Re: [PATCH v2 01/22] iommufd/viommu: Add driver-allocated vDEVICE support

On 4/26/25 13:57, Nicolin Chen wrote:

@@ -120,6 +128,13 @@ struct iommufd_viommu {

•                array->entry_num to report the number of handled requests.
  

•                The data structure of the array entry must be defined in
  

•                include/uapi/linux/iommufd.h
  

• • @vdevice_alloc: Allocate a vDEVICE object and init its driver-level structure

• •             or HW procedure. Note that the core-level structure is filled
    

• •             by the iommufd core after calling this op. @virt_id carries a
    

• •             per-vIOMMU virtual ID for the driver to initialize its HW.
    

I'm wondering whether the 'per-vIOMMU virtual ID' is intended to be generic for other features that might require a vdevice. I'm also not sure where this virtual ID originates when I read it here. Could it potentially come from the KVM instance? If so, how about retrieving it directly from a struct kvm pointer? My understanding is that vIOMMU in IOMMUFD acts as a handle to KVM, so perhaps we should maintain a reference to the kvm pointer within the iommufd_viommu structure?

• • @vdevice_destroy: Clean up all driver-specific parts of an iommufd_vdevice.

• •               The memory of the vDEVICE will be free-ed by iommufd core
    

• •               after calling this op
    

  */ struct iommufd_viommu_ops { void (*destroy)(struct iommufd_viommu *viommu);

@@ -128,6 +143,10 @@ struct iommufd_viommu_ops { const struct iommu_user_data *user_data); int (*cache_invalidate)(struct iommufd_viommu *viommu, struct iommu_user_data_array *array);

• struct iommufd_vdevice *(*vdevice_alloc)(struct iommufd_viommu *viommu,

• 				 struct device *dev,
  

• 				 u64 virt_id);
  

• void (*vdevice_destroy)(struct iommufd_vdevice *vdev); };

Thanks, baolu