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Tue, 13 Aug 2019 01:44:30 -0700 (PDT) Subject: Re: [RFC PATCH v6 02/92] kvm: introspection: add basic ioctls (hook/unhook) To: =?UTF-8?Q?Adalbert_Laz=c4=83r?= , kvm@vger.kernel.org Cc: linux-mm@kvack.org, virtualization@lists.linux-foundation.org, =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= , Konrad Rzeszutek Wilk , Tamas K Lengyel , Mathieu Tarral , =?UTF-8?Q?Samuel_Laur=c3=a9n?= , Patrick Colp , Jan Kiszka , Stefan Hajnoczi , Weijiang Yang , Yu C Zhang , =?UTF-8?Q?Mihai_Don=c8=9bu?= , =?UTF-8?Q?Mircea_C=c3=aerjaliu?= References: <20190809160047.8319-1-alazar@bitdefender.com> <20190809160047.8319-3-alazar@bitdefender.com> From: Paolo Bonzini Openpgp: preference=signencrypt Message-ID: <58808ef0-57b1-47ac-a115-e1dd64a15b0a@redhat.com> Date: Tue, 13 Aug 2019 10:44:28 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <20190809160047.8319-3-alazar@bitdefender.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 09/08/19 17:59, Adalbert Laz=C4=83r wrote: > +static int kvmi_recv(void *arg) > +{ > + struct kvmi *ikvm =3D arg; > + > + kvmi_info(ikvm, "Hooking VM\n"); > + > + while (kvmi_msg_process(ikvm)) > + ; > + > + kvmi_info(ikvm, "Unhooking VM\n"); > + > + kvmi_end_introspection(ikvm); > + > + return 0; > +} > + Rename this to kvmi_recv_thread instead, please. > + > + /* > + * Make sure all the KVM/KVMI structures are linked and no pointer > + * is read as NULL after the reference count has been set. > + */ > + smp_mb__before_atomic(); This is an smp_wmb(), not an smp_mb__before_atomic(). Add a comment that it pairs with the refcount_inc_not_zero in kvmi_get. > + refcount_set(&kvm->kvmi_ref, 1); > + > @@ -57,8 +183,27 @@ void kvmi_destroy_vm(struct kvm *kvm) > if (!ikvm) > return; > =20 > + /* trigger socket shutdown - kvmi_recv() will start shutdown process = */ > + kvmi_sock_shutdown(ikvm); > + > kvmi_put(kvm); > =20 > /* wait for introspection resources to be released */ > wait_for_completion_killable(&kvm->kvmi_completed); > } > + This addition means that kvmi_destroy_vm should have called kvmi_end_introspection instead. In patch 1, kvmi_end_introspection should have been just kvmi_put, now this patch can add kvmi_sock_shutdown= . Paolo