Messages in this thread | | | Date | Fri, 13 Jan 2023 12:03:06 +0530 | Subject | Re: [PATCH net-next 08/11] sfc: implement device status related vdpa config operations | From | Gautam Dawar <> |
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On 1/13/23 11:50, Jason Wang wrote: > Caution: This message originated from an External Source. Use proper caution when opening attachments, clicking links, or responding. > > > 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). Ok. Is it expected that a queue restart (set_vq_ready(0) followed by set_vq_ready(1)) will start the queue from the last queue configuration when VIRTIO_F_RING_RESET isn't negotiated? > > 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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