Messages in this thread | | | From | Jason Wang <> | Date | Fri, 13 Jan 2023 14:20:03 +0800 | Subject | Re: [PATCH net-next 08/11] sfc: implement device status related vdpa config operations |
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On Fri, Jan 13, 2023 at 2:11 PM Gautam Dawar <gdawar@amd.com> wrote: > > > On 1/13/23 09:58, Jason Wang wrote: > > Caution: This message originated from an External Source. Use proper caution when opening attachments, clicking links, or responding. > > > > > > On Wed, Jan 11, 2023 at 2:36 PM Jason Wang <jasowang@redhat.com> wrote: > >> On Mon, Jan 9, 2023 at 6:21 PM Gautam Dawar <gdawar@amd.com> wrote: > >>> > >>> On 12/14/22 12:15, Jason Wang wrote: > >>>> Caution: This message originated from an External Source. Use proper caution when opening attachments, clicking links, or responding. > >>>> > >>>> > >>>> On Wed, Dec 7, 2022 at 10:57 PM Gautam Dawar <gautam.dawar@amd.com> wrote: > >>>>> vDPA config opertions to handle get/set device status and device > >>>>> reset have been implemented. > >>>>> > >>>>> Signed-off-by: Gautam Dawar <gautam.dawar@amd.com> > >>>>> --- > >>>>> drivers/net/ethernet/sfc/ef100_vdpa.c | 7 +- > >>>>> drivers/net/ethernet/sfc/ef100_vdpa.h | 1 + > >>>>> drivers/net/ethernet/sfc/ef100_vdpa_ops.c | 133 ++++++++++++++++++++++ > >>>>> 3 files changed, 140 insertions(+), 1 deletion(-) > >>>>> > >>>>> diff --git a/drivers/net/ethernet/sfc/ef100_vdpa.c b/drivers/net/ethernet/sfc/ef100_vdpa.c > >>>>> index 04d64bfe3c93..80bca281a748 100644 > >>>>> --- a/drivers/net/ethernet/sfc/ef100_vdpa.c > >>>>> +++ b/drivers/net/ethernet/sfc/ef100_vdpa.c > >>>>> @@ -225,9 +225,14 @@ static int vdpa_allocate_vis(struct efx_nic *efx, unsigned int *allocated_vis) > >>>>> > >>>>> static void ef100_vdpa_delete(struct efx_nic *efx) > >>>>> { > >>>>> + struct vdpa_device *vdpa_dev; > >>>>> + > >>>>> if (efx->vdpa_nic) { > >>>>> + vdpa_dev = &efx->vdpa_nic->vdpa_dev; > >>>>> + ef100_vdpa_reset(vdpa_dev); > >>>> Any reason we need to reset during delete? > >>> ef100_reset_vdpa_device() does the necessary clean-up including freeing > >>> irqs, deleting filters and deleting the vrings which is required while > >>> removing the vdpa device or unloading the driver. > >> That's fine but the name might be a little bit confusing since vDPA > >> reset is not necessary here. > >> > >>>>> + > >>>>> /* replace with _vdpa_unregister_device later */ > >>>>> - put_device(&efx->vdpa_nic->vdpa_dev.dev); > >>>>> + put_device(&vdpa_dev->dev); > >>>>> efx->vdpa_nic = NULL; > >>>>> } > >>>>> efx_mcdi_free_vis(efx); > >>>>> diff --git a/drivers/net/ethernet/sfc/ef100_vdpa.h b/drivers/net/ethernet/sfc/ef100_vdpa.h > >>>>> index a33edd6dda12..1b0bbba88154 100644 > >>>>> --- a/drivers/net/ethernet/sfc/ef100_vdpa.h > >>>>> +++ b/drivers/net/ethernet/sfc/ef100_vdpa.h > >>>>> @@ -186,6 +186,7 @@ int ef100_vdpa_add_filter(struct ef100_vdpa_nic *vdpa_nic, > >>>>> enum ef100_vdpa_mac_filter_type type); > >>>>> int ef100_vdpa_irq_vectors_alloc(struct pci_dev *pci_dev, u16 nvqs); > >>>>> void ef100_vdpa_irq_vectors_free(void *data); > >>>>> +int ef100_vdpa_reset(struct vdpa_device *vdev); > >>>>> > >>>>> static inline bool efx_vdpa_is_little_endian(struct ef100_vdpa_nic *vdpa_nic) > >>>>> { > >>>>> diff --git a/drivers/net/ethernet/sfc/ef100_vdpa_ops.c b/drivers/net/ethernet/sfc/ef100_vdpa_ops.c > >>>>> index 132ddb4a647b..718b67f6da90 100644 > >>>>> --- a/drivers/net/ethernet/sfc/ef100_vdpa_ops.c > >>>>> +++ b/drivers/net/ethernet/sfc/ef100_vdpa_ops.c > >>>>> @@ -251,6 +251,62 @@ static bool