linux-kernel - Re: iommu/vt-d: Cure VF irqdomain hickup

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Date:   Mon, 16 Nov 2020 10:47:23 +0100
From:   Geert Uytterhoeven <geert@...ux-m68k.org>
To:     Thomas Gleixner <tglx@...utronix.de>
Cc:     Jason Gunthorpe <jgg@...dia.com>,
        Ziyad Atiyyeh <ziyadat@...dia.com>,
        Itay Aveksis <itayav@...dia.com>,
        Moshe Shemesh <moshe@...dia.com>,
        LKML <linux-kernel@...r.kernel.org>,
        "the arch/x86 maintainers" <x86@...nel.org>,
        Joerg Roedel <joro@...tes.org>,
        Linux IOMMU <iommu@...ts.linux-foundation.org>,
        linux-pci <linux-pci@...r.kernel.org>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Marc Zyngier <maz@...nel.org>,
        David Woodhouse <dwmw2@...radead.org>
Subject: Re: iommu/vt-d: Cure VF irqdomain hickup

Hi Thomas,

On Thu, Nov 12, 2020 at 8:16 PM Thomas Gleixner <tglx@...utronix.de> wrote:
> The recent changes to store the MSI irqdomain pointer in struct device
> missed that Intel DMAR does not register virtual function devices.  Due to
> that a VF device gets the plain PCI-MSI domain assigned and then issues
> compat MSI messages which get caught by the interrupt remapping unit.
>
> Cure that by inheriting the irq domain from the physical function
> device.
>
> That's a temporary workaround. The correct fix is to inherit the irq domain
> from the bus, but that's a larger effort which needs quite some other
> changes to the way how x86 manages PCI and MSI domains.
>
> Fixes: 85a8dfc57a0b ("iommm/vt-d: Store irq domain in struct device")
> Reported-by: Jason Gunthorpe <jgg@...dia.com>
> Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
> ---
>  drivers/iommu/intel/dmar.c |   19 ++++++++++++++++++-
>  1 file changed, 18 insertions(+), 1 deletion(-)
>
> --- a/drivers/iommu/intel/dmar.c
> +++ b/drivers/iommu/intel/dmar.c
> @@ -333,6 +333,11 @@ static void  dmar_pci_bus_del_dev(struct
>         dmar_iommu_notify_scope_dev(info);
>  }
>
> +static inline void vf_inherit_msi_domain(struct pci_dev *pdev)
> +{
> +       dev_set_msi_domain(&pdev->dev, dev_get_msi_domain(&pdev->physfn->dev));

If CONFIG_PCI_ATS is not set:

    error: 'struct pci_dev' has no member named 'physfn'

http://kisskb.ellerman.id.au/kisskb/buildresult/14400927/

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds