Re: [PATCH v3 12/16] iommu/vt-d: report unrecoverable device faults

[Lu Baolu]

Hi,

On 11/18/2017 02:55 AM, Jacob Pan wrote:
> Currently, when device DMA faults are detected by IOMMU the fault
> reasons are printed but the driver of the offending device is

"... but the driver of the offending device is not involved in ..."

Best regards,
Lu Baolu

> involved in fault handling.
> This patch uses per device fault reporting API to send fault event
> data for further processing.
> Offending device is identified by the source ID in VT-d fault reason
> report registers.
>
> Signed-off-by: Liu, Yi L <yi.l.liu@xxxxxxxxxxxxxxx>
> Signed-off-by: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx>
> Signed-off-by: Ashok Raj <ashok.raj@xxxxxxxxx>
> ---
>  drivers/iommu/dmar.c | 94 +++++++++++++++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 93 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c
> index 38ee91b..b1f67fc2 100644
> --- a/drivers/iommu/dmar.c
> +++ b/drivers/iommu/dmar.c
> @@ -1555,6 +1555,31 @@ static const char *irq_remap_fault_reasons[] =
>  	"Blocked an interrupt request due to source-id verification failure",
>  };
>  
> +/* fault data and status */
> +enum intel_iommu_fault_reason {
> +	INTEL_IOMMU_FAULT_REASON_SW,
> +	INTEL_IOMMU_FAULT_REASON_ROOT_NOT_PRESENT,
> +	INTEL_IOMMU_FAULT_REASON_CONTEXT_NOT_PRESENT,
> +	INTEL_IOMMU_FAULT_REASON_CONTEXT_INVALID,
> +	INTEL_IOMMU_FAULT_REASON_BEYOND_ADDR_WIDTH,
> +	INTEL_IOMMU_FAULT_REASON_PTE_WRITE_ACCESS,
> +	INTEL_IOMMU_FAULT_REASON_PTE_READ_ACCESS,
> +	INTEL_IOMMU_FAULT_REASON_NEXT_PT_INVALID,
> +	INTEL_IOMMU_FAULT_REASON_ROOT_ADDR_INVALID,
> +	INTEL_IOMMU_FAULT_REASON_CONTEXT_PTR_INVALID,
> +	INTEL_IOMMU_FAULT_REASON_NONE_ZERO_RTP,
> +	INTEL_IOMMU_FAULT_REASON_NONE_ZERO_CTP,
> +	INTEL_IOMMU_FAULT_REASON_NONE_ZERO_PTE,
> +	NR_INTEL_IOMMU_FAULT_REASON,
> +};
> +
> +/* fault reasons that are allowed to be reported outside IOMMU subsystem */
> +#define INTEL_IOMMU_FAULT_REASON_ALLOWED			\
> +	((1ULL << INTEL_IOMMU_FAULT_REASON_BEYOND_ADDR_WIDTH) |	\
> +		(1ULL << INTEL_IOMMU_FAULT_REASON_PTE_WRITE_ACCESS) |	\
> +		(1ULL << INTEL_IOMMU_FAULT_REASON_PTE_READ_ACCESS))
> +
> +
>  static const char *dmar_get_fault_reason(u8 fault_reason, int *fault_type)
>  {
>  	if (fault_reason >= 0x20 && (fault_reason - 0x20 <
> @@ -1635,6 +1660,69 @@ void dmar_msi_read(int irq, struct msi_msg *msg)
>  	raw_spin_unlock_irqrestore(&iommu->register_lock, flag);
>  }
>  
> +static enum iommu_fault_reason to_iommu_fault_reason(u8 reason)
> +{
> +	if (reason >= NR_INTEL_IOMMU_FAULT_REASON) {
> +		pr_warn("unknown DMAR fault reason %d\n", reason);
> +		return IOMMU_FAULT_REASON_UNKNOWN;
> +	}
> +	switch (reason) {
