Messages in this thread | | | Date | Wed, 25 May 2022 09:41:56 +0200 | From | Stefano Garzarella <> | Subject | Re: [PATCH v2 4/4] vdpa_sim: Implement stop vdpa op |
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On Tue, May 24, 2022 at 07:06:10PM +0200, Eugenio Pérez wrote: >Implement stop operation for vdpa_sim devices, so vhost-vdpa will offer >that backend feature and userspace can effectively stop the device. > >This is a must before get virtqueue indexes (base) for live migration, >since the device could modify them after userland gets them. There are >individual ways to perform that action for some devices >(VHOST_NET_SET_BACKEND, VHOST_VSOCK_SET_RUNNING, ...) but there was no >way to perform it for any vhost device (and, in particular, vhost-vdpa). > >After the return of ioctl with stop != 0, the device MUST finish any >pending operations like in flight requests. It must also preserve all >the necessary state (the virtqueue vring base plus the possible device >specific states) that is required for restoring in the future. The >device must not change its configuration after that point. > >After the return of ioctl with stop == 0, the device can continue >processing buffers as long as typical conditions are met (vq is enabled, >DRIVER_OK status bit is enabled, etc). > >In the future, we will provide features similar to >VHOST_USER_GET_INFLIGHT_FD so the device can save pending operations. > >Signed-off-by: Eugenio Pérez <eperezma@redhat.com> >--- > drivers/vdpa/vdpa_sim/vdpa_sim.c | 21 +++++++++++++++++++++ > drivers/vdpa/vdpa_sim/vdpa_sim.h | 1 + > drivers/vdpa/vdpa_sim/vdpa_sim_blk.c | 3 +++ > drivers/vdpa/vdpa_sim/vdpa_sim_net.c | 3 +++ > 4 files changed, 28 insertions(+) > >diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c >index 50d721072beb..0515cf314bed 100644 >--- a/drivers/vdpa/vdpa_sim/vdpa_sim.c >+++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c >@@ -107,6 +107,7 @@ static void vdpasim_do_reset(struct vdpasim *vdpasim) > for (i = 0; i < vdpasim->dev_attr.nas; i++) > vhost_iotlb_reset(&vdpasim->iommu[i]); > >+ vdpasim->running = true; > spin_unlock(&vdpasim->iommu_lock); > > vdpasim->features = 0; >@@ -505,6 +506,24 @@ static int vdpasim_reset(struct vdpa_device *vdpa) > return 0; > } > >+static int vdpasim_stop(struct vdpa_device *vdpa, bool stop) >+{ >+ struct vdpasim *vdpasim = vdpa_to_sim(vdpa); >+ int i; >+ >+ spin_lock(&vdpasim->lock); >+ vdpasim->running = !stop; >+ if (vdpasim->running) { >+ /* Check for missed buffers */ >+ for (i = 0; i < vdpasim->dev_attr.nvqs; ++i) >+ vdpasim_kick_vq(vdpa, i); >+ >+ } >+ spin_unlock(&vdpasim->lock); >+ >+ return 0; >+} >+ > static size_t vdpasim_get_config_size(struct vdpa_device *vdpa) > { > struct vdpasim *vdpasim = vdpa_to_sim(vdpa); >@@ -694,6 +713,7 @@ static const struct vdpa_config_ops vdpasim_config_ops = { > .get_status = vdpasim_get_status, > .set_status = vdpasim_set_status, > .reset = vdpasim_reset, >+ .stop = vdpasim_stop, > .get_config_size = vdpasim_get_config_size, > .get_config = vdpasim_get_config, > .set_config = vdpasim_set_config, >@@ -726,6 +746,7 @@ static const struct vdpa_config_ops vdpasim_batch_config_ops = { > .get_status = vdpasim_get_status, > .set_status = vdpasim_set_status, > .reset = vdpasim_reset, >+ .stop = vdpasim_stop, > .get_config_size = vdpasim_get_config_size, > .get_config = vdpasim_get_config, > .set_config = vdpasim_set_config, >diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.h b/drivers/vdpa/vdpa_sim/vdpa_sim.h >index 622782e92239..061986f30911 100644 >--- a/drivers/vdpa/vdpa_sim/vdpa_sim.h >+++ b/drivers/vdpa/vdpa_sim/vdpa_sim.h >@@ -66,6 +66,7 @@ struct vdpasim { > u32 generation; > u64 features; > u32 groups; >+ bool running; > /* spinlock to synchronize iommu table */ > spinlock_t iommu_lock; > }; >diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c b/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c >index 42d401d43911..bcdb1982c378 100644 >--- a/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c >+++ b/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c >@@ -204,6 +204,9 @@ static void vdpasim_blk_work(struct work_struct *work) > if (!(vdpasim->status & VIRTIO_CONFIG_S_DRIVER_OK)) > goto out; > >+ if (!vdpasim->running) >+ goto out; >+
Not related to this series, but I think in vdpa_sim_blk.c we should implement something similar to what we already do in vdpa_sim_net.c and re-schedule the work after X requests handled, otherwise we risk never stopping if there are always requests to handle.
Also for supporting multiple queues, that could be a problem, but for now we only support one, so there should be no problem.
I have other patches to send for vdpa_sim_blk.c, so if you want I can do that in my series.
Thanks, Stefano
> for (i = 0; i < VDPASIM_BLK_VQ_NUM; i++) { > struct vdpasim_virtqueue *vq = &vdpasim->vqs[i]; > >diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim_net.c b/drivers/vdpa/vdpa_sim/vdpa_sim_net.c >index 5125976a4df8..886449e88502 100644 >--- a/drivers/vdpa/vdpa_sim/vdpa_sim_net.c >+++ b/drivers/vdpa/vdpa_sim/vdpa_sim_net.c >@@ -154,6 +154,9 @@ static void vdpasim_net_work(struct work_struct *work) > > spin_lock(&vdpasim->lock); > >+ if (!vdpasim->running) >+ goto out; >+ > if (!(vdpasim->status & VIRTIO_CONFIG_S_DRIVER_OK)) > goto out; > >-- >2.27.0 >
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