Re: [PATCH RESEND v2 03/17] KVM: X86: Don't track dirty for KVM_SET_[TSS_ADDR|IDENTITY_MAP_ADDR]

From: Paolo Bonzini
Date: Mon Dec 23 2019 - 12:59:02 EST


On 23/12/19 18:27, Peter Xu wrote:
> Yes. Though it is a bit tricky in that then we'll also need to make
> sure to take slots_lock or srcu to protect that hva (say, we must drop
> that hva reference before we release the locks, otherwise the hva
> could gone under us, iiuc).

Yes, kvm->slots_lock is taken by x86_set_memory_region. We need to move
that to the callers, of which several are already taking the lock (all
except vmx_set_tss_addr and kvm_arch_destroy_vm).

Paolo

> So if we want to do that we'd better
> comment on that hva value very explicitly, just in case some future
> callers of __x86_set_memory_region could cache it somewhere.