Any comments on this?
Cheers,
James.
> On 24 Oct 2019, at 13:52, James Sewart <jamessew...@arista.com> wrote:
>
> The PLX PEX NTB forwards DMA transactions using Requester ID's that don't
> exist as
> PCI devices. The devfn for a transaction is used as an index into a lookup
> table
> storing the origin of a transaction on the other side of the bridge.
>
> This patch aliases all possible devfn's to the NTB device so that any
> transaction
> coming in is governed by the mappings for the NTB.
>
> Signed-Off-By: James Sewart <jamessew...@arista.com>
> ---
> drivers/pci/quirks.c | 22 ++++++++++++++++++++++
> 1 file changed, 22 insertions(+)
>
> diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
> index 320255e5e8f8..647f546e427f 100644
> --- a/drivers/pci/quirks.c
> +++ b/drivers/pci/quirks.c
> @@ -5315,6 +5315,28 @@ SWITCHTEC_QUIRK(0x8574); /* PFXI 64XG3 */
> SWITCHTEC_QUIRK(0x8575); /* PFXI 80XG3 */
> SWITCHTEC_QUIRK(0x8576); /* PFXI 96XG3 */
>
> +/*
> + * PLX NTB uses devfn proxy IDs to move TLPs between NT endpoints. These IDs
> + * are used to forward responses to the originator on the other side of the
> + * NTB. Alias all possible IDs to the NTB to permit access when the IOMMU is
> + * turned on.
> + */
> +static void quirk_PLX_NTB_dma_alias(struct pci_dev *pdev)
> +{
> + if (!pdev->dma_alias_mask)
> + pdev->dma_alias_mask = kcalloc(BITS_TO_LONGS(U8_MAX),
> + sizeof(long), GFP_KERNEL);
> + if (!pdev->dma_alias_mask) {
> + dev_warn(&pdev->dev, "Unable to allocate DMA alias mask\n");
> + return;
> + }
> +
> + // PLX NTB may use all 256 devfns
> + memset(pdev->dma_alias_mask, U8_MAX, (U8_MAX+1)/BITS_PER_BYTE);
> +}
> +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_PLX, 0x87b0, quirk_PLX_NTB_dma_alias);
> +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_PLX, 0x87b1, quirk_PLX_NTB_dma_alias);
> +
> /*
> * On Lenovo Thinkpad P50 SKUs with a Nvidia Quadro M1000M, the BIOS does
> * not always reset the secondary Nvidia GPU between reboots if the system
> --
> 2.19.1
>
>
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