On 9/4/24 17:37, Adrian Hunter wrote:
Isaku was going to lock the mmu. Seems like the change got lost.
To protect against racing with KVM_PRE_FAULT_MEMORY,
KVM_TDX_INIT_MEM_REGION, tdx_sept_set_private_spte() etc
e.g. Rename tdx_td_finalizemr to __tdx_td_finalizemr and add:
static int tdx_td_finalizemr(struct kvm *kvm, struct kvm_tdx_cmd *cmd)
{
int ret;
write_lock(&kvm->mmu_lock);
ret = __tdx_td_finalizemr(kvm, cmd);
write_unlock(&kvm->mmu_lock);
return ret;
}
kvm->slots_lock is better. In tdx_vcpu_init_mem_region() you can take
it before the is_td_finalized() so that there is a lock that is clearly
protecting kvm_tdx->finalized between the two. (I also suggest
switching to guard() in tdx_vcpu_init_mem_region()).
Also, I think that in patch 16 (whether merged or not) nr_premapped
should not be incremented, once kvm_tdx->finalized has been set?
Paolo