is_qid_invalid(struct ef100_vdpa_nic *vdpa_nic, u16 idx, > >>>>> return false; > >>>>> } > >>>>> > >>>>> +static void ef100_reset_vdpa_device(struct ef100_vdpa_nic *vdpa_nic) > >>>>> +{ > >>>>> + int i; > >>>>> + > >>>>> + WARN_ON(!mutex_is_locked(&vdpa_nic->lock)); > >>>>> + > >>>>> + if (!vdpa_nic->status) > >>>>> + return; > >>>>> + > >>>>> + vdpa_nic->vdpa_state = EF100_VDPA_STATE_INITIALIZED; > >>>>> + vdpa_nic->status = 0; > >>>>> + vdpa_nic->features = 0; > >>>>> + for (i = 0; i < (vdpa_nic->max_queue_pairs * 2); i++) > >>>>> + reset_vring(vdpa_nic, i); > >>>>> +} > >>>>> + > >>>>> +/* May be called under the rtnl lock */ > >>>>> +int ef100_vdpa_reset(struct vdpa_device *vdev) > >>>>> +{ > >>>>> + struct ef100_vdpa_nic *vdpa_nic = get_vdpa_nic(vdev); > >>>>> + > >>>>> + /* vdpa device can be deleted anytime but the bar_config > >>>>> + * could still be vdpa and hence efx->state would be STATE_VDPA. > >>>>> + * Accordingly, ensure vdpa device exists before reset handling > >>>>> + */ > >>>>> + if (!vdpa_nic) > >>>>> + return -ENODEV; > >>>>> + > >>>>> + mutex_lock(&vdpa_nic->lock); > >>>>> + ef100_reset_vdpa_device(vdpa_nic); > >>>>> + mutex_unlock(&vdpa_nic->lock); > >>>>> + return 0; > >>>>> +} > >>>>> + > >>>>> +static int start_vdpa_device(struct ef100_vdpa_nic *vdpa_nic) > >>>>> +{ > >>>>> + int rc = 0; > >>>>> + int i, j; > >>>>> + > >>>>> + for (i = 0; i < (vdpa_nic->max_queue_pairs * 2); i++) { > >>>>> + if (can_create_vring(vdpa_nic, i)) { > >>>>> + rc = create_vring(vdpa_nic, i); > >>>> So I think we can safely remove the create_vring() in set_vq_ready() > >>>> since it's undefined behaviour if set_vq_ready() is called after > >>>> DRIVER_OK. > >>> Is this (undefined) behavior documented in the virtio spec? > >> This part is kind of tricky: > >> > >> PCI transport has a queue_enable field. And recently, > >> VIRTIO_F_RING_RESET was introduced. Let's start without that first: > >> > >> In > >> > >> 4.1.4.3.2 Driver Requirements: Common configuration structure layout > >> > >> It said: > >> > >> "The driver MUST configure the other virtqueue fields before enabling > >> the virtqueue with queue_enable." > >> > >> and > >> > >> "The driver MUST NOT write a 0 to queue_enable." > >> > >> My understanding is that: > >> > >> 1) Write 0 is forbidden > >> 2) Write 1 after DRIVER_OK is undefined behaviour (or need to clarify) > >> > >> With VIRTIO_F_RING_RESET is negotiated: > >> > >> " > >> If VIRTIO_F_RING_RESET has been negotiated, after the driver writes 1 > >> to queue_reset to reset the queue, the driver MUST NOT consider queue > >> reset to be complete until it reads back 0 in queue_reset. The driver > >> MAY re-enable the queue by writing 1 to queue_enable after ensuring > >> that other virtqueue fields have been set up correctly. The driver MAY > >> set driver-writeable queue configuration values to different values > >> than those that were used before the queue reset. (see 2.6.1). > >> " > >> > >> Write 1 to queue_enable after DRIVER_OK and after the queue is reset is allowed. > >> > >> Thanks > > Btw, I just realized that we need to stick to the current behaviour, > > that is to say, to allow set_vq_ready() to be called after DRIVER_OK. > > So, both set_vq_ready() and DRIVER_OK are required for vring creation > and their order doesn't matter. Is that correct?
Yes.
> > Also, will set_vq_ready(0) after DRIVER_OK result in queue deletion?
I think it should be treated as suspended or stopped. Since the device should survive from kicking the vq even if the driver does set_vq_ready(0).
