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SubjectRe: [PATCH 1/9] iommu: Move iommu fault data to linux/iommu.h
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On 2023/7/11 14:05, Tian, Kevin wrote:
>> From: Lu Baolu <baolu.lu@linux.intel.com>
>> Sent: Tuesday, July 11, 2023 9:07 AM
>> +
>> +enum iommu_fault_reason {
>> + IOMMU_FAULT_REASON_UNKNOWN = 0,
>> +
>> + /* Could not access the PASID table (fetch caused external abort) */
>> + IOMMU_FAULT_REASON_PASID_FETCH,
>> +
>> + /* PASID entry is invalid or has configuration errors */
>> + IOMMU_FAULT_REASON_BAD_PASID_ENTRY,
>> +
>> + /*
>> + * PASID is out of range (e.g. exceeds the maximum PASID
>> + * supported by the IOMMU) or disabled.
>> + */
>> + IOMMU_FAULT_REASON_PASID_INVALID,
>> +
>> + /*
>> + * An external abort occurred fetching (or updating) a translation
>> + * table descriptor
>> + */
>> + IOMMU_FAULT_REASON_WALK_EABT,
>> +
>> + /*
>> + * Could not access the page table entry (Bad address),
>> + * actual translation fault
>> + */
>> + IOMMU_FAULT_REASON_PTE_FETCH,
>> +
>> + /* Protection flag check failed */
>> + IOMMU_FAULT_REASON_PERMISSION,
>> +
>> + /* access flag check failed */
>> + IOMMU_FAULT_REASON_ACCESS,
>> +
>> + /* Output address of a translation stage caused Address Size fault */
>> + IOMMU_FAULT_REASON_OOR_ADDRESS,
>> +};
>> +
>> +/**
>> + * struct iommu_fault_unrecoverable - Unrecoverable fault data
>> + * @reason: reason of the fault, from &enum iommu_fault_reason
>> + * @flags: parameters of this fault (IOMMU_FAULT_UNRECOV_* values)
>> + * @pasid: Process Address Space ID
>> + * @perm: requested permission access using by the incoming transaction
>> + * (IOMMU_FAULT_PERM_* values)
>> + * @addr: offending page address
>> + * @fetch_addr: address that caused a fetch abort, if any
>> + */
>> +struct iommu_fault_unrecoverable {
>> + __u32 reason;
>> +#define IOMMU_FAULT_UNRECOV_PASID_VALID (1 << 0)
>> +#define IOMMU_FAULT_UNRECOV_ADDR_VALID (1 << 1)
>> +#define IOMMU_FAULT_UNRECOV_FETCH_ADDR_VALID (1 << 2)
>> + __u32 flags;
>> + __u32 pasid;
>> + __u32 perm;
>> + __u64 addr;
>> + __u64 fetch_addr;
>> +};
>
> Currently there is no handler for unrecoverable faults.
>
> Both Intel/ARM register iommu_queue_iopf() as the device fault handler.
> It returns -EOPNOTSUPP for unrecoverable faults.
>
> In your series the common iommu_handle_io_pgfault() also only works
> for PRQ.
>
> It kinds of suggest above definitions are dead code, though arm-smmu-v3
> does attempt to set them.
>
> Probably it's right time to remove them.
>
> In the future even if there might be a need of forwarding unrecoverable
> faults to the user via iommufd, fault reasons reported by the physical
> IOMMU doesn't make any sense to the guest. Presumably the vIOMMU
> should walk guest configurations to set a fault reason which makes sense
> from guest p.o.v.

I am fine to remove unrecoverable faults data. But it was added by Jean,
so I'd like to know his opinion on this.

Best regards,
baolu

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