[dpdk-dev] [PATCH 6/6] virtio: add virtio v1.0 support

Yuanhan Liu yuanhan.liu at linux.intel.com
Thu Dec 10 04:54:10 CET 2015


Modern (v1.0) virtio pci device defines several pci capabilities.
Each cap has a configure structure corresponding to it, and the
cap.bar and cap.offset fields tell us where to find it.

And thanks to the RTE_PCI_DRV_NEED_MAPPING, which already maps all
the bar space for us, we could easily locate to a cfg structure by:

    cfg_addr = dev->mem_resources[cap.bar].addr + cap.offset;

Therefore, the entrance of enabling modern (v1.0) pci device support
is to iterate the pci capability lists, and to locate some configs
we care; and they are:

- common cfg

  For generic virtio and virtuqueu configuration, such as setting/getting
  features, enabling a specific queue, and so on.

- nofity cfg

  Combining with `queue_notify_off' from common cfg, we could use it to
  notify a specific virt queue.

- device cfg

  Where virtio_net_config structure locates.

If any of above cap is not found, we fallback to the legacy virtio
handling.

If succeed, hw->vtpci_ops is assigned to modern_ops, where all
operations are implemented by reading/writing a (or few) specific
configuration space from above 3 cfg structures. And that's basically
how this patch works.

Besides those changes, virtio 1.0 introduces a new status field:
FEATURES_OK, which is set after features negotiation is done.

Last, set the VIRTIO_F_VERSION_1 feature flag.

Signed-off-by: Yuanhan Liu <yuanhan.liu at linux.intel.com>
---
 drivers/net/virtio/virtio_ethdev.c |  16 +-
 drivers/net/virtio/virtio_ethdev.h |   3 +-
 drivers/net/virtio/virtio_pci.c    | 313 ++++++++++++++++++++++++++++++++++++-
 drivers/net/virtio/virtio_pci.h    |  65 ++++++++
 drivers/net/virtio/virtqueue.h     |   2 +
 5 files changed, 395 insertions(+), 4 deletions(-)

diff --git a/drivers/net/virtio/virtio_ethdev.c b/drivers/net/virtio/virtio_ethdev.c
index 9847ed8..1f9de01 100644
--- a/drivers/net/virtio/virtio_ethdev.c
+++ b/drivers/net/virtio/virtio_ethdev.c
@@ -927,7 +927,7 @@ virtio_vlan_filter_set(struct rte_eth_dev *dev, uint16_t vlan_id, int on)
 	return virtio_send_command(hw->cvq, &ctrl, &len, 1);
 }
 
-static void
+static int
 virtio_negotiate_features(struct virtio_hw *hw)
 {
 	uint64_t host_features;
@@ -949,6 +949,17 @@ virtio_negotiate_features(struct virtio_hw *hw)
 	hw->guest_features = vtpci_negotiate_features(hw, host_features);
 	PMD_INIT_LOG(DEBUG, "features after negotiate = %"PRIx64,
 		hw->guest_features);
+
+	if (hw->modern) {
+		if (!vtpci_with_feature(hw, VIRTIO_F_VERSION_1)) {
+			PMD_INIT_LOG(ERR,
+				"VIRTIO_F_VERSION_1 features is not enabled");
+			return -1;
+		}
+		vtpci_set_status(hw, VIRTIO_CONFIG_STATUS_FEATURES_OK);
+	}
+
+	return 0;
 }
 
 /*
@@ -1032,7 +1043,8 @@ eth_virtio_dev_init(struct rte_eth_dev *eth_dev)
 
 	/* Tell the host we've known how to drive the device. */
 	vtpci_set_status(hw, VIRTIO_CONFIG_STATUS_DRIVER);
-	virtio_negotiate_features(hw);
+	if (virtio_negotiate_features(hw) < 0)
+		return -1;
 
 	/* If host does not support status then disable LSC */
 	if (!vtpci_with_feature(hw, VIRTIO_NET_F_STATUS))
diff --git a/drivers/net/virtio/virtio_ethdev.h b/drivers/net/virtio/virtio_ethdev.h
index ae2d47d..fed9571 100644
--- a/drivers/net/virtio/virtio_ethdev.h
+++ b/drivers/net/virtio/virtio_ethdev.h
@@ -64,7 +64,8 @@
 	 1u << VIRTIO_NET_F_CTRL_VQ	  |	\
 	 1u << VIRTIO_NET_F_CTRL_RX	  |	\
 	 1u << VIRTIO_NET_F_CTRL_VLAN	  |	\
-	 1u << VIRTIO_NET_F_MRG_RXBUF)
+	 1u << VIRTIO_NET_F_MRG_RXBUF	  |	\
+	 1ULL << VIRTIO_F_VERSION_1)
 
 /*
  * CQ function prototype
diff --git a/drivers/net/virtio/virtio_pci.c b/drivers/net/virtio/virtio_pci.c
index 26b0a0c..7862d7f 100644
--- a/drivers/net/virtio/virtio_pci.c
+++ b/drivers/net/virtio/virtio_pci.c
@@ -31,6 +31,7 @@
  *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 #include <stdint.h>
+#include <linux/pci_regs.h>
 
 #ifdef RTE_EXEC_ENV_LINUXAPP
  #include <dirent.h>
@@ -448,6 +449,205 @@ static const struct virtio_pci_ops legacy_ops = {
 };
 
