Re: [PATCH net-next 05/11] sfc: implement vdpa device config operations
From: Gautam Dawar
Date: Thu Dec 15 2022 - 04:54:46 EST
On 12/14/22 12:14, 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 10:56 PM Gautam Dawar <gautam.dawar@xxxxxxx> wrote:
vDPA config operations can be broadly categorized in to either
virtqueue operations, device operations or DMA operations.
This patch implements most of the device level config operations.
SN1022 supports VIRTIO_F_IN_ORDER which is supported by the DPDK
virtio driver but not the kernel virtio driver. Due to a bug in
QEMU (https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgitlab.com%2Fqemu-project%2Fqemu%2F-%2Fissues%2F331%23&data=05%7C01%7Cgautam.dawar%40amd.com%7C58787eb502484eeaa6f508dadd9ea016%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C638065970623127805%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=cVomPr2aFJBHW7kwzeZJrNHuU6oTYOTV14eOS%2BpeNVc%3D&reserved=0), with
vhost-vdpa, this feature bit is returned with guest kernel virtio
driver in set_features config operation. The fix for this bug
(qemu_commit c33f23a419f95da16ab4faaf08be635c89b96ff0) is available
in QEMU versions 6.1.0 and later. Hence, that's the oldest QEMU
version required for testing with the vhost-vdpa driver.
With older QEMU releases, VIRTIO_F_IN_ORDER is negotiated but
not honored causing Firmware exception.
Signed-off-by: Gautam Dawar <gautam.dawar@xxxxxxx>
---
drivers/net/ethernet/sfc/ef100_vdpa.h | 14 ++
drivers/net/ethernet/sfc/ef100_vdpa_ops.c | 148 ++++++++++++++++++++++
2 files changed, 162 insertions(+)
diff --git a/drivers/net/ethernet/sfc/ef100_vdpa.h b/drivers/net/ethernet/sfc/ef100_vdpa.h
index 83f6d819f6a5..be7650c3166a 100644
--- a/drivers/net/ethernet/sfc/ef100_vdpa.h
+++ b/drivers/net/ethernet/sfc/ef100_vdpa.h
@@ -21,6 +21,18 @@
/* Max queue pairs currently supported */
#define EF100_VDPA_MAX_QUEUES_PAIRS 1
+/* Device ID of a virtio net device */
+#define EF100_VDPA_VIRTIO_NET_DEVICE_ID VIRTIO_ID_NET
+
+/* Vendor ID of Xilinx vDPA NIC */
+#define EF100_VDPA_VENDOR_ID PCI_VENDOR_ID_XILINX
+
+/* Max number of Buffers supported in the virtqueue */
+#define EF100_VDPA_VQ_NUM_MAX_SIZE 512
+
+/* Alignment requirement of the Virtqueue */
+#define EF100_VDPA_VQ_ALIGN 4096
+
/**
* enum ef100_vdpa_nic_state - possible states for a vDPA NIC
*
@@ -61,6 +73,7 @@ enum ef100_vdpa_vq_type {
* @net_config: virtio_net_config data
* @mac_address: mac address of interface associated with this vdpa device
* @mac_configured: true after MAC address is configured
+ * @cfg_cb: callback for config change
*/
struct ef100_vdpa_nic {
struct vdpa_device vdpa_dev;
@@ -76,6 +89,7 @@ struct ef100_vdpa_nic {
struct virtio_net_config net_config;
u8 *mac_address;
bool mac_configured;
+ struct vdpa_callback cfg_cb;
};
int ef100_vdpa_init(struct efx_probe_data *probe_data);
diff --git a/drivers/net/ethernet/sfc/ef100_vdpa_ops.c b/drivers/net/ethernet/sfc/ef100_vdpa_ops.c
index 31952931c198..87899baa1c52 100644
--- a/drivers/net/ethernet/sfc/ef100_vdpa_ops.c
+++ b/drivers/net/ethernet/sfc/ef100_vdpa_ops.c
@@ -10,12 +10,148 @@
#include <linux/vdpa.h>
#include "ef100_vdpa.h"
+#include "mcdi_vdpa.h"
static struct ef100_vdpa_nic *get_vdpa_nic(struct vdpa_device *vdev)
{
return container_of(vdev, struct ef100_vdpa_nic, vdpa_dev);
}
+static u32 ef100_vdpa_get_vq_align(struct vdpa_device *vdev)
+{
+ return EF100_VDPA_VQ_ALIGN;
+}
+
+static u64 ef100_vdpa_get_device_features(struct vdpa_device *vdev)
+{
+ struct ef100_vdpa_nic *vdpa_nic = get_vdpa_nic(vdev);
+ u64 features;
+ int rc;
+
+ rc = efx_vdpa_get_features(vdpa_nic->efx,
+ EF100_VDPA_DEVICE_TYPE_NET, &features);
+ if (rc) {
+ dev_err(&vdev->dev, "%s: MCDI get features error:%d\n",
+ __func__, rc);
+ /* Returning 0 as value of features will lead to failure
+ * of feature negotiation.
