[RFC PATCH v2 4/7] iommufd: Associate kvm pointer to iommufd ctx

[Tian, Kevin]

> From: Sean Christopherson <seanjc at google.com>
> Sent: Tuesday, June 25, 2024 3:29 AM
> 
> On Mon, Jun 24, 2024, Oliver Upton wrote:
> > VMID=0 is associated with the host's MMU context, which is relevant when
> > running {n,h}VHE mode, as the VMID tags TLB entries even if stage-2
> > translation is disabled (HCR_EL2.VM = 0).
> 
> Heh, I assumed VMID=0 is the host MMU, Intel and AMD have the same
> effective
> behavior :-)

side note - Intel VT-d spec recommends stage-1 translations using a
VMID different from those associated with stage-2, but not necessarily
to be 0. intel-iommu driver uses '1' so far:

/*
 * Domain ID reserved for pasid entries programmed for first-level
 * only and pass-through transfer modes.
 */
#define FLPT_DEFAULT_DID                1