hw/arm/smmuv3: Add page table walk for stage-2

In preparation for adding stage-2 support, add Stage-2 PTW code.
Only Aarch64 format is supported as stage-1.

Nesting stage-1 and stage-2 is not supported right now.

HTTU is not supported, SW is expected to maintain the Access flag.
This is described in the SMMUv3 manual(IHI 0070.E.a)
"5.2. Stream Table Entry" in "[181] S2AFFD".
This flag determines the behavior on access of a stage-2 page whose
descriptor has AF == 0:
- 0b0: An Access flag fault occurs (stall not supported).
- 0b1: An Access flag fault never occurs.
An Access fault takes priority over a Permission fault.

There are 3 address size checks for stage-2 according to
(IHI 0070.E.a) in "3.4. Address sizes".
- As nesting is not supported, input address is passed directly to
stage-2, and is checked against IAS.
We use cfg->oas to hold the OAS when stage-1 is not used, this is set
in the next patch.
This check is done outside of smmu_ptw_64_s2 as it is not part of
stage-2(it throws stage-1 fault), and the stage-2 function shouldn't
change it's behavior when nesting is supported.
When nesting is supported and we figure out how to combine TLB for
stage-1 and stage-2 we can move this check into the stage-1 function
as described in ARM DDI0487I.a in pseudocode
aarch64/translation/vmsa_translation/AArch64.S1Translate
aarch64/translation/vmsa_translation/AArch64.S1DisabledOutput

- Input to stage-2 is checked against s2t0sz, and throws stage-2
transaltion fault if exceeds it.

- Output of stage-2 is checked against effective PA output range.

Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Mostafa Saleh <smostafa@google.com>
Tested-by: Eric Auger <eric.auger@redhat.com>
Tested-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Message-id: 20230516203327.2051088-5-smostafa@google.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2 files changed