| Message ID | 20220526124338.36247-4-eperezma@redhat.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | Implement vdpasim stop operation | expand |
| Context | Check | Description |
|---|---|---|
| netdev/tree_selection | success | Not a local patch |
On Thu, May 26, 2022 at 02:43:37PM +0200, Eugenio Pérez wrote: > The ioctl adds support for stop the device from userspace. > > Signed-off-by: Eugenio Pérez <eperezma@redhat.com> > --- > drivers/vhost/vdpa.c | 18 ++++++++++++++++++ > include/uapi/linux/vhost.h | 14 ++++++++++++++ > 2 files changed, 32 insertions(+) > > diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c > index 32713db5831d..d1d19555c4b7 100644 > --- a/drivers/vhost/vdpa.c > +++ b/drivers/vhost/vdpa.c > @@ -478,6 +478,21 @@ static long vhost_vdpa_get_vqs_count(struct vhost_vdpa *v, u32 __user *argp) > return 0; > } > > +static long vhost_vdpa_stop(struct vhost_vdpa *v, u32 __user *argp) > +{ > + struct vdpa_device *vdpa = v->vdpa; > + const struct vdpa_config_ops *ops = vdpa->config; > + int stop; > + > + if (!ops->stop) > + return -EOPNOTSUPP; > + > + if (copy_from_user(&stop, argp, sizeof(stop))) > + return -EFAULT; > + > + return ops->stop(vdpa, stop); > +} > + > static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v, unsigned int cmd, > void __user *argp) > { > @@ -650,6 +665,9 @@ static long vhost_vdpa_unlocked_ioctl(struct file *filep, > case VHOST_VDPA_GET_VQS_COUNT: > r = vhost_vdpa_get_vqs_count(v, argp); > break; > + case VHOST_VDPA_STOP: > + r = vhost_vdpa_stop(v, argp); > + break; > default: > r = vhost_dev_ioctl(&v->vdev, cmd, argp); > if (r == -ENOIOCTLCMD) > diff --git a/include/uapi/linux/vhost.h b/include/uapi/linux/vhost.h > index cab645d4a645..c7e47b29bf61 100644 > --- a/include/uapi/linux/vhost.h > +++ b/include/uapi/linux/vhost.h > @@ -171,4 +171,18 @@ > #define VHOST_VDPA_SET_GROUP_ASID _IOW(VHOST_VIRTIO, 0x7C, \ > struct vhost_vring_state) > > +/* Stop or resume a device so it does not process virtqueue requests anymore > + * > + * 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). > + */ > +#define VHOST_VDPA_STOP _IOW(VHOST_VIRTIO, 0x7D, int) > + > #endif I wonder how does this interact with the admin vq idea. I.e. if we stop all VQs then apparently admin vq can't work either ... Thoughts? > -- > 2.31.1
On Wed, Jun 1, 2022 at 1:03 PM Michael S. Tsirkin <mst@redhat.com> wrote: > > On Thu, May 26, 2022 at 02:43:37PM +0200, Eugenio Pérez wrote: > > The ioctl adds support for stop the device from userspace. > > > > Signed-off-by: Eugenio Pérez <eperezma@redhat.com> > > --- > > drivers/vhost/vdpa.c | 18 ++++++++++++++++++ > > include/uapi/linux/vhost.h | 14 ++++++++++++++ > > 2 files changed, 32 insertions(+) > > > > diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c > > index 32713db5831d..d1d19555c4b7 100644 > > --- a/drivers/vhost/vdpa.c > > +++ b/drivers/vhost/vdpa.c > > @@ -478,6 +478,21 @@ static long vhost_vdpa_get_vqs_count(struct vhost_vdpa *v, u32 __user *argp) > > return 0; > > } > > > > +static long vhost_vdpa_stop(struct vhost_vdpa *v, u32 __user *argp) > > +{ > > + struct vdpa_device *vdpa = v->vdpa; > > + const struct vdpa_config_ops *ops = vdpa->config; > > + int stop; > > + > > + if (!ops->stop) > > + return -EOPNOTSUPP; > > + > > + if (copy_from_user(&stop, argp, sizeof(stop))) > > + return -EFAULT; > > + > > + return ops->stop(vdpa, stop); > > +} > > + > > static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v, unsigned int cmd, > > void __user *argp) > > { > > @@ -650,6 +665,9 @@ static long vhost_vdpa_unlocked_ioctl(struct file *filep, > > case VHOST_VDPA_GET_VQS_COUNT: > > r = vhost_vdpa_get_vqs_count(v, argp); > > break; > > + case VHOST_VDPA_STOP: > > + r = vhost_vdpa_stop(v, argp); > > + break; > > default: > > r = vhost_dev_ioctl(&v->vdev, cmd, argp); > > if (r == -ENOIOCTLCMD) > > diff --git a/include/uapi/linux/vhost.h b/include/uapi/linux/vhost.h > > index cab645d4a645..c7e47b29bf61 100644 > > --- a/include/uapi/linux/vhost.h > > +++ b/include/uapi/linux/vhost.h > > @@ -171,4 +171,18 @@ > > #define VHOST_VDPA_SET_GROUP_ASID _IOW(VHOST_VIRTIO, 0x7C, \ > > struct vhost_vring_state) > > > > +/* Stop or resume a device so it does not process virtqueue requests anymore > > + * > > + * 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). > > + */ > > +#define VHOST_VDPA_STOP _IOW(VHOST_VIRTIO, 0x7D, int) > > + > > #endif > > I wonder how does this interact with the admin vq idea. > I.e. if we stop all VQs then apparently admin vq can't > work either ... > Thoughts? > Copying here the answer to Parav, feel free to answer to any thread or highlight if I missed something :). Using the admin vq proposal terminology of "device group". -- This would stop a device of a device group, but not the whole virtqueue group. If the admin VQ is offered by the PF (since it's not exposed to the guest), it will continue accepting requests as normal. If it's exposed in the VF, I think the best bet is to shadow it, since guest and host requests could conflict. Since this is offered through vdpa, the device backend driver can route it to whatever method works better for the hardware. For example, to send an admin vq command to the PF. That's why it's important to keep the feature as self-contained and orthogonal to others as possible. -- > > -- > > 2.31.1 >
> From: Eugenio Perez Martin <eperezma@redhat.com> > Sent: Wednesday, June 1, 2022 7:15 AM > > On Wed, Jun 1, 2022 at 1:03 PM Michael S. Tsirkin <mst@redhat.com> wrote: > > > > On Thu, May 26, 2022 at 02:43:37PM +0200, Eugenio Pérez wrote: > > > The ioctl adds support for stop the device from userspace. > > > > > > Signed-off-by: Eugenio Pérez <eperezma@redhat.com> > > > --- > > > drivers/vhost/vdpa.c | 18 ++++++++++++++++++ > > > include/uapi/linux/vhost.h | 14 ++++++++++++++ > > > 2 files changed, 32 insertions(+) > > > > > > diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c index > > > 32713db5831d..d1d19555c4b7 100644 > > > --- a/drivers/vhost/vdpa.c > > > +++ b/drivers/vhost/vdpa.c > > > @@ -478,6 +478,21 @@ static long vhost_vdpa_get_vqs_count(struct > vhost_vdpa *v, u32 __user *argp) > > > return 0; > > > } > > > > > > +static long vhost_vdpa_stop(struct vhost_vdpa *v, u32 __user *argp) > > > +{ > > > + struct vdpa_device *vdpa = v->vdpa; > > > + const struct vdpa_config_ops *ops = vdpa->config; > > > + int stop; > > > + > > > + if (!ops->stop) > > > + return -EOPNOTSUPP; > > > + > > > + if (copy_from_user(&stop, argp, sizeof(stop))) > > > + return -EFAULT; > > > + > > > + return ops->stop(vdpa, stop); > > > +} > > > + > > > static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v, unsigned int > cmd, > > > void __user *argp) { @@ -650,6 > > > +665,9 @@ static long vhost_vdpa_unlocked_ioctl(struct file *filep, > > > case VHOST_VDPA_GET_VQS_COUNT: > > > r = vhost_vdpa_get_vqs_count(v, argp); > > > break; > > > + case VHOST_VDPA_STOP: > > > + r = vhost_vdpa_stop(v, argp); > > > + break; > > > default: > > > r = vhost_dev_ioctl(&v->vdev, cmd, argp); > > > if (r == -ENOIOCTLCMD) diff --git > > > a/include/uapi/linux/vhost.h b/include/uapi/linux/vhost.h index > > > cab645d4a645..c7e47b29bf61 100644 > > > --- a/include/uapi/linux/vhost.h > > > +++ b/include/uapi/linux/vhost.h > > > @@ -171,4 +171,18 @@ > > > #define VHOST_VDPA_SET_GROUP_ASID _IOW(VHOST_VIRTIO, 0x7C, > \ > > > struct vhost_vring_state) > > > > > > +/* Stop or resume a device so it does not process virtqueue > > > +requests anymore > > > + * > > > + * 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). > > > + */ > > > +#define VHOST_VDPA_STOP _IOW(VHOST_VIRTIO, 0x7D, int) > > > + A better name is VHOST_VDPA_SET_STATE State = stop/suspend State = start/resume Suspend/resume seems more logical, as opposed start/stop, because it more clearly indicates that the resume (start) is from some programmed beginning (and not first boot). > > > #endif > > > > I wonder how does this interact with the admin vq idea. > > I.e. if we stop all VQs then apparently admin vq can't work either ... > > Thoughts? > > > > Copying here the