Commit 1fcf0512 authored by Michael S. Tsirkin's avatar Michael S. Tsirkin Committed by Rusty Russell
Browse files

virtio_pci: modern driver 



Lightly tested against qemu.

One thing *not* implemented here is separate mappings
for descriptor/avail/used rings. That's nice to have,
will be done later after we have core support.

This also exposes the PCI layout to userspace, and
adds macros for PCI layout offsets:

QEMU wants it, so why not?  Trust, but verify.

Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent 71d70c26

drivers/virtio/Makefile

+1 −1
Original line number Diff line number Diff line 
obj-$(CONFIG_VIRTIO) += virtio.o virtio_ring.o

obj-$(CONFIG_VIRTIO_MMIO) += virtio_mmio.o

obj-$(CONFIG_VIRTIO_PCI) += virtio_pci.o

virtio_pci-y := virtio_pci_legacy.o virtio_pci_common.o

virtio_pci-y := virtio_pci_modern.o virtio_pci_legacy.o virtio_pci_common.o

obj-$(CONFIG_VIRTIO_BALLOON) += virtio_balloon.o

drivers/virtio/virtio_pci_common.c

+11 −3
Original line number Diff line number Diff line
@@ -505,6 +505,8 @@ static int virtio_pci_probe(struct pci_dev *pci_dev, 
	if (rc)

		goto err_request_regions;



	rc = virtio_pci_modern_probe(vp_dev);

	if (rc == -ENODEV)

		rc = virtio_pci_legacy_probe(vp_dev);

	if (rc)

		goto err_probe;
@@ -518,7 +520,10 @@ static int virtio_pci_probe(struct pci_dev *pci_dev, 
	return 0;



err_register:

	if (vp_dev->ioaddr)

	     virtio_pci_legacy_remove(vp_dev);

	else

	     virtio_pci_modern_remove(vp_dev);

err_probe:

	pci_release_regions(pci_dev);

err_request_regions:
@@ -534,7 +539,10 @@ static void virtio_pci_remove(struct pci_dev *pci_dev) 


	unregister_virtio_device(&vp_dev->vdev);



	virtio_pci_legacy_remove(pci_dev);

	if (vp_dev->ioaddr)

		virtio_pci_legacy_remove(vp_dev);

	else

		virtio_pci_modern_remove(vp_dev);



	pci_release_regions(pci_dev);

	pci_disable_device(pci_dev);

drivers/virtio/virtio_pci_common.h

+22 −3
Original line number Diff line number Diff line
@@ -53,12 +53,29 @@ struct virtio_pci_device { 
	struct virtio_device vdev;

	struct pci_dev *pci_dev;



	/* In legacy mode, these two point to within ->legacy. */

	/* Where to read and clear interrupt */

	u8 __iomem *isr;



	/* Modern only fields */

	/* The IO mapping for the PCI config space (non-legacy mode) */

	struct virtio_pci_common_cfg __iomem *common;

	/* Device-specific data (non-legacy mode)  */

	void __iomem *device;



	/* So we can sanity-check accesses. */

	size_t device_len;



	/* Capability for when we need to map notifications per-vq. */

	int notify_map_cap;



	/* Multiply queue_notify_off by this value. (non-legacy mode). */

	u32 notify_offset_multiplier;



	/* Legacy only field */

	/* the IO mapping for the PCI config space */

	void __iomem *ioaddr;



	/* the IO mapping for ISR operation */

	void __iomem *isr;



	/* a list of queues so we can dispatch IRQs */

	spinlock_t lock;

	struct list_head virtqueues;
@@ -129,5 +146,7 @@ int vp_set_vq_affinity(struct virtqueue *vq, int cpu); 


int virtio_pci_legacy_probe(struct virtio_pci_device *);

void virtio_pci_legacy_remove(struct virtio_pci_device *);

int virtio_pci_modern_probe(struct virtio_pci_device *);

void virtio_pci_modern_remove(struct virtio_pci_device *);



#endif

drivers/virtio/virtio_pci_modern.c

0 → 100644
+587 −0
Original line number Diff line number Diff line 
/*

 * Virtio PCI driver - modern (virtio 1.0) device support

 *

 * This module allows virtio devices to be used over a virtual PCI device.