 
+#define MODERN_READ_DEF(nr_bits, type)		\
+static inline type				\
+modern_read##nr_bits(type *addr)		\
+{						\
+	return *(volatile type *)addr;		\
+}
+
+#define MODERN_WRITE_DEF(nr_bits, type)		\
+static inline void				\
+modern_write##nr_bits(type val, type *addr)	\
+{						\
+	*(volatile type *)addr = val;		\
+}
+
+MODERN_READ_DEF (8, uint8_t)
+MODERN_WRITE_DEF(8, uint8_t)
+
+MODERN_READ_DEF (16, uint16_t)
+MODERN_WRITE_DEF(16, uint16_t)
+
+MODERN_READ_DEF (32, uint32_t)
+MODERN_WRITE_DEF(32, uint32_t)
+
+static inline void
+modern_write64_twopart(uint64_t val, uint32_t *lo, uint32_t *hi)
+{
+	modern_write32((uint32_t)val, lo);
+	modern_write32(val >> 32,     hi);
+}
+
+static void
+modern_read_dev_config(struct virtio_hw *hw, uint64_t offset,
+		       void *dst, int length)
+{
+	int i;
+	uint8_t *p;
+	uint8_t old_gen, new_gen;
+
+	do {
+		old_gen = modern_read8(&hw->common_cfg->config_generation);
+
+		p = dst;
+		for (i = 0;  i < length; i++)
+			*p++ = modern_read8((uint8_t *)hw->dev_cfg + offset + i);
+
+		new_gen = modern_read8(&hw->common_cfg->config_generation);
+	} while (old_gen != new_gen);
+}
+
+static void
+modern_write_dev_config(struct virtio_hw *hw, uint64_t offset,
+		        void *src, int length)
+{
+	int i;
+	uint8_t *p = src;
+
+	for (i = 0;  i < length; i++)
+		modern_write8(*p++, (uint8_t *)hw->dev_cfg + offset + i);
+}
+
+static uint64_t
+modern_get_features(struct virtio_hw *hw)
+{
+	uint32_t features_lo, features_hi;
+
+	modern_write32(0, &hw->common_cfg->device_feature_select);
+	features_lo = modern_read32(&hw->common_cfg->device_feature);
+
+	modern_write32(1, &hw->common_cfg->device_feature_select);
+	features_hi = modern_read32(&hw->common_cfg->device_feature);
+
+	return ((uint64_t)(features_hi) << 32) | features_lo;
+}
+
+static void
+modern_set_features(struct virtio_hw *hw, uint64_t features)
+{
+	modern_write32(0, &hw->common_cfg->guest_feature_select);
+	modern_write32(features & ((1ULL<<32) - 1),
+		&hw->common_cfg->guest_feature);
+
+	modern_write32(1, &hw->common_cfg->guest_feature_select);
+	modern_write32(features >> 32,
+		&hw->common_cfg->guest_feature);
+}
+
+static uint8_t
+modern_get_status(struct virtio_hw *hw)
+{
+	return modern_read8(&hw->common_cfg->device_status);
+}
+
+static void
+modern_set_status(struct virtio_hw *hw, uint8_t status)
+{
+	modern_write8(status, &hw->common_cfg->device_status);
+}
+
+static void
+modern_reset(struct virtio_hw *hw)
+{
+	modern_set_status(hw, VIRTIO_CONFIG_STATUS_RESET);
+	modern_get_status(hw);
+}
+
+static uint8_t
+modern_get_isr(struct virtio_hw *hw __rte_unused)
+{
+	/* FIXME: xxx */
+	return 0;
+}
+
+static uint16_t
+modern_set_irq(struct virtio_hw *hw __rte_unused, uint16_t vec __rte_unused)
+{
+	/* FIXME: xxx */
+	return 0;
+}
+
+static uint16_t
+modern_get_queue_num(struct virtio_hw *hw, uint16_t queue_id)
+{
+	modern_write16(queue_id, &hw->common_cfg->queue_select);
+	return modern_read16(&hw->common_cfg->queue_size);
+}
+
+static void
+modern_setup_queue(struct virtio_hw *hw, struct virtqueue *vq)
+{
+	uint64_t desc_addr, avail_addr, used_addr;
+	uint16_t notify_off;
+
+	desc_addr = vq->mz->phys_addr;
+	avail_addr = desc_addr + vq->vq_nentries * sizeof(struct vring_desc);
+	used_addr = RTE_ALIGN_CEIL(avail_addr + offsetof(struct vring_avail,
+							 ring[vq->vq_nentries]),
+				   VIRTIO_PCI_VRING_ALIGN);
+
+	modern_write16(vq->vq_queue_index, &hw->common_cfg->queue_select);
+
+	modern_write64_twopart(desc_addr, &hw->common_cfg->queue_desc_lo,
+					  &hw->common_cfg->queue_desc_hi);
+	modern_write64_twopart(avail_addr, &hw->common_cfg->queue_avail_lo,
+					   &hw->common_cfg->queue_avail_hi);
+	modern_write64_twopart(used_addr, &hw->common_cfg->queue_used_lo,
+					  &hw->common_cfg->queue_used_hi);
+
+	notify_off = modern_read16(&hw->common_cfg->queue_notify_off);
+	vq->notify_addr = (void *)((uint8_t *)hw->notify_base +
+				notify_off * hw->notify_off_multiplier);
+
+	modern_write16(1, &hw->common_cfg->queue_enable);
+
+	PMD_INIT_LOG(DEBUG, "queue %u addresses:", vq->vq_queue_index);
+	PMD_INIT_LOG(DEBUG, "\t desc_addr: %"PRIx64, desc_addr);
+	PMD_INIT_LOG(DEBUG, "\t aval_addr: %"PRIx64, avail_addr);
+	PMD_INIT_LOG(DEBUG, "\t used_addr: %"PRIx64, used_addr);
+	PMD_INIT_LOG(DEBUG, "\t notify addr: %p (notify offset: %u)",
+		vq->notify_addr, notify_off);
+}
+
+static void
+modern_del_queue(struct virtio_hw *hw, struct virtqueue *vq)
+{
+	modern_write16(vq->vq_queue_index, &hw->common_cfg->queue_select);
+
+	modern_write64_twopart(0, &hw->common_cfg->queue_desc_lo,
+				  &hw->common_cfg->queue_desc_hi);
+	modern_write64_twopart(0, &hw->common_cfg->queue_avail_lo,
+				  &hw->common_cfg->queue_avail_hi);
+	modern_write64_twopart(0, &hw->common_cfg->queue_used_lo,
+				  &hw->common_cfg->queue_used_hi);
+
+	modern_write16(0, &hw->common_cfg->queue_enable);
+}
+
+static void
+modern_notify_queue(struct virtio_hw *hw __rte_unused, struct virtqueue *vq)
+{
+	modern_write16(1, vq->notify_addr);
+}
+
+static const struct virtio_pci_ops modern_ops = {
+	.read_dev_cfg	= modern_read_dev_config,
+	.write_dev_cfg	= modern_write_dev_config,
+	.reset		= modern_reset,
+	.get_status	= modern_get_status,
+	.set_status	= modern_set_status,
+	.get_features	= modern_get_features,
+	.set_features	= modern_set_features,
+	.get_isr	= modern_get_isr,
+	.set_irq	= modern_set_irq,
+	.get_queue_num	= modern_get_queue_num,
+	.setup_queue	= modern_setup_queue,
+	.del_queue	= modern_del_queue,
+	.notify_queue	= modern_notify_queue,
+};
+
+
 void
 vtpci_read_dev_config(struct virtio_hw *hw, uint64_t offset,
 		      void *dst, int length)
@@ -514,15 +714,126 @@ vtpci_irq_config(struct virtio_hw *hw, uint16_t vec)
 	return hw->vtpci_ops->set_irq(hw, vec);
 }
 