+ */
+ return 0;
+ }
+
+ /* SN1022 supports VIRTIO_F_IN_ORDER which is supported by the DPDK
+ * virtio driver but not the kernel virtio driver. Due to a bug in
+ * QEMU (https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgitlab.com%2Fqemu-project%2Fqemu%2F-%2Fissues%2F331%23&data=05%7C01%7Cgautam.dawar%40amd.com%7C58787eb502484eeaa6f508dadd9ea016%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C638065970623127805%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=cVomPr2aFJBHW7kwzeZJrNHuU6oTYOTV14eOS%2BpeNVc%3D&reserved=0), with
+ * vhost-vdpa, this feature bit is returned with guest kernel virtio
+ * driver in set_features config operation. The fix for this bug
+ * (commit c33f23a419f95da16ab4faaf08be635c89b96ff0) is available
+ * in QEMU versions 6.1.0 and later. Hence, that's the oldest QEMU
+ * version required for testing with the vhost-vdpa driver.
+ */
I don't see why this comment is placed here?
As the comment was related to VIRTIO_F_IN_ORDER, I thought of adding it
in config operation related to virtio features handling. But I think
since it is already added in the commit description, this code comment
can be removed.
+ features |= BIT_ULL(VIRTIO_NET_F_MAC);
+
+ return features;
+}
+
+static int ef100_vdpa_set_driver_features(struct vdpa_device *vdev,
+ u64 features)
+{
+ struct ef100_vdpa_nic *vdpa_nic = get_vdpa_nic(vdev);
+ u64 verify_features;
+ int rc;
+
+ mutex_lock(&vdpa_nic->lock);
+ if (vdpa_nic->vdpa_state != EF100_VDPA_STATE_INITIALIZED) {
Under which case could we reach this condition? The
vdpa_device_register() should be called after switching the state to
EF100_VDPA_STATE_INITIALIZED.
You're right. I'll remove this check as state is set to
EF100_VDPA_STATE_INITIALIZED soon after vdpa_alloc_device but before
_vdpa_register_device()
+ dev_err(&vdev->dev, "%s: Invalid state %u\n",
+ __func__, vdpa_nic->vdpa_state);
+ rc = -EINVAL;
+ goto err;
+ }
+ verify_features = features & ~BIT_ULL(VIRTIO_NET_F_MAC);
+ rc = efx_vdpa_verify_features(vdpa_nic->efx,
+ EF100_VDPA_DEVICE_TYPE_NET,
+ verify_features);
It looks to me this will use MC_CMD_VIRTIO_TEST_FEATURES command, I
wonder if it's better to use
MC_CMD_VIRTIO_SET_FEATURES to align with the virtio spec and maybe
change efx_vdpa_verify_features to efx_vdpa_set_features()?
Yes, it makes more sense to match the function names with the operations
in virtio spec. However, MC_CMD_VIRTIO_TEST_FEATURES queries if the
passed set of features is supported and it fails in case either driver
requests an unsupported feature or misses a feature that device requires.
Hence, it's more of a verification of feature set than applying/setting
them.
