[dpdk-dev] [PATCH 4/5] virtio: clarify feature bit handling

[Stephen Hemminger <stephen@networkplumber.org>]

From: Stephen Hemminger <shemming@brocade.com>

Change the features from bit mask to bit number. This allows the
DPDK driver to use the definitions from Linux (yes the header
files already use a license compatiable with DPDK). This makes DPDK
driver handle future feature bit changes.

Get rid of double negative code in the feature bit intialization.
Instead just have a new define with the list of feature bits implemented.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
 drivers/net/virtio/virtio_ethdev.c | 17 +------
 drivers/net/virtio/virtio_ethdev.h | 27 ++++-------
 drivers/net/virtio/virtio_pci.h    | 96 +++++++++++++++++++-------------------
 drivers/net/virtio/virtqueue.h     |  8 +---
 4 files changed, 61 insertions(+), 87 deletions(-)

diff --git a/drivers/net/virtio/virtio_ethdev.c b/drivers/net/virtio/virtio_ethdev.c
index ad49fc1..2afa371 100644
--- a/drivers/net/virtio/virtio_ethdev.c
+++ b/drivers/net/virtio/virtio_ethdev.c
@@ -799,23 +799,10 @@ virtio_vlan_filter_set(struct rte_eth_dev *dev, uint16_t vlan_id, int on)
 static void
 virtio_negotiate_features(struct virtio_hw *hw)
 {
-	uint32_t host_features, mask;
-
-	/* checksum offload not implemented */
-	mask = VIRTIO_NET_F_CSUM | VIRTIO_NET_F_GUEST_CSUM;
-
-	/* TSO and LRO are only available when their corresponding
-	 * checksum offload feature is also negotiated.
-	 */
-	mask |= VIRTIO_NET_F_HOST_TSO4 | VIRTIO_NET_F_HOST_TSO6 | VIRTIO_NET_F_HOST_ECN;
-	mask |= VIRTIO_NET_F_GUEST_TSO4 | VIRTIO_NET_F_GUEST_TSO6 | VIRTIO_NET_F_GUEST_ECN;
-	mask |= VTNET_LRO_FEATURES;
-
-	/* not negotiating INDIRECT descriptor table support */
-	mask |= VIRTIO_RING_F_INDIRECT_DESC;
+	uint32_t host_features;
 
 	/* Prepare guest_features: feature that driver wants to support */
-	hw->guest_features = VTNET_FEATURES & ~mask;
+	hw->guest_features = VIRTIO_PMD_GUEST_FEATURES;
 	PMD_INIT_LOG(DEBUG, "guest_features before negotiate = %x",
 		hw->guest_features);
 
diff --git a/drivers/net/virtio/virtio_ethdev.h b/drivers/net/virtio/virtio_ethdev.h
index e6d4533..df2cb7d 100644
--- a/drivers/net/virtio/virtio_ethdev.h
+++ b/drivers/net/virtio/virtio_ethdev.h
@@ -56,24 +56,15 @@
 #define VIRTIO_MAX_RX_PKTLEN  9728
 
 /* Features desired/implemented by this driver. */
-#define VTNET_FEATURES \
-	(VIRTIO_NET_F_MAC       | \
-	VIRTIO_NET_F_STATUS     | \
-	VIRTIO_NET_F_MQ         | \
-	VIRTIO_NET_F_CTRL_MAC_ADDR | \
-	VIRTIO_NET_F_CTRL_VQ    | \
-	VIRTIO_NET_F_CTRL_RX    | \
-	VIRTIO_NET_F_CTRL_VLAN  | \
-	VIRTIO_NET_F_CSUM       | \
-	VIRTIO_NET_F_HOST_TSO4  | \
-	VIRTIO_NET_F_HOST_TSO6  | \
-	VIRTIO_NET_F_HOST_ECN   | \
-	VIRTIO_NET_F_GUEST_CSUM | \
-	VIRTIO_NET_F_GUEST_TSO4 | \
-	VIRTIO_NET_F_GUEST_TSO6 | \
-	VIRTIO_NET_F_GUEST_ECN  | \
-	VIRTIO_NET_F_MRG_RXBUF  | \
-	VIRTIO_RING_F_INDIRECT_DESC)
+#define VIRTIO_PMD_GUEST_FEATURES		\
+	(1u << VIRTIO_NET_F_MAC		  |	\
+	 1u << VIRTIO_NET_F_STATUS	  |	\
+	 1u << VIRTIO_NET_F_MQ		  |	\
+	 1u << VIRTIO_NET_F_CTRL_MAC_ADDR |	\
+	 1u << VIRTIO_NET_F_CTRL_VQ	  |	\
+	 1u << VIRTIO_NET_F_CTRL_RX	  |	\
+	 1u << VIRTIO_NET_F_CTRL_VLAN	  |	\
+	 1u << VIRTIO_NET_F_MRG_RXBUF)
 
