Re: [PATCH v1 15/19] memory: Add an API for ATS support

["Michael S. Tsirkin" <mst@redhat.com>]

On Fri, Nov 29, 2024 at 07:44:00AM +0000, CLEMENT MATHIEU--DRIF wrote:
> From: Clément Mathieu--Drif <clement.mathieu--drif@eviden.com>
> 
> IOMMU have to implement iommu_ats_request_translation to support ATS.
> 
> Devices can use IOMMU_TLB_ENTRY_TRANSLATION_ERROR to check the tlb
> entries returned by a translation request.
> 
> We decided not to use the existing translation operation for 2 reasons.
> First, ATS is designed to translate ranges and not isolated addresses.
> Second, we need ATS-specific parameters.
> 
> Signed-off-by: Clément Mathieu--Drif <clement.mathieu--drif@eviden.com>
> ---
>  include/exec/memory.h | 26 ++++++++++++++++++++++++++
>  system/memory.c       | 20 ++++++++++++++++++++
>  2 files changed, 46 insertions(+)
> 
> diff --git a/include/exec/memory.h b/include/exec/memory.h
> index c0d064dbd8..14166e2874 100644
> --- a/include/exec/memory.h
> +++ b/include/exec/memory.h
> @@ -148,6 +148,10 @@ struct IOMMUTLBEntry {
>      uint32_t         pasid;
>  };
>  
> +/* Check if an IOMMU TLB entry indicates a translation error */
> +#define IOMMU_TLB_ENTRY_TRANSLATION_ERROR(entry) ((((entry)->perm) & IOMMU_RW) \
> +                                                    == IOMMU_NONE)
> +
>  /*
>   * Bitmap for different IOMMUNotifier capabilities. Each notifier can
>   * register with one or multiple IOMMU Notifier capability bit(s).
> @@ -525,6 +529,20 @@ struct IOMMUMemoryRegionClass {
>       * @iommu: the IOMMUMemoryRegion
>       */
>      int (*num_indexes)(IOMMUMemoryRegion *iommu);
> +
> +    /**
> +     * @iommu_ats_request_translation:
> +     * This method must be implemented if the IOMMU has ATS enabled
> +     *
> +     * @see pci_ats_request_translation_pasid
> +     */
> +    ssize_t (*iommu_ats_request_translation)(IOMMUMemoryRegion *iommu,
> +                                             bool priv_req, bool exec_req,
> +                                             hwaddr addr, size_t length,
> +                                             bool no_write,
> +                                             IOMMUTLBEntry *result,
> +                                             size_t result_length,
> +                                             uint32_t *err_count);
>  };
>  
>  typedef struct RamDiscardListener RamDiscardListener;
> @@ -1883,6 +1901,14 @@ void memory_region_iommu_replay(IOMMUMemoryRegion *iommu_mr, IOMMUNotifier *n);
>  void memory_region_unregister_iommu_notifier(MemoryRegion *mr,
>                                               IOMMUNotifier *n);
>  
> +ssize_t memory_region_iommu_ats_request_translation(IOMMUMemoryRegion *iommu_mr,
> +                                                bool priv_req, bool exec_req,
> +                                                hwaddr addr, size_t length,
> +                                                bool no_write,
> +                                                IOMMUTLBEntry *result,
> +                                                size_t result_length,
> +                                                uint32_t *err_count);
> +
>  /**
>   * memory_region_iommu_get_attr: return an IOMMU attr if get_attr() is
>   * defined on the IOMMU.
> diff --git a/system/memory.c b/system/memory.c
> index 85f6834cb3..7f6f3798e6 100644
> --- a/system/memory.c
> +++ b/system/memory.c
> @@ -2011,6 +2011,26 @@ void memory_region_unregister_iommu_notifier(MemoryRegion *mr,
>      memory_region_update_iommu_notify_flags(iommu_mr, NULL);
>  }
>  
> +ssize_t memory_region_iommu_ats_request_translation(IOMMUMemoryRegion *iommu_mr,
> +                                                    bool priv_req,
> +                                                    bool exec_req,
> +                                                    hwaddr addr, size_t length,
> +                                                    bool no_write,
> +                                                    IOMMUTLBEntry *result,
> +                                                    size_t result_length,
> +                                                    uint32_t *err_count)
> +{
> +    IOMMUMemoryRegionClass *imrc = memory_region_get_iommu_class_nocheck(iommu_mr);
> +


line too long - just call the variable mr.

> +    if (!imrc->iommu_ats_request_translation) {
> +        return -ENODEV;
> +    }
> +
> +    return imrc->iommu_ats_request_translation(iommu_mr, priv_req, exec_req,
> +                                               addr, length, no_write, result,
> +                                               result_length, err_count);
> +}
> +
>  void memory_region_notify_iommu_one(IOMMUNotifier *notifier,
>                                      const IOMMUTLBEvent *event)
>  {
> -- 
> 2.47.0