+static inline void *
+get_cfg_addr(struct rte_pci_device *dev, struct virtio_pci_cap *cap)
+{
+	uint8_t  bar    = cap->bar;
+	uint32_t length = cap->length;
+	uint32_t offset = cap->offset;
+	uint8_t *base;
+
+	if (unlikely(bar > 5)) {
+		PMD_INIT_LOG(ERR, "invalid bar: %u", bar);
+		return NULL;
+	}
+
+	if (unlikely(offset + length > dev->mem_resource[bar].len)) {
+		PMD_INIT_LOG(ERR,
+			"invalid cap: overflows bar space: %u > %"PRIu64,
+			offset + length, dev->mem_resource[bar].len);
+		return NULL;
+	}
+
+	base = dev->mem_resource[bar].addr;
+	if (unlikely(base == NULL)) {
+		PMD_INIT_LOG(ERR, "bar %u base addr is NULL", bar);
+		return NULL;
+	}
+
+	return base + offset;
+}
+
+static int
+virtio_read_caps(struct rte_pci_device *dev, struct virtio_hw *hw)
+{
+	uint8_t pos;
+	struct virtio_pci_cap cap;
+	int ret;
+
+	ret = rte_eal_pci_read_config(dev, &pos, 1, PCI_CAPABILITY_LIST);
+	if (ret < 0) {
+		PMD_INIT_LOG(DEBUG, "failed to read pci capability list");
+		return -1;
+	}
+
+	while (pos) {
+		ret = rte_eal_pci_read_config(dev, &cap, sizeof(cap), pos);
+		if (ret < 0) {
+			PMD_INIT_LOG(ERR,
+				"failed to read pci cap at pos: %x", pos);
+			break;
+		}
+
+		if (cap.cap_vndr != PCI_CAP_ID_VNDR) {
+			PMD_INIT_LOG(DEBUG,
+				"[%2x] skipping non VNDR cap id: %02x",
+				pos, cap.cap_vndr);
+			goto next;
+		}
+
+		PMD_INIT_LOG(DEBUG,
+			"[%2x] cfg type: %u, bar: %u, offset: %04x, len: %u",
+			pos, cap.cfg_type, cap.bar, cap.offset, cap.length);
+
+		switch (cap.cfg_type) {
+		case VIRTIO_PCI_CAP_COMMON_CFG:
+			hw->common_cfg = get_cfg_addr(dev, &cap);
+			break;
+		case VIRTIO_PCI_CAP_NOTIFY_CFG:
+			rte_eal_pci_read_config(dev, &hw->notify_off_multiplier,
+						4, pos + sizeof(cap));
+			hw->notify_base = get_cfg_addr(dev, &cap);
+			break;
+		case VIRTIO_PCI_CAP_DEVICE_CFG:
+			hw->dev_cfg = get_cfg_addr(dev, &cap);
+			break;
+		}
+
+	next:
+		pos = cap.cap_next;
+	}
+
+	if (hw->common_cfg == NULL || hw->notify_base == NULL ||
+	    hw->dev_cfg == NULL) {
+		PMD_INIT_LOG(INFO, "no modern virtio pci device found.");
+		return -1;
+	}
+
+	PMD_INIT_LOG(INFO, "found modern virtio pci device.");
+
+	PMD_INIT_LOG(DEBUG, "common cfg mapped at: %p", hw->common_cfg);
+	PMD_INIT_LOG(DEBUG, "device cfg mapped at: %p", hw->dev_cfg);
+	PMD_INIT_LOG(DEBUG, "notify base: %p, notify off multiplier: %u",
+		hw->notify_base, hw->notify_off_multiplier);
+
+	return 0;
+}
+
 int
 vtpci_init(struct rte_pci_device *dev, struct virtio_hw *hw)
 {
-	hw->vtpci_ops = &legacy_ops;
+	hw->dev = dev;
 
