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Message-ID: <CACGkMEuMfcuUOCv_S62Y6Ju-HS7yqikEEYxy_h7+vkLrtnTg6A@mail.gmail.com>
Date: Wed, 14 Dec 2022 14:46:09 +0800
From: Jason Wang <jasowang@...hat.com>
To: Gautam Dawar <gautam.dawar@....com>
Cc: linux-net-drivers@....com, netdev@...r.kernel.org,
eperezma@...hat.com, tanuj.kamde@....com, Koushik.Dutta@....com,
harpreet.anand@....com, Edward Cree <ecree.xilinx@...il.com>,
Martin Habets <habetsm.xilinx@...il.com>,
"David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>,
Jakub Kicinski <kuba@...nel.org>,
Paolo Abeni <pabeni@...hat.com>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH net-next 10/11] sfc: implement vdpa config_ops for dma operations
On Wed, Dec 7, 2022 at 10:57 PM Gautam Dawar <gautam.dawar@....com> wrote:
>
> Although sfc uses the platform IOMMU but it still
> implements the DMA config operations to deal with
> possible IOVA overlap with the MCDI DMA buffer and
> relocates the latter if such overlap is detected.
>
> Signed-off-by: Gautam Dawar <gautam.dawar@....com>
> ---
> drivers/net/ethernet/sfc/ef100_vdpa.c | 140 ++++++++++++++++++++++
> drivers/net/ethernet/sfc/ef100_vdpa.h | 3 +
> drivers/net/ethernet/sfc/ef100_vdpa_ops.c | 111 +++++++++++++++++
> drivers/net/ethernet/sfc/net_driver.h | 12 ++
> 4 files changed, 266 insertions(+)
>
> diff --git a/drivers/net/ethernet/sfc/ef100_vdpa.c b/drivers/net/ethernet/sfc/ef100_vdpa.c
> index b9368eb1acd5..16681d164fd1 100644
> --- a/drivers/net/ethernet/sfc/ef100_vdpa.c
> +++ b/drivers/net/ethernet/sfc/ef100_vdpa.c
> @@ -309,6 +309,140 @@ static int vdpa_update_domain(struct ef100_vdpa_nic *vdpa_nic)
> vdpa_nic->geo_aper_end + 1, 0);
> }
>
> +static int ef100_vdpa_alloc_buffer(struct efx_nic *efx, struct efx_buffer *buf)
> +{
> + struct ef100_vdpa_nic *vdpa_nic = efx->vdpa_nic;
> + struct device *dev = &vdpa_nic->vdpa_dev.dev;
> + int rc;
> +
> + buf->addr = kzalloc(buf->len, GFP_KERNEL);
> + if (!buf->addr)
> + return -ENOMEM;
> +
> + rc = iommu_map(vdpa_nic->domain, buf->dma_addr,
> + virt_to_phys(buf->addr), buf->len,
> + IOMMU_READ | IOMMU_WRITE | IOMMU_CACHE);
> + if (rc)
> + dev_err(dev, "iommu_map failed, rc: %d\n", rc);
> +
> + return rc;
> +}
> +
> +static void ef100_vdpa_free_buffer(struct ef100_vdpa_nic *vdpa_nic,
> + struct efx_buffer *buf)
> +{
> + struct device *dev = &vdpa_nic->vdpa_dev.dev;
> + int rc;
> +
> + rc = iommu_unmap(vdpa_nic->domain, buf->dma_addr, buf->len);
> + if (rc < 0)
> + dev_err(dev, "iommu_unmap failed, rc: %d\n", rc);
> +
> + kfree(buf->addr);
> +}
> +
> +int ef100_setup_ef100_mcdi_buffer(struct ef100_vdpa_nic *vdpa_nic)
> +{
> + struct efx_nic *efx = vdpa_nic->efx;
> + struct ef100_nic_data *nic_data;
