From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:39310) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gAbeT-0004sx-ID for qemu-devel@nongnu.org; Thu, 11 Oct 2018 10:09:29 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gAbeP-000620-WE for qemu-devel@nongnu.org; Thu, 11 Oct 2018 10:09:19 -0400 Received: from mx1.redhat.com ([209.132.183.28]:35882) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1gAbeP-00060H-G4 for qemu-devel@nongnu.org; Thu, 11 Oct 2018 10:09:17 -0400 From: wexu@redhat.com Date: Thu, 11 Oct 2018 10:08:29 -0400 Message-Id: <1539266915-15216-7-git-send-email-wexu@redhat.com> In-Reply-To: <1539266915-15216-1-git-send-email-wexu@redhat.com> References: <1539266915-15216-1-git-send-email-wexu@redhat.com> Subject: [Qemu-devel] [[RFC v3 06/12] virtio: get avail bytes check for packed ring List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: jasowang@redhat.com, tiwei.bie@intel.com, wexu@redhat.com, jfreimann@redhat.com, maxime.coquelin@redhat.com From: Wei Xu Same thought as 1.0 except a bit confused when trying to reuse 'shadow_avail_idx', so the interrelated new event_idx and the wrap counter for notifications has been introduced in previous patch. Signed-off-by: Wei Xu --- hw/virtio/virtio.c | 176 ++++++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 173 insertions(+), 3 deletions(-) diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index 86f88da..13c6c98 100644 --- a/hw/virtio/virtio.c +++ b/hw/virtio/virtio.c @@ -375,6 +375,17 @@ int virtio_queue_ready(VirtQueue *vq) return vq->vring.avail != 0; } +static void vring_packed_desc_read(VirtIODevice *vdev, VRingPackedDesc *desc, + MemoryRegionCache *cache, int i) +{ + address_space_read_cached(cache, i * sizeof(VRingPackedDesc), + desc, sizeof(VRingPackedDesc)); + virtio_tswap16s(vdev, &desc->flags); + virtio_tswap64s(vdev, &desc->addr); + virtio_tswap32s(vdev, &desc->len); + virtio_tswap16s(vdev, &desc->id); +} + static void vring_packed_desc_read_flags(VirtIODevice *vdev, VRingPackedDesc *desc, MemoryRegionCache *cache, int i) { @@ -672,9 +683,9 @@ static int virtqueue_read_next_desc(VirtIODevice *vdev, VRingDesc *desc, return VIRTQUEUE_READ_DESC_MORE; } -void virtqueue_get_avail_bytes(VirtQueue *vq, unsigned int *in_bytes, - unsigned int *out_bytes, - unsigned max_in_bytes, unsigned max_out_bytes) +static void virtqueue_split_get_avail_bytes(VirtQueue *vq, + unsigned int *in_bytes, unsigned int *out_bytes, + unsigned max_in_bytes, unsigned max_out_bytes) { VirtIODevice *vdev = vq->vdev; unsigned int max, idx; @@ -797,6 +808,165 @@ err: goto done; } +static void virtqueue_packed_get_avail_bytes(VirtQueue *vq, + unsigned int *in_bytes, unsigned int *out_bytes, + unsigned max_in_bytes, unsigned max_out_bytes) +{ + VirtIODevice *vdev = vq->vdev; + unsigned int max, idx; + unsigned int total_bufs, in_total, out_total; + MemoryRegionCache *desc_cache; + VRingMemoryRegionCaches *caches; + MemoryRegionCache indirect_desc_cache = MEMORY_REGION_CACHE_INVALID; + int64_t len = 0; + VRingPackedDesc desc; + bool wrap_counter; + + if (unlikely(!vq->vring.desc)) { + if (in_bytes) { + *in_bytes = 0; + } + if (out_bytes) { + *out_bytes = 0; + } + return; + } + + rcu_read_lock(); + idx = vq->last_avail_idx; + wrap_counter = vq->avail_wrap_counter; + total_bufs = in_total = out_total = 0; + + max = vq->vring.num; + caches = vring_get_region_caches(vq); + if (caches->desc.len < max * sizeof(VRingPackedDesc)) { + virtio_error(vdev, "Cannot map descriptor ring"); + goto err; + } + + desc_cache = &caches->desc; + vring_packed_desc_read(vdev, &desc, desc_cache, idx); + /* Make sure we see all the fields*/ + smp_rmb(); + while (is_desc_avail(&desc, wrap_counter)) { + unsigned int num_bufs; + unsigned int i = 0; + + num_bufs = total_bufs; + + if (desc.flags & VRING_DESC_F_INDIRECT) { + if (desc.len % sizeof(VRingPackedDesc)) { + virtio_error(vdev, "Invalid size for indirect buffer table"); + goto err; + } + + /* If we've got too many, that implies a descriptor loop. */ + if (num_bufs >= max) { + virtio_error(vdev, "Looped descriptor"); + goto err; + } + + /* loop over the indirect descriptor table */ + len = address_space_cache_init(&indirect_desc_cache, + vdev->dma_as, + desc.addr, desc.len, false); + desc_cache = &indirect_desc_cache; + if (len < desc.len) { + virtio_error(vdev, "Cannot map indirect buffer"); + goto err; + } + + max = desc.len / sizeof(VRingPackedDesc); + num_bufs = i = 0; + vring_packed_desc_read(vdev, &desc, desc_cache, i); + /* Make sure we see all the fields*/ + smp_rmb(); + } + + do { + /* If we've got too many, that implies a descriptor loop. */ + if (++num_bufs > max) { + virtio_error(vdev, "Looped descriptor"); + goto err; + } + + if (desc.flags & VRING_DESC_F_WRITE) { + in_total += desc.len; + } else { + out_total += desc.len; + } + if (in_total >= max_in_bytes && out_total >= max_out_bytes) { + goto done; + } + + if (desc_cache == &indirect_desc_cache) { + if (++i > vq->vring.num) { + virtio_error(vdev, "Looped descriptor"); + goto err; + } + vring_packed_desc_read(vdev, &desc, desc_cache, i); + } else { + if (++idx >= vq->vring.num) { + idx -= vq->vring.num; + wrap_counter = !wrap_counter; + } + vring_packed_desc_read(vdev, &desc, desc_cache, idx); + } + /* Make sure we see the flags */ + smp_rmb(); + } while (desc.flags & VRING_DESC_F_NEXT); + + if (desc_cache == &indirect_desc_cache) { + address_space_cache_destroy(&indirect_desc_cache); + total_bufs++; + /* We missed one step on for indirect desc */ + idx++; + if (++idx >= vq->vring.num) { + idx -= vq->vring.num; + wrap_counter = !wrap_counter; + } + } else { + total_bufs = num_bufs; + } + + desc_cache = &caches->desc; + vring_packed_desc_read(vdev, &desc, desc_cache, idx); + /* Make sure we see all the fields */ + smp_rmb(); + } + + /* Set up index and wrap counter for an interrupt when no enough desc */ + vq->event_idx = idx; + vq->event_wrap_counter = wrap_counter; +done: + address_space_cache_destroy(&indirect_desc_cache); + if (in_bytes) { + *in_bytes = in_total; + } + if (out_bytes) { + *out_bytes = out_total; + } + rcu_read_unlock(); + return; + +err: + in_total = out_total = 0; + goto done; +} + +void virtqueue_get_avail_bytes(VirtQueue *vq, unsigned int *in_bytes, + unsigned int *out_bytes, + unsigned max_in_bytes, unsigned max_out_bytes) +{ + if (virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED)) { + virtqueue_packed_get_avail_bytes(vq, in_bytes, out_bytes, + max_in_bytes, max_out_bytes); + } else { + virtqueue_split_get_avail_bytes(vq, in_bytes, out_bytes, + max_in_bytes, max_out_bytes); + } +} + int virtqueue_avail_bytes(VirtQueue *vq, unsigned int in_bytes, unsigned int out_bytes) { -- 1.8.3.1