On Fri, Jan 15, 2021 at 05:43:42PM +0530, Vivek Gautam wrote:
> Fault type information can tell about a page request fault or
> an unreceoverable fault, and further additions to fault reasons
> and the related PASID information can help in handling faults
> efficiently.
> 
> Signed-off-by: Vivek Gautam <vivek.gau...@arm.com>
> Cc: Joerg Roedel <j...@8bytes.org>
> Cc: Will Deacon <will.dea...@arm.com>
> Cc: Michael S. Tsirkin <m...@redhat.com>
> Cc: Robin Murphy <robin.mur...@arm.com>
> Cc: Jean-Philippe Brucker <jean-phili...@linaro.org>
> Cc: Eric Auger <eric.au...@redhat.com>
> Cc: Alex Williamson <alex.william...@redhat.com>
> Cc: Kevin Tian <kevin.t...@intel.com>
> Cc: Jacob Pan <jacob.jun....@linux.intel.com>
> Cc: Liu Yi L <yi.l....@intel.com>
> Cc: Lorenzo Pieralisi <lorenzo.pieral...@arm.com>
> Cc: Shameerali Kolothum Thodi <shameerali.kolothum.th...@huawei.com>
> ---
>  drivers/iommu/virtio-iommu.c      | 27 +++++++++++++++++++++++++--
>  include/uapi/linux/virtio_iommu.h | 13 ++++++++++++-
>  2 files changed, 37 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/iommu/virtio-iommu.c b/drivers/iommu/virtio-iommu.c
> index 9cc3d35125e9..10ef9e98214a 100644
> --- a/drivers/iommu/virtio-iommu.c
> +++ b/drivers/iommu/virtio-iommu.c
> @@ -652,9 +652,16 @@ static int viommu_fault_handler(struct viommu_dev 
> *viommu,
>       char *reason_str;
>  
>       u8 reason       = fault->reason;
> +     u16 type        = fault->flt_type;
>       u32 flags       = le32_to_cpu(fault->flags);
>       u32 endpoint    = le32_to_cpu(fault->endpoint);
>       u64 address     = le64_to_cpu(fault->address);
> +     u32 pasid       = le32_to_cpu(fault->pasid);
> +
> +     if (type == VIRTIO_IOMMU_FAULT_F_PAGE_REQ) {
> +             dev_info(viommu->dev, "Page request fault - unhandled\n");
> +             return 0;
> +     }
>  
>       switch (reason) {
>       case VIRTIO_IOMMU_FAULT_R_DOMAIN:
> @@ -663,6 +670,21 @@ static int viommu_fault_handler(struct viommu_dev 
> *viommu,
>       case VIRTIO_IOMMU_FAULT_R_MAPPING:
>               reason_str = "page";
>               break;
> +     case VIRTIO_IOMMU_FAULT_R_WALK_EABT:
> +             reason_str = "page walk external abort";
> +             break;
> +     case VIRTIO_IOMMU_FAULT_R_PTE_FETCH:
> +             reason_str = "pte fetch";
> +             break;
> +     case VIRTIO_IOMMU_FAULT_R_PERMISSION:
> +             reason_str = "permission";
> +             break;
> +     case VIRTIO_IOMMU_FAULT_R_ACCESS:
> +             reason_str = "access";
> +             break;
> +     case VIRTIO_IOMMU_FAULT_R_OOR_ADDRESS:
> +             reason_str = "output address";
> +             break;
>       case VIRTIO_IOMMU_FAULT_R_UNKNOWN:
>       default:
>               reason_str = "unknown";
> @@ -671,8 +693,9 @@ static int viommu_fault_handler(struct viommu_dev *viommu,
>  
>       /* TODO: find EP by ID and report_iommu_fault */
>       if (flags & VIRTIO_IOMMU_FAULT_F_ADDRESS)
> -             dev_err_ratelimited(viommu->dev, "%s fault from EP %u at %#llx 
> [%s%s%s]\n",
> -                                 reason_str, endpoint, address,
> +             dev_err_ratelimited(viommu->dev,
> +                                 "%s fault from EP %u PASID %u at %#llx 
> [%s%s%s]\n",
> +                                 reason_str, endpoint, pasid, address,
>                                   flags & VIRTIO_IOMMU_FAULT_F_READ ? "R" : 
> "",
>                                   flags & VIRTIO_IOMMU_FAULT_F_WRITE ? "W" : 
> "",
>                                   flags & VIRTIO_IOMMU_FAULT_F_EXEC ? "X" : 
> "");
> diff --git a/include/uapi/linux/virtio_iommu.h 
> b/include/uapi/linux/virtio_iommu.h
> index 608c8d642e1f..a537d82777f7 100644
> --- a/include/uapi/linux/virtio_iommu.h
> +++ b/include/uapi/linux/virtio_iommu.h
> @@ -290,19 +290,30 @@ struct virtio_iommu_req_invalidate {
>  #define VIRTIO_IOMMU_FAULT_R_UNKNOWN         0
>  #define VIRTIO_IOMMU_FAULT_R_DOMAIN          1
>  #define VIRTIO_IOMMU_FAULT_R_MAPPING         2
> +#define VIRTIO_IOMMU_FAULT_R_WALK_EABT               3
> +#define VIRTIO_IOMMU_FAULT_R_PTE_FETCH               4
> +#define VIRTIO_IOMMU_FAULT_R_PERMISSION              5
> +#define VIRTIO_IOMMU_FAULT_R_ACCESS          6
> +#define VIRTIO_IOMMU_FAULT_R_OOR_ADDRESS     7
>  
>  #define VIRTIO_IOMMU_FAULT_F_READ            (1 << 0)
>  #define VIRTIO_IOMMU_FAULT_F_WRITE           (1 << 1)
>  #define VIRTIO_IOMMU_FAULT_F_EXEC            (1 << 2)
>  #define VIRTIO_IOMMU_FAULT_F_ADDRESS         (1 << 8)
>  
> +#define VIRTIO_IOMMU_FAULT_F_DMA_UNRECOV     1
> +#define VIRTIO_IOMMU_FAULT_F_PAGE_REQ                2

Currently all reported faults are unrecoverable, so to be consistent
DMA_UNRECOV should be 0. But I'd prefer having just a new "page request"
flag in the flags field, instead of the flt_type field.

For page requests we'll also need a 16-bit fault ID field to store the PRI
"page request group index" or the stall "stag". "last" and "privileged"
flags as well, to match the PRI page request. And a new command to
complete a page fault.

> +
>  struct virtio_iommu_fault {
>       __u8                                    reason;
> -     __u8                                    reserved[3];
> +     __le16                                  flt_type;
> +     __u8                                    reserved;
>       __le32                                  flags;
>       __le32                                  endpoint;
>       __u8                                    reserved2[4];

Why not replace reserved2 with the pasid?  It fits perfectly :)

Thanks,
Jean

>       __le64                                  address;
> +     __le32                                  pasid;
> +     __u8                                    reserved3[4];
>  };
>  
>  #endif
> -- 
> 2.17.1
> 
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