Re: [PATCH 0/4] KVM: nVMX: Fix migration of nested guests when eVMCS is in use

From: Paolo Bonzini
Date: Mon May 03 2021 - 11:43:43 EST

On 03/05/21 17:08, Vitaly Kuznetsov wrote:
Win10 guests with WSL2 enabled sometimes crash on migration when
enlightened VMCS was used. The condition seems to be induced by the
situation when L2->L1 exit is caused immediately after migration and
before L2 gets a chance to run (e.g. when there's an interrupt pending).

Interesting, I think it gets to nested_vmx_vmexit before

if (kvm_check_request(KVM_REQ_GET_NESTED_STATE_PAGES, vcpu)) {
if (unlikely(!kvm_x86_ops.nested_ops->get_nested_state_pages(vcpu))) {
r = 0;
goto out;

due to the infamous calls to check_nested_events that are scattered
through KVM?