lkml.org 
[lkml]   [2019]   [May]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH v2 15/30] virtio: Implement get_shm_region for PCI transport
    Date
    From: Sebastien Boeuf <sebastien.boeuf@intel.com>

    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>
    ---
    drivers/virtio/virtio_pci_modern.c | 108 +++++++++++++++++++++++++++++
    include/uapi/linux/virtio_pci.h | 10 +++
    2 files changed, 118 insertions(+)

    diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c
    index 07571daccfec..51c9e6eca5ac 100644
    --- a/drivers/virtio/virtio_pci_modern.c
    +++ b/drivers/virtio/virtio_pci_modern.c
    @@ -446,6 +446,112 @@ 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_shm_cap)) {
    + printk(KERN_ERR "%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_shm_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_shm_cap,
    + offset_hi),
    + &tmp32);
    + res_offset |= ((u64)tmp32) << 32;
    + pci_read_config_dword(dev,
    + pos + offsetof(struct virtio_pci_shm_cap,
    + 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;
    + char *bar_name;
    + int ret;
    +
    + if (!virtio_pci_find_shm_cap(pci_dev, id, &bar, &offset, &len)) {
    + return false;
    + }
    +
    + ret = pci_request_region(pci_dev, bar, "virtio-pci-shm");
    + if (ret < 0) {
    + dev_err(&pci_dev->dev, "%s: failed to request BAR\n",
    + __func__);
    + return false;
    + }
    +
    + phys_addr = pci_resource_start(pci_dev, bar);
    + bar_len = pci_resource_len(pci_dev, bar);
    +
    + 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,
    @@ -460,6 +566,7 @@ 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 = {
    @@ -476,6 +583,7 @@ 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,
    };

    /**
    diff --git a/include/uapi/linux/virtio_pci.h b/include/uapi/linux/virtio_pci.h
    index 90007a1abcab..31841a60a4ad 100644
    --- a/include/uapi/linux/virtio_pci.h
    +++ b/include/uapi/linux/virtio_pci.h
    @@ -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 {
    @@ -163,6 +165,14 @@ struct virtio_pci_cfg_cap {
    __u8 pci_cfg_data[4]; /* Data for BAR access. */
    };

    +/* Fields in VIRTIO_PCI_CAP_SHARED_MEMORY_CFG */
    +struct virtio_pci_shm_cap {
    + struct virtio_pci_cap cap;
    + __le32 offset_hi; /* Most sig 32 bits of offset */
    + __le32 length_hi; /* Most sig 32 bits of length */
    + __u8 id; /* To distinguish shm chunks */
    +};
    +
    /* Macro versions of offsets for the Old Timers! */
    #define VIRTIO_PCI_CAP_VNDR 0
    #define VIRTIO_PCI_CAP_NEXT 1
    --
    2.20.1
    \
     
     \ /
      Last update: 2019-05-15 21:29    [W:6.114 / U:0.096 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site