On Tue, Dec 10, 2024 at 08:49:40AM +0530, Aneesh Kumar K.V wrote:
>
> Hi Dan,
>
> Dan Williams <dan.j.williams@xxxxxxxxx> writes:
> > +int pci_ide_stream_setup(struct pci_dev *pdev, struct pci_ide *ide,
> > + enum pci_ide_flags flags)
> > +{
> > + struct pci_host_bridge *hb = pci_find_host_bridge(pdev->bus);
> > + struct pci_dev *rp = pcie_find_root_port(pdev);
> > + int mem = 0, rc;
> > +
> > + if (ide->stream_id < 0 || ide->stream_id > U8_MAX) {
> > + pci_err(pdev, "Setup fail: Invalid stream id: %d\n", ide->stream_id);
> > + return -ENXIO;
> > + }
> > +
> > + if (test_and_set_bit_lock(ide->stream_id, hb->ide_stream_ids)) {
> > + pci_err(pdev, "Setup fail: Busy stream id: %d\n",
> > + ide->stream_id);
> > + return -EBUSY;
> > + }
> > +
>
> Considering we are using the hostbridge ide_stream_ids bitmap, why is
> the stream_id allocation not generic? ie, any reason why a stream id alloc
> like below will not work?
Should be illustrating in commit log.
"The other design detail for TSM-coordinated IDE establishment is that
the TSM manages allocation of stream-ids, this is why the stream_id is
passed in to pci_ide_stream_setup()."
This is true for Intel TDX.
Thanks,
Yilun
>
> static int pcie_ide_sel_streamid_alloc(struct pci_dev *pdev)
> {
> int stream_id;
> struct pci_host_bridge *hb;
>
> hb = pci_find_host_bridge(pdev->bus);
>
> stream_id = find_first_zero_bit(hb->ide_stream_ids, hb->nr_ide_streams);
> if (stream_id >= hb->nr_ide_streams)
> return -EBUSY;
>
> return stream_id;
> }
>
> -aneesh
>
