Function fetch_with_pmp

crates/virtual-machine/src/cpu/pipeline/fetch.rs:12–32

(
    bus: &mut SystemBus,
    pc: u64,
    satp: u64,
    priv_mode: PrivilegeMode,
    mstatus: u64,
    pmpcfg0: u64,
    pmpaddr0: u64,
    tlb: &mut mmu::Tlb,
)

/// Returns `InstructionAccessFault` on misalignment or bus error.
pub fn fetch_with_pmp(
    bus: &mut SystemBus,
    pc: u64,
    ctx: mmu::TranslationContext,
    tlb: &mut mmu::Tlb,
) -> Result<u32, VmError> {
    if pc & 0x3 != 0 {
        return Err(VmError::InstructionAccessFault(pc));
    }

    let phys_addr = mmu::translate_with_pmp(pc, bus, ctx, mmu::AccessKind::Execute, tlb)?;

    bus.read_word(phys_addr)
        .map_err(|_| VmError::InstructionAccessFault(pc))
}

/// Backwards-compatible wrapper: old callers without PMP info should use this.
/// Uses a throwaway TLB, so it never benefits from caching (test/diagnostic use).
pub fn fetch(
    bus: &mut SystemBus,
    pc: u64,
    satp: u64,
    priv_mode: PrivilegeMode,
    mstatus: u64,
) -> Result<u32, VmError> {