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From:   Thomas Gleixner <tglx@linutronix.de>
To:     Geert Uytterhoeven <geert@linux-m68k.org>
Cc:     Jason Gunthorpe <jgg@nvidia.com>,
        Ziyad Atiyyeh <ziyadat@nvidia.com>,
        Itay Aveksis <itayav@nvidia.com>,
        Moshe Shemesh <moshe@nvidia.com>,
        LKML <linux-kernel@vger.kernel.org>,
        the arch/x86 maintainers <x86@kernel.org>,
        Joerg Roedel <joro@8bytes.org>,
        Linux IOMMU <iommu@lists.linux-foundation.org>,
        linux-pci <linux-pci@vger.kernel.org>,
        Bjorn Helgaas <bhelgaas@google.com>,
        Marc Zyngier <maz@kernel.org>,
        David Woodhouse <dwmw2@infradead.org>
Subject: Re: iommu/vt-d: Cure VF irqdomain hickup
In-Reply-To: <CAMuHMdXA7wfJovmfSH2nbAhN0cPyCiFHodTvg4a8Hm9rx5Dj-w@mail.gmail.com>
References: <20200826111628.794979401@linutronix.de> <20201112125531.GA873287@nvidia.com> <87mtzmmzk6.fsf@nanos.tec.linutronix.de> <87k0uqmwn4.fsf@nanos.tec.linutronix.de> <87d00imlop.fsf@nanos.tec.linutronix.de> <CAMuHMdXA7wfJovmfSH2nbAhN0cPyCiFHodTvg4a8Hm9rx5Dj-w@mail.gmail.com>
Date:   Mon, 16 Nov 2020 13:50:32 +0100
Message-ID: <87lff1zcrr.fsf@nanos.tec.linutronix.de>
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Geert,

On Mon, Nov 16 2020 at 10:47, Geert Uytterhoeven wrote:
> On Thu, Nov 12, 2020 at 8:16 PM Thomas Gleixner <tglx@linutronix.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@nvidia.com>
>> Signed-off-by: Thomas Gleixner <tglx@linutronix.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'
>

thanks for pointing that out. Yet moar ifdeffery, oh well...

Thanks,

        tglx