Align the page tracking maximum message size with the device's
capability instead of relying on PAGE_SIZE.
This adjustment resolves a mismatch on systems where PAGE_SIZE is 64K,
but the firmware only supports a maximum message size of 4K.
Now that we rely on the device's capability for max_message_size, we
must account for potential future increases in its value.
Key considerations include:
- Supporting message sizes that exceed a single system page (e.g., an 8K
message on a 4K system).
- Ensuring the RQ size is adjusted to accommodate at least 4
WQEs/messages, in line with the device specification.
The above has been addressed as part of the patch.
Fixes: 79c3cf279926 ("vfio/mlx5: Init QP based resources for dirty tracking")
Reviewed-by: Cédric Le Goater <clg@xxxxxxxxxx>
Tested-by: Yingshun Cui <yicui@xxxxxxxxxx>
Signed-off-by: Yishai Hadas <yishaih@xxxxxxxxxx>
---
Changes from V0:
https://lore.kernel.org/kvm/20241125113249.155127-1-yishaih@xxxxxxxxxx/T/
- Rename 'page_start' to 'kaddr' as was suggested by Cédric.
- Add the Tested-by and Reviewed-by clauses.
drivers/vfio/pci/mlx5/cmd.c | 47 +++++++++++++++++++++++++++----------
1 file changed, 35 insertions(+), 12 deletions(-)
diff --git a/drivers/vfio/pci/mlx5/cmd.c b/drivers/vfio/pci/mlx5/cmd.c
index 7527e277c898..eb7387ee6ebd 100644
--- a/drivers/vfio/pci/mlx5/cmd.c
+++ b/drivers/vfio/pci/mlx5/cmd.c
@@ -1517,7 +1517,8 @@ int mlx5vf_start_page_tracker(struct vfio_device *vdev,
struct mlx5_vhca_qp *host_qp;
struct mlx5_vhca_qp *fw_qp;
struct mlx5_core_dev *mdev;
- u32 max_msg_size = PAGE_SIZE;
+ u32 log_max_msg_size;
+ u32 max_msg_size;
u64 rq_size = SZ_2M;
u32 max_recv_wr;
int err;
@@ -1534,6 +1535,12 @@ int mlx5vf_start_page_tracker(struct vfio_device *vdev,
}
mdev = mvdev->mdev;
+ log_max_msg_size = MLX5_CAP_ADV_VIRTUALIZATION(mdev, pg_track_log_max_msg_size);
+ max_msg_size = (1ULL << log_max_msg_size);
+ /* The RQ must hold at least 4 WQEs/messages for successful QP creation */
+ if (rq_size < 4 * max_msg_size)
+ rq_size = 4 * max_msg_size;
+
memset(tracker, 0, sizeof(*tracker));
tracker->uar = mlx5_get_uars_page(mdev);
if (IS_ERR(tracker->uar)) {
@@ -1623,25 +1630,41 @@ set_report_output(u32 size, int index, struct mlx5_vhca_qp *qp,
{
u32 entry_size = MLX5_ST_SZ_BYTES(page_track_report_entry);
u32 nent = size / entry_size;
+ u32 nent_in_page;
+ u32 nent_to_set;
struct page *page;
+ u32 page_offset;
+ u32 page_index;
+ u32 buf_offset;
+ void *kaddr;
u64 addr;
u64 *buf;
int i;
- if (WARN_ON(index >= qp->recv_buf.npages ||
+ buf_offset = index * qp->max_msg_size;
+ if (WARN_ON(buf_offset + size >= qp->recv_buf.npages * PAGE_SIZE ||
(nent > qp->max_msg_size / entry_size)))
return;
- page = qp->recv_buf.page_list[index];
- buf = kmap_local_page(page);
- for (i = 0; i < nent; i++) {
- addr = MLX5_GET(page_track_report_entry, buf + i,
- dirty_address_low);
- addr |= (u64)MLX5_GET(page_track_report_entry, buf + i,
- dirty_address_high) << 32;
- iova_bitmap_set(dirty, addr, qp->tracked_page_size);
- }
- kunmap_local(buf);
+ do {
+ page_index = buf_offset / PAGE_SIZE;
+ page_offset = buf_offset % PAGE_SIZE;
+ nent_in_page = (PAGE_SIZE - page_offset) / entry_size;
+ page = qp->recv_buf.page_list[page_index];
+ kaddr = kmap_local_page(page);
+ buf = kaddr + page_offset;
+ nent_to_set = min(nent, nent_in_page);
+ for (i = 0; i < nent_to_set; i++) {
+ addr = MLX5_GET(page_track_report_entry, buf + i,
+ dirty_address_low);
+ addr |= (u64)MLX5_GET(page_track_report_entry, buf + i,
+ dirty_address_high) << 32;
+ iova_bitmap_set(dirty, addr, qp->tracked_page_size);
+ }
+ kunmap_local(kaddr);
+ buf_offset += (nent_to_set * entry_size);
+ nent -= nent_to_set;
+ } while (nent);
}
static void
--
2.18.1
