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survives ccp reload). */ >> +static bool snp_cpu_hotplug_disabled; > > Do you really need this? > Yes. cpu_hotplug_disable()/cpu_hotplug_enable() are refcounted (cpu_hotplug_disabled++/--, with a WARN on underflow), so they have to be balanced. This flag collapses them to exactly one outstanding disable per SNP-active window, because the disable and enable sites are not reached a symmetric number of times: - On firmware without SNP_X86_SHUTDOWN_SUPPORTED, __sev_snp_shutdown_locked() does not call snp_shutdown() (it's gated on data.x86_snp_shutdown), so SNP stays enabled in hardware — SNP_EN stays set and hotplug stays disabled — while sev->snp_initialized is cleared. Re-init after that is routine, the SNP ioctls self-bracket init and shutdown (e.g. SNP_COMMIT, SNP_SET_CONFIG, SNP_VLEK_LOAD): if (!sev->snp_initialized) snp_move_to_init_state(...); /* -> __sev_snp_init_locked -> snp_prepare() */ ... SNP_CMD ... if (shutdown_required) __sev_snp_shutdown_locked(...); - So whenever SNP isn't already initialized (psp_init_on_probe off, or after a prior legacy shutdown), every such ioctl does init -> command -> legacy shutdown. Each init reaches snp_prepare() with SNP_EN already set, and the disable now sits at the top of snp_prepare(), so it fires on every cycle. Without this flag that keeps bumping cpu_hotplug_disabled while the legacy shutdown never re-enables — hotplug ends up stuck disabled. This flag makes all but the first disable a no-op. - Also, importantly, kvm-amd module reload on legacy firmware is the same pattern: unload leaves SNP_EN set, reload re-inits.) - On the enable side it avoids an unbalanced cpu_hotplug_enable() when the teardown/failure paths run without an outstanding disable (e.g. shutdown of a never-fully-initialized SNP). So it's not redundant with cpu_hotplug_disabled — it tracks whether the outstanding disable belongs to this SNP-active window in this kernel, which keeps the single disable/enable balanced across the asymmetric legacy-vs-full SNP teardown paths and re-init. Thanks, Ashish