Merge branch 'gve-alternate-missed-completions'

Jeroen de Borst says:

====================
gve: Handle alternate miss-completions

Some versions of the virtual NIC present miss-completions in
an alternative way. Let the diver handle these alternate completions
and announce this capability to the device.

The capability is announced uing a new AdminQ command that sends
driver information to the device. The device can refuse a driver
if it is lacking support for a capability, or it can adopt it's
behavior to work around OS specific issues.

Changed in v5:
- Removed comments in fucntion calls
- Switched ENOTSUPP back to EOPNOTSUPP and made sure it gets passed
Changed in v4:
- Clarified new AdminQ command in cover letter
- Changed EOPNOTSUPP to ENOTSUPP to match device's response
Changed in v3:
- Rewording cover letter
- Added 'Reviewed-by: Jesse Brandeburg <jesse.brandeburg@intel.com>'
Changes in v2:
- Changed the subject to include 'gve:'
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/google/gve/gve.h

@@ -563,6 +563,7 @@ struct gve_priv {
 	u32 adminq_report_stats_cnt;
 	u32 adminq_report_link_speed_cnt;
 	u32 adminq_get_ptype_map_cnt;
+	u32 adminq_verify_driver_compatibility_cnt;
 
 	/* Global stats */
 	u32 interface_up_cnt; /* count of times interface turned up since last reset */

drivers/net/ethernet/google/gve/gve_adminq.c

@@ -289,7 +289,7 @@ static int gve_adminq_parse_err(struct gve_priv *priv, u32 status)
 	case GVE_ADMINQ_COMMAND_ERROR_RESOURCE_EXHAUSTED:
 		return -ENOMEM;
 	case GVE_ADMINQ_COMMAND_ERROR_UNIMPLEMENTED:
-		return -ENOTSUPP;
+		return -EOPNOTSUPP;
 	default:
 		dev_err(&priv->pdev->dev, "parse_aq_err: unknown status code %d\n", status);
 		return -EINVAL;
@@ -407,6 +407,9 @@ static int gve_adminq_issue_cmd(struct gve_priv *priv,
 	case GVE_ADMINQ_GET_PTYPE_MAP:
 		priv->adminq_get_ptype_map_cnt++;
 		break;
+	case GVE_ADMINQ_VERIFY_DRIVER_COMPATIBILITY:
+		priv->adminq_verify_driver_compatibility_cnt++;
+		break;
 	default:
 		dev_err(&priv->pdev->dev, "unknown AQ command opcode %d\n", opcode);
 	}
@@ -878,6 +881,22 @@ int gve_adminq_report_stats(struct gve_priv *priv, u64 stats_report_len,
 	return gve_adminq_execute_cmd(priv, &cmd);
 }
 
+int gve_adminq_verify_driver_compatibility(struct gve_priv *priv,
+					   u64 driver_info_len,
+					   dma_addr_t driver_info_addr)
+{
+	union gve_adminq_command cmd;
+
+	memset(&cmd, 0, sizeof(cmd));
+	cmd.opcode = cpu_to_be32(GVE_ADMINQ_VERIFY_DRIVER_COMPATIBILITY);
+	cmd.verify_driver_compatibility = (struct gve_adminq_verify_driver_compatibility) {
+		.driver_info_len = cpu_to_be64(driver_info_len),
+		.driver_info_addr = cpu_to_be64(driver_info_addr),
+	};
+
+	return gve_adminq_execute_cmd(priv, &cmd);
+}
+
 int gve_adminq_report_link_speed(struct gve_priv *priv)
 {
 	union gve_adminq_command gvnic_cmd;

drivers/net/ethernet/google/gve/gve_adminq.h

@@ -24,6 +24,7 @@ enum gve_adminq_opcodes {
 	GVE_ADMINQ_REPORT_STATS			= 0xC,
 	GVE_ADMINQ_REPORT_LINK_SPEED		= 0xD,
 	GVE_ADMINQ_GET_PTYPE_MAP		= 0xE,
+	GVE_ADMINQ_VERIFY_DRIVER_COMPATIBILITY	= 0xF,
 };
 
