On Thu, Mar 26, 2026 at 2:57 PM Eugenio Perez Martin <[email protected]> wrote: > > On Thu, Mar 26, 2026 at 3:44 AM Jason Wang <[email protected]> wrote: > > > > On Tue, Mar 24, 2026 at 11:24 PM Michael S. Tsirkin <[email protected]> wrote: > > > > > > On Tue, Mar 24, 2026 at 03:01:47PM +0100, Eugenio Perez Martin wrote: > > > > On Fri, Mar 13, 2026 at 8:08 AM Eugenio Perez Martin > > > > <[email protected]> wrote: > > > > > > > > > > On Fri, Mar 13, 2026 at 7:05 AM Jason Wang <[email protected]> > > > > > wrote: > > > > > > > > > > > > On Thu, Mar 12, 2026 at 2:24 PM Eugenio Perez Martin > > > > > > <[email protected]> wrote: > > > > > > > > > > > > > > On Thu, Mar 12, 2026 at 4:58 AM Jason Wang <[email protected]> > > > > > > > wrote: > > > > > > > > > > > > > > > > On Wed, Mar 11, 2026 at 3:08 AM Eugenio Pérez > > > > > > > > <[email protected]> wrote: > > > > > > > > > > > > > > > > > > Add the VDUSE_F_QUEUE_READY feature flag. This allows the > > > > > > > > > kernel module > > > > > > > > > to explicitly signal userspace when a specific virtqueue has > > > > > > > > > been > > > > > > > > > enabled. > > > > > > > > > > > > > > > > > > In scenarios like Live Migration of VirtIO net devices, the > > > > > > > > > dataplane > > > > > > > > > starts after the control virtqueue allowing QEMU to apply > > > > > > > > > configuration > > > > > > > > > in the destination device. > > > > > > > > > > > > > > > > > > Signed-off-by: Eugenio Pérez <[email protected]> > > > > > > > > > --- > > > > > > > > > v2: > > > > > > > > > * Fix comment of vduse_dev_request.vq_ready > > > > > > > > > * Set vq_ready before sending the message to the VDUSE > > > > > > > > > userland > > > > > > > > > instance, avoiding the need for SMP sync after receiving > > > > > > > > > the message. > > > > > > > > > --- > > > > > > > > > drivers/vdpa/vdpa_user/vduse_dev.c | 28 > > > > > > > > > +++++++++++++++++++++++++++- > > > > > > > > > include/uapi/linux/vduse.h | 18 ++++++++++++++++++ > > > > > > > > > 2 files changed, 45 insertions(+), 1 deletion(-) > > > > > > > > > > > > > > > > > > diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c > > > > > > > > > b/drivers/vdpa/vdpa_user/vduse_dev.c > > > > > > > > > index 17e0358d3a68..4f642b95a7cb 100644 > > > > > > > > > --- a/drivers/vdpa/vdpa_user/vduse_dev.c > > > > > > > > > +++ b/drivers/vdpa/vdpa_user/vduse_dev.c > > > > > > > > > @@ -9,6 +9,7 @@ > > > > > > > > > */ > > > > > > > > > > > > > > > > > > #include "linux/virtio_net.h" > > > > > > > > > +#include <linux/bits.h> > > > > > > > > > #include <linux/cleanup.h> > > > > > > > > > #include <linux/init.h> > > > > > > > > > #include <linux/module.h> > > > > > > > > > @@ -53,7 +54,7 @@ > > > > > > > > > #define IRQ_UNBOUND -1 > > > > > > > > > > > > > > > > > > /* Supported VDUSE features */ > > > > > > > > > -static const uint64_t vduse_features; > > > > > > > > > +static const uint64_t vduse_features = > > > > > > > > > BIT_U64(VDUSE_F_QUEUE_READY); > > > > > > > > > > > > > > > > > > /* > > > > > > > > > * VDUSE instance have not asked the vduse API version, so > > > > > > > > > assume 0. > > > > > > > > > @@ -120,6 +121,7 @@ struct vduse_dev { > > > > > > > > > char *name; > > > > > > > > > struct mutex lock; > > > > > > > > > spinlock_t msg_lock; > > > > > > > > > + u64 vduse_features; > > > > > > > > > u64 msg_unique; > > > > > > > > > u32 msg_timeout; > > > > > > > > > wait_queue_head_t waitq; > > > > > > > > > @@ -601,8 +603,29 @@ static void > > > > > > > > > vduse_vdpa_set_vq_ready(struct vdpa_device *vdpa, > > > > > > > > > { > > > > > > > > > struct vduse_dev *dev = vdpa_to_vduse(vdpa); > > > > > > > > > struct vduse_virtqueue *vq = dev->vqs[idx]; > > > > > > > > > + struct vduse_dev_msg msg = { 0 }; > > > > > > > > > + int r; > > > > > > > > > > > > > > > > > > vq->ready = ready; > > > > > > > > > + > > > > > > > > > + if (!