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[109.64.41.91]) by smtp.gmail.com with ESMTPSA id s7sm3687653wrr.60.2020.06.02.06.06.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 02 Jun 2020 06:06:12 -0700 (PDT) Date: Tue, 2 Jun 2020 09:06:10 -0400 From: "Michael S. Tsirkin" To: linux-kernel@vger.kernel.org Cc: Eugenio =?utf-8?b?UMOpcmV6?= , Jason Wang , kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org Subject: [PATCH RFC 07/13] vhost: format-independent API for used buffers Message-ID: <20200602130543.578420-8-mst@redhat.com> References: <20200602130543.578420-1-mst@redhat.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200602130543.578420-1-mst@redhat.com> X-Mailer: git-send-email 2.24.1.751.gd10ce2899c X-Mutt-Fcc: =sent Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Add a new API that doesn't assume used ring, heads, etc. For now, we keep the old APIs around to make it easier to convert drivers. Signed-off-by: Michael S. Tsirkin --- drivers/vhost/vhost.c | 52 ++++++++++++++++++++++++++++++++++--------- drivers/vhost/vhost.h | 17 +++++++++++++- 2 files changed, 58 insertions(+), 11 deletions(-) diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index b4a6e44d56a8..be822f0c9428 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -2292,13 +2292,12 @@ static int fetch_descs(struct vhost_virtqueue *vq) * number of output then some number of input descriptors, it's actually two * iovecs, but we pack them into one and note how many of each there were. * - * This function returns the descriptor number found, or vq->num (which is - * never a valid descriptor number) if none was found. A negative code is - * returned on error. */ -int vhost_get_vq_desc(struct vhost_virtqueue *vq, - struct iovec iov[], unsigned int iov_size, - unsigned int *out_num, unsigned int *in_num, - struct vhost_log *log, unsigned int *log_num) + * This function returns a value > 0 if a descriptor was found, or 0 if none were found. + * A negative code is returned on error. */ +int vhost_get_avail_buf(struct vhost_virtqueue *vq, struct vhost_buf *buf, + struct iovec iov[], unsigned int iov_size, + unsigned int *out_num, unsigned int *in_num, + struct vhost_log *log, unsigned int *log_num) { int ret = fetch_descs(vq); int i; @@ -2311,6 +2310,8 @@ int vhost_get_vq_desc(struct vhost_virtqueue *vq, *out_num = *in_num = 0; if (unlikely(log)) *log_num = 0; + buf->in_len = buf->out_len = 0; + buf->descs = 0; for (i = vq->first_desc; i < vq->ndescs; ++i) { unsigned iov_count = *in_num + *out_num; @@ -2340,6 +2341,7 @@ int vhost_get_vq_desc(struct vhost_virtqueue *vq, /* If this is an input descriptor, * increment that count. */ *in_num += ret; + buf->in_len += desc->len; if (unlikely(log && ret)) { log[*log_num].addr = desc->addr; log[*log_num].len = desc->len; @@ -2355,9 +2357,11 @@ int vhost_get_vq_desc(struct vhost_virtqueue *vq, goto err; } *out_num += ret; + buf->out_len += desc->len; } - ret = desc->id; + buf->id = desc->id; + ++buf->descs; if (!(desc->flags & VRING_DESC_F_NEXT)) break; @@ -2365,7 +2369,7 @@ int vhost_get_vq_desc(struct vhost_virtqueue *vq, vq->first_desc = i + 1; - return ret; + return 1; err: for (i = vq->first_desc; i < vq->ndescs; ++i) @@ -2375,7 +2379,15 @@ int vhost_get_vq_desc(struct vhost_virtqueue *vq, return ret; } -EXPORT_SYMBOL_GPL(vhost_get_vq_desc); +EXPORT_SYMBOL_GPL(vhost_get_avail_buf); + +/* Reverse the effect of vhost_get_avail_buf. Useful for error handling. */ +void vhost_discard_avail_bufs(struct vhost_virtqueue *vq, + struct vhost_buf *buf, unsigned count) +{ + vhost_discard_vq_desc(vq, count); +} +EXPORT_SYMBOL_GPL(vhost_discard_avail_bufs); static int __vhost_add_used_n(struct vhost_virtqueue *vq, struct vring_used_elem *heads, @@ -2459,6 +2471,26 @@ int vhost_add_used(struct vhost_virtqueue *vq, unsigned int head, int len) } EXPORT_SYMBOL_GPL(vhost_add_used); +int vhost_put_used_buf(struct vhost_virtqueue *vq, struct vhost_buf *buf) +{ + return vhost_add_used(vq, buf->id, buf->in_len); +} +EXPORT_SYMBOL_GPL(vhost_put_used_buf); + +int vhost_put_used_n_bufs(struct vhost_virtqueue *vq, + struct vhost_buf *bufs, unsigned count) +{ + unsigned i; + + for (i = 0; i < count; ++i) { + vq->heads[i].id = cpu_to_vhost32(vq, bufs[i].id); + vq->heads[i].len = cpu_to_vhost32(vq, bufs[i].in_len); + } + + return vhost_add_used_n(vq, vq->heads, count); +} +EXPORT_SYMBOL_GPL(vhost_put_used_n_bufs); + static bool vhost_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq) { __u16 old, new; diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h index a67bda9792ec..6c10e99ff334 100644 --- a/drivers/vhost/vhost.h +++ b/drivers/vhost/vhost.h @@ -67,6 +67,13 @@ struct vhost_desc { u16 id; }; +struct vhost_buf { + u32 out_len; + u32 in_len; + u16 descs; + u16 id; +}; + /* The virtqueue structure describes a queue attached to a device. */ struct vhost_virtqueue { struct vhost_dev *dev; @@ -193,7 +200,12 @@ int vhost_get_vq_desc(struct vhost_virtqueue *, unsigned int *out_num, unsigned int *in_num, struct vhost_log *log, unsigned int *log_num); void vhost_discard_vq_desc(struct vhost_virtqueue *, int n); - +int vhost_get_avail_buf(struct vhost_virtqueue *, struct vhost_buf *buf, + struct iovec iov[], unsigned int iov_count, + unsigned int *out_num, unsigned int *in_num, + struct vhost_log *log, unsigned int *log_num); +void vhost_discard_avail_bufs(struct vhost_virtqueue *, + struct vhost_buf *, unsigned count); int vhost_vq_init_access(struct vhost_virtqueue *); int vhost_add_used(struct vhost_virtqueue *, unsigned int head, int len); int vhost_add_used_n(struct vhost_virtqueue *, struct vring_used_elem *heads, @@ -202,6 +214,9 @@ void vhost_add_used_and_signal(struct vhost_dev *, struct vhost_virtqueue *, unsigned int id, int len); void vhost_add_used_and_signal_n(struct vhost_dev *, struct vhost_virtqueue *, struct vring_used_elem *heads, unsigned count); +int vhost_put_used_buf(struct vhost_virtqueue *, struct vhost_buf *buf); +int vhost_put_used_n_bufs(struct vhost_virtqueue *, + struct vhost_buf *bufs, unsigned count); void vhost_signal(struct vhost_dev *, struct vhost_virtqueue *); void vhost_disable_notify(struct vhost_dev *, struct vhost_virtqueue *); bool vhost_vq_avail_empty(struct vhost_dev *, struct vhost_virtqueue *);