linux-kernel - Re: [PATCH V6 13/19] virtio_ring: introduce virtqueue ops

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <CACGkMEtfDr7v2HECZMSSrR97eZjwbT_wTuDtcX312ObqgE=Jhg@mail.gmail.com>
Date: Mon, 22 Sep 2025 09:00:45 +0800
From: Jason Wang <jasowang@...hat.com>
To: "Michael S. Tsirkin" <mst@...hat.com>
Cc: xuanzhuo@...ux.alibaba.com, eperezma@...hat.com, 
	virtualization@...ts.linux.dev, linux-kernel@...r.kernel.org
Subject: Re: [PATCH V6 13/19] virtio_ring: introduce virtqueue ops

On Mon, Sep 22, 2025 at 2:33 AM Michael S. Tsirkin <mst@...hat.com> wrote:
>
> On Fri, Sep 19, 2025 at 03:31:48PM +0800, Jason Wang wrote:
> > This patch introduces virtqueue ops which is a set of the callbacks
> > that will be called for different queue layout or features. This would
> > help to avoid branches for split/packed and will ease the future
> > implementation like in order.
> >
> > Note that in order to eliminate the indirect calls this patch uses
> > global array of const ops to allow compiler to avoid indirect
> > branches.
> >
> > Tested with CONFIG_MITIGATION_RETPOLINE, no performance differences
> > were noticed.
> >
> > Acked-by: Eugenio Pérez <eperezma@...hat.com>
> > Suggested-by: Michael S. Tsirkin <mst@...hat.com>
> > Signed-off-by: Jason Wang <jasowang@...hat.com>
> > ---
> >  drivers/virtio/virtio_ring.c | 173 ++++++++++++++++++++++++++---------
> >  1 file changed, 130 insertions(+), 43 deletions(-)
> >
> > diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
> > index b1b6af297061..1045c553ee65 100644
> > --- a/drivers/virtio/virtio_ring.c
> > +++ b/drivers/virtio/virtio_ring.c
> > @@ -67,6 +67,12 @@
> >  #define LAST_ADD_TIME_INVALID(vq)
> >  #endif
> >
> > +enum vq_layout {
> > +     SPLIT = 0,
> > +     PACKED,
> > +     VQ_TYPE_MAX,
> > +};
> > +
> >  struct vring_desc_state_split {
> >       void *data;                     /* Data for callback. */
> >
> > @@ -159,12 +165,28 @@ struct vring_virtqueue_packed {
> >       size_t event_size_in_bytes;
> >  };
> >
> > +struct vring_virtqueue;
> > +
> > +struct virtqueue_ops {
> > +     int (*add)(struct vring_virtqueue *_vq, struct scatterlist *sgs[],
> > +                unsigned int total_sg, unsigned int out_sgs,
> > +                unsigned int in_sgs, void *data,
> > +                void *ctx, bool premapped, gfp_t gfp);
>
> Why is it _vq here?

Fixed.

>
>
> > +     void *(*get)(struct vring_virtqueue *vq, unsigned int *len, void **ctx);
> > +     bool (*kick_prepare)(struct vring_virtqueue *vq);
> > +     void (*disable_cb)(struct vring_virtqueue *vq);
> > +     bool (*enable_cb_delayed)(struct vring_virtqueue *vq);
> > +     unsigned int (*enable_cb_prepare)(struct vring_virtqueue *vq);
> > +     bool (*poll)(const struct vring_virtqueue *vq, u16 last_used_idx);
> > +     void *(*detach_unused_buf)(struct vring_virtqueue *vq);
> > +     bool (*more_used)(const struct vring_virtqueue *vq);
> > +     int (*resize)(struct vring_virtqueue *vq, u32 num);
> > +     void (*reset)(struct vring_virtqueue *vq);
> > +};
> > +
> >  struct vring_virtqueue {
> >       struct virtqueue vq;
> >
> > -     /* Is this a packed ring? */
> > -     bool packed_ring;
> > -
> >       /* Is DMA API used? */
> >       bool use_map_api;
> >
> > @@ -180,6 +202,8 @@ struct vring_virtqueue {
> >       /* Host publishes avail event idx */
> >       bool event;
> >
> > +     enum vq_layout layout;
> > +
> >       /* Head of free buffer list. */
> >       unsigned int free_head;
> >       /* Number we've added since last sync. */
> > @@ -231,6 +255,12 @@ static void vring_free(struct virtqueue *_vq);
> >
> >  #define to_vvq(_vq) container_of_const(_vq, struct vring_virtqueue, vq)
> >
> > +
>
> why the extra empty line?
>

And fix this.

Thanks