From: Dmitry Safonov <0x7f454c46@gmail.com>
To: James Sewart <jamessewart@arista.com>, iommu@lists.linux-foundation.org
Cc: Bjorn Helgaas <bhelgaas@google.com>,
linux-pci@vger.kernel.org, Logan Gunthorpe <logang@deltatee.com>,
linux-kernel@vger.kernel.org, Dmitry Safonov <dima@arista.com>
Subject: Re: [PATCH] Ensure pci transactions coming from PLX NTB are handled when IOMMU is turned on
Date: Wed, 20 Nov 2019 17:48:45 +0000 [thread overview]
Message-ID: <5c3b56dd-7088-e544-6628-01506f7b84e8@gmail.com> (raw)
In-Reply-To: <0B8FAD0D-B598-4CEA-A614-67F4C7C5B9CA@arista.com>
+Cc: linux-pci@vger.kernel.org
+Cc: Bjorn Helgaas <bhelgaas@google.com>
+Cc: Logan Gunthorpe <logang@deltatee.com>
On 11/5/19 12:17 PM, James Sewart wrote:
> Any comments on this?
>
> Cheers,
> James.
>
>> On 24 Oct 2019, at 13:52, James Sewart <jamessewart@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 <jamessewart@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
>>
>>
>
Thanks,
Dmitry
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next prev parent reply other threads:[~2019-11-20 17:48 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-24 12:52 [PATCH] Ensure pci transactions coming from PLX NTB are handled when IOMMU is turned on James Sewart via iommu
2019-11-05 12:17 ` James Sewart via iommu
2019-11-20 17:48 ` Dmitry Safonov [this message]
2019-11-20 19:30 ` Logan Gunthorpe
2019-11-20 19:49 ` Bjorn Helgaas
2019-11-20 19:32 ` Bjorn Helgaas
2019-11-26 17:03 ` [PATCH v2] PCI: Add DMA alias quirk for PLX PEX NTB James Sewart via iommu
2019-11-26 17:06 ` Logan Gunthorpe
2019-11-26 17:36 ` [PATCH v3 1/2] PCI: Add helper pci_add_dma_alias_range James Sewart via iommu
2019-11-26 17:37 ` [PATCH v3 2/2] PCI: Add DMA alias quirk for PLX PEX NTB James Sewart via iommu
2019-11-26 17:38 ` [PATCH v2] " Christoph Hellwig
2019-11-27 13:27 ` [PATCH v3 1/2] PCI: Add parameter nr_devfns to pci_add_dma_alias James Sewart via iommu
2019-11-27 13:28 ` [PATCH v3 2/2] PCI: Add DMA alias quirk for PLX PEX NTB James Sewart via iommu
2019-11-27 17:38 ` [PATCH v3 1/2] PCI: Add parameter nr_devfns to pci_add_dma_alias Logan Gunthorpe
2019-11-29 12:49 ` [PATCH v4 " James Sewart via iommu
2019-11-29 12:49 ` [PATCH v4 2/2] PCI: Add DMA alias quirk for PLX PEX NTB James Sewart via iommu
2019-11-29 16:50 ` [PATCH v4 1/2] PCI: Add parameter nr_devfns to pci_add_dma_alias Logan Gunthorpe
2019-11-29 17:19 ` James Sewart via iommu
2019-11-29 17:26 ` Logan Gunthorpe
2019-11-29 17:56 ` [PATCH v5 1/3] PCI: Fix off by one in dma_alias_mask allocation size James Sewart via iommu
2019-11-29 17:56 ` [PATCH v5 2/3] PCI: Add parameter nr_devfns to pci_add_dma_alias James Sewart via iommu
2019-11-29 17:57 ` [PATCH v5 3/3] PCI: Add DMA alias quirk for PLX PEX NTB James Sewart via iommu
2019-12-02 17:03 ` [PATCH v5 2/3] PCI: Add parameter nr_devfns to pci_add_dma_alias Christoph Hellwig
2019-11-29 17:58 ` [PATCH v5 1/3] PCI: Fix off by one in dma_alias_mask allocation size Logan Gunthorpe
2019-12-02 17:03 ` Christoph Hellwig
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