 /*
  * CQ function prototype
diff --git a/drivers/net/virtio/virtio_pci.h b/drivers/net/virtio/virtio_pci.h
index 64d9c34..47f722a 100644
--- a/drivers/net/virtio/virtio_pci.h
+++ b/drivers/net/virtio/virtio_pci.h
@@ -96,26 +96,6 @@ struct virtqueue;
 #define VIRTIO_CONFIG_STATUS_FAILED    0x80
 
 /*
- * Generate interrupt when the virtqueue ring is
- * completely used, even if we've suppressed them.
- */
-#define VIRTIO_F_NOTIFY_ON_EMPTY (1 << 24)
-
-/*
- * The guest should never negotiate this feature; it
- * is used to detect faulty drivers.
- */
-#define VIRTIO_F_BAD_FEATURE (1 << 30)
-
-/*
- * Some VirtIO feature bits (currently bits 28 through 31) are
- * reserved for the transport being used (eg. virtio_ring), the
- * rest are per-device feature bits.
- */
-#define VIRTIO_TRANSPORT_F_START 28
-#define VIRTIO_TRANSPORT_F_END   32
-
-/*
  * Each virtqueue indirect descriptor list must be physically contiguous.
  * To allow us to malloc(9) each list individually, limit the number
  * supported to what will fit in one page. With 4KB pages, this is a limit
@@ -128,33 +108,55 @@ struct virtqueue;
 #define VIRTIO_MAX_INDIRECT ((int) (PAGE_SIZE / 16))
 
 /* The feature bitmap for virtio net */
-#define VIRTIO_NET_F_CSUM       0x00001 /* Host handles pkts w/ partial csum */
-#define VIRTIO_NET_F_GUEST_CSUM 0x00002 /* Guest handles pkts w/ partial csum*/
-#define VIRTIO_NET_F_MAC        0x00020 /* Host has given MAC address. */
-#define VIRTIO_NET_F_GSO        0x00040 /* Host handles pkts w/ any GSO type */
-#define VIRTIO_NET_F_GUEST_TSO4 0x00080 /* Guest can handle TSOv4 in. */
-#define VIRTIO_NET_F_GUEST_TSO6 0x00100 /* Guest can handle TSOv6 in. */
-#define VIRTIO_NET_F_GUEST_ECN  0x00200 /* Guest can handle TSO[6] w/ ECN in.*/
-#define VIRTIO_NET_F_GUEST_UFO  0x00400 /* Guest can handle UFO in. */
-#define VIRTIO_NET_F_HOST_TSO4  0x00800 /* Host can handle TSOv4 in. */
-#define VIRTIO_NET_F_HOST_TSO6  0x01000 /* Host can handle TSOv6 in. */
-#define VIRTIO_NET_F_HOST_ECN   0x02000 /* Host can handle TSO[6] w/ ECN in. */
-#define VIRTIO_NET_F_HOST_UFO   0x04000 /* Host can handle UFO in. */
-#define VIRTIO_NET_F_MRG_RXBUF  0x08000 /* Host can merge receive buffers. */
-#define VIRTIO_NET_F_STATUS     0x10000 /* virtio_net_config.status available*/
-#define VIRTIO_NET_F_CTRL_VQ    0x20000 /* Control channel available */
-#define VIRTIO_NET_F_CTRL_RX    0x40000 /* Control channel RX mode support */
-#define VIRTIO_NET_F_CTRL_VLAN  0x80000 /* Control channel VLAN filtering */
-#define VIRTIO_NET_F_CTRL_RX_EXTRA  0x100000 /* Extra RX mode control support */
-#define VIRTIO_RING_F_INDIRECT_DESC 0x10000000 /* Support for indirect buffer descriptors. */
-/* The guest publishes the used index for which it expects an interrupt
- * at the end of the avail ring. Host should ignore the avail->flags field.
- * The host publishes the avail index for which it expects a kick
- * at the end of the used ring. Guest should ignore the used->flags field.
+#define VIRTIO_NET_F_CSUM	0	/* Host handles pkts w/ partial csum */
+#define VIRTIO_NET_F_GUEST_CSUM	1	/* Guest handles pkts w/ partial csum */
+#define VIRTIO_NET_F_MAC	5	/* Host has given MAC address. */
+#define VIRTIO_NET_F_GUEST_TSO4	7	/* Guest can handle TSOv4 in. */
+#define VIRTIO_NET_F_GUEST_TSO6	8	/* Guest can handle TSOv6 in. */
+#define VIRTIO_NET_F_GUEST_ECN	9	/* Guest can handle TSO[6] w/ ECN in. */
+#define VIRTIO_NET_F_GUEST_UFO	10	/* Guest can handle UFO in. */
+#define VIRTIO_NET_F_HOST_TSO4	11	/* Host can handle TSOv4 in. */
+#define VIRTIO_NET_F_HOST_TSO6	12	/* Host can handle TSOv6 in. */
+#define VIRTIO_NET_F_HOST_ECN	13	/* Host can handle TSO[6] w/ ECN in. */
+#define VIRTIO_NET_F_HOST_UFO	14	/* Host can handle UFO in. */
+#define VIRTIO_NET_F_MRG_RXBUF	15	/* Host can merge receive buffers. */
+#define VIRTIO_NET_F_STATUS	16	/* virtio_net_config.status available */
+#define VIRTIO_NET_F_CTRL_VQ	17	/* Control channel available */
+#define VIRTIO_NET_F_CTRL_RX	18	/* Control channel RX mode support */
+#define VIRTIO_NET_F_CTRL_VLAN	19	/* Control channel VLAN filtering */
+#define VIRTIO_NET_F_CTRL_RX_EXTRA 20	/* Extra RX mode control support */
+#define VIRTIO_NET_F_GUEST_ANNOUNCE 21	/* Guest can announce device on the
+					 * network */
+#define VIRTIO_NET_F_MQ		22	/* Device supports Receive Flow
+					 * Steering */
+#define VIRTIO_NET_F_CTRL_MAC_ADDR 23	/* Set MAC address */
+
+/* Do we get callbacks when the ring is completely used, even if we've
+ * suppressed them? */
+#define VIRTIO_F_NOTIFY_ON_EMPTY	24
+
+/* Can the device handle any descriptor layout? */
+#define VIRTIO_F_ANY_LAYOUT		27
+
+/* We support indirect buffer descriptors */
+#define VIRTIO_RING_F_INDIRECT_DESC	28
+
+/*
+ * Some VirtIO feature bits (currently bits 28 through 31) are
+ * reserved for the transport being used (eg. virtio_ring), the
+ * rest are per-device feature bits.
  */
-#define VIRTIO_RING_F_EVENT_IDX 0x20000000
+#define VIRTIO_TRANSPORT_F_START 28
+#define VIRTIO_TRANSPORT_F_END   32
+
+/* The Guest publishes the used index for which it expects an interrupt
+ * at the end of the avail ring. Host should ignore the avail->flags field. */
+/* The Host publishes the avail index for which it expects a kick
+ * at the end of the used ring. Guest should ignore the used->flags field. */
+#define VIRTIO_RING_F_EVENT_IDX		29
 