Thanks
> > > > > It is needed for the cvq trap and migration for control virtqueue: > > > > https://www.mail-archive.com/qemu-devel@nongnu.org/msg931491.html > > > > Thanks > > > > > >> > >>> If so, can > >>> you please point me to the section of virtio spec that calls this order > >>> (set_vq_ready() after setting DRIVER_OK) undefined? Is it just that the > >>> queue can't be enabled after DRIVER_OK or the reverse (disabling the > >>> queue) after DRIVER_OK is not allowed? > >>>>> + if (rc) > >>>>> + goto clear_vring; > >>>>> + } > >>>>> + } > >>>>> + vdpa_nic->vdpa_state = EF100_VDPA_STATE_STARTED; > >>>>> + return rc; > >>>>> + > >>>>> +clear_vring: > >>>>> + for (j = 0; j < i; j++) > >>>>> + if (vdpa_nic->vring[j].vring_created) > >>>>> + delete_vring(vdpa_nic, j); > >>>>> + return rc; > >>>>> +} > >>>>> + > >>>>> static int ef100_vdpa_set_vq_address(struct vdpa_device *vdev, > >>>>> u16 idx, u64 desc_area, u64 driver_area, > >>>>> u64 device_area) > >>>>> @@ -568,6 +624,80 @@ static u32 ef100_vdpa_get_vendor_id(struct vdpa_device *vdev) > >>>>> return EF100_VDPA_VENDOR_ID; > >>>>> } > >>>>> > >>>>> +static u8 ef100_vdpa_get_status(struct vdpa_device *vdev) > >>>>> +{ > >>>>> + struct ef100_vdpa_nic *vdpa_nic = get_vdpa_nic(vdev); > >>>>> + u8 status; > >>>>> + > >>>>> + mutex_lock(&vdpa_nic->lock); > >>>>> + status = vdpa_nic->status; > >>>>> + mutex_unlock(&vdpa_nic->lock); > >>>>> + return status; > >>>>> +} > >>>>> + > >>>>> +static void ef100_vdpa_set_status(struct vdpa_device *vdev, u8 status) > >>>>> +{ > >>>>> + struct ef100_vdpa_nic *vdpa_nic = get_vdpa_nic(vdev); > >>>>> + u8 new_status; > >>>>> + int rc; > >>>>> + > >>>>> + mutex_lock(&vdpa_nic->lock); > >>>>> + if (!status) { > >>>>> + dev_info(&vdev->dev, > >>>>> + "%s: Status received is 0. Device reset being done\n", > >>>>> + __func__); > >>>>> + ef100_reset_vdpa_device(vdpa_nic); > >>>>> + goto unlock_return; > >>>>> + } > >>>>> + new_status = status & ~vdpa_nic->status; > >>>>> + if (new_status == 0) { > >>>>> + dev_info(&vdev->dev, > >>>>> + "%s: New status same as current status\n", __func__); > >>>>> + goto unlock_return; > >>>>> + } > >>>>> + if (new_status & VIRTIO_CONFIG_S_FAILED) { > >>>>> + ef100_reset_vdpa_device(vdpa_nic); > >>>>> + goto unlock_return; > >>>>> + } > >>>>> + > >>>>> + if (new_status & VIRTIO_CONFIG_S_ACKNOWLEDGE && > >>>>> + vdpa_nic->vdpa_state == EF100_VDPA_STATE_INITIALIZED) { > >>>> As replied before, I think there's no need to check > >>>> EF100_VDPA_STATE_INITIALIZED, otherwise it could be a bug somewhere. > >>> Ok. Will remove the check against EF100_VDPA_STATE_INITIALIZED. > >>>>> + vdpa_nic->status |= VIRTIO_CONFIG_S_ACKNOWLEDGE; > >>>>> + new_status &= ~VIRTIO_CONFIG_S_ACKNOWLEDGE; > >>>>> + } > >>>>> + if (new_status & VIRTIO_CONFIG_S_DRIVER && > >>>>> + vdpa_nic->vdpa_state == EF100_VDPA_STATE_INITIALIZED) { > >>>>> + vdpa_nic->status |= VIRTIO_CONFIG_S_DRIVER; > >>>>> + new_status &= ~VIRTIO_CONFIG_S_DRIVER; > >>>>> + } > >>>>> + if (new_status & VIRTIO_CONFIG_S_FEATURES_OK && > >>>>> + vdpa_nic->vdpa_state == EF100_VDPA_STATE_INITIALIZED) { > >>>>> + vdpa_nic->status |= VIRTIO_CONFIG_S_FEATURES_OK; > >>>>> + vdpa_nic->vdpa_state = EF100_VDPA_STATE_NEGOTIATED; > >>>> I think we can simply map EF100_VDPA_STATE_NEGOTIATED to > >>>> VIRTIO_CONFIG_S_FEATURES_OK. > >>>> > >>>> E.g the code doesn't fail the feature negotiation by clearing the > >>>> VIRTIO_CONFIG_S_FEATURES_OK when ef100_vdpa_set_driver_feature fails? > >>> Ok. > >>>> Thanks > >>> Regards, > >>> > >>> Gautam > >>> >
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