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

[Thomas Gleixner]

Geert,

On Mon, Nov 16 2020 at 10:47, Geert Uytterhoeven wrote:
> On Thu, Nov 12, 2020 at 8:16 PM Thomas Gleixner <tglx@xxxxxxxxxxxxx> 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@xxxxxxxxxx>
>> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
>> ---
>>  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