Re: [PATCH net-next v2 12/14] sfc: unmap VF's MCDI buffer when switching to vDPA mode

[Jason Wang <jasowang@redhat.com>]

在 2023/3/13 15:09, Gautam Dawar 写道:
>
> On 3/10/23 10:35, Jason Wang wrote:
>> Caution: This message originated from an External Source. Use proper 
>> caution when opening attachments, clicking links, or responding.
>>
>>
>> On Tue, Mar 7, 2023 at 7:38 PM Gautam Dawar <gautam.dawar@amd.com> 
>> wrote:
>>> To avoid clash of IOVA range of VF's MCDI DMA buffer with the guest
>>> buffer IOVAs, unmap the MCDI buffer when switching to vDPA mode
>>> and use PF's IOMMU domain for running VF's MCDI commands.
>>>
>>> Signed-off-by: Gautam Dawar <gautam.dawar@amd.com>
>>> ---
>>>   drivers/net/ethernet/sfc/ef100_nic.c      |  1 -
>>>   drivers/net/ethernet/sfc/ef100_vdpa.c     | 25 ++++++++++++++++
>>>   drivers/net/ethernet/sfc/ef100_vdpa.h     |  3 ++
>>>   drivers/net/ethernet/sfc/ef100_vdpa_ops.c | 35 
>>> +++++++++++++++++++++++
>>>   drivers/net/ethernet/sfc/mcdi.h           |  3 ++
>>>   drivers/net/ethernet/sfc/net_driver.h     | 12 ++++++++
>>>   6 files changed, 78 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/net/ethernet/sfc/ef100_nic.c 
>>> b/drivers/net/ethernet/sfc/ef100_nic.c
>>> index cd9f724a9e64..1bffc1994ed8 100644
>>> --- a/drivers/net/ethernet/sfc/ef100_nic.c
>>> +++ b/drivers/net/ethernet/sfc/ef100_nic.c
>>> @@ -33,7 +33,6 @@
>>>
>>>   #define EF100_MAX_VIS 4096
>>>   #define EF100_NUM_MCDI_BUFFERS 1
>>> -#define MCDI_BUF_LEN (8 + MCDI_CTL_SDU_LEN_MAX)
>>>
>>>   #define EF100_RESET_PORT ((ETH_RESET_MAC | ETH_RESET_PHY) << 
>>> ETH_RESET_SHARED_SHIFT)
>>>
>>> diff --git a/drivers/net/ethernet/sfc/ef100_vdpa.c 
>>> b/drivers/net/ethernet/sfc/ef100_vdpa.c
>>> index 5c9f29f881a6..30ca4ab00175 100644
>>> --- a/drivers/net/ethernet/sfc/ef100_vdpa.c
>>> +++ b/drivers/net/ethernet/sfc/ef100_vdpa.c
>>> @@ -223,10 +223,19 @@ 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;
>>> +       int rc;
>>>
>>>          if (efx->vdpa_nic) {
>>>                  vdpa_dev = &efx->vdpa_nic->vdpa_dev;
>>>                  ef100_vdpa_reset(vdpa_dev);
>>> +               if (efx->mcdi_buf_mode == EFX_BUF_MODE_VDPA) {
>>> +                       rc = ef100_vdpa_map_mcdi_buffer(efx);
>>> +                       if (rc) {
>>> +                               pci_err(efx->pci_dev,
>>> +                                       "map_mcdi_buffer failed, 
>>> err: %d\n",
>>> +                                       rc);
>>> +                       }
>>> +               }
>>>
>>>                  /* replace with _vdpa_unregister_device later */
>>>                  put_device(&vdpa_dev->dev);
>>> @@ -276,6 +285,21 @@ static int get_net_config(struct ef100_vdpa_nic 
>>> *vdpa_nic)
>>>          return 0;
>>>   }
>>>
>>> +static void unmap_mcdi_buffer(struct efx_nic *efx)
>>> +{
>>> +       struct ef100_nic_data *nic_data = efx->nic_data;
>>> +       struct efx_mcdi_iface *mcdi;
>>> +
>>> +       mcdi = efx_mcdi(efx);
>>> +       spin_lock_bh(&mcdi->iface_lock);
>>> +       /* Save current MCDI mode to be restored later */
