Re: [PATCH 1/7] KVM: x86: Free vCPUs before freeing VM state
From: Yan Zhao <hidden>
Date: 2025-02-25 07:46:44
Also in:
kvm, kvm-riscv, kvmarm, linux-mips, linux-riscv, linuxppc-dev, lkml, loongarch
quoted hunk ↗ jump to hunk
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 58b82d6fd77c..045c61cc7e54 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c@@ -12890,11 +12890,11 @@ void kvm_arch_destroy_vm(struct kvm *kvm) mutex_unlock(&kvm->slots_lock); } kvm_unload_vcpu_mmus(kvm); + kvm_destroy_vcpus(kvm); kvm_x86_call(vm_destroy)(kvm); kvm_free_msr_filter(srcu_dereference_check(kvm->arch.msr_filter, &kvm->srcu, 1)); kvm_pic_destroy(kvm); kvm_ioapic_destroy(kvm); - kvm_destroy_vcpus(kvm); kvfree(rcu_dereference_check(kvm->arch.apic_map, 1)); kfree(srcu_dereference_check(kvm->arch.pmu_event_filter, &kvm->srcu, 1)); kvm_mmu_uninit_vm(kvm);
After this change, now the sequence is that
1. kvm_arch_pre_destroy_vm()
2. kvm_arch_destroy_vm()
2.1 kvm_destroy_vcpus()
2.2 .vm_destroy hook
2.3 kvm_mmu_uninit_vm() --> mirror root ref is 1 upon here. Zap the mirror
root and reclaim SETP page table pages.
2.4 .vm_free hook
Since TDX needs to reclaim the TDR page after reclaiming all other pages, we
currently added a vm_free hook at 2.4, after 2.3.
Could we move kvm_mmu_uninit_vm() before the .vm_destroy hook and after
kvm_destroy_vcpus()?
Or move the .vm_destroy hook after kvm_mmu_uninit_vm(), e.g. after
kvm_page_track_cleanup()?
Otherwise, TDX still needs to introduce the .vm_free hook, which is invoked at
the end of kvm_arch_destroy_vm().