Re: [PATCH v4 01/14] KVM: Allow architectures to disallow pre-fault

[sashiko-bot@kernel.org]

> All existing architectures which implement KVM pre-fault (x86, s390) have
> mechanisms for disallowing pre-faulting.
> 
> Currently these are open coded as part of kvm_arch_vcpu_pre_fault_memory().
> 
> Formalise this by moving them into a new kvm_arch_pre_fault_allowed() hook,
> which every architecture selecting CONFIG_KVM_GENERIC_PRE_FAULT_MEMORY must
> implement, returning an error code if the operation is disallowed or 0
> otherwise.
> 
> The hook is called early in the generic code, allowing architectures to
> disallow the operation prior to vCPU load.
> 
> This is important, as kvm_vcpu_pre_fault_memory() is the only place where
> generic code can call vcpu_load() on a vCPU that has not yet been
> initialised.
> 
> This lays the foundation for a future change which implements pre-faulting
> for arm64 which needs to disallow the mechanism for uninitialised vCPUs.
> 
> Suggested-by: Oliver Upton <oupton@kernel.org>
> Signed-off-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>

Sashiko has reviewed this patch and found no issues. It looks great!

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Sashiko AI review · https://sashiko.dev/#/patchset/20260923-kvm-arm-prefault-v4-0-d4b0b4dfa8c3@kernel.org?part=1