From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Wang Subject: [PATCH net-next V2 7/8] vhost: event suppression for packed ring Date: Mon, 16 Jul 2018 11:28:10 +0800 Message-ID: <1531711691-6769-8-git-send-email-jasowang__48330.1160893918$1531712039$gmane$org@redhat.com> References: <1531711691-6769-1-git-send-email-jasowang@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1531711691-6769-1-git-send-email-jasowang@redhat.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: mst@redhat.com, jasowang@redhat.com Cc: kvm@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, maxime.coquelin@redhat.com, wexu@redhat.com List-Id: virtualization@lists.linuxfoundation.org This patch introduces support for event suppression. This is done by have a two areas: device area and driver area. One side could then try to disable or enable (delayed) notification from other side by using a boolean hint or event index interface in the areas. For more information, please refer Virtio spec. Signed-off-by: Jason Wang --- drivers/vhost/vhost.c | 191 ++++++++++++++++++++++++++++++++++++++++++++++---- drivers/vhost/vhost.h | 10 ++- 2 files changed, 185 insertions(+), 16 deletions(-) diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index 63b79e8..0459f8b 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -1115,10 +1115,15 @@ static int vq_access_ok_packed(struct vhost_virtqueue *vq, unsigned int num, struct vring_used __user *used) { struct vring_packed_desc *packed = (struct vring_packed_desc *)desc; + struct vring_packed_desc_event *driver_event = + (struct vring_packed_desc_event *)avail; + struct vring_packed_desc_event *device_event = + (struct vring_packed_desc_event *)used; - /* TODO: check device area and driver area */ return access_ok(VERIFY_READ, packed, num * sizeof(*packed)) && - access_ok(VERIFY_WRITE, packed, num * sizeof(*packed)); + access_ok(VERIFY_WRITE, packed, num * sizeof(*packed)) && + access_ok(VERIFY_READ, driver_event, sizeof(*driver_event)) && + access_ok(VERIFY_WRITE, device_event, sizeof(*device_event)); } static int vq_access_ok_split(struct vhost_virtqueue *vq, unsigned int num, @@ -1193,14 +1198,27 @@ static bool iotlb_access_ok(struct vhost_virtqueue *vq, return true; } -int vq_iotlb_prefetch(struct vhost_virtqueue *vq) +int vq_iotlb_prefetch_packed(struct vhost_virtqueue *vq) +{ + int num = vq->num; + + return iotlb_access_ok(vq, VHOST_ACCESS_RO, (u64)(uintptr_t)vq->desc, + num * sizeof(*vq->desc), VHOST_ADDR_DESC) && + iotlb_access_ok(vq, VHOST_ACCESS_WO, (u64)(uintptr_t)vq->desc, + num * sizeof(*vq->desc), VHOST_ADDR_DESC) && + iotlb_access_ok(vq, VHOST_ACCESS_RO, + (u64)(uintptr_t)vq->driver_event, + sizeof(*vq->driver_event), VHOST_ADDR_AVAIL) && + iotlb_access_ok(vq, VHOST_ACCESS_WO, + (u64)(uintptr_t)vq->device_event, + sizeof(*vq->device_event), VHOST_ADDR_USED); +} + +int vq_iotlb_prefetch_split(struct vhost_virtqueue *vq) { size_t s = vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0; unsigned int num = vq->num; - if (!vq->iotlb) - return 1; - return iotlb_access_ok(vq, VHOST_ACCESS_RO, (u64)(uintptr_t)vq->desc, num * sizeof(*vq->desc), VHOST_ADDR_DESC) && iotlb_access_ok(vq, VHOST_ACCESS_RO, (u64)(uintptr_t)vq->avail, @@ -1212,6 +1230,17 @@ int vq_iotlb_prefetch(struct vhost_virtqueue *vq) num * sizeof(*vq->used->ring) + s, VHOST_ADDR_USED); } + +int vq_iotlb_prefetch(struct vhost_virtqueue *vq) +{ + if (!vq->iotlb) + return 1; + + if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED)) + return vq_iotlb_prefetch_packed(vq); + else + return vq_iotlb_prefetch_split(vq); +} EXPORT_SYMBOL_GPL(vq_iotlb_prefetch); /* Can we log writes? */ @@ -1771,6 +1800,50 @@ static int vhost_update_used_flags(struct vhost_virtqueue *vq) return 0; } +static int vhost_update_device_flags(struct vhost_virtqueue *vq, + __virtio16 device_flags) +{ + void __user *flags; + + if (vhost_put_user(vq, device_flags, &vq->device_event->flags, + VHOST_ADDR_USED) < 0) + return -EFAULT; + if (unlikely(vq->log_used)) { + /* Make sure the flag is seen before log. */ + smp_wmb(); + /* Log used flag write. */ + flags = &vq->device_event->flags; + log_write(vq->log_base, vq->log_addr + + (flags - (void __user *)vq->device_event), + sizeof(vq->device_event->flags)); + if (vq->log_ctx) + eventfd_signal(vq->log_ctx, 1); + } + return 0; +} + +static int vhost_update_device_off_wrap(struct vhost_virtqueue *vq, + __virtio16 device_off_wrap) +{ + void __user *off_wrap; + + if (vhost_put_user(vq, device_off_wrap, &vq->device_event->off_wrap, + VHOST_ADDR_USED) < 0) + return -EFAULT; + if (unlikely(vq->log_used)) { + /* Make sure the flag is seen before log. */ + smp_wmb(); + /* Log used flag write. */ + off_wrap = &vq->device_event->off_wrap; + log_write(vq->log_base, vq->log_addr + + (off_wrap - (void __user *)vq->device_event), + sizeof(vq->device_event->off_wrap)); + if (vq->log_ctx) + eventfd_signal(vq->log_ctx, 1); + } + return 0; +} + static