answer to Parav, feel free to answer to any thread or > highlight if I missed something :). Using the admin vq proposal terminology of > "device group". > > -- > This would stop a device of a device > group, but not the whole virtqueue group. If the admin VQ is offered by the > PF (since it's not exposed to the guest), it will continue accepting requests as > normal. If it's exposed in the VF, I think the best bet is to shadow it, since > guest and host requests could conflict. > vhost-vdpa device is exposed for a VF through vp-vdpa driver to user land. Now vp-vdpa driver will have to choose between using config register vs using AQ to suspend/resume the device. Why not always begin with more superior interface of AQ that address multiple of these needs for LM case? For LM case, more you explore, we realize that either VF relying on PF's AQ for query/config/setup/restore makes more sense or have its own dedicated AQ. VM's suspend/resume operation can be handled through the shadow Q. > Since this is offered through vdpa, the device backend driver can route it to > whatever method works better for the hardware. For example, to send an > admin vq command to the PF. That's why it's important to keep the feature > as self-contained and orthogonal to others as possible. > -- > > > > -- > > > 2.31.1 > >
On Wed, Jun 1, 2022 at 9:13 PM Parav Pandit <parav@nvidia.com> wrote: > > > > > From: Eugenio Perez Martin <eperezma@redhat.com> > > Sent: Wednesday, June 1, 2022 7:15 AM > > > > On Wed, Jun 1, 2022 at 1:03 PM Michael S. Tsirkin <mst@redhat.com> wrote: > > > > > > On Thu, May 26, 2022 at 02:43:37PM +0200, Eugenio Pérez wrote: > > > > The ioctl adds support for stop the device from userspace. > > > > > > > > Signed-off-by: Eugenio Pérez <eperezma@redhat.com> > > > > --- > > > > drivers/vhost/vdpa.c | 18 ++++++++++++++++++ > > > > include/uapi/linux/vhost.h | 14 ++++++++++++++ > > > > 2 files changed, 32 insertions(+) > > > > > > > > diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c index > > > > 32713db5831d..d1d19555c4b7 100644 > > > > --- a/drivers/vhost/vdpa.c > > > > +++ b/drivers/vhost/vdpa.c > > > > @@ -478,6 +478,21 @@ static long vhost_vdpa_get_vqs_count(struct > > vhost_vdpa *v, u32 __user *argp) > > > > return 0; > > > > } > > > > > > > > +static long vhost_vdpa_stop(struct vhost_vdpa *v, u32 __user *argp) > > > > +{ > > > > + struct vdpa_device *vdpa = v->vdpa; > > > > + const struct vdpa_config_ops *ops = vdpa->config; > > > > + int stop; > > > > + > > > > + if (!ops->stop) > > > > + return -EOPNOTSUPP; > > > > + > > > > + if (copy_from_user(&stop, argp, sizeof(stop))) > > > > + return -EFAULT; > > > > + > > > > + return ops->stop(vdpa, stop); > > > > +} > > > > + > > > > static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v, unsigned int > > cmd, > > > > void __user *argp) { @@ -650,6 > > > > +665,9 @@ static long vhost_vdpa_unlocked_ioctl(struct file *filep, > > > > case VHOST_VDPA_GET_VQS_COUNT: > > > > r = vhost_vdpa_get_vqs_count(v, argp); > > > > break; > > > > + case VHOST_VDPA_STOP: > > > > + r = vhost_vdpa_stop(v, argp); > > > > + break; > > > > default: > > > > r = vhost_dev_ioctl(&v->vdev, cmd, argp); > > > > if (r == -ENOIOCTLCMD) diff --git > > > > a/include/uapi/linux/vhost.h b/include/uapi/linux/vhost.h index > > > > cab645d4a645..c7e47b29bf61 100644 > > > > --- a/include/uapi/linux/vhost.h > > > > +++ b/include/uapi/linux/vhost.h > > > > @@ -171,4 +171,18 @@ > > > > #define VHOST_VDPA_SET_GROUP_ASID _IOW(VHOST_VIRTIO, 0x7C, > > \ > > > > struct vhost_vring_state) > > > > > > > > +/* Stop or resume a device so it does not process virtqueue > > > > +requests anymore > > > > + * > > > > + * 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). > > > > + */ > > > > +#define VHOST_VDPA_STOP _IOW(VHOST_VIRTIO, 0x7D, int) > > > > + > A better name is VHOST_VDPA_SET_STATE > State = stop/suspend > State = start/resume > > Suspend/resume seems more logical, as opposed start/stop, because it more clearly indicates that the resume (start) is