Re: [PATCH net-next v2 12/14] sfc: unmap VF's MCDI buffer when switching to vDPA mode
From: Jason Wang
Date: Fri Mar 10 2023 - 00:07:58 EST
On Tue, Mar 7, 2023 at 7:38 PM Gautam Dawar <gautam.dawar@xxxxxxx> 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@xxxxxxx>
> ---
> 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.
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.
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
>