> + struct efx_mcdi_iface *mcdi;
> + struct efx_buffer mcdi_buf;
> + enum efx_mcdi_mode mode;
> + struct device *dev;
> + int rc;
> +
> + /* Switch to poll mode MCDI mode */
> + nic_data = efx->nic_data;
> + dev = &vdpa_nic->vdpa_dev.dev;
> + mcdi = efx_mcdi(efx);
> + mode = mcdi->mode;
> + efx_mcdi_mode_poll(efx);
> + efx_mcdi_flush_async(efx);
> +
> + /* First, allocate the MCDI buffer for EF100 mode */
> + rc = efx_nic_alloc_buffer(efx, &mcdi_buf,
> + MCDI_BUF_LEN, GFP_KERNEL);
> + if (rc) {
> + dev_err(dev, "nic alloc buf failed, rc: %d\n", rc);
> + goto restore_mode;
> + }
> +
> + /* unmap and free the vDPA MCDI buffer now */
> + ef100_vdpa_free_buffer(vdpa_nic, &nic_data->mcdi_buf);
> + memcpy(&nic_data->mcdi_buf, &mcdi_buf, sizeof(struct efx_buffer));
> + efx->mcdi_buf_mode = EFX_BUF_MODE_EF100;
> +
> +restore_mode:
> + if (mode == MCDI_MODE_EVENTS)
> + efx_mcdi_mode_event(efx);
> +
> + return rc;
> +}
> +
> +int ef100_setup_vdpa_mcdi_buffer(struct efx_nic *efx, u64 mcdi_iova)
> +{
> + struct ef100_nic_data *nic_data = efx->nic_data;
> + struct efx_mcdi_iface *mcdi = efx_mcdi(efx);
> + enum efx_mcdi_mode mode = mcdi->mode;
> + struct efx_buffer mcdi_buf;
> + int rc;
> +
> + efx_mcdi_mode_poll(efx);
> + efx_mcdi_flush_async(efx);
> +
> + /* First, prepare the MCDI buffer for vDPA mode */
> + mcdi_buf.dma_addr = mcdi_iova;
> + /* iommu_map requires page aligned memory */
> + mcdi_buf.len = PAGE_ALIGN(MCDI_BUF_LEN);
> + rc = ef100_vdpa_alloc_buffer(efx, &mcdi_buf);
> + if (rc) {
> + pci_err(efx->pci_dev, "alloc vdpa buf failed, rc: %d\n", rc);
> + goto restore_mode;
> + }
> +
> + /* All set-up, free the EF100 MCDI buffer now */
> + efx_nic_free_buffer(efx, &nic_data->mcdi_buf);
> + memcpy(&nic_data->mcdi_buf, &mcdi_buf, sizeof(struct efx_buffer));
> + efx->mcdi_buf_mode = EFX_BUF_MODE_VDPA;
> +
> +restore_mode:
> + if (mode == MCDI_MODE_EVENTS)
> + efx_mcdi_mode_event(efx);
> + return rc;
> +}
> +
> +int ef100_remap_vdpa_mcdi_buffer(struct efx_nic *efx, u64 mcdi_iova)
> +{
> + struct ef100_nic_data *nic_data = efx->nic_data;
> + struct ef100_vdpa_nic *vdpa_nic = efx->vdpa_nic;
> + struct efx_mcdi_iface *mcdi = efx_mcdi(efx);
> + struct efx_buffer *mcdi_buf;
> + int rc;
> +
> + mcdi_buf = &nic_data->mcdi_buf;
> + spin_lock_bh(&mcdi->iface_lock);
> +
> + rc = iommu_unmap(vdpa_nic->domain, mcdi_buf->dma_addr, mcdi_buf->len);
> + if (rc < 0) {
> + pci_err(efx->pci_dev, "iommu_unmap failed, rc: %d\n", rc);
> + goto out;
> + }
> +
> + rc = iommu_map(vdpa_nic->domain, mcdi_iova,
> + virt_to_phys(mcdi_buf->addr),
> + mcdi_buf->len,
> + IOMMU_READ | IOMMU_WRITE | IOMMU_CACHE);
> + if (rc) {
> + pci_err(efx->pci_dev, "iommu_map failed, rc: %d\n", rc);
