Messages in this thread | | | Date | Fri, 13 Jan 2023 11:40:39 +0530 | Subject | Re: [PATCH net-next 08/11] sfc: implement device status related vdpa config operations | From | Gautam Dawar <> |
| |
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?
Also, will set_vq_ready(0) after DRIVER_OK result in queue deletion?
> > 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 >>>
| |