 /* Admin queue status codes */
@@ -146,6 +147,51 @@ enum gve_sup_feature_mask {
 
 #define GVE_DEV_OPT_LEN_GQI_RAW_ADDRESSING 0x0
 
+#define GVE_VERSION_STR_LEN 128
+
+enum gve_driver_capbility {
+	gve_driver_capability_gqi_qpl = 0,
+	gve_driver_capability_gqi_rda = 1,
+	gve_driver_capability_dqo_qpl = 2, /* reserved for future use */
+	gve_driver_capability_dqo_rda = 3,
+	gve_driver_capability_alt_miss_compl = 4,
+};
+
+#define GVE_CAP1(a) BIT((int)a)
+#define GVE_CAP2(a) BIT(((int)a) - 64)
+#define GVE_CAP3(a) BIT(((int)a) - 128)
+#define GVE_CAP4(a) BIT(((int)a) - 192)
+
+#define GVE_DRIVER_CAPABILITY_FLAGS1 \
+	(GVE_CAP1(gve_driver_capability_gqi_qpl) | \
+	 GVE_CAP1(gve_driver_capability_gqi_rda) | \
+	 GVE_CAP1(gve_driver_capability_dqo_rda) | \
+	 GVE_CAP1(gve_driver_capability_alt_miss_compl))
+
+#define GVE_DRIVER_CAPABILITY_FLAGS2 0x0
+#define GVE_DRIVER_CAPABILITY_FLAGS3 0x0
+#define GVE_DRIVER_CAPABILITY_FLAGS4 0x0
+
+struct gve_driver_info {
+	u8 os_type;	/* 0x01 = Linux */
+	u8 driver_major;
+	u8 driver_minor;
+	u8 driver_sub;
+	__be32 os_version_major;
+	__be32 os_version_minor;
+	__be32 os_version_sub;
+	__be64 driver_capability_flags[4];
+	u8 os_version_str1[GVE_VERSION_STR_LEN];
+	u8 os_version_str2[GVE_VERSION_STR_LEN];
+};
+
+struct gve_adminq_verify_driver_compatibility {
+	__be64 driver_info_len;
+	__be64 driver_info_addr;
+};
+
+static_assert(sizeof(struct gve_adminq_verify_driver_compatibility) == 16);
+
 struct gve_adminq_configure_device_resources {
 	__be64 counter_array;
 	__be64 irq_db_addr;
@@ -345,6 +391,8 @@ union gve_adminq_command {
 			struct gve_adminq_report_stats report_stats;
 			struct gve_adminq_report_link_speed report_link_speed;
 			struct gve_adminq_get_ptype_map get_ptype_map;
+			struct gve_adminq_verify_driver_compatibility
+						verify_driver_compatibility;
 		};
 	};
 	u8 reserved[64];
@@ -372,6 +420,9 @@ int gve_adminq_unregister_page_list(struct gve_priv *priv, u32 page_list_id);
 int gve_adminq_set_mtu(struct gve_priv *priv, u64 mtu);
 int gve_adminq_report_stats(struct gve_priv *priv, u64 stats_report_len,
 			    dma_addr_t stats_report_addr, u64 interval);
+int gve_adminq_verify_driver_compatibility(struct gve_priv *priv,
+					   u64 driver_info_len,
+					   dma_addr_t driver_info_addr);
 int gve_adminq_report_link_speed(struct gve_priv *priv);
 
 struct gve_ptype_lut;

drivers/net/ethernet/google/gve/gve_desc_dqo.h

@@ -176,6 +176,11 @@ static_assert(sizeof(struct gve_tx_compl_desc) == 8);
 #define GVE_COMPL_TYPE_DQO_MISS 0x1 /* Miss path completion */
 #define GVE_COMPL_TYPE_DQO_REINJECTION 0x3 /* Re-injection completion */
 
+/* The most significant bit in the completion tag can change the completion
+ * type from packet completion to miss path completion.
+ */
+#define GVE_ALT_MISS_COMPL_BIT BIT(15)
+
 /* Descriptor to post buffers to HW on buffer queue. */
 struct gve_rx_desc_dqo {
 	__le16 buf_id; /* ID returned in Rx completion descriptor */

drivers/net/ethernet/google/gve/gve_main.c

@@ -12,6 +12,8 @@
 #include <linux/sched.h>
 #include <linux/timer.h>
 #include <linux/workqueue.h>
+#include <linux/utsname.h>
+#include <linux/version.h>
 #include <net/sch_generic.h>
 #include "gve.h"
 #include "gve_dqo.h"
@@ -30,6 +32,49 @@
 const char gve_version_str[] = GVE_VERSION;
 static const char gve_version_prefix[] = GVE_VERSION_PREFIX;
 