 * This can be used with QEMU based VMMs like KVM or Xen.

 *

 * Copyright IBM Corp. 2007

 * Copyright Red Hat, Inc. 2014

 *

 * Authors:

 *  Anthony Liguori  <aliguori@us.ibm.com>

 *  Rusty Russell <rusty@rustcorp.com.au>

 *  Michael S. Tsirkin <mst@redhat.com>

 *

 * This work is licensed under the terms of the GNU GPL, version 2 or later.

 * See the COPYING file in the top-level directory.

 *

 */



#define VIRTIO_PCI_NO_LEGACY

#include "virtio_pci_common.h"



static void __iomem *map_capability(struct pci_dev *dev, int off,

				    size_t minlen,

				    u32 align,

				    u32 start, u32 size,

				    size_t *len)

{

	u8 bar;

	u32 offset, length;

	void __iomem *p;



	pci_read_config_byte(dev, off + offsetof(struct virtio_pci_cap,

						 bar),

			     &bar);

	pci_read_config_dword(dev, off + offsetof(struct virtio_pci_cap, offset),

			     &offset);

	pci_read_config_dword(dev, off + offsetof(struct virtio_pci_cap, length),

			      &length);



	if (length <= start) {

		dev_err(&dev->dev,

			"virtio_pci: bad capability len %u (>%u expected)\n",

			length, start);

		return NULL;

	}



	if (length - start < minlen) {

		dev_err(&dev->dev,

			"virtio_pci: bad capability len %u (>=%zu expected)\n",

			length, minlen);

		return NULL;

	}



	length -= start;



	if (start + offset < offset) {

		dev_err(&dev->dev,

			"virtio_pci: map wrap-around %u+%u\n",

			start, offset);

		return NULL;

	}



	offset += start;



	if (offset & (align - 1)) {

		dev_err(&dev->dev,

			"virtio_pci: offset %u not aligned to %u\n",

			offset, align);

		return NULL;

	}



	if (length > size)

		length = size;



	if (len)

		*len = length;



	if (minlen + offset < minlen ||

	    minlen + offset > pci_resource_len(dev, bar)) {

		dev_err(&dev->dev,

			"virtio_pci: map virtio %zu@%u "

			"out of range on bar %i length %lu\n",

			minlen, offset,

			bar, (unsigned long)pci_resource_len(dev, bar));

		return NULL;

	}



	p = pci_iomap_range(dev, bar, offset, length);

	if (!p)

		dev_err(&dev->dev,

			"virtio_pci: unable to map virtio %u@%u on bar %i\n",

			length, offset, bar);

	return p;

}



static void iowrite64_twopart(u64 val, __le32 __iomem *lo, __le32 __iomem *hi)

{

	iowrite32((u32)val, lo);

	iowrite32(val >> 32, hi);

}



/* virtio config->get_features() implementation */

static u64 vp_get_features(struct virtio_device *vdev)

{

	struct virtio_pci_device *vp_dev = to_vp_device(vdev);

	u64 features;



	iowrite32(0, &vp_dev->common->device_feature_select);

	features = ioread32(&vp_dev->common->device_feature);

	iowrite32(1, &vp_dev->common->device_feature_select);

	features |= ((u64)ioread32(&vp_dev->common->device_feature) << 32);



	return features;

}



/* virtio config->finalize_features() implementation */

static int vp_finalize_features(struct virtio_device *vdev)

{

	struct virtio_pci_device *vp_dev = to_vp_device(vdev);



	/* Give virtio_ring a chance to accept features. */

	vring_transport_features(vdev);



	if (!__virtio_test_bit(vdev, VIRTIO_F_VERSION_1)) {

		dev_err(&vdev->dev, "virtio: device uses modern interface "

			"but does not have VIRTIO_F_VERSION_1\n");

		return -EINVAL;

	}



	iowrite32(0, &vp_dev->common->guest_feature_select);

	iowrite32((u32)vdev->features, &vp_dev->common->guest_feature);

	iowrite32(1, &vp_dev->common->guest_feature_select);

	iowrite32(vdev->features >> 32, &vp_dev->common->guest_feature);



	return 0;

}



/* virtio config->get() implementation */

static void vp_get(struct virtio_device *vdev, unsigned offset,

		   void *buf, unsigned len)

{

	struct virtio_pci_device *vp_dev = to_vp_device(vdev);

	u8 b;

	__le16 w;

	__le32 l;



	BUG_ON(offset + len > vp_dev->device_len);



	switch (len) {

	case 1:

		b = ioread8(vp_dev->device + offset);

		memcpy(buf, &b, sizeof b);

		break;

	case 2:

		w = cpu_to_le16(ioread16(vp_dev->device + offset));

		memcpy(buf, &w, sizeof w);

		break;

	case 4:

		l = cpu_to_le32(ioread32(vp_dev->device + offset));

		memcpy(buf, &l, sizeof l);

		break;

	case 8:

		l = cpu_to_le32(ioread32(vp_dev->device + offset));

		memcpy(buf, &l, sizeof l);

		l = cpu_to_le32(ioread32(vp_dev->device + offset + sizeof l));

		memcpy(buf + sizeof l, &l, sizeof l);

		break;

	default:

		BUG();

	}

}



/* the config->set() implementation.  it's symmetric to the config->get()

 * implementation */

static void vp_set(struct virtio_device *vdev, unsigned offset,

		   const void *buf, unsigned len)

{

	struct virtio_pci_device *vp_dev = to_vp_device(vdev);

	u8 b;

	__le16 w;

	__le32 l;



	BUG_ON(offset + len > vp_dev->device_len);



	switch (len) {

	case 1:

		memcpy(&b, buf, sizeof b);

		iowrite8(b, vp_dev->device + offset);

		break;

	case 2:

		memcpy(&w, buf, sizeof w);

		iowrite16(le16_to_cpu(w), vp_dev->device + offset);

		break;

	case 4:

		memcpy(&l, buf, sizeof l);

		iowrite32(le32_to_cpu(l), vp_dev->device + offset);

		break;

	case 8:

		memcpy(&l, buf, sizeof l);

		iowrite32(le32_to_cpu(l), vp_dev->device + offset);

		memcpy(&l, buf + sizeof l, sizeof l);

		iowrite32(le32_to_cpu(l), vp_dev->device + offset + sizeof l);

		break;

	default:

		BUG();

	}

}



static u32 vp_generation(struct virtio_device *vdev)

{

	struct virtio_pci_device *vp_dev = to_vp_device(vdev);

	return ioread8(&vp_dev->common->config_generation);

}



/* config->{get,set}_status() implementations */

static u8 vp_get_status(struct virtio_device *vdev)

{

	struct virtio_pci_device *vp_dev = to_vp_device(vdev);

	return ioread8(&vp_dev->common->device_status);

}



static void vp_set_status(struct virtio_device *vdev, u8 status)

{

	struct virtio_pci_device *vp_dev = to_vp_device(vdev);

	/* We should never be setting status to 0. */

	BUG_ON(status == 0);

	iowrite8(status, &vp_dev->common->device_status);

}



static void vp_reset(struct virtio_device *vdev)

{

	struct virtio_pci_device *vp_dev = to_vp_device(vdev);

	/* 0 status means a reset. */

	iowrite8(0, &vp_dev->common->device_status);

	/* Flush out the status write, and flush in device writes,

	 * including MSI-X interrupts, if any. */

	ioread8(&vp_dev->common->device_status);

	/* Flush pending VQ/configuration callbacks. */

	vp_synchronize_vectors(vdev);

}



static u16 vp_config_vector(struct virtio_pci_device *vp_dev, u16 vector)

{

	/* Setup the vector used for configuration events */

	iowrite16(vector, &vp_dev->common->msix_config);

	/* Verify we had enough resources to assign the vector */

	/* Will also flush the write out to device */

	return ioread16(&vp_dev->common->msix_config);

}



static size_t vring_pci_size(u16 num)