> +	case INTEL_IOMMU_FAULT_REASON_SW:
> +	case INTEL_IOMMU_FAULT_REASON_ROOT_NOT_PRESENT:
> +	case INTEL_IOMMU_FAULT_REASON_CONTEXT_NOT_PRESENT:
> +	case INTEL_IOMMU_FAULT_REASON_CONTEXT_INVALID:
> +	case INTEL_IOMMU_FAULT_REASON_BEYOND_ADDR_WIDTH:
> +	case INTEL_IOMMU_FAULT_REASON_ROOT_ADDR_INVALID:
> +	case INTEL_IOMMU_FAULT_REASON_CONTEXT_PTR_INVALID:
> +		return IOMMU_FAULT_REASON_INTERNAL;
> +	case INTEL_IOMMU_FAULT_REASON_NEXT_PT_INVALID:
> +	case INTEL_IOMMU_FAULT_REASON_PTE_WRITE_ACCESS:
> +	case INTEL_IOMMU_FAULT_REASON_PTE_READ_ACCESS:
> +		return IOMMU_FAULT_REASON_PERMISSION;
> +	default:
> +		return IOMMU_FAULT_REASON_UNKNOWN;
> +	}
> +}
> +
> +static void report_fault_to_device(struct intel_iommu *iommu, u64 addr, int type,
> +				int fault_type, enum intel_iommu_fault_reason reason, u16 sid)
> +{
> +	struct iommu_fault_event event;
> +	struct pci_dev *pdev;
> +	u8 bus, devfn;
> +
> +	/* check if fault reason is worth reporting outside IOMMU */
> +	if (!((1 << reason) & INTEL_IOMMU_FAULT_REASON_ALLOWED)) {
> +		pr_debug("Fault reason %d not allowed to report to device\n",
> +			reason);
> +		return;
> +	}
> +
> +	bus = PCI_BUS_NUM(sid);
> +	devfn = PCI_DEVFN(PCI_SLOT(sid), PCI_FUNC(sid));
> +	/*
> +	 * we need to check if the fault reporting is requested for the
> +	 * offending device.
> +	 */
> +	pdev = pci_get_bus_and_slot(bus, devfn);
> +	if (!pdev) {
> +		pr_warn("No PCI device found for source ID %x\n", sid);
> +		return;
> +	}
> +	/*
> +	 * unrecoverable fault is reported per IOMMU, notifier handler can
> +	 * resolve PCI device based on source ID.
> +	 */
> +	event.reason = to_iommu_fault_reason(reason);
> +	event.addr = addr;
> +	event.type = IOMMU_FAULT_DMA_UNRECOV;
> +	event.prot = type ? IOMMU_READ : IOMMU_WRITE;
> +	dev_warn(&pdev->dev, "report device unrecoverable fault: %d, %x, %d\n",
> +		event.reason, sid, event.type);
> +	iommu_report_device_fault(&pdev->dev, &event);
> +	pci_dev_put(pdev);
> +}
> +
>  static int dmar_fault_do_one(struct intel_iommu *iommu, int type,
>  		u8 fault_reason, u16 source_id, unsigned long long addr)
>  {
> @@ -1648,11 +1736,15 @@ static int dmar_fault_do_one(struct intel_iommu *iommu, int type,
>  			source_id >> 8, PCI_SLOT(source_id & 0xFF),
>  			PCI_FUNC(source_id & 0xFF), addr >> 48,
>  			fault_reason, reason);
> -	else
> +	else {
>  		pr_err("[%s] Request device [%02x:%02x.%d] fault addr %llx [fault reason %02d] %s\n",
>  		       type ? "DMA Read" : "DMA Write",
>  		       source_id >> 8, PCI_SLOT(source_id & 0xFF),
>  		       PCI_FUNC(source_id & 0xFF), addr, fault_reason, reason);
> +	}
> +	report_fault_to_device(iommu, addr, type, fault_type,
> +			fault_reason, source_id);
> +
>  	return 0;
>  }
>