+static int gve_verify_driver_compatibility(struct gve_priv *priv)
+{
+	int err;
+	struct gve_driver_info *driver_info;
+	dma_addr_t driver_info_bus;
+
+	driver_info = dma_alloc_coherent(&priv->pdev->dev,
+					 sizeof(struct gve_driver_info),
+					 &driver_info_bus, GFP_KERNEL);
+	if (!driver_info)
+		return -ENOMEM;
+
+	*driver_info = (struct gve_driver_info) {
+		.os_type = 1, /* Linux */
+		.os_version_major = cpu_to_be32(LINUX_VERSION_MAJOR),
+		.os_version_minor = cpu_to_be32(LINUX_VERSION_SUBLEVEL),
+		.os_version_sub = cpu_to_be32(LINUX_VERSION_PATCHLEVEL),
+		.driver_capability_flags = {
+			cpu_to_be64(GVE_DRIVER_CAPABILITY_FLAGS1),
+			cpu_to_be64(GVE_DRIVER_CAPABILITY_FLAGS2),
+			cpu_to_be64(GVE_DRIVER_CAPABILITY_FLAGS3),
+			cpu_to_be64(GVE_DRIVER_CAPABILITY_FLAGS4),
+		},
+	};
+	strscpy(driver_info->os_version_str1, utsname()->release,
+		sizeof(driver_info->os_version_str1));
+	strscpy(driver_info->os_version_str2, utsname()->version,
+		sizeof(driver_info->os_version_str2));
+
+	err = gve_adminq_verify_driver_compatibility(priv,
+						     sizeof(struct gve_driver_info),
+						     driver_info_bus);
+
+	/* It's ok if the device doesn't support this */
+	if (err == -EOPNOTSUPP)
+		err = 0;
+
+	dma_free_coherent(&priv->pdev->dev,
+			  sizeof(struct gve_driver_info),
+			  driver_info, driver_info_bus);
+	return err;
+}
+
 static netdev_tx_t gve_start_xmit(struct sk_buff *skb, struct net_device *dev)
 {
 	struct gve_priv *priv = netdev_priv(dev);
@@ -1368,6 +1413,13 @@ static int gve_init_priv(struct gve_priv *priv, bool skip_describe_device)
 		return err;
 	}
 
+	err = gve_verify_driver_compatibility(priv);
+	if (err) {
+		dev_err(&priv->pdev->dev,
+			"Could not verify driver compatibility: err=%d\n", err);
+		goto err;
+	}
+
 	if (skip_describe_device)
 		goto setup_device;
 

drivers/net/ethernet/google/gve/gve_tx_dqo.c

@@ -953,12 +953,18 @@ int gve_clean_tx_done_dqo(struct gve_priv *priv, struct gve_tx_ring *tx,
 			atomic_set_release(&tx->dqo_compl.hw_tx_head, tx_head);
 		} else if (type == GVE_COMPL_TYPE_DQO_PKT) {
 			u16 compl_tag = le16_to_cpu(compl_desc->completion_tag);
-
+			if (compl_tag & GVE_ALT_MISS_COMPL_BIT) {
+				compl_tag &= ~GVE_ALT_MISS_COMPL_BIT;
+				gve_handle_miss_completion(priv, tx, compl_tag,
+							   &miss_compl_bytes,
+							   &miss_compl_pkts);
+			} else {
 				gve_handle_packet_completion(priv, tx, !!napi,
 							     compl_tag,
 							     &pkt_compl_bytes,
 							     &pkt_compl_pkts,
-						     /*is_reinjection=*/false);
+							     false);
+			}
 		} else if (type == GVE_COMPL_TYPE_DQO_MISS) {
 			u16 compl_tag = le16_to_cpu(compl_desc->completion_tag);
 
@@ -972,7 +978,7 @@ int gve_clean_tx_done_dqo(struct gve_priv *priv, struct gve_tx_ring *tx,
 						     compl_tag,
 						     &reinject_compl_bytes,
 						     &reinject_compl_pkts,
-						     /*is_reinjection=*/true);
+						     true);
 		}
 
 		tx->dqo_compl.head =