The core of the machine-type support is the new operations table,
kvm_ops_t. This acts as a standard C-style virtual table decoupling the
generic KVM core logic from target specific hardware emualtion. The
kvm_t VM instance now points to an ops table, which defines the
"personality" of the guest. A kvm_probe() factory function has been
added to initialize a kvm_t instance with the correct ops table for a
given machine type (eg, Switch 1).
The ops table's .mmio_read and .mmio_write function pointers are the
link between the armv8 CPU core and this new MMIO dispatcher. When a
physical memory access is determined to be MMIO, the VM will call the
appropriate function pointer, which in turn will use the MMIO dispatcher
to find and execute the correct device handler.
The initial implementation for the Switch 1 target
(targets/switch1/hardware/probe.cpp) is a stub. The bootstrapping
logic will be added in subsequent patches.
Signed-off-by: Ronald Caesar <github43132@proton.me>
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>
