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Tue, 21 Jan 2020 12:26:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1579609606; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=zualVJnuuXpl6/Pdtv9LeqTT4rFRhcJUc2mo7tQMMUs=; b=c4WG5zdsGLTmcLUkSrjTjcEB6SDdSchYkz4Hit+y84JoqiInvP2l+NJyy4Q8Nk8yX6JQ/4 nsf5M1nbN39IPCovKc2NhLv+i7aumlh5NrVNp6B69kUQMa5vxRP7Y1UffL26rIgUG3O8Cx F++8f2Gu6K6be5NHTFSdQIiMPSoGRlg= From: "Dr. David Alan Gilbert (git)" To: qemu-devel@nongnu.org, stefanha@redhat.com, vgoyal@redhat.com, berrange@redhat.com, slp@redhat.com, philmd@redhat.com Subject: [PATCH v2 027/109] virtiofsd: Fast path for virtio read Date: Tue, 21 Jan 2020 12:23:11 +0000 Message-Id: <20200121122433.50803-28-dgilbert@redhat.com> In-Reply-To: <20200121122433.50803-1-dgilbert@redhat.com> References: <20200121122433.50803-1-dgilbert@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-MC-Unique: 7zi6IP4TNIyVuxbX-Lq6-g-1 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 207.211.31.120 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: m.mizuma@jp.fujitsu.com, misono.tomohiro@jp.fujitsu.com Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: pass (identity @redhat.com) Content-Type: text/plain; charset="utf-8" From: "Dr. David Alan Gilbert" Readv the data straight into the guests buffer. Signed-off-by: Dr. David Alan Gilbert With fix by: Signed-off-by: Eryu Guan Reviewed-by: Masayoshi Mizuma --- tools/virtiofsd/fuse_lowlevel.c | 5 + tools/virtiofsd/fuse_virtio.c | 162 ++++++++++++++++++++++++++++++++ tools/virtiofsd/fuse_virtio.h | 4 + 3 files changed, 171 insertions(+) diff --git a/tools/virtiofsd/fuse_lowlevel.c b/tools/virtiofsd/fuse_lowleve= l.c index ded7268dc5..5c182676a6 100644 --- a/tools/virtiofsd/fuse_lowlevel.c +++ b/tools/virtiofsd/fuse_lowlevel.c @@ -474,6 +474,11 @@ static int fuse_send_data_iov_fallback(struct fuse_ses= sion *se, return fuse_send_msg(se, ch, iov, iov_count); } =20 + if (fuse_lowlevel_is_virtio(se) && buf->count =3D=3D 1 && + buf->buf[0].flags =3D=3D (FUSE_BUF_IS_FD | FUSE_BUF_FD_SEEK)) { + return virtio_send_data_iov(se, ch, iov, iov_count, buf, len); + } + abort(); /* Will have taken vhost path */ return 0; } diff --git a/tools/virtiofsd/fuse_virtio.c b/tools/virtiofsd/fuse_virtio.c index f1adeb6345..7e2711b504 100644 --- a/tools/virtiofsd/fuse_virtio.c +++ b/tools/virtiofsd/fuse_virtio.c @@ -230,6 +230,168 @@ err: return ret; } =20 +/* + * Callback from fuse_send_data_iov_* when it's virtio and the buffer + * is a single FD with FUSE_BUF_IS_FD | FUSE_BUF_FD_SEEK + * We need send the iov and then the buffer. + * Return 0 on success + */ +int virtio_send_data_iov(struct fuse_session *se, struct fuse_chan *ch, + struct iovec *iov, int count, struct fuse_bufvec = *buf, + size_t len) +{ + int ret =3D 0; + VuVirtqElement *elem; + VuVirtq *q; + + assert(count >=3D 1); + assert(iov[0].iov_len >=3D sizeof(struct fuse_out_header)); + + struct fuse_out_header *out =3D iov[0].iov_base; + /* TODO: Endianness! */ + + size_t iov_len =3D iov_size(iov, count); + size_t tosend_len =3D iov_len + len; + + out->len =3D tosend_len; + + fuse_log(FUSE_LOG_DEBUG, "%s: count=3D%d len=3D%zd iov_len=3D%zd\n", _= _func__, + count, len, iov_len); + + /* unique =3D=3D 0 is notification which we don't support */ + assert(out->unique); + + /* For virtio we always have ch */ + assert(ch); + assert(!ch->qi->reply_sent); + elem =3D ch->qi->qe; + q =3D &ch->qi->virtio_dev->dev.vq[ch->qi->qidx]; + + /* The 'in' part of the elem is to qemu */ + unsigned int in_num =3D elem->in_num; + struct iovec *in_sg =3D elem->in_sg; + size_t in_len =3D iov_size(in_sg, in_num); + fuse_log(FUSE_LOG_DEBUG, "%s: elem %d: with %d in desc of length %zd\n= ", + __func__, elem->index, in_num, in_len); + + /* + * The elem should have room for a 'fuse_out_header' (out from fuse) + * plus the data based on the len in the header. + */ + if (in_len < sizeof(struct fuse_out_header)) { + fuse_log(FUSE_LOG_ERR, "%s: elem %d too short for out_header\n", + __func__, elem->index); + ret =3D E2BIG; + goto err; + } + if (in_len < tosend_len) { + fuse_log(FUSE_LOG_ERR, "%s: elem %d too small for data len %zd\n", + __func__, elem->index, tosend_len); + ret =3D E2BIG; + goto err; + } + + /* TODO: Limit to 'len' */ + + /* First copy the header data from iov->in_sg */ + copy_iov(iov, count, in_sg, in_num, iov_len); + + /* + * Build a copy of the the in_sg iov so we can skip bits in it, + * including changing the offsets + */ + struct iovec *in_sg_cpy =3D calloc(sizeof(struct iovec), in_num); + assert(in_sg_cpy); + memcpy(in_sg_cpy, in_sg, sizeof(struct iovec) * in_num); + /* These get updated as we skip */ + struct iovec *in_sg_ptr =3D in_sg_cpy; + int in_sg_cpy_count =3D in_num; + + /* skip over parts of in_sg that contained the header iov */ + size_t skip_size =3D iov_len; + + size_t in_sg_left =3D 0; + do { + while (skip_size !=3D 0 && in_sg_cpy_count) { + if (skip_size >=3D in_sg_ptr[0].iov_len) { + skip_size -=3D in_sg_ptr[0].iov_len; + in_sg_ptr++; + in_sg_cpy_count--; + } else { + in_sg_ptr[0].iov_len -=3D skip_size; + in_sg_ptr[0].iov_base +=3D skip_size; + break; + } + } + + int i; + for (i =3D 0, in_sg_left =3D 0; i < in_sg_cpy_count; i++) { + in_sg_left +=3D in_sg_ptr[i].iov_len; + } + fuse_log(FUSE_LOG_DEBUG, + "%s: after skip skip_size=3D%zd in_sg_cpy_count=3D%d " + "in_sg_left=3D%zd\n", + __func__, skip_size, in_sg_cpy_count, in_sg_left); + ret =3D preadv(buf->buf[0].fd, in_sg_ptr, in_sg_cpy_count, + buf->buf[0].pos); + + if (ret =3D=3D -1) { + ret =3D errno; + fuse_log(FUSE_LOG_DEBUG, "%s: preadv failed (%m) len=3D%zd\n", + __func__, len); + free(in_sg_cpy); + goto err; + } + fuse_log(FUSE_LOG_DEBUG, "%s: preadv ret=3D%d len=3D%zd\n", __func= __, + ret, len); + if (ret < len && ret) { + fuse_log(FUSE_LOG_DEBUG, "%s: ret < len\n", __func__); + /* Skip over this much next time around */ + skip_size =3D ret; + buf->buf[0].pos +=3D ret; + len -=3D ret; + + /* Lets do another read */ + continue; + } + if (!ret) { + /* EOF case? */ + fuse_log(FUSE_LOG_DEBUG, "%s: !ret in_sg_left=3D%zd\n", __func= __, + in_sg_left); + break; + } + if (ret !=3D len) { + fuse_log(FUSE_LOG_DEBUG, "%s: ret!=3Dlen\n", __func__); + ret =3D EIO; + free(in_sg_cpy); + goto err; + } + in_sg_left -=3D ret; + len -=3D ret; + } while (in_sg_left); + free(in_sg_cpy); + + /* Need to fix out->len on EOF */ + if (len) { + struct fuse_out_header *out_sg =3D in_sg[0].iov_base; + + tosend_len -=3D len; + out_sg->len =3D tosend_len; + } + + ret =3D 0; + + vu_queue_push(&se->virtio_dev->dev, q, elem, tosend_len); + vu_queue_notify(&se->virtio_dev->dev, q); + +err: + if (ret =3D=3D 0) { + ch->qi->reply_sent =3D true; + } + + return ret; +} + /* Thread function for individual queues, created when a queue is 'started= ' */ static void *fv_queue_thread(void *opaque) { diff --git a/tools/virtiofsd/fuse_virtio.h b/tools/virtiofsd/fuse_virtio.h index 135a14875a..cc676b9193 100644 --- a/tools/virtiofsd/fuse_virtio.h +++ b/tools/virtiofsd/fuse_virtio.h @@ -26,4 +26,8 @@ int virtio_loop(struct fuse_session *se); int virtio_send_msg(struct fuse_session *se, struct fuse_chan *ch, struct iovec *iov, int count); =20 +int virtio_send_data_iov(struct fuse_session *se, struct fuse_chan *ch, + struct iovec *iov, int count, + struct fuse_bufvec *buf, size_t len); + #endif --=20 2.24.1