{

	/* We only need a cacheline separation. */

	return PAGE_ALIGN(vring_size(num, SMP_CACHE_BYTES));

}



static void *alloc_virtqueue_pages(int *num)

{

	void *pages;



	/* TODO: allocate each queue chunk individually */

	for (; *num && vring_pci_size(*num) > PAGE_SIZE; *num /= 2) {

		pages = alloc_pages_exact(vring_pci_size(*num),

					  GFP_KERNEL|__GFP_ZERO|__GFP_NOWARN);

		if (pages)

			return pages;

	}



	if (!*num)

		return NULL;



	/* Try to get a single page. You are my only hope! */

	return alloc_pages_exact(vring_pci_size(*num), GFP_KERNEL|__GFP_ZERO);

}



static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,

				  struct virtio_pci_vq_info *info,

				  unsigned index,

				  void (*callback)(struct virtqueue *vq),

				  const char *name,

				  u16 msix_vec)

{

	struct virtio_pci_common_cfg __iomem *cfg = vp_dev->common;

	struct virtqueue *vq;

	u16 num, off;

	int err;



	if (index >= ioread16(&cfg->num_queues))

		return ERR_PTR(-ENOENT);



	/* Select the queue we're interested in */

	iowrite16(index, &cfg->queue_select);



	/* Check if queue is either not available or already active. */

	num = ioread16(&cfg->queue_size);

	if (!num || ioread8(&cfg->queue_enable))

		return ERR_PTR(-ENOENT);



	if (num & (num - 1)) {

		dev_warn(&vp_dev->pci_dev->dev, "bad queue size %u", num);

		return ERR_PTR(-EINVAL);

	}



	/* get offset of notification word for this vq */

	off = ioread16(&cfg->queue_notify_off);



	info->num = num;

	info->msix_vector = msix_vec;



	info->queue = alloc_virtqueue_pages(&info->num);

	if (info->queue == NULL)

		return ERR_PTR(-ENOMEM);



	/* create the vring */

	vq = vring_new_virtqueue(index, info->num,

				 SMP_CACHE_BYTES, &vp_dev->vdev,

				 true, info->queue, vp_notify, callback, name);

	if (!vq) {

		err = -ENOMEM;

		goto err_new_queue;

	}



	/* activate the queue */

	iowrite16(num, &cfg->queue_size);

	iowrite64_twopart(virt_to_phys(info->queue),

			  &cfg->queue_desc_lo, &cfg->queue_desc_hi);

	iowrite64_twopart(virt_to_phys(virtqueue_get_avail(vq)),

			  &cfg->queue_avail_lo, &cfg->queue_avail_hi);

	iowrite64_twopart(virt_to_phys(virtqueue_get_used(vq)),

			  &cfg->queue_used_lo, &cfg->queue_used_hi);



	vq->priv = (void __force *)map_capability(vp_dev->pci_dev,

				  vp_dev->notify_map_cap, 2, 2,

				  off * vp_dev->notify_offset_multiplier, 2,

				  NULL);



	if (!vq->priv) {

		err = -ENOMEM;

		goto err_map_notify;

	}



	if (msix_vec != VIRTIO_MSI_NO_VECTOR) {

		iowrite16(msix_vec, &cfg->queue_msix_vector);

		msix_vec = ioread16(&cfg->queue_msix_vector);

		if (msix_vec == VIRTIO_MSI_NO_VECTOR) {

			err = -EBUSY;

			goto err_assign_vector;

		}

	}



	return vq;



err_assign_vector:

	pci_iounmap(vp_dev->pci_dev, (void __iomem __force *)vq->priv);

err_map_notify:

	vring_del_virtqueue(vq);

err_new_queue:

	free_pages_exact(info->queue, vring_pci_size(info->num));

	return ERR_PTR(err);

}



static int vp_modern_find_vqs(struct virtio_device *vdev, unsigned nvqs,

			      struct virtqueue *vqs[],

			      vq_callback_t *callbacks[],

			      const char *names[])

{

	struct virtio_pci_device *vp_dev = to_vp_device(vdev);

	struct virtqueue *vq;

	int rc = vp_find_vqs(vdev, nvqs, vqs, callbacks, names);



	if (rc)

		return rc;



	/* Select and activate all queues. Has to be done last: once we do

	 * this, there's no way to go back except reset.

	 */

	list_for_each_entry(vq, &vdev->vqs, list) {

		iowrite16(vq->index, &vp_dev->common->queue_select);

		iowrite8(1, &vp_dev->common->queue_enable);

	}



	return 0;

}



static void del_vq(struct virtio_pci_vq_info *info)

{

	struct virtqueue *vq = info->vq;

	struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev);



	iowrite16(vq->index, &vp_dev->common->queue_select);



	if (vp_dev->msix_enabled) {

		iowrite16(VIRTIO_MSI_NO_VECTOR,

			  &vp_dev->common->queue_msix_vector);

		/* Flush the write out to device */

		ioread16(&vp_dev->common->queue_msix_vector);

	}



	pci_iounmap(vp_dev->pci_dev, (void __force __iomem *)vq->priv);



	vring_del_virtqueue(vq);



	free_pages_exact(info->queue, vring_pci_size(info->num));

}



static const struct virtio_config_ops virtio_pci_config_ops = {

	.get		= vp_get,

	.set		= vp_set,

	.generation	= vp_generation,

	.get_status	= vp_get_status,

	.set_status	= vp_set_status,

	.reset		= vp_reset,

	.find_vqs	= vp_modern_find_vqs,

	.del_vqs	= vp_del_vqs,

	.get_features	= vp_get_features,

	.finalize_features = vp_finalize_features,

	.bus_name	= vp_bus_name,

	.set_vq_affinity = vp_set_vq_affinity,

};



/**

 * virtio_pci_find_capability - walk capabilities to find device info.

 * @dev: the pci device

 * @cfg_type: the VIRTIO_PCI_CAP_* value we seek

 * @ioresource_types: IORESOURCE_MEM and/or IORESOURCE_IO.

 *

 * Returns offset of the capability, or 0.

 */

static inline int virtio_pci_find_capability(struct pci_dev *dev, u8 cfg_type,

					     u32 ioresource_types)

{

	int pos;



	for (pos = pci_find_capability(dev, PCI_CAP_ID_VNDR);

	     pos > 0;

	     pos = pci_find_next_capability(dev, pos, PCI_CAP_ID_VNDR)) {

		u8 type, bar;

		pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,

							 cfg_type),

				     &type);

		pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,

							 bar),

				     &bar);



		/* Ignore structures with reserved BAR values */

		if (bar > 0x5)

			continue;



		if (type == cfg_type) {

			if (pci_resource_len(dev, bar) &&

			    pci_resource_flags(dev, bar) & ioresource_types)

				return pos;

		}

	}

	return 0;

}



static void virtio_pci_release_dev(struct device *_d)

{

	struct virtio_device *vdev = dev_to_virtio(_d);

	struct virtio_pci_device *vp_dev = to_vp_device(vdev);



	kfree(vp_dev);

}



/* TODO: validate the ABI statically. */

static inline void check_offsets(void)

{

}



/* the PCI probing function */

int virtio_pci_modern_probe(struct virtio_pci_device *vp_dev)

{

	struct pci_dev *pci_dev = vp_dev->pci_dev;

	int err, common, isr, notify, device;

	u32 notify_length;



	check_offsets();



	/* We only own devices >= 0x1000 and <= 0x107f: leave the rest. */

	if (pci_dev->device < 0x1000 || pci_dev->device > 0x107f)

		return -ENODEV;



	if (pci_dev->device < 0x1040) {

		/* Transitional devices: use the PCI subsystem device id as

		 * virtio device id, same as legacy driver always did.

