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([2001:b07:6468:f312:8ca6:a836:a237:fed1]) by smtp.googlemail.com with ESMTPSA id g9-20020aa7c849000000b00412fc6bf26dsm11202939edt.80.2022.03.31.02.34.35 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 31 Mar 2022 02:34:36 -0700 (PDT) Message-ID: <0c830e36-fcf2-fab6-aed9-7b6a6736140f@redhat.com> Date: Thu, 31 Mar 2022 11:34:35 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.7.0 Subject: Re: [PATCH] KVM: MMU: propagate alloc_workqueue failure Content-Language: en-US To: David Matlack Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org References: <20220330165510.213111-1-pbonzini@redhat.com> From: Paolo Bonzini In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 3/31/22 01:51, David Matlack wrote: >> -void kvm_mmu_init_vm(struct kvm *kvm) >> +int kvm_mmu_init_vm(struct kvm *kvm) >> { >> struct kvm_page_track_notifier_node *node = &kvm->arch.mmu_sp_tracker; >> + int r; >> >> + INIT_LIST_HEAD(&kvm->arch.active_mmu_pages); >> + INIT_LIST_HEAD(&kvm->arch.zapped_obsolete_pages); >> + INIT_LIST_HEAD(&kvm->arch.lpage_disallowed_mmu_pages); > > I agree with moving these but that should probably be done in a separate > commit. Ok. >> - kvm->arch.tdp_mmu_zap_wq = >> - alloc_workqueue("kvm", WQ_UNBOUND|WQ_MEM_RECLAIM|WQ_CPU_INTENSIVE, 0); >> - >> - return true; >> + kvm->arch.tdp_mmu_zap_wq = wq; > > Suggest moving this to just after checking the return value of > alloc_workqueue(). This is intentional, in case we have other future allocations, to avoid having to NULL out the field in the unwind path. It's a matter of taste I guess. >> + return 1; > > Perhaps return 0 until we have a reason to differentiate the 2 cases. Yeah, though I wanted to preserve the previous behavior. >> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c >> index fe2171b11441..89b6efb7f504 100644 >> --- a/arch/x86/kvm/x86.c >> +++ b/arch/x86/kvm/x86.c >> @@ -11629,12 +11629,13 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) >> >> ret = kvm_page_track_init(kvm); >> if (ret) >> - return ret; >> + goto out; > > nit: This goto is unnecessary. True, but I prefer to be consistent in using "goto" so that any future additions are careful about preserving the chain. Paolo