-#define VIRTIO_NET_S_LINK_UP 1 /* Link is up */
+#define VIRTIO_NET_S_LINK_UP	1	/* Link is up */
+#define VIRTIO_NET_S_ANNOUNCE	2	/* Announcement is needed */
 
 /*
  * Maximum number of virtqueues per device.
@@ -243,9 +245,9 @@ outl_p(unsigned int data, unsigned int port)
 	outl_p((unsigned int)(value), (VIRTIO_PCI_REG_ADDR((hw), (reg))))
 
 static inline int
-vtpci_with_feature(struct virtio_hw *hw, uint32_t feature)
+vtpci_with_feature(struct virtio_hw *hw, uint32_t bit)
 {
-	return (hw->guest_features & feature) != 0;
+	return (hw->guest_features & (1u << bit)) != 0;
 }
 
 /*
diff --git a/drivers/net/virtio/virtqueue.h b/drivers/net/virtio/virtqueue.h
index 9d6079e..7789411 100644
--- a/drivers/net/virtio/virtqueue.h
+++ b/drivers/net/virtio/virtqueue.h
@@ -202,18 +202,12 @@ struct virtqueue {
 };
 
 /* If multiqueue is provided by host, then we suppport it. */
-#ifndef VIRTIO_NET_F_MQ
-/* Device supports Receive Flow Steering */
-#define VIRTIO_NET_F_MQ 0x400000
 #define VIRTIO_NET_CTRL_MQ   4
 #define VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET        0
 #define VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MIN        1
 #define VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MAX        0x8000
-#endif
-#ifndef VIRTIO_NET_F_CTRL_MAC_ADDR
-#define VIRTIO_NET_F_CTRL_MAC_ADDR 0x800000
+
 #define VIRTIO_NET_CTRL_MAC_ADDR_SET         1
-#endif
 
 /**
  * This is the first element of the scatter-gather list.  If you don't
-- 
2.1.4