		 */

		vp_dev->vdev.id.device = pci_dev->subsystem_device;

	} else {

		/* Modern devices: simply use PCI device id, but start from 0x1040. */

		vp_dev->vdev.id.device = pci_dev->device - 0x1040;

	}

	vp_dev->vdev.id.vendor = pci_dev->subsystem_vendor;



	if (virtio_device_is_legacy_only(vp_dev->vdev.id))

		return -ENODEV;



	/* check for a common config: if not, use legacy mode (bar 0). */

	common = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_COMMON_CFG,

					    IORESOURCE_IO | IORESOURCE_MEM);

	if (!common) {

		dev_info(&pci_dev->dev,

			 "virtio_pci: leaving for legacy driver\n");

		return -ENODEV;

	}



	/* If common is there, these should be too... */

	isr = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_ISR_CFG,

					 IORESOURCE_IO | IORESOURCE_MEM);

	notify = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_NOTIFY_CFG,

					    IORESOURCE_IO | IORESOURCE_MEM);

	if (!isr || !notify) {

		dev_err(&pci_dev->dev,

			"virtio_pci: missing capabilities %i/%i/%i\n",

			common, isr, notify);

		return -EINVAL;

	}



	/* Device capability is only mandatory for devices that have

	 * device-specific configuration.

	 */

	device = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_DEVICE_CFG,

					    IORESOURCE_IO | IORESOURCE_MEM);



	err = -EINVAL;

	vp_dev->common = map_capability(pci_dev, common,

					sizeof(struct virtio_pci_common_cfg), 4,

					0, sizeof(struct virtio_pci_common_cfg),

					NULL);

	if (!vp_dev->common)

		goto err_map_common;

	vp_dev->isr = map_capability(pci_dev, isr, sizeof(u8), 1,

				     0, 1,

				     NULL);

	if (!vp_dev->isr)

		goto err_map_isr;



	/* Read notify_off_multiplier from config space. */

	pci_read_config_dword(pci_dev,

			      notify + offsetof(struct virtio_pci_notify_cap,

						notify_off_multiplier),

			      &vp_dev->notify_offset_multiplier);

	/* Read notify length from config space. */

	pci_read_config_dword(pci_dev,

			      notify + offsetof(struct virtio_pci_notify_cap,

						cap.length),

			      &notify_length);



	vp_dev->notify_map_cap = notify;



	/* Again, we don't know how much we should map, but PAGE_SIZE

	 * is more than enough for all existing devices.

	 */

	if (device) {

		vp_dev->device = map_capability(pci_dev, device, 0, 4,

						0, PAGE_SIZE,

						&vp_dev->device_len);

		if (!vp_dev->device)

			goto err_map_device;

	}



	vp_dev->vdev.config = &virtio_pci_config_ops;



	vp_dev->config_vector = vp_config_vector;

	vp_dev->setup_vq = setup_vq;

	vp_dev->del_vq = del_vq;



	return 0;



err_map_device:

	pci_iounmap(pci_dev, vp_dev->isr);

err_map_isr:

	pci_iounmap(pci_dev, vp_dev->common);

err_map_common:

	return err;

}



void virtio_pci_modern_remove(struct virtio_pci_device *vp_dev)

{

	struct pci_dev *pci_dev = vp_dev->pci_dev;



	if (vp_dev->device)

		pci_iounmap(pci_dev, vp_dev->device);

	pci_iounmap(pci_dev, vp_dev->isr);

	pci_iounmap(pci_dev, vp_dev->common);

}

include/uapi/linux/virtio_pci.h

+4 −3
Original line number Diff line number Diff line
@@ -117,10 +117,11 @@ struct virtio_pci_cap { 
	__u8 cap_vndr;		/* Generic PCI field: PCI_CAP_ID_VNDR */

	__u8 cap_next;		/* Generic PCI field: next ptr. */

	__u8 cap_len;		/* Generic PCI field: capability length */

	__u8 type_and_bar;	/* Upper 3 bits: bar.

				 * Lower 3 is VIRTIO_PCI_CAP_*_CFG. */

	__u8 cfg_type;		/* Identifies the structure. */

	__u8 bar;		/* Where to find it. */

	__u8 padding[3];	/* Pad to full dword. */

	__le32 offset;		/* Offset within bar. */

	__le32 length;		/* Length. */

	__le32 length;		/* Length of the structure, in bytes. */

};



#define VIRTIO_PCI_CAP_BAR_SHIFT	5

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