From: Sebastien Boeuf <sebastien.boeuf@xxxxxxxxx> On PCI the shm regions are found using capability entries; find a region by searching for the capability. Cc: kvm@xxxxxxxxxxxxxxx Signed-off-by: Sebastien Boeuf <sebastien.boeuf@xxxxxxxxx> Signed-off-by: Dr. David Alan Gilbert <dgilbert@xxxxxxxxxx> Signed-off-by: kbuild test robot <lkp@xxxxxxxxx> --- drivers/virtio/virtio_pci_modern.c | 108 +++++++++++++++++++++++++++++ include/uapi/linux/virtio_pci.h | 11 ++- 2 files changed, 118 insertions(+), 1 deletion(-) diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c index 7abcc50838b8..1cdedd93f42a 100644 --- a/drivers/virtio/virtio_pci_modern.c +++ b/drivers/virtio/virtio_pci_modern.c @@ -443,6 +443,112 @@ 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_cap64)) { + 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_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; + 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, @@ -457,6 +563,7 @@ 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 = { @@ -473,6 +580,7 @@ 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..fe9f43680a1d 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 { @@ -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. */ -- 2.20.1