Introduce a software-based page table walker for the arm64 MMU
emulation. This is foundational component for handling GVA-GPA
translations when a request missses the (future) software TLB.
For now, it handles only Page descriptors and does not yet support Block
descriptors or permission checks. These will be added in subsequent
patches.
Signed-off-by: Ronald Caesar <github43132@proton.me>
A new function, mmu_gva_to_gpa(), will be the sole entry point for
resolving guest virtual addresses. This initial implementation models
the processor's state on reset. The function inspects the M bit from the
emulated SCTLR_EL1 register. If the bit is clear, address mapping (GVA =
GPA) is performed. This is an architecturally-mandated behavior required
for the Arm guest to execute its initiall boot code before enabling
virtual memory.
Signed-off-by: Ronald Caesar <github43132@proton.me>
Pound's asserts were broken from the very beginning and I've just
realized this. Fixing it is not my problem.
Signed-off-by: Ronald Caesar <github43132@proton.me>
The term "memory" is really ambiguous in the context of an emulator,
especially since the MMU is being developed. It can refer to host memory, or
guest memory, or both.
Signed-off-by: Ronald Caesar <github43132@proton.me>
The term "aarch64" is the formal name for Armv8-A architecture. However,
I found that the establish convention across the wider open source
ecosystem is to use the short name "arm64".
Signed-off-by: Ronald Caesar <github43132@proton.me>