>>> +       efx->vdpa_nic->mcdi_mode = mcdi->mode;
>>> +       efx->mcdi_buf_mode = EFX_BUF_MODE_VDPA;
>>> +       mcdi->mode = MCDI_MODE_FAIL;
>>> +       spin_unlock_bh(&mcdi->iface_lock);
>>> +       efx_nic_free_buffer(efx, &nic_data->mcdi_buf);
>>> +}
>>> +
>>>   static struct ef100_vdpa_nic *ef100_vdpa_create(struct efx_nic *efx,
>>>                                                  const char *dev_name,
>>>                                                  enum 
>>> ef100_vdpa_class dev_type,
>>> @@ -342,6 +366,7 @@ static struct ef100_vdpa_nic 
>>> *ef100_vdpa_create(struct efx_nic *efx,
>>>          for (i = 0; i < EF100_VDPA_MAC_FILTER_NTYPES; i++)
>>>                  vdpa_nic->filters[i].filter_id = 
>>> EFX_INVALID_FILTER_ID;
>>>
>>> +       unmap_mcdi_buffer(efx);
>>>          rc = get_net_config(vdpa_nic);
>>>          if (rc)
>>>                  goto err_put_device;
>>> diff --git a/drivers/net/ethernet/sfc/ef100_vdpa.h 
>>> b/drivers/net/ethernet/sfc/ef100_vdpa.h
>>> index 49fb6be04eb3..0913ac2519cb 100644
>>> --- a/drivers/net/ethernet/sfc/ef100_vdpa.h
>>> +++ b/drivers/net/ethernet/sfc/ef100_vdpa.h
>>> @@ -147,6 +147,7 @@ struct ef100_vdpa_filter {
>>>    * @status: device status as per VIRTIO spec
>>>    * @features: negotiated feature bits
>>>    * @max_queue_pairs: maximum number of queue pairs supported
>>> + * @mcdi_mode: MCDI mode at the time of unmapping VF mcdi buffer
>>>    * @net_config: virtio_net_config data
>>>    * @vring: vring information of the vDPA device.
>>>    * @mac_address: mac address of interface associated with this 
>>> vdpa device
>>> @@ -166,6 +167,7 @@ struct ef100_vdpa_nic {
>>>          u8 status;
>>>          u64 features;
>>>          u32 max_queue_pairs;
>>> +       enum efx_mcdi_mode mcdi_mode;
>>>          struct virtio_net_config net_config;
>>>          struct ef100_vdpa_vring_info 
>>> vring[EF100_VDPA_MAX_QUEUES_PAIRS * 2];
>>>          u8 *mac_address;
>>> @@ -185,6 +187,7 @@ int ef100_vdpa_add_filter(struct ef100_vdpa_nic 
>>> *vdpa_nic,
>>>   int ef100_vdpa_init_vring(struct ef100_vdpa_nic *vdpa_nic, u16 idx);
>>>   void ef100_vdpa_irq_vectors_free(void *data);
>>>   int ef100_vdpa_reset(struct vdpa_device *vdev);
>>> +int ef100_vdpa_map_mcdi_buffer(struct efx_nic *efx);
>>>
>>>   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 db86c2693950..c6c9458f0e6f 100644
>>> --- a/drivers/net/ethernet/sfc/ef100_vdpa_ops.c
>>> +++ b/drivers/net/ethernet/sfc/ef100_vdpa_ops.c
>>> @@ -711,12 +711,47 @@ static int ef100_vdpa_suspend(struct 
>>> vdpa_device *vdev)
>>>          mutex_unlock(&vdpa_nic->lock);
>>>          return rc;
>>>   }
>>> +
>>> +int ef100_vdpa_map_mcdi_buffer(struct efx_nic *efx)
>>> +{
>> The name of this function is confusing, it's actually map buffer for
>> ef100 netdev mode.
>
> Yeah, I get your point. Actually, I am using the prefix ef100_vdpa_ 
> for extern functions and this function is just mapping the  MCDI 
> buffer resulting in the name ef100_vdpa_map_mcdi_buffer().
>
> I think ef100_vdpa_map_vf_mcdi_buffer() would remove this confusion. 
> What do you think?


