Turn the 16 bit padding into a page_size field to allow the device to
pass its required page size with format PAGE_SIZE >> 12.
Signed-off-by: Sergio Lopez <slp@xxxxxxxxxx>
---
drivers/virtio/virtio_pci_modern.c | 29 +++++++++++++++++++++++++----
include/uapi/linux/virtio_pci.h | 2 +-
2 files changed, 26 insertions(+), 5 deletions(-)
diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c
index 79616ce5057bf3b2b88cae7e8fb7729efa9dd632..26e9cd5148c0f10209c34d12e65d64490a855d75 100644
--- a/drivers/virtio/virtio_pci_modern.c
+++ b/drivers/virtio/virtio_pci_modern.c
@@ -770,14 +770,16 @@ 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)
+static int virtio_pci_find_shm_cap(struct virtio_device *vdev, struct pci_dev *dev,
+ u8 required_id, u8 *bar, u64 *offset, u64 *len,
+ u16 *page_size)
{
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, res_bar;
+ u16 res_psize = 0;
u32 tmp32;
u64 res_offset, res_length;
@@ -808,6 +810,23 @@ static int virtio_pci_find_shm_cap(struct pci_dev *dev, u8 required_id,
* Looks good.
*/
+ if (__virtio_test_bit(vdev, VIRTIO_F_SHM_PAGE_SIZE)) {
+ pci_read_config_word(dev, pos + offsetof(struct virtio_pci_cap,
+ page_size), &res_psize);
+ if (!res_psize) {
+ dev_err(&dev->dev, "%s: shm cap with invalid page size on "
+ "a device with VIRTIO_F_SHM_PAGE_SIZE feature\n",
+ __func__);
+ res_psize = 4096 >> 12;
+ }
+ }
+
+ /* For backwards compatibility, if the device didn't specify a
+ * page size, assume it to be 4096.
+ */
+ if (!res_psize)
+ res_psize = 4096 >> 12;
+
/* Read the lower 32bit of length and offset */
pci_read_config_dword(dev, pos + offsetof(struct virtio_pci_cap,
offset), &tmp32);
@@ -829,6 +848,7 @@ static int virtio_pci_find_shm_cap(struct pci_dev *dev, u8 required_id,
*bar = res_bar;
*offset = res_offset;
*len = res_length;
+ *page_size = res_psize;
return pos;
}
@@ -841,11 +861,12 @@ static bool vp_get_shm_region(struct virtio_device *vdev,
struct virtio_pci_device *vp_dev = to_vp_device(vdev);
struct pci_dev *pci_dev = vp_dev->pci_dev;
u8 bar;
+ u16 page_size;
u64 offset, len;
phys_addr_t phys_addr;
size_t bar_len;
- if (!virtio_pci_find_shm_cap(pci_dev, id, &bar, &offset, &len))
+ if (!virtio_pci_find_shm_cap(vdev, pci_dev, id, &bar, &offset, &len, &page_size))
return false;
phys_addr = pci_resource_start(pci_dev, bar);
@@ -865,7 +886,7 @@ static bool vp_get_shm_region(struct virtio_device *vdev,
region->len = len;
region->addr = (u64) phys_addr + offset;
- region->page_size = 4096 >> 12;
+ region->page_size = page_size;
return true;
}
diff --git a/include/uapi/linux/virtio_pci.h b/include/uapi/linux/virtio_pci.h
index 8549d4571257142ac6c9dad5c01369923791a85a..fb0ccb7a125d8178c1f78333c4d2f43540e1764b 100644
--- a/include/uapi/linux/virtio_pci.h
+++ b/include/uapi/linux/virtio_pci.h
@@ -127,7 +127,7 @@ struct virtio_pci_cap {
__u8 cfg_type; /* Identifies the structure. */
__u8 bar; /* Where to find it. */
__u8 id; /* Multiple capabilities of the same type */
- __u8 padding[2]; /* Pad to full dword. */
+ __u16 page_size; /* Device page size (PAGE_SIZE >> 12). */
__le32 offset; /* Offset within bar. */
__le32 length; /* Length of the structure, in bytes. */
};
--
2.48.1
