Re: [PATCH] iommu/vt-d: improve IOMMU fault information

[Baolu Lu <baolu.lu@linux.intel.com>]

On 5/25/26 11:47, Guanghui Feng wrote:
> In some environments, multiple PCIe segments exist, and PCIe device
> information needs to be differentiated and identified based on the
> segment. When an IOMMU fault event occurs, the IOMMU and device segment
> information should be output in detail in dmar_fault_do_one.
> 
> Signed-off-by: Guanghui Feng <guanghuifeng@linux.alibaba.com>
> ---
>   drivers/iommu/intel/dmar.c | 11 ++++++++---
>   1 file changed, 8 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/iommu/intel/dmar.c b/drivers/iommu/intel/dmar.c
> index d33c119a935e..ca9afbb55e76 100644
> --- a/drivers/iommu/intel/dmar.c
> +++ b/drivers/iommu/intel/dmar.c
> @@ -1894,7 +1894,8 @@ static int dmar_fault_do_one(struct intel_iommu *iommu, int type,
>   	reason = dmar_get_fault_reason(fault_reason, &fault_type);
>   
>   	if (fault_type == INTR_REMAP) {
> -		pr_err("[INTR-REMAP] Request device [%02x:%02x.%d] fault index 0x%llx [fault reason 0x%02x] %s\n",
> +		pr_err("[DMAR:%s] [INTR-REMAP] Request device [%04x:%02x:%02x.%d] fault index 0x%llx [fault reason 0x%02x] %s\n",
> +		       iommu->name, iommu->segment,
>   		       source_id >> 8, PCI_SLOT(source_id & 0xFF),
>   		       PCI_FUNC(source_id & 0xFF), addr >> 48,
>   		       fault_reason, reason);
> @@ -1903,14 +1904,18 @@ static int dmar_fault_do_one(struct intel_iommu *iommu, int type,
>   	}
>   
>   	if (pasid == IOMMU_PASID_INVALID)
> -		pr_err("[%s NO_PASID] Request device [%02x:%02x.%d] fault addr 0x%llx [fault reason 0x%02x] %s\n",
> +		pr_err("[DMAR:%s] [%s NO_PASID] Request device [%04x:%02x:%02x.%d] fault addr 0x%llx [fault reason 0x%02x] %s\n",
> +		       iommu->name,

Do you really need to dump "iommu->name"? It is purely assigned by the
IOMMU driver software. Do you mind explaining what kind of information
you want to get from it?

>   		       type ? "DMA Read" : "DMA Write",
> +		       iommu->segment,
>   		       source_id >> 8, PCI_SLOT(source_id & 0xFF),
>   		       PCI_FUNC(source_id & 0xFF), addr,
>   		       fault_reason, reason);
>   	else
> -		pr_err("[%s PASID 0x%x] Request device [%02x:%02x.%d] fault addr 0x%llx [fault reason 0x%02x] %s\n",
> +		pr_err("[DMAR:%s] [%s PASID 0x%x] Request device [%04x:%02x:%02x.%d] fault addr 0x%llx [fault reason 0x%02x] %s\n",
> +		       iommu->name,
>   		       type ? "DMA Read" : "DMA Write", pasid,
> +		       iommu->segment,
>   		       source_id >> 8, PCI_SLOT(source_id & 0xFF),
>   		       PCI_FUNC(source_id & 0xFF), addr,
>   		       fault_reason, reason);

Thanks,
baolu