Re: [PATCH v3] PCI: Mark broken INTx masking for Mellanox devices

[Bjorn Helgaas <bhelgaas@google.com>]

On Tue, Aug 12, 2014 at 09:48:11PM +1000, Gavin Shan wrote:
> The VFIO driver is routing LSI interrupts by capturing, masking,
> and then delivering. When passing though Mellanox adapters from
> host to guest, interrupt storm was reported from host and guest.
> That's because we can't mask the LSI interrupt with help of PCI
> command register.
> 
>  # lspci | grep Mellanox
>  0001:05:00.0 Ethernet controller: Mellanox Technologies MT27500 \
>               Family [ConnectX-3]
>  0005:01:00.0 Ethernet controller: Mellanox Technologies MT26448 \
>               [ConnectX EN 10GigE, PCIe 2.0 5GT/s] (rev b0)
> 
> It's confirmed by Amir Vadai that all Mellanox devices have same
> problem. The patch marks broken INTx masking for all Mellanox
> adapters.
> 
> Cc: Amir Vadai <amirv@mellanox.com>
> Suggested-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>

I applied this with Amir's ack to pci/virtualization for v3.18.

It's possible Mellanox will someday make a device where INTx masking works.
I guess we'll have to deal with that if and when it happens.

> ---
> v3: Mark broken INTx masking for all Mellanox adapters
> ---
>  drivers/pci/quirks.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
> index 80c2d01..da062d8 100644
> --- a/drivers/pci/quirks.c
> +++ b/drivers/pci/quirks.c
> @@ -2985,6 +2985,8 @@ DECLARE_PCI_FIXUP_HEADER(0x1814, 0x0601, /* Ralink RT2800 802.11n PCI */
>   */
>  DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_REALTEK, 0x8169,
>  			 quirk_broken_intx_masking);
> +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_MELLANOX, PCI_ANY_ID,
> +			 quirk_broken_intx_masking);
>  
>  #ifdef CONFIG_ACPI
>  /*
> -- 
> 1.8.3.2
> 
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