On Sat, Jul 20, 2019 at 11:28:50AM +1000, Alexey Kardashevskiy wrote: > QEMU already implements H_CAS called by SLOF. The existing handler > prepares a diff FDT and SLOF applies it on top of its current tree. > In SLOF-less setup when the user explicitly selected "bios=no", > this updates the FDT from the OS, updates it and writes back to the OS. > The new behavior is advertised to the OS via "/chosen/qemu,h_cas". I don't love having two different paths here, I'm wondering if we can unify things at all. I have wondered at some points if there's anything preventing us just giving a whole new device tree at CAS, rather than selected updates - that could simplify several things. > Signed-off-by: Alexey Kardashevskiy > --- > include/hw/ppc/spapr.h | 5 +++++ > hw/ppc/spapr.c | 24 ++++++++++++++++----- > hw/ppc/spapr_hcall.c | 49 +++++++++++++++++++++++++++++++++++++++--- > 3 files changed, 70 insertions(+), 8 deletions(-) > > diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h > index 7f5d7a70d27e..73cd9cf25b83 100644 > --- a/include/hw/ppc/spapr.h > +++ b/include/hw/ppc/spapr.h > @@ -766,9 +766,14 @@ struct SpaprEventLogEntry { > > void spapr_events_init(SpaprMachineState *sm); > void spapr_dt_events(SpaprMachineState *sm, void *fdt); > +int spapr_h_cas_do_compose_response(SpaprMachineState *spapr, void *fdt, > + SpaprOptionVector *ov5_updates); > int spapr_h_cas_compose_response(SpaprMachineState *sm, > target_ulong addr, target_ulong size, > SpaprOptionVector *ov5_updates); > +#define FDT_MAX_SIZE 0x100000 > +void *spapr_build_fdt(SpaprMachineState *spapr); > + > void close_htab_fd(SpaprMachineState *spapr); > void spapr_setup_hpt_and_vrma(SpaprMachineState *spapr); > void spapr_free_hpt(SpaprMachineState *spapr); > diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c > index b097a99951f1..f84895f4a8b4 100644 > --- a/hw/ppc/spapr.c > +++ b/hw/ppc/spapr.c > @@ -978,6 +978,19 @@ static bool spapr_hotplugged_dev_before_cas(void) > return false; > } > > +int spapr_h_cas_do_compose_response(SpaprMachineState *spapr, void *fdt, > + SpaprOptionVector *ov5_updates) Not a great function name. > +{ > + /* Fixup cpu nodes */ > + _FDT((spapr_fixup_cpu_dt(fdt, spapr))); > + > + if (spapr_dt_cas_updates(spapr, fdt, ov5_updates)) { > + return -1; > + } > + > + return 0; > +} > + > int spapr_h_cas_compose_response(SpaprMachineState *spapr, > target_ulong addr, target_ulong size, > SpaprOptionVector *ov5_updates) > @@ -1009,10 +1022,7 @@ int spapr_h_cas_compose_response(SpaprMachineState *spapr, > _FDT((fdt_open_into(fdt_skel, fdt, size))); > g_free(fdt_skel); > > - /* Fixup cpu nodes */ > - _FDT((spapr_fixup_cpu_dt(fdt, spapr))); > - > - if (spapr_dt_cas_updates(spapr, fdt, ov5_updates)) { > + if (spapr_h_cas_do_compose_response(spapr, fdt, ov5_updates)) { > return -1; > } > > @@ -1232,6 +1242,10 @@ static void spapr_dt_chosen(SpaprMachineState *spapr, void *fdt) > > /* We always implemented RTAS as hcall, tell guests to call it directly */ > _FDT(fdt_setprop_cell(fdt, chosen, "qemu,h_rtas", 1)); > + /* Tell the guest that H_CAS will return the entire FDT now, not the diff */ > + if (!spapr->bios_enabled) { > + _FDT(fdt_setprop_cell(fdt, chosen, "qemu,h_cas", 1)); As with H_RTAS< using qemu,hypertas-functions would be more appropriate for this. > + } > > spapr_dt_ov5_platform_support(spapr, fdt, chosen); > > @@ -1262,7 +1276,7 @@ static void spapr_dt_hypervisor(SpaprMachineState *spapr, void *fdt) > } > } > > -static void *spapr_build_fdt(SpaprMachineState *spapr) > +void *spapr_build_fdt(SpaprMachineState *spapr) > { > MachineState *machine = MACHINE(spapr); > MachineClass *mc = MACHINE_GET_CLASS(machine); > diff --git a/hw/ppc/spapr_hcall.c b/hw/ppc/spapr_hcall.c > index b964d94f330b..c5cb06c9d507 100644 > --- a/hw/ppc/spapr_hcall.c > +++ b/hw/ppc/spapr_hcall.c > @@ -17,6 +17,7 @@ > #include "hw/ppc/spapr_ovec.h" > #include "mmu-book3s-v3.h" > #include "hw/mem/memory-device.h" > +#include "sysemu/device_tree.h" > > static bool has_spr(PowerPCCPU *cpu, int spr) > { > @@ -1774,9 +1775,51 @@ static target_ulong h_client_architecture_support(PowerPCCPU *cpu, > /* legacy hash or new hash: */ > spapr_setup_hpt_and_vrma(spapr); > } > - spapr->cas_reboot = > - (spapr_h_cas_compose_response(spapr, args[1], args[2], > - ov5_updates) != 0); > + > + if (spapr->bios_enabled) { > + spapr->cas_reboot = > + (spapr_h_cas_compose_response(spapr, args[1], args[2], > + ov5_updates) != 0); > + } else { > + int size; > + void *fdt, *fdt_skel; > + struct fdt_header hdr = { 0 }; > + > + cpu_physical_memory_read(args[1], &hdr, sizeof(hdr)); > + size = fdt32_to_cpu(hdr.totalsize); > + if (size > FDT_MAX_SIZE) { > + return H_NOT_AVAILABLE; > + } > + > + fdt_skel = g_malloc0(size); > + cpu_physical_memory_read(args[1], fdt_skel, size); > + > + fdt = g_malloc0(FDT_MAX_SIZE); > + fdt_open_into(fdt_skel, fdt, FDT_MAX_SIZE); > + g_free(fdt_skel); fdt_open_into() explicitly permits using the same buffer for both arguments, so you don't need two allocations here - you can just allocate FDT_MAX_SIZE, read it in, then fdt_open_into() in place. You probably should check for errors from fdt_open_into(), though. > + > + if (spapr_h_cas_do_compose_response(spapr, fdt, ov5_updates)) { > + g_free(fdt); > + return H_NOT_AVAILABLE; > + } > + fdt_pack(fdt); > + if (fdt_totalsize(fdt) > FDT_MAX_SIZE) { This can't actually happen - you only ever allocated a buffer of size FDT_MAX_SIZE, so if the DT was going to exceed that you would have hit FDT_ERR_NOSPACE in an earlier step. > + error_report("FDT too big ! 0x%x bytes (max is 0x%x)", > + fdt_totalsize(fdt), FDT_MAX_SIZE); > + g_free(fdt); > + return H_NOT_AVAILABLE; > + } > + > + /* Load the fdt */ > + cpu_physical_memory_write(args[1], fdt, fdt_totalsize(fdt)); > + > + g_free(spapr->fdt_blob); > + spapr->fdt_size = fdt_totalsize(fdt); > + spapr->fdt_initial_size = spapr->fdt_size; > + spapr->fdt_blob = fdt; > + > + qemu_fdt_dumpdtb(fdt, fdt_totalsize(fdt)); > + } > } > > /* -- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson