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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: Sebastien Boeuf <sebastien.boeuf@intel.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: kbuild test robot <lkp@intel.com>
Acked-by: Michael 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: Miklos Szeredi <mszeredi@redhat.com>
This commit is contained in:
Sebastien Boeuf 2020-08-19 18:19:42 -04:00 committed by Miklos Szeredi
parent 5bfe37ca8a
commit 0dd4ff93f4
2 changed files with 105 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

95
drivers/virtio/virtio_pci_modern.c
View File

@ -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,
};
/**

11
include/uapi/linux/virtio_pci.h
View File

@ -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. */