Sean Christopherson <[email protected]> writes: > On Tue, Jul 28, 2026, Tarun Sahu wrote: >> Introduce the LIVEUPDATE_GUEST_MEMFD Kconfig option. This option >> enables live update support for KVM guest_memfd files, enabling >> guest_memfd-backed memory preservation across kernel upgrades. >> >> Currently this support only guest_memfd files that are full-shared >> (INIT_SHARED and no support for private_mem). > > Why? Specifically, why do we need/want a separate Kconfig for guest_memfd > liveupdate versus KVM liveupdate? I can _maybe_ see a KVM-wide Kconfig, but > even that seems like a stretch given that (AFAIK) hypervisors are the one and > only use-case for liveupdate.
LIVEUPDATE is used in many subsystem. It is possible to enable liveupdate and kvm without enabling KVM_GUEST_MEMFD. So GUEST_MEMFD preservation must depend on CONFIG_LIVEUPDATE and KVM_GUEST_MEMFD both. LIVEUPDATE_GUEST_MEMFD Kconfig is wrapper on both of them. It need not to be visible in menu, So I can make it hidden. WDYT? Also, KVM VM_FILE preservation and GUEST_MEMFD preservation both depends on LIVEUPDATE_GUEST_MEMFD in this patch series. [PATCH 05/11]* Which is wrong. So I will update KVM VM_FILE preservation to depend only on CONFIG_LIVEUPDATE. *https://lore.kernel.org/all/[email protected]/#Z31virt:kvm:Makefile.kvm ~Tarun
