On Mon, 7 Aug 2023 13:57:53 -0700
Brett Creeley <brett.creeley@xxxxxxx> wrote:
...
> +static int pds_vfio_dirty_enable(struct pds_vfio_pci_device *pds_vfio,
> + struct rb_root_cached *ranges, u32 nnodes,
> + u64 *page_size)
> +{
> + struct pci_dev *pdev = pds_vfio->vfio_coredev.pdev;
> + struct device *pdsc_dev = &pci_physfn(pdev)->dev;
> + struct pds_vfio_dirty *dirty = &pds_vfio->dirty;
> + u64 region_start, region_size, region_page_size;
> + struct pds_lm_dirty_region_info *region_info;
> + struct interval_tree_node *node = NULL;
> + u8 max_regions = 0, num_regions;
> + dma_addr_t regions_dma = 0;
> + u32 num_ranges = nnodes;
> + u32 page_count;
> + u16 len;
> + int err;
> +
> + dev_dbg(&pdev->dev, "vf%u: Start dirty page tracking\n",
> + pds_vfio->vf_id);
> +
> + if (pds_vfio_dirty_is_enabled(pds_vfio))
> + return -EINVAL;
> +
> + /* find if dirty tracking is disabled, i.e. num_regions == 0 */
> + err = pds_vfio_dirty_status_cmd(pds_vfio, 0, &max_regions,
> + &num_regions);
> + if (err < 0) {
> + dev_err(&pdev->dev, "Failed to get dirty status, err %pe\n",
> + ERR_PTR(err));
> + return err;
> + } else if (num_regions) {
> + dev_err(&pdev->dev,
> + "Dirty tracking already enabled for %d regions\n",
> + num_regions);
> + return -EEXIST;
> + } else if (!max_regions) {
> + dev_err(&pdev->dev,
> + "Device doesn't support dirty tracking, max_regions %d\n",
> + max_regions);
> + return -EOPNOTSUPP;
> + }
> +
> + /*
> + * Only support 1 region for now. If there are any large gaps in the
> + * VM's address regions, then this would be a waste of memory as we are
> + * generating 2 bitmaps (ack/seq) from the min address to the max
> + * address of the VM's address regions. In the future, if we support
> + * more than one region in the device/driver we can split the bitmaps
> + * on the largest address region gaps. We can do this split up to the
> + * max_regions times returned from the dirty_status command.
> + */
Isn't this a pretty unfortunately limitation given QEMU makes a 1TB
hole on AMD hosts? Or maybe I misunderstand.
https://gitlab.com/qemu-project/qemu/-/commit/8504f129450b909c88e199ca44facd35d38ba4de
Thanks,
Alex