> + goto out;
> + }
> +
> + mcdi_buf->dma_addr = mcdi_iova;
> +out:
> + spin_unlock_bh(&mcdi->iface_lock);
> + return rc;
> +}
> +
> static struct ef100_vdpa_nic *ef100_vdpa_create(struct efx_nic *efx,
> const char *dev_name,
> enum ef100_vdpa_class dev_type,
> @@ -391,6 +525,12 @@ static struct ef100_vdpa_nic *ef100_vdpa_create(struct efx_nic *efx,
> goto err_put_device;
> }
>
> + rc = ef100_setup_vdpa_mcdi_buffer(efx, EF100_VDPA_IOVA_BASE_ADDR);
> + if (rc) {
> + pci_err(efx->pci_dev, "realloc mcdi failed, err: %d\n", rc);
> + goto err_put_device;
> + }
> +
> 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 c3c77029973d..f15d8739dcde 100644
> --- a/drivers/net/ethernet/sfc/ef100_vdpa.h
> +++ b/drivers/net/ethernet/sfc/ef100_vdpa.h
> @@ -202,6 +202,9 @@ int ef100_vdpa_add_filter(struct ef100_vdpa_nic *vdpa_nic,
> 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);
> +int ef100_setup_ef100_mcdi_buffer(struct ef100_vdpa_nic *vdpa_nic);
> +int ef100_setup_vdpa_mcdi_buffer(struct efx_nic *efx, u64 mcdi_iova);
> +int ef100_remap_vdpa_mcdi_buffer(struct efx_nic *efx, u64 mcdi_iova);
>
> 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 8c198d949fdb..7c632f179bcf 100644
> --- a/drivers/net/ethernet/sfc/ef100_vdpa_ops.c
> +++ b/drivers/net/ethernet/sfc/ef100_vdpa_ops.c
> @@ -12,6 +12,7 @@
> #include "ef100_vdpa.h"
> #include "ef100_iova.h"
> #include "io.h"
> +#include "ef100_iova.h"
> #include "mcdi_vdpa.h"
>
> /* Get the queue's function-local index of the associated VI
> @@ -739,14 +740,121 @@ static void ef100_vdpa_set_config(struct vdpa_device *vdev, unsigned int offset,
> }
> }
>
> +static bool is_iova_overlap(u64 iova1, u64 size1, u64 iova2, u64 size2)
> +{
> + return max(iova1, iova2) < min(iova1 + size1, iova2 + size2);
> +}
> +
> +static int ef100_vdpa_dma_map(struct vdpa_device *vdev,
> + unsigned int asid,
> + u64 iova, u64 size,
> + u64 pa, u32 perm, void *opaque)
> +{
> + struct ef100_vdpa_nic *vdpa_nic;
> + struct ef100_nic_data *nic_data;
> + unsigned int mcdi_buf_len;
> + dma_addr_t mcdi_buf_addr;
> + u64 mcdi_iova = 0;
> + int rc;
> +
> + vdpa_nic = get_vdpa_nic(vdev);
> + nic_data = vdpa_nic->efx->nic_data;
> + mcdi_buf_addr = nic_data->mcdi_buf.dma_addr;
> + mcdi_buf_len = nic_data->mcdi_buf.len;
> +
> + /* Validate the iova range against geo aperture */
> + if (iova < vdpa_nic->geo_aper_start ||
> + ((iova + size - 1) > vdpa_nic->geo_aper_end)) {
> + dev_err(&vdpa_nic->vdpa_dev.dev,
> + "%s: iova range (%llx, %llx) not within geo aperture\n",
> + __func__, iova, (iova + size));
> + return -EINVAL;
It might be helpful to advertise this geo via get_iova_range().
Thanks
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