can retry immediately — okay bestie, run it back 🔁
• -EFAULT when accessing invalid guest addresses — invalid guest address said absolutely not 🙈
• -ENOMEM if out of memory — the memory budget is giving empty 😭

🦋 SEE ALSO 🦋

Kernel file ./arch/s390/kvm/s390/gaccess.c — and the whole related squad is:

• guest_translate_gva(9)
• guest_range_to_gpas(9)
• __cmpxchg_with_key(9)
• cmpxchg_guest_abs_with_key(9)
• guest_translate_address_with_key(9)
• check_gva_range(9)
• check_gpa_range(9)
• kvm_s390_check_low_addr_prot_real(9)
• walk_guest_tables(9)

mwah 💋 that’s the whole page, bestie — from ./arch/s390/kvm/s390, dated October 2026. go handle those shadow faults, icon 👑✨