from some programmed beginning (and not first boot). > It's fine to move to that nomenclature in my opinion. > > > > #endif > > > > > > I wonder how does this interact with the admin vq idea. > > > I.e. if we stop all VQs then apparently admin vq can't work either ... > > > Thoughts? > > > > > > > Copying here the answer to Parav, feel free to answer to any thread or > > highlight if I missed something :). Using the admin vq proposal terminology of > > "device group". > > > > -- > > This would stop a device of a device > > group, but not the whole virtqueue group. If the admin VQ is offered by the > > PF (since it's not exposed to the guest), it will continue accepting requests as > > normal. If it's exposed in the VF, I think the best bet is to shadow it, since > > guest and host requests could conflict. > > > > vhost-vdpa device is exposed for a VF through vp-vdpa driver to user land. > Now vp-vdpa driver will have to choose between using config register vs using AQ to suspend/resume the device. > vp_vdpa cannot choose if the virtio device has an admin vq or any other feature, it just wraps the virtio device. If that virtio device does not expose AQ, vp_vdpa cannot expose it. > Why not always begin with more superior interface of AQ that address multiple of these needs for LM case? > Because it doesn't address valid use cases like vp_vdpa with no AQ, devices that are not VF, or nested virtualization. VHOST_VDPA_STOP / VHOST_VDPA_SET_STATE does not replace AQ commands: It's just the way vhost-vdpa exposes that capability to qemu. vdpa backend is free to choose whatever methods it finds better to implement it. > For LM case, more you explore, we realize that either VF relying on PF's AQ for query/config/setup/restore makes more sense or have its own dedicated AQ. > This ioctl does not mandate that the device cannot implement it through AQ, or that the device has to be a VF. Thanks! > VM's suspend/resume operation can be handled through the shadow Q. > > > Since this is offered through vdpa, the device backend driver can route it to > > whatever method works better for the hardware. For example, to send an > > admin vq command to the PF. That's why it's important to keep the feature > > as self-contained and orthogonal to others as possible. > > -- > > > > > > -- > > > > 2.31.1 > > > >
diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c index 32713db5831d..d1d19555c4b7 100644 --- a/drivers/vhost/vdpa.c +++ b/drivers/vhost/vdpa.c @@ -478,6 +478,21 @@ static long vhost_vdpa_get_vqs_count(struct vhost_vdpa *v, u32 __user *argp) return 0; } +static long vhost_vdpa_stop(struct vhost_vdpa *v, u32 __user *argp) +{ + struct vdpa_device *vdpa = v->vdpa; + const struct vdpa_config_ops *ops = vdpa->config; + int stop; + + if (!ops->stop) + return -EOPNOTSUPP; + + if (copy_from_user(&stop, argp, sizeof(stop))) + return -EFAULT; + + return ops->stop(vdpa, stop); +} + static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v, unsigned int cmd, void __user *argp) { @@ -650,6 +665,9 @@ static long vhost_vdpa_unlocked_ioctl(struct file *filep, case VHOST_VDPA_GET_VQS_COUNT: r = vhost_vdpa_get_vqs_count(v, argp); break; + case VHOST_VDPA_STOP: + r = vhost_vdpa_stop(v, argp); + break; default: r = vhost_dev_ioctl(&v->vdev, cmd, argp); if (r == -ENOIOCTLCMD) diff --git a/include/uapi/linux/vhost.h b/include/uapi/linux/vhost.h index cab645d4a645..c7e47b29bf61 100644 --- a/include/uapi/linux/vhost.h +++ b/include/uapi/linux/vhost.h @@ -171,4 +171,18 @@ #define VHOST_VDPA_SET_GROUP_ASID _IOW(VHOST_VIRTIO, 0x7C, \ struct vhost_vring_state) +/* Stop or resume a device so it does not process virtqueue requests anymore + * + * 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). + */ +#define VHOST_VDPA_STOP _IOW(VHOST_VIRTIO, 0x7D, int) + #endif
The ioctl adds support for stop the device from userspace. Signed-off-by: Eugenio Pérez <eperezma@redhat.com> --- drivers/vhost/vdpa.c | 18 ++++++++++++++++++ include/uapi/linux/vhost.h | 14 ++++++++++++++ 2 files changed, 32 insertions(+)