Commit 0dd4ff93 authored by Sebastien Boeuf's avatar Sebastien Boeuf Committed by Miklos Szeredi
Browse files

virtio: Implement get_shm_region for PCI transport 



On PCI the shm regions are found using capability entries;
find a region by searching for the capability.

Signed-off-by: default avatarSebastien Boeuf <sebastien.boeuf@intel.com>
Signed-off-by: default avatarDr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: default avatarkbuild test robot <lkp@intel.com>
Acked-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Cc: kvm@vger.kernel.org
Cc: virtualization@lists.linux-foundation.org
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Signed-off-by: default avatarMiklos Szeredi <mszeredi@redhat.com>
parent 5bfe37ca

drivers/virtio/virtio_pci_modern.c

+95 −0
Original line number Diff line number Diff line
@@ -444,6 +444,99 @@ static void del_vq(struct virtio_pci_vq_info *info) 
	vring_del_virtqueue(vq);

}



static int virtio_pci_find_shm_cap(struct pci_dev *dev, u8 required_id,

				   u8 *bar, u64 *offset, u64 *len)

{

	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, cap_len, id;

		u32 tmp32;

		u64 res_offset, res_length;



		pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,

							 cfg_type), &type);

		if (type != VIRTIO_PCI_CAP_SHARED_MEMORY_CFG)

			continue;



		pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,

							 cap_len), &cap_len);

		if (cap_len != sizeof(struct virtio_pci_cap64)) {

			dev_err(&dev->dev, "%s: shm cap with bad size offset:"

				" %d size: %d\n", __func__, pos, cap_len);

			continue;

		}



		pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,

							 id), &id);

		if (id != required_id)

			continue;



		/* Type, and ID match, looks good */

		pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,

							 bar), bar);



		/* Read the lower 32bit of length and offset */

		pci_read_config_dword(dev, pos + offsetof(struct virtio_pci_cap,

							  offset), &tmp32);

		res_offset = tmp32;

		pci_read_config_dword(dev, pos + offsetof(struct virtio_pci_cap,

							  length), &tmp32);

		res_length = tmp32;



		/* and now the top half */

		pci_read_config_dword(dev,

				      pos + offsetof(struct virtio_pci_cap64,

						     offset_hi), &tmp32);

		res_offset |= ((u64)tmp32) << 32;

		pci_read_config_dword(dev,

				      pos + offsetof(struct virtio_pci_cap64,

						     length_hi), &tmp32);

		res_length |= ((u64)tmp32) << 32;



		*offset = res_offset;

		*len = res_length;



		return pos;

	}

	return 0;

}



static bool vp_get_shm_region(struct virtio_device *vdev,

			      struct virtio_shm_region *region, u8 id)

{

	struct virtio_pci_device *vp_dev = to_vp_device(vdev);

	struct pci_dev *pci_dev = vp_dev->pci_dev;

	u8 bar;

	u64 offset, len;

	phys_addr_t phys_addr;

	size_t bar_len;



	if (!virtio_pci_find_shm_cap(pci_dev, id, &bar, &offset, &len))

		return false;



	phys_addr = pci_resource_start(pci_dev, bar);

	bar_len = pci_resource_len(pci_dev, bar);



	if ((offset + len) < offset) {

		dev_err(&pci_dev->dev, "%s: cap offset+len overflow detected\n",

			__func__);

		return false;

	}



	if (offset + len > bar_len) {

		dev_err(&pci_dev->dev, "%s: bar shorter than cap offset+len\n",

			__func__);

		return false;

	}



	region->len = len;

	region->addr = (u64) phys_addr + offset;



	return true;

}



static const struct virtio_config_ops virtio_pci_config_nodev_ops = {

	.get		= NULL,

	.set		= NULL,
@@ -458,6 +551,7 @@ static const struct virtio_config_ops virtio_pci_config_nodev_ops = { 
	.bus_name	= vp_bus_name,

	.set_vq_affinity = vp_set_vq_affinity,

	.get_vq_affinity = vp_get_vq_affinity,

	.get_shm_region  = vp_get_shm_region,

};



static const struct virtio_config_ops virtio_pci_config_ops = {
@@ -474,6 +568,7 @@ static const struct virtio_config_ops virtio_pci_config_ops = { 
	.bus_name	= vp_bus_name,

	.set_vq_affinity = vp_set_vq_affinity,

	.get_vq_affinity = vp_get_vq_affinity,

	.get_shm_region  = vp_get_shm_region,

};



/**

include/uapi/linux/virtio_pci.h

+10 −1
Original line number Diff line number Diff line
@@ -113,6 +113,8 @@ 
#define VIRTIO_PCI_CAP_DEVICE_CFG	4

/* PCI configuration access */

#define VIRTIO_PCI_CAP_PCI_CFG		5

/* Additional shared memory capability */

#define VIRTIO_PCI_CAP_SHARED_MEMORY_CFG 8



/* This is the PCI capability header: */

struct virtio_pci_cap {
@@ -121,11 +123,18 @@ struct virtio_pci_cap { 
	__u8 cap_len;		/* Generic PCI field: capability length */

	__u8 cfg_type;		/* Identifies the structure. */

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

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

	__u8 id;		/* Multiple capabilities of the same type */

	__u8 padding[2];	/* Pad to full dword. */

	__le32 offset;		/* Offset within bar. */

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

};



struct virtio_pci_cap64 {

	struct virtio_pci_cap cap;

	__le32 offset_hi;             /* Most sig 32 bits of offset */

	__le32 length_hi;             /* Most sig 32 bits of length */

};



struct virtio_pci_notify_cap {

	struct virtio_pci_cap cap;

	__le32 notify_off_multiplier;	/* Multiplier for queue_notify_off. */

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