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Tsirkin" , Jason Wang Subject: [PULL V2 07/25] vhost: Check for queue full at vhost_svq_add Date: Wed, 20 Jul 2022 17:02:55 +0800 Message-Id: <20220720090313.55169-8-jasowang@redhat.com> In-Reply-To: <20220720090313.55169-1-jasowang@redhat.com> References: <20220720090313.55169-1-jasowang@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 2.85 on 10.11.54.10 Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=170.10.129.124; envelope-from=jasowang@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -28 X-Spam_score: -2.9 X-Spam_bar: -- X-Spam_report: (-2.9 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.082, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: pass (identity @redhat.com) X-ZM-MESSAGEID: 1658308310426100001 From: Eugenio P=C3=A9rez The series need to expose vhost_svq_add with full functionality, including checking for full queue. Signed-off-by: Eugenio P=C3=A9rez Reviewed-by: Michael S. Tsirkin Signed-off-by: Jason Wang --- hw/virtio/vhost-shadow-virtqueue.c | 59 +++++++++++++++++++++-------------= ---- 1 file changed, 33 insertions(+), 26 deletions(-) diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-vi= rtqueue.c index e272c33..11302ea 100644 --- a/hw/virtio/vhost-shadow-virtqueue.c +++ b/hw/virtio/vhost-shadow-virtqueue.c @@ -233,21 +233,29 @@ static void vhost_svq_kick(VhostShadowVirtqueue *svq) * Add an element to a SVQ. * * The caller must check that there is enough slots for the new element. It - * takes ownership of the element: In case of failure, it is free and the = SVQ - * is considered broken. + * takes ownership of the element: In case of failure not ENOSPC, it is fr= ee. + * + * Return -EINVAL if element is invalid, -ENOSPC if dev queue is full */ -static bool vhost_svq_add(VhostShadowVirtqueue *svq, VirtQueueElement *ele= m) +static int vhost_svq_add(VhostShadowVirtqueue *svq, VirtQueueElement *elem) { unsigned qemu_head; - bool ok =3D vhost_svq_add_split(svq, elem, &qemu_head); + unsigned ndescs =3D elem->in_num + elem->out_num; + bool ok; + + if (unlikely(ndescs > vhost_svq_available_slots(svq))) { + return -ENOSPC; + } + + ok =3D vhost_svq_add_split(svq, elem, &qemu_head); if (unlikely(!ok)) { g_free(elem); - return false; + return -EINVAL; } =20 svq->ring_id_maps[qemu_head] =3D elem; vhost_svq_kick(svq); - return true; + return 0; } =20 /** @@ -274,7 +282,7 @@ static void vhost_handle_guest_kick(VhostShadowVirtqueu= e *svq) =20 while (true) { VirtQueueElement *elem; - bool ok; + int r; =20 if (svq->next_guest_avail_elem) { elem =3D g_steal_pointer(&svq->next_guest_avail_elem); @@ -286,25 +294,24 @@ static void vhost_handle_guest_kick(VhostShadowVirtqu= eue *svq) break; } =20 - if (elem->out_num + elem->in_num > vhost_svq_available_slots(s= vq)) { - /* - * This condition is possible since a contiguous buffer in= GPA - * does not imply a contiguous buffer in qemu's VA - * scatter-gather segments. If that happens, the buffer ex= posed - * to the device needs to be a chain of descriptors at this - * moment. - * - * SVQ cannot hold more available buffers if we are here: - * queue the current guest descriptor and ignore further k= icks - * until some elements are used. - */ - svq->next_guest_avail_elem =3D elem; - return; - } - - ok =3D vhost_svq_add(svq, elem); - if (unlikely(!ok)) { - /* VQ is broken, just return and ignore any other kicks */ + r =3D vhost_svq_add(svq, elem); + if (unlikely(r !=3D 0)) { + if (r =3D=3D -ENOSPC) { + /* + * This condition is possible since a contiguous buffe= r in + * GPA does not imply a contiguous buffer in qemu's VA + * scatter-gather segments. If that happens, the buffer + * exposed to the device needs to be a chain of descri= ptors + * at this moment. + * + * SVQ cannot hold more available buffers if we are he= re: + * queue the current guest descriptor and ignore kicks + * until some elements are used. + */ + svq->next_guest_avail_elem =3D elem; + } + + /* VQ is full or broken, just return and ignore kicks */ return; } } --=20 2.7.4