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From: "Patel, Nirmal" <nirmal.patel@linux.intel.com>
To: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: linux-pci@vger.kernel.org, maz@kernel.org
Subject: Re: [PATCH 1/2] PCI: vmd: Assign VMD IRQ domain before enumeration
Date: Wed, 11 May 2022 09:57:19 -0700	[thread overview]
Message-ID: <fccd0dc4-fe00-6f34-0fd3-3cedcbcb8ca3@linux.intel.com> (raw)
In-Reply-To: <Ynt9jJU78JnIiZ7z@lpieralisi>

On 5/11/2022 2:10 AM, Lorenzo Pieralisi wrote:
> [Adding Marc, to keep an eye on IRQ domain usage]
>
> On Mon, May 02, 2022 at 01:48:59AM -0700, Nirmal Patel wrote:
>> VMD creates and assigns a separate IRQ domain when MSI-X remapping is
>> enabled. For example VMD-MSI. But VMD doesn't assign IRQ domain when
>> MSI-X remapping is disabled resulting child devices getting default
>> PCI-MSI IRQ domain. Now when interrupt remapping is enabled by
>> intel-iommu all the PCI devices are assigned INTEL-IR-MSI domain
>> including VMD endpoints. But devices behind VMD get PCI-MSI IRQ domain
>> when VMD create a root bus and configures child devices.
> I would encourage you to rewrite this log, it is unclear - granted,
> I don't know intel-iommu internals - but IMHO if you explain the
> issue and the fix thoroughly this could avoid repeating what
> you have to do in patch(2).
>
> Please describe how VMD handles IRQ domains and how you are fixing
> that.
>
> Thanks,
> Lorenzo
I will add more information to the commit logs.

Thanks,
nirmal

>> As a result DMAR errors were observed when interrupt remapping was
>> enabled on Intel Icelake CPUs. For instance:
>>
>>   DMAR: DRHD: handling fault status reg 2
>>   DMAR: [INTR-REMAP] Request device [0xe2:0x00.0] fault index 0xa00 [fault reason 0x25] Blocked a compatibility format interrupt request
>>
>> Signed-off-by: Nirmal Patel <nirmal.patel@linux.intel.com>
>> ---
>>  drivers/pci/controller/vmd.c | 3 +++
>>  1 file changed, 3 insertions(+)
>>
>> diff --git a/drivers/pci/controller/vmd.c b/drivers/pci/controller/vmd.c
>> index eb05cceab964..5015adc04d19 100644
>> --- a/drivers/pci/controller/vmd.c
>> +++ b/drivers/pci/controller/vmd.c
>> @@ -853,6 +853,9 @@ static int vmd_enable_domain(struct vmd_dev *vmd, unsigned long features)
>>  	vmd_attach_resources(vmd);
>>  	if (vmd->irq_domain)
>>  		dev_set_msi_domain(&vmd->bus->dev, vmd->irq_domain);
>> +	else
>> +		dev_set_msi_domain(&vmd->bus->dev,
>> +				   dev_get_msi_domain(&vmd->dev->dev));
>>  
>>  	vmd_acpi_begin();
>>  
>> -- 
>> 2.26.2
>>


  reply	other threads:[~2022-05-11 16:57 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-05-02  8:48 [PATCH 0/2] PCI: vmd: IRQ domain assignment to sub devices Nirmal Patel
2022-05-02  8:48 ` [PATCH 1/2] PCI: vmd: Assign VMD IRQ domain before enumeration Nirmal Patel
2022-05-11  9:10   ` Lorenzo Pieralisi
2022-05-11 16:57     ` Patel, Nirmal [this message]
2022-05-02  8:49 ` [PATCH 2/2] PCI: vmd: Revert 2565e5b69c44 ("PCI: vmd: Do not disable MSI-X remapping if interrupt remapping is enabled by IOMMU.") Nirmal Patel

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