Re: [PATCH v3 01/14] KVM: Allow architectures to disallow pre-fault
From: Fuad Tabba <fuad.tabba@linux.dev>
Date: 2026-09-23 10:54:58
Also in:
kvm, kvmarm, linux-doc, linux-kselftest, lkml
Hi Lorenzo, On Tue, 22 Sep 2026 19:07:53 +0100, Oliver Upton [off-list ref] wrote: [...]
I'd favor doing something like below and sticking the comment inline in the ioctl handler. Unless I'm missing something blatantly obvious, I don't see why the x86 or s390 pre-conditions can't be tested early too.
[...]
quoted hunk ↗ jump to hunk
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
[...]
quoted hunk ↗ jump to hunk
+int kvm_arch_pre_fault_allowed(struct kvm_vcpu *vcpu) +{ + if (!kvm_vcpu_initialized(vcpu)) + return -ENOEXEC; + + return 0; +}
The same goes for arm64's pKVM check: kvm_arch_vcpu_pre_fault_memory() returns -EOPNOTSUPP for is_protected_kvm_enabled() only after vcpu_load(), so on a pKVM host the ioctl loads a vCPU the hypervisor may not have created yet before rejecting it. Could that check move into kvm_arch_pre_fault_allowed() as well? Cheers, /fuad