On Wed, Dec 20, 2023 at 02:24:27PM -0500, Frank Li wrote:
> For the inbound MEM/IO TLPs, iATU on the endpoint expects the target
> address to be aligned to the size of the BAR. For configurable BARs, there
> is no issue because both host and endpoint will know the exact size of the
> BAR region. But for fixed size BARs available in some controllers, if the
> BAR size advertised by the endpoint is not same as of the actual BAR size
> used in the controller, then the MEM/IO TLPs generated by the host will not
> be translated properly by the endpoint iATU.
>
> So if the fixed size BARs are available in endpoint controllers, always use
> the actual BAR size.
>
You should add a note saying that you are fixing the issue only for DB BAR and a
similar fix is needed for other MW BARs.
> Fixes: e35f56bb0330 ("PCI: endpoint: Support NTB transfer between RC and EP")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Frank Li <Frank.Li@xxxxxxx>
With that,
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
- Mani
> ---
>
> Notes:
> Change from v2 to v3
> - rework commti message
> - add fixes and cc stable
> - return -ENOMEN when request size > fix bar size
> Change from v1 to v2
> - Remove unnessary set align when fix_bar_size.
>
> drivers/pci/endpoint/functions/pci-epf-vntb.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/drivers/pci/endpoint/functions/pci-epf-vntb.c b/drivers/pci/endpoint/functions/pci-epf-vntb.c
> index 3f60128560ed0..85120978fb8c9 100644
> --- a/drivers/pci/endpoint/functions/pci-epf-vntb.c
> +++ b/drivers/pci/endpoint/functions/pci-epf-vntb.c
> @@ -550,6 +550,14 @@ static int epf_ntb_db_bar_init(struct epf_ntb *ntb)
>
> barno = ntb->epf_ntb_bar[BAR_DB];
>
> + if (epc_features->bar_fixed_size[barno]) {
> + if (size > epc_features->bar_fixed_size[barno]) {
> + dev_err(dev, "Fixed BAR%d is too small for doorbell\n", barno);
> + return -ENOMEM;
> + }
> + size = epc_features->bar_fixed_size[barno];
> + }
> +
> mw_addr = pci_epf_alloc_space(ntb->epf, size, barno, align, 0);
> if (!mw_addr) {
> dev_err(dev, "Failed to allocate OB address\n");
> --
> 2.34.1
>
>
--
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