Commit 9c7c5430 authored by Yishai Hadas's avatar Yishai Hadas Committed by Alex Williamson
Browse files

vfio/mlx5: Align the page tracking max message size with the device capability 



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: 79c3cf27 ("vfio/mlx5: Init QP based resources for dirty tracking")
Reviewed-by: default avatarCédric Le Goater <clg@redhat.com>
Tested-by: default avatarYingshun Cui <yicui@redhat.com>
Signed-off-by: default avatarYishai Hadas <yishaih@nvidia.com>
Link: https://lore.kernel.org/r/20241205122654.235619-1-yishaih@nvidia.com


Signed-off-by: default avatarAlex Williamson <alex.williamson@redhat.com>
parent 40384c84

drivers/vfio/pci/mlx5/cmd.c

+35 −12
Original line number Diff line number Diff line
@@ -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++) {

	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(buf);

		kunmap_local(kaddr);

		buf_offset += (nent_to_set * entry_size);

		nent -= nent_to_set;

	} while (nent);

}



static void