Not a native speaker, but for me, it would be better to remove "vdpa" 
from the name since the buffer is not used by vDPA (if I understand the 
code correctly).


>
>>
>> Actually, I wonder why not moving this to init/fini of bar config ops
>> or if we use aux bus, it should be done during aux driver
>> probe/remove.
> It makes sense, however we store the last mcdi mode (poll or events) 
> in vdpa_nic->mcdi_mode to restore later, which requires vdpa_nic to be 
> allocated that happens later than switching to vdpa bar_config.


Ok.

Thanks


>> Thanks
>>
>>
>>> +       struct ef100_nic_data *nic_data = efx->nic_data;
>>> +       struct efx_mcdi_iface *mcdi;
>>> +       int rc;
>>> +
>>> +       /* Update VF's MCDI buffer when switching out of vdpa mode */
>>> +       rc = efx_nic_alloc_buffer(efx, &nic_data->mcdi_buf,
>>> +                                 MCDI_BUF_LEN, GFP_KERNEL);
>>> +       if (rc)
>>> +               return rc;
>>> +
>>> +       mcdi = efx_mcdi(efx);
>>> +       spin_lock_bh(&mcdi->iface_lock);
>>> +       mcdi->mode = efx->vdpa_nic->mcdi_mode;
>>> +       efx->mcdi_buf_mode = EFX_BUF_MODE_EF100;
>>> +       spin_unlock_bh(&mcdi->iface_lock);
>>> +
>>> +       return 0;
>>> +}
>>> +
>>>   static void ef100_vdpa_free(struct vdpa_device *vdev)
>>>   {
>>>          struct ef100_vdpa_nic *vdpa_nic = get_vdpa_nic(vdev);
>>> +       int rc;
>>>          int i;
>>>
>>>          if (vdpa_nic) {
>>> +               if (vdpa_nic->efx->mcdi_buf_mode == 
>>> EFX_BUF_MODE_VDPA) {
>>> +                       /* This will only be called via call to 
>>> put_device()
>>> +                        * on vdpa device creation failure
>>> +                        */
>>> +                       rc = ef100_vdpa_map_mcdi_buffer(vdpa_nic->efx);
>>> +                       if (rc) {
>>> +                               dev_err(&vdev->dev,
>>> +                                       "map_mcdi_buffer failed, 
>>> err: %d\n",
>>> +                                       rc);
>>> +                       }
>>> +               }
>>> +
>>>                  for (i = 0; i < (vdpa_nic->max_queue_pairs * 2); 
>>> i++) {
>>>                          reset_vring(vdpa_nic, i);
>>>                          if (vdpa_nic->vring[i].vring_ctx)
>>> diff --git a/drivers/net/ethernet/sfc/mcdi.h 
>>> b/drivers/net/ethernet/sfc/mcdi.h
>>> index 2c526d2edeb6..bc4de3b4e6f3 100644
>>> --- a/drivers/net/ethernet/sfc/mcdi.h
>>> +++ b/drivers/net/ethernet/sfc/mcdi.h
>>> @@ -6,6 +6,9 @@
>>>
>>>   #ifndef EFX_MCDI_H
>>>   #define EFX_MCDI_H
>>> +#include "mcdi_pcol.h"
>>> +
>>> +#define MCDI_BUF_LEN (8 + MCDI_CTL_SDU_LEN_MAX)
>>>
>>>   /**
>>>    * enum efx_mcdi_state - MCDI request handling state
>>> diff --git a/drivers/net/ethernet/sfc/net_driver.h 
>>> b/drivers/net/ethernet/sfc/net_driver.h
>>> index 948c7a06403a..9cdfeb6ad05a 100644
>>> --- a/drivers/net/ethernet/sfc/net_driver.h
>>> +++ b/drivers/net/ethernet/sfc/net_driver.h
>>> @@ -848,6 +848,16 @@ enum efx_xdp_tx_queues_mode {
>>>
>>>   struct efx_mae;
>>>
>>> +/**
>>> + * enum efx_buf_alloc_mode - buffer allocation mode
>>> + * @EFX_BUF_MODE_EF100: buffer setup in ef100 mode
>>> + * @EFX_BUF_MODE_VDPA: buffer setup in vdpa mode
>>> + */
>>> +enum efx_buf_alloc_mode {
>>> +       EFX_BUF_MODE_EF100,
>>> +       EFX_BUF_MODE_VDPA
>>> +};
>>> +
>>>   /**
>>>    * struct efx_nic - an Efx NIC
>>>    * @name: Device name (net device name or bus id before net device 
>>> registered)
>>> @@ -877,6 +887,7 @@ struct efx_mae;
>>>    * @irq_rx_mod_step_us: Step size for IRQ moderation for RX event 
>>> queues
>>>    * @irq_rx_moderation_us: IRQ moderation time for RX event queues
>>>    * @msg_enable: Log message enable flags
>>> + * @mcdi_buf_mode: mcdi buffer allocation mode
>>>    * @state: Device state number (%STATE_*). Serialised by the 
>>> rtnl_lock.
>>>    * @reset_pending: Bitmask for pending resets
>>>    * @tx_queue: TX DMA queues
>>> @@ -1045,6 +1056,7 @@ struct efx_nic {
>>>          u32 msg_enable;
>>>
>>>          enum nic_state state;
>>> +       enum efx_buf_alloc_mode mcdi_buf_mode;
>>>          unsigned long reset_pending;
>>>
>>>          struct efx_channel *channel[EFX_MAX_CHANNELS];
>>> -- 
>>> 2.30.1
>>>
>