+	/*
+	 * Try if we can succeed reading virtio pci caps, which exists
+	 * only on modern pci device. If failed, we fallback to legacy
+	 * virtio hanlding.
+	 */
+	if (virtio_read_caps(dev, hw) == 0) {
+		PMD_INIT_LOG(INFO, "moderen virtio pci detected.");
+		hw->vtpci_ops = &modern_ops;
+		hw->modern    = 1;
+		return 0;
+	}
+
+	PMD_INIT_LOG(INFO, "trying with legacy virtio pci.");
 	if (legacy_virtio_resource_init(dev) < 0)
 		return -1;
+
+	hw->vtpci_ops = &legacy_ops;
 	hw->use_msix = legacy_virtio_has_msix(&dev->addr);
 	hw->io_base  = (uint32_t)(uintptr_t)dev->mem_resource[0].addr;
+	hw->modern   = 0;
 
 	return 0;
 }
diff --git a/drivers/net/virtio/virtio_pci.h b/drivers/net/virtio/virtio_pci.h
index 0900cd0..8ff51d2 100644
--- a/drivers/net/virtio/virtio_pci.h
+++ b/drivers/net/virtio/virtio_pci.h
@@ -93,6 +93,7 @@ struct virtqueue;
 #define VIRTIO_CONFIG_STATUS_ACK       0x01
 #define VIRTIO_CONFIG_STATUS_DRIVER    0x02
 #define VIRTIO_CONFIG_STATUS_DRIVER_OK 0x04
+#define VIRTIO_CONFIG_STATUS_FEATURES_OK 0x08
 #define VIRTIO_CONFIG_STATUS_FAILED    0x80
 
 /*
@@ -141,6 +142,8 @@ struct virtqueue;
 /* We support indirect buffer descriptors */
 #define VIRTIO_RING_F_INDIRECT_DESC	28
 
+#define VIRTIO_F_VERSION_1		32
+
 /*
  * Some VirtIO feature bits (currently bits 28 through 31) are
  * reserved for the transport being used (eg. virtio_ring), the
@@ -163,6 +166,60 @@ struct virtqueue;
  */
 #define VIRTIO_MAX_VIRTQUEUES 8
 