int vhost_update_avail_event(struct vhost_virtqueue *vq, u16 avail_event) { if (vhost_put_user(vq, cpu_to_vhost16(vq, vq->avail_idx), @@ -2754,16 +2827,13 @@ int vhost_add_used_n(struct vhost_virtqueue *vq, } EXPORT_SYMBOL_GPL(vhost_add_used_n); -static bool vhost_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq) +static bool vhost_notify_split(struct vhost_dev *dev, + struct vhost_virtqueue *vq) { __u16 old, new; __virtio16 event; bool v; - /* TODO: check driver area */ - if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED)) - return true; - /* Flush out used index updates. This is paired * with the barrier that the Guest executes when enabling * interrupts. */ @@ -2796,6 +2866,64 @@ static bool vhost_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq) return vring_need_event(vhost16_to_cpu(vq, event), new, old); } +static bool vhost_notify_packed(struct vhost_dev *dev, + struct vhost_virtqueue *vq) +{ + __virtio16 event_off_wrap, event_flags; + __u16 old, new, off_wrap; + bool v; + + /* Flush out used descriptors updates. This is paired + * with the barrier that the Guest executes when enabling + * interrupts. + */ + smp_mb(); + + if (vhost_get_avail(vq, event_flags, + &vq->driver_event->flags) < 0) { + vq_err(vq, "Failed to get driver desc_event_flags"); + return true; + } + + if (!vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX)) + return event_flags != + cpu_to_vhost16(vq, VRING_EVENT_F_DISABLE); + + old = vq->signalled_used; + v = vq->signalled_used_valid; + new = vq->signalled_used = vq->last_used_idx; + vq->signalled_used_valid = true; + + if (event_flags != cpu_to_vhost16(vq, VRING_EVENT_F_DESC)) + return event_flags != + cpu_to_vhost16(vq, VRING_EVENT_F_DISABLE); + + /* Read desc event flags before event_off and event_wrap */ + smp_rmb(); + + if (vhost_get_avail(vq, event_off_wrap, + &vq->driver_event->off_wrap) < 0) { + vq_err(vq, "Failed to get driver desc_event_off/wrap"); + return true; + } + + off_wrap = vhost16_to_cpu(vq, event_off_wrap); + + if (unlikely(!v)) + return true; + + return vhost_vring_packed_need_event(vq, vq->last_used_wrap_counter, + off_wrap, new, old); +} + +static bool vhost_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq) +{ + if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED)) + return vhost_notify_packed(dev, vq); + else + return vhost_notify_split(dev, vq); +} + /* This actually signals the guest, using eventfd. */ void vhost_signal(struct vhost_dev *dev, struct vhost_virtqueue *vq) { @@ -2873,10 +3001,34 @@ static bool vhost_enable_notify_packed(struct vhost_dev *dev, struct vhost_virtqueue *vq) { struct vring_packed_desc *d = vq->desc_packed + vq->avail_idx; - __virtio16 flags; + __virtio16 flags = cpu_to_vhost16(vq, VRING_EVENT_F_ENABLE); int ret; - /* TODO: enable notification through device area */ + if (!(vq->used_flags & VRING_USED_F_NO_NOTIFY)) + return false; + vq->used_flags &= ~VRING_USED_F_NO_NOTIFY; + + if (vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX)) { + __virtio16 off_wrap = cpu_to_vhost16(vq, vq->avail_idx | + vq->avail_wrap_counter << 15); + + ret = vhost_update_device_off_wrap(vq, off_wrap); + if (ret) { + vq_err(vq, "Failed to write to off warp at %p: %d\n", + &vq->device_event->off_wrap, ret); + return false; + } + /* Make sure off_wrap is wrote before flags */ + smp_wmb(); + flags = cpu_to_vhost16(vq, VRING_EVENT_F_DESC); + } + + ret = vhost_update_device_flags(vq, flags); + if (ret) { + vq_err(vq, "Failed to enable notification at %p: %d\n", + &vq->device_event->flags, ret); + return false; + } /* They could have slipped one in as we were doing that: make * sure it's written, then check again. @@ -2943,7 +3095,18 @@ EXPORT_SYMBOL_GPL(vhost_enable_notify); static void vhost_disable_notify_packed(struct vhost_dev *dev, struct vhost_virtqueue *vq) { - /* TODO: disable notification through device area */ + __virtio16 flags; + int r; + + if (vq->used_flags & VRING_USED_F_NO_NOTIFY) + return; + vq->used_flags |= VRING_USED_F_NO_NOTIFY; + + flags = cpu_to_vhost16(vq, VRING_EVENT_F_DISABLE); + r = vhost_update_device_flags(vq, flags); + if (r) + vq_err(vq, "Failed to enable notification at %p: %d\n", + &vq->device_event->flags, r); } static void vhost_disable_notify_split(struct vhost_dev *dev, diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h index 73c2a78..3a7fc4b 100644 --- a/drivers/vhost/vhost.h +++ b/drivers/vhost/vhost.h @@ -96,8 +96,14 @@ struct vhost_virtqueue { struct vring_desc __user *desc; struct vring_packed_desc __user *desc_packed; }; - struct vring_avail __user *avail; - struct vring_used __user *used; + union { + struct vring_avail __user *avail; + struct vring_packed_desc_event __user *driver_event; + }; + union { + struct vring_used __user *used; + struct vring_packed_desc_event __user *device_event; + }; const struct vhost_umem_node *meta_iotlb[VHOST_NUM_ADDRS]; struct file *kick; struct eventfd_ctx *call_ctx; -- 2.7.4