+
+ if (rc) {
+ dev_err(&vdev->dev, "%s: MCDI verify features error:%d\n",
+ __func__, rc);
+ goto err;
+ }
+
+ vdpa_nic->features = features;
+err:
+ mutex_unlock(&vdpa_nic->lock);
+ return rc;
+}
+
+static u64 ef100_vdpa_get_driver_features(struct vdpa_device *vdev)
+{
+ struct ef100_vdpa_nic *vdpa_nic = get_vdpa_nic(vdev);
+
+ return vdpa_nic->features;
+}
+
+static void ef100_vdpa_set_config_cb(struct vdpa_device *vdev,
+ struct vdpa_callback *cb)
+{
+ struct ef100_vdpa_nic *vdpa_nic = get_vdpa_nic(vdev);
+
+ if (cb)
+ vdpa_nic->cfg_cb = *cb;
+}
+
+static u16 ef100_vdpa_get_vq_num_max(struct vdpa_device *vdev)
+{
+ return EF100_VDPA_VQ_NUM_MAX_SIZE;
+}
+
+static u32 ef100_vdpa_get_device_id(struct vdpa_device *vdev)
+{
+ return EF100_VDPA_VIRTIO_NET_DEVICE_ID;
+}
+
+static u32 ef100_vdpa_get_vendor_id(struct vdpa_device *vdev)
+{
+ return EF100_VDPA_VENDOR_ID;
+}
+
+static size_t ef100_vdpa_get_config_size(struct vdpa_device *vdev)
+{
+ return sizeof(struct virtio_net_config);
+}
+
+static void ef100_vdpa_get_config(struct vdpa_device *vdev,
+ unsigned int offset,
+ void *buf, unsigned int len)
+{
+ struct ef100_vdpa_nic *vdpa_nic = get_vdpa_nic(vdev);
+
+ /* Avoid the possibility of wrap-up after the sum exceeds U32_MAX */
+ if (WARN_ON(((u64)offset + len) > sizeof(struct virtio_net_config))) {
+ dev_err(&vdev->dev,
+ "%s: Offset + len exceeds config size\n", __func__);
+ return;
I wonder if we need similar checks in the vdpa core.
Yes, it would be better to have this validation at one place (vdpa
framework) instead of individual vendor drivers. Although I am not sure
if the framework can choose the correct config size based on the device
class.
+ }
+ memcpy(buf, (u8 *)&vdpa_nic->net_config + offset, len);
+}
+
+static void ef100_vdpa_set_config(struct vdpa_device *vdev, unsigned int offset,
+ const void *buf, unsigned int len)
+{
+ struct ef100_vdpa_nic *vdpa_nic = get_vdpa_nic(vdev);
+
+ /* Avoid the possibility of wrap-up after the sum exceeds U32_MAX */
+ if (WARN_ON(((u64)offset + len) > sizeof(vdpa_nic->net_config))) {
+ dev_err(&vdev->dev,
+ "%s: Offset + len exceeds config size\n", __func__);
+ return;
+ }
+
+ memcpy((u8 *)&vdpa_nic->net_config + offset, buf, len);
+ if (is_valid_ether_addr(vdpa_nic->mac_address))
+ vdpa_nic->mac_configured = true;
Do we need to update hardware filters?
Yes, it's done in a later patch where filters support is added (sfc:
implement filters for receiving traffic).
Thanks
+}
+
static void ef100_vdpa_free(struct vdpa_device *vdev)
{
struct ef100_vdpa_nic *vdpa_nic = get_vdpa_nic(vdev);
@@ -24,5 +160,17 @@ static void ef100_vdpa_free(struct vdpa_device *vdev)
}
const struct vdpa_config_ops ef100_vdpa_config_ops = {
+ .get_vq_align = ef100_vdpa_get_vq_align,
+ .get_device_features = ef100_vdpa_get_device_features,
+ .set_driver_features = ef100_vdpa_set_driver_features,
+ .get_driver_features = ef100_vdpa_get_driver_features,
+ .set_config_cb = ef100_vdpa_set_config_cb,
+ .get_vq_num_max = ef100_vdpa_get_vq_num_max,
+ .get_device_id = ef100_vdpa_get_device_id,
+ .get_vendor_id = ef100_vdpa_get_vendor_id,
+ .get_config_size = ef100_vdpa_get_config_size,
+ .get_config = ef100_vdpa_get_config,
+ .set_config = ef100_vdpa_set_config,
+ .get_generation = NULL,
.free = ef100_vdpa_free,
};
--
2.30.1