Hi Paolo, There's a fork that has linux-user support. We'll get it added into the downstream riscv-qemu repo and include that in the next patch set instead of softmmu.
Thanks, Sagar On Mon, Sep 26, 2016 at 5:44 AM, Paolo Bonzini <pbonz...@redhat.com> wrote: > > > On 26/09/2016 14:38, Bastian Koppelmann wrote: > > On 09/26/2016 02:21 PM, Paolo Bonzini wrote: > >> > >> > >> On 26/09/2016 12:56, Sagar Karandikar wrote: > >>> +#ifndef CONFIG_USER_ONLY > >>> +DEF_HELPER_4(csrrw, tl, env, tl, tl, tl) > >>> +DEF_HELPER_5(csrrs, tl, env, tl, tl, tl, tl) > >>> +DEF_HELPER_5(csrrc, tl, env, tl, tl, tl, tl) > >>> +DEF_HELPER_2(sret, tl, env, tl) > >>> +DEF_HELPER_2(mret, tl, env, tl) > >>> +DEF_HELPER_1(tlb_flush, void, env) > >>> +DEF_HELPER_1(fence_i, void, env) > >>> +#endif /* !CONFIG_USER_ONLY */ > >> > >> The system emulation spec is still in flux, I think we should only add > >> user-mode emulation for now. > >> > > > > Hi Paolo, > > > > by user-mode emulation you still mean softmmu and not linux-user, right? > > So just drop the system instructions for now. > > I don't think that's possible; all RISC-V machines include at least > M-mode, whose precise definitions requires the privileged interface > specification which hasn't been finalized yet. So only linux-user is > stable enough. > > In fact, based on some recent discussions on the RISC-V isa-dev mailing > list, it looks like some memory protection features _beyond_ the > privileged interface specification are in practice required to secure > M-mode from the supervisor. I'm not sure what's the point in defining a > separate mandatory M-mode (supervisor mode cannot even enable paging > without help from M-mode, on the other hand a processor that only has M- > and U-modes cannot enable paging) but not providing the tools to > actually enforce privilege separation for it. > > All in all, while I'm happy that the RISC-V project uses QEMU for > development, I don't think that the privileged interface specification > is mature enough for inclusion in QEMU. It's very different for > linux-user user-mode emulation of course, it's great to have that upstream. > > Thanks, > > Paolo >