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[35.185.214.157]) by smtp.gmail.com with ESMTPSA id f15sm4876552pgv.92.2021.07.29.14.17.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 29 Jul 2021 14:17:20 -0700 (PDT) Date: Thu, 29 Jul 2021 21:17:16 +0000 From: Sean Christopherson To: Peter Gonda Cc: kvm@vger.kernel.org, Brijesh Singh , Marc Orr , Paolo Bonzini , David Rientjes , "Dr . David Alan Gilbert" , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/3 V3] KVM, SEV: Refactor out function for unregistering encrypted regions Message-ID: References: <20210726195015.2106033-1-pgonda@google.com> <20210726195015.2106033-2-pgonda@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210726195015.2106033-2-pgonda@google.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Prefer "KVM: SVM:" or "KVM: SEV:" in the shortlog, i.e. colon instead of comma after KVM. On Mon, Jul 26, 2021, Peter Gonda wrote: > Factor out helper function for freeing the encrypted region list. > > Signed-off-by: Peter Gonda > Reviewed-by: Brijesh Singh > Reviewed-by: Marc Orr > Cc: Paolo Bonzini > Cc: Sean Christopherson > Cc: David Rientjes > Cc: Dr. David Alan Gilbert > Cc: Brijesh Singh > Cc: Vitaly Kuznetsov > Cc: Wanpeng Li > Cc: Jim Mattson > Cc: Joerg Roedel > Cc: Thomas Gleixner > Cc: Ingo Molnar > Cc: Borislav Petkov > Cc: "H. Peter Anvin" > Cc: kvm@vger.kernel.org > Cc: linux-kernel@vger.kernel.org > --- > arch/x86/kvm/svm/sev.c | 26 +++++++++++++++++--------- > 1 file changed, 17 insertions(+), 9 deletions(-) > > diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c > index b59c464bcdfa..6cb61d36fd5e 100644 > --- a/arch/x86/kvm/svm/sev.c > +++ b/arch/x86/kvm/svm/sev.c > @@ -1775,11 +1775,25 @@ int svm_vm_copy_asid_from(struct kvm *kvm, unsigned int source_fd) > return ret; > } > > +static void unregister_enc_regions(struct kvm *kvm, > + struct list_head *mem_regions) Indentation is wonky. There's an extra tab and an extra space. > +{ > + struct enc_region *pos, *q; > + > + lockdep_assert_held(&kvm->lock); > + > + if (list_empty(mem_regions)) > + return; > + > + list_for_each_entry_safe(pos, q, mem_regions, list) { > + __unregister_enc_region_locked(kvm, pos); > + cond_resched(); > + } > +} > + > void sev_vm_destroy(struct kvm *kvm) > { > struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info; > - struct list_head *head = &sev->regions_list; > - struct list_head *pos, *q; > > if (!sev_guest(kvm)) > return; > @@ -1803,13 +1817,7 @@ void sev_vm_destroy(struct kvm *kvm) > * if userspace was terminated before unregistering the memory regions > * then lets unpin all the registered memory. > */ > - if (!list_empty(head)) { > - list_for_each_safe(pos, q, head) { > - __unregister_enc_region_locked(kvm, > - list_entry(pos, struct enc_region, list)); > - cond_resched(); > - } > - } > + unregister_enc_regions(kvm, &sev->regions_list); > > mutex_unlock(&kvm->lock); Is there any reason for taking kvm->lock in this path? The VM is being destroyed, there should be no other references, i.e. this is the only task that can be doing anything with @kvm. The lock is harmless, it just always gives me pause to see the cond_resched() while holding kvm->lock. > -- > 2.32.0.432.gabb21c7263-goog >