From: Baolu Lu baolu.lu@linux.intel.com Sent: Sunday, April 27, 2025 2:24 PM
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 ininclude/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
for PCI it's the virtual BDF in the guest PCI topology, hence provided by the VMM when calling @vdevice_alloc:
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?
It's OK to maintain a KVM pointer in viommu (for which I recall such discussion for confidential io), but obviously it's not the requirement in this series.