(dev->vduse_features & > > > > > > > > > BIT_U64(VDUSE_F_QUEUE_READY))) > > > > > > > > > + return; > > > > > > > > > + > > > > > > > > > + msg.req.type = VDUSE_SET_VQ_READY; > > > > > > > > > + msg.req.vq_ready.num = idx; > > > > > > > > > + msg.req.vq_ready.ready = !!ready; > > > > > > > > > + > > > > > > > > > + r = vduse_dev_msg_sync(dev, &msg); > > > > > > > > > + > > > > > > > > > + if (r < 0) { > > > > > > > > > + dev_dbg(&vdpa->dev, "device refuses to set vq > > > > > > > > > %u ready %u", > > > > > > > > > + idx, ready); > > > > > > > > > + > > > > > > > > > + /* We can't do better than break the device > > > > > > > > > in this case */ > > > > > > > > > > > > > > > > It's better to explain why we can't depend on > > > > > > > > vduse_dev_msg_sync() here. > > > > > > > > > > > > > > > > For example it did: > > > > > > > > > > > > > > > > if (unlikely(dev->broken)) > > > > > > > > return -EIO; > > > > > > > > > > > > > > > > init_waitqueue_head(&msg->waitq); > > > > > > > > spin_lock(&dev->msg_lock); > > > > > > > > if (unlikely(dev->broken)) { > > > > > > > > spin_unlock(&dev->msg_lock); > > > > > > > > return -EIO; > > > > > > > > } > > > > > > > > > > > > > > > > and > > > > > > > > > > > > > > > > if (!msg->completed) { > > > > > > > > list_del(&msg->list); > > > > > > > > msg->resp.result = VDUSE_REQ_RESULT_FAILED; > > > > > > > > /* Mark the device as malfunction when there is > > > > > > > > a timeout */ > > > > > > > > if (!ret) > > > > > > > > vduse_dev_broken(dev); > > > > > > > > } > > > > > > > > > > > > > > > > > > > > > > I'm not sure I follow you here. > > > > > > > > > > > > > > We can't do better than breaking the device because the function > > > > > > > returns no error state, and the caller does not expect an error > > > > > > > code. > > > > > > > Do you mean we can't depend on vduse_dev_msg_sync to call > > > > > > > vduse_dev_broken(dev) by itself? > > > > > > > > > > > > I think I meant, reset seems to be more heavyweight than suspend. > > > > > > > > > > > > So if reset can fail, I don't see reason ot break device only for > > > > > > suspend failure. > > > > > > > > > > > > > > > > Sorry I still don't get you. > > > > > > > > > > This series does not implement suspend at all. It doesn't modify the > > > > > VDUSE device reset or the virtio reset behavior. It only implements > > > > > the vq ready message for the device. If the device returns an error > > > > > from that operation, what is your proposal for when the driver sends > > > > > new messages like resume? > > > > > > > > > > > > > Friendly ping. > > > > > > Jason, more comments? If this is to go in it has to go into linux next. > > > > A typo, basically I meant that reset is more heavyweight than queue > > ready. If we decide to check the response for queue ready, we need to > > check the reset as well. > > > > But I'm fine if you think we can start from this. > > > > If you mean something like this: > diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c > b/drivers/vdpa/vdpa_user/vduse_dev.c > index 6202f6902fcd..23b850023417 100644 > --- a/drivers/vdpa/vdpa_user/vduse_dev.c > +++ b/drivers/vdpa/vdpa_user/vduse_dev.c > @@ -816,7 +816,8 @@ static int vduse_vdpa_reset(struct vdpa_device *vdpa) > struct vduse_dev *dev = vdpa_to_vduse(vdpa); > int ret = vduse_dev_set_status(dev, 0); > > - vduse_dev_reset(dev); > + if (ret == 0) > + vduse_dev_reset(dev);
Something like this but we need to check if it's a timeout as queue ready. > > return ret; > } > > --- > > I totally agree. But in my opinion, it's outside this series' scope. I > can send a patch on top. > Works for me. Thanks
