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SubjectRe: [Virtio-fs] [PATCH 04/19] virtio: Implement get_shm_region for PCI transport
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On 2019/8/22 1:57, Vivek Goyal wrote:
> 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.
>
> Cc: kvm@vger.kernel.org
> 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>
> ---
> 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

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