+/* Common configuration */
+#define VIRTIO_PCI_CAP_COMMON_CFG	1
+/* Notifications */
+#define VIRTIO_PCI_CAP_NOTIFY_CFG	2
+/* ISR Status */
+#define VIRTIO_PCI_CAP_ISR_CFG		3
+/* Device specific configuration */
+#define VIRTIO_PCI_CAP_DEVICE_CFG	4
+/* PCI configuration access */
+#define VIRTIO_PCI_CAP_PCI_CFG		5
+
+/* This is the PCI capability header: */
+struct virtio_pci_cap {
+	uint8_t cap_vndr;		/* Generic PCI field: PCI_CAP_ID_VNDR */
+	uint8_t cap_next;		/* Generic PCI field: next ptr. */
+	uint8_t cap_len;		/* Generic PCI field: capability length */
+	uint8_t cfg_type;		/* Identifies the structure. */
+	uint8_t bar;			/* Where to find it. */
+	uint8_t padding[3];		/* Pad to full dword. */
+	uint32_t offset;		/* Offset within bar. */
+	uint32_t length;		/* Length of the structure, in bytes. */
+};
+
+struct virtio_pci_notify_cap {
+	struct virtio_pci_cap cap;
+	uint32_t notify_off_multiplier;	/* Multiplier for queue_notify_off. */
+};
+
+/* Fields in VIRTIO_PCI_CAP_COMMON_CFG: */
+struct virtio_pci_common_cfg {
+	/* About the whole device. */
+	uint32_t device_feature_select;	/* read-write */
+	uint32_t device_feature;	/* read-only */
+	uint32_t guest_feature_select;	/* read-write */
+	uint32_t guest_feature;		/* read-write */
+	uint16_t msix_config;		/* read-write */
+	uint16_t num_queues;		/* read-only */
+	uint8_t device_status;		/* read-write */
+	uint8_t config_generation;	/* read-only */
+
+	/* About a specific virtqueue. */
+	uint16_t queue_select;		/* read-write */
+	uint16_t queue_size;		/* read-write, power of 2. */
+	uint16_t queue_msix_vector;	/* read-write */
+	uint16_t queue_enable;		/* read-write */
+	uint16_t queue_notify_off;	/* read-only */
+	uint32_t queue_desc_lo;		/* read-write */
+	uint32_t queue_desc_hi;		/* read-write */
+	uint32_t queue_avail_lo;	/* read-write */
+	uint32_t queue_avail_hi;	/* read-write */
+	uint32_t queue_used_lo;		/* read-write */
+	uint32_t queue_used_hi;		/* read-write */
+};
+
 struct virtio_hw;
 
 struct virtio_pci_ops {
@@ -188,6 +245,8 @@ struct virtio_pci_ops {
 	void (*notify_queue)(struct virtio_hw *hw, struct virtqueue *vq);
 };
 
+struct virtio_net_config;
+
 struct virtio_hw {
 	struct virtqueue *cvq;
 	uint32_t    io_base;
@@ -198,7 +257,13 @@ struct virtio_hw {
 	uint8_t	    vlan_strip;
 	uint8_t	    use_msix;
 	uint8_t     started;
+	uint8_t     modern;
 	uint8_t     mac_addr[ETHER_ADDR_LEN];
+	uint32_t    notify_off_multiplier;
+	uint16_t    *notify_base;
+	struct rte_pci_device *dev;
+	struct virtio_pci_common_cfg *common_cfg;
+	struct virtio_net_config *dev_cfg;
 	const struct virtio_pci_ops *vtpci_ops;
 };
 
diff --git a/drivers/net/virtio/virtqueue.h b/drivers/net/virtio/virtqueue.h
index d7fb450..99d4fa9 100644
--- a/drivers/net/virtio/virtqueue.h
+++ b/drivers/net/virtio/virtqueue.h
@@ -202,6 +202,8 @@ struct virtqueue {
 	/* Size bins in array as RFC 2819, undersized [0], 64 [1], etc */
 	uint64_t	size_bins[8];
 
+	uint16_t	*notify_addr;
+
 	struct vq_desc_extra {
 		void              *cookie;
 		uint16_t          ndescs;
-- 
1.9.0



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