From 6787d27b04a79524c547c60701400eb0418e3533 Mon Sep 17 00:00:00 2001 From: Michael Roth Date: Mon, 24 Oct 2016 23:47:29 -0500 Subject: spapr: add option vector handling in CAS-generated resets In some cases, ibm,client-architