dev-arm: SMMUv3 Table walks using TnSZ

TnSZ is needed when selecting the starting level of a table
walk, since it directly affects the number of IA bits.
This has been implemented by adding T0SZ and S2T0SZ to the
translation context.
T1SZ is not used at the moment since the current model doesn't
support TTB1.

Change-Id: I75663475c4dc01e5986cd93f8deafcdf7b1ece82
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-by: Michiel Van Tol <michiel.vantol@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/19630
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>

dev-arm: Use override keyword for SMMUv3 PTOPS

Replacing the "virtual" keyword

Change-Id: I0e7b4b683ea222827a67c3a81f0deea0e906c7e5
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-by: Michiel Van Tol <michiel.vantol@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/19629
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>

dev-arm: Add 16K granule support to SMMUv3 model

Added the necessary PageTableOps that match the 16K granule
translation regime.

Change-Id: I46ef07939cb4bdc8c0bbbeeeb6a50a9ab0d64de0
Reviewed-by: Michiel Van Tol <michiel.vantol@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/19628
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>

dev-arm: Implement a SMMUv3 model

This is an implementation of the SMMUv3 architecture.

What can it do?
- Single-stage and nested translation with 4k or 64k granule. 16k would
be straightforward to add.
- Large pages are supported.
- Works with any gem5 device as long as it is issuing packets with a
valid (Sub)StreamId

What it can't do?
- Fragment stage 1 page when the underlying stage 2 page is smaller. S1
page size > S2 page size is not supported
- Invalidations take zero time. This wouldn't be hard to fix.
- Checkpointing is not supported
- Stall/resume for faulting transactions is not supported

Additional contributors:
- Michiel W. van Tol <Michiel.VanTol@arm.com>
- Giacomo Travaglini <giacomo.travaglini@arm.com>

Change-Id: Ibc606fccd9199b2c1ba739c6335c846ffaa4d564
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/19008
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>