target/riscv/cpu_helper.c: add PMA access fault

We're not doing anything special w.r.t PMA (Physical Memory Access) related faults, handling them like regular faults that will eventually turn to be regular page faults. Turns out we can't do that. Priv spec section "Virtual Address Translation Process" mentions: "If a store to the PTE at address a+va.vpn[i]×PTESIZE would violate a PMA or PMP check, raise an access-fault exception corresponding to the original access type." This means that we should handle PMA violations with access faults, like we're already doing with PMP. One clear code path where we should throw a PMA failure, exposed by [1], is the error return from address_space_ld* call. There's a separated issue with the error code being returned by them (it always return DECODE_ERROR even with 'rejected' reads) that we're going to work around it by assuming that we did a good job with the PTE address sanitization beforehand, and interpret that the error here is related to PMA. This is of course not ideal but fixing this QEMU API is out of scope for this work. All this said, we'll set the new pmp_pma_violation flag when we have either a PMP or a PMA fault, and everything else shall fall into place. [1] https://gitlab.com/qemu-project/qemu/-/work_items/3502 Resolves: https://gitlab.com/qemu-project/qemu/-/work_items/3502 Signed-off-by: Daniel Henrique Barboza <daniel.barboza@oss.qualcomm.com> Reviewed-by: Alistair Francis <alistair.francis@wdc.com> Reviewed-by: Chao Liu <chao.liu.zevorn@gmail.com> Message-ID: <20260522172502.320529-1-daniel.barboza@oss.qualcomm.com> Signed-off-by: Alistair Francis <alistair.francis@wdc.com>