On 2019/8/22 1:57, Vivek Goyal wrote: > 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; 'char *bar_name' should be cleaned up to avoid compiling warning. And I wonder if you mix tab and blankspace for code indent? Or it's just my email display problem? Thanks, Jun