From: Sahil <icegambit91@gmail.com>
To: Eugenio Perez Martin <eperezma@redhat.com>
Cc: qemu-level <qemu-devel@nongnu.org>,
Stefano Garzarella <sgarzare@redhat.com>
Subject: Re: Intention to work on GSoC project
Date: Mon, 13 May 2024 19:19:16 +0530 [thread overview]
Message-ID: <2282965.iZASKD2KPV@valdaarhun> (raw)
In-Reply-To: <12430761.O9o76ZdvQC@valdaarhun>
Hi,
On Wednesday, May 8, 2024 8:53:12 AM GMT+5:30 Sahil wrote:
> Hi,
>
> On Tuesday, May 7, 2024 12:44:33 PM IST Eugenio Perez Martin wrote:
> > [...]
> >
> > > Shall I start by implementing a mechanism to check if the feature bit
> > > "VIRTIO_F_RING_PACKED" is set (using "virtio_vdev_has_feature")? And
> > > if it's supported, "vhost_svq_add" should call "vhost_svq_add_packed".
> > > Following this, I can then start implementing "vhost_svq_add_packed"
> > > and progress from there.
> > >
> > > What are your thoughts on this?
> >
> > Yes, that's totally right.
> >
> > I recommend you to also disable _F_EVENT_IDX to start, so the first
> > version is easier.
> >
> > Also, you can send as many incomplete RFCs as you want. For example,
> > you can send a first version that only implements reading of the guest
> > avail ring, so we know we're aligned on that. Then, we can send
> > subsequents RFCs adding features on top.
>
I have started working on implementing packed virtqueue support in
vhost-shadow-virtqueue.c. The changes I have made so far are very
minimal. I have one confusion as well.
In "vhost_svq_add()" [1], a structure of type "VhostShadowVirtqueue"
is being used. My initial idea was to create a whole new structure (eg:
VhostShadowVirtqueuePacked). But I realized that "VhostShadowVirtqueue"
is being used in a lot of other places such as in "struct vhost_vdpa" [2]
(in "vhost-vdpa.h"). So maybe this isn't a good idea.
The problem is that "VhostShadowVirtqueue" has a member of type "struct
vring" [3] which represents a split virtqueue [4]. My idea now is to instead
wrap this member in a union so that the struct would look something like
this.
struct VhostShadowVirtqueue {
union {
struct vring vring;
struct packed_vring vring;
}
...
}
I am not entirely sure if this is a good idea. It is similar to what's been done
in linux's "drivers/virtio/virtio_ring.c" ("struct vring_virtqueue" [5]).
I thought I would ask this first before continuing further.
Thanks,
Sahil
[1] https://gitlab.com/qemu-project/qemu/-/blob/master/hw/virtio/vhost-shadow-virtqueue.c#L249
[2] https://gitlab.com/qemu-project/qemu/-/blob/master/include/hw/virtio/vhost-vdpa.h#L69
[3] https://gitlab.com/qemu-project/qemu/-/blob/master/hw/virtio/vhost-shadow-virtqueue.h#L52
[4] https://gitlab.com/qemu-project/qemu/-/blob/master/include/standard-headers/linux/virtio_ring.h#L156
[5] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/virtio/virtio_ring.c#n199
next prev parent reply other threads:[~2024-05-13 13:50 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-25 21:38 Intention to work on GSoC project Sahil
2024-02-29 8:32 ` Stefano Garzarella
2024-02-29 19:02 ` Sahil
2024-03-01 7:40 ` Eugenio Perez Martin
2024-03-01 18:29 ` Sahil
2024-03-14 15:09 ` Eugenio Perez Martin
2024-03-15 7:14 ` Sahil
2024-03-15 11:27 ` Eugenio Perez Martin
2024-03-16 20:26 ` Sahil
2024-03-18 19:47 ` Sahil
2024-03-20 16:29 ` Eugenio Perez Martin
2024-03-25 13:20 ` Sahil
2024-04-01 18:23 ` daleyoung4242
2024-04-02 4:58 ` Sahil
2024-04-02 11:38 ` Eugenio Perez Martin
2024-04-03 14:36 ` Sahil
2024-04-03 18:37 ` Eugenio Perez Martin
2024-04-04 19:06 ` Sahil
2024-04-14 18:52 ` Sahil
2024-04-15 8:57 ` Eugenio Perez Martin
2024-04-15 19:42 ` Sahil
2024-04-16 8:41 ` Eugenio Perez Martin
2024-04-17 4:23 ` Sahil
2024-05-06 19:00 ` Sahil
2024-05-07 7:14 ` Eugenio Perez Martin
2024-05-08 3:23 ` Sahil
2024-05-13 13:49 ` Sahil [this message]
2024-05-13 14:23 ` Eugenio Perez Martin
2024-05-13 18:04 ` Sahil
2024-03-20 15:57 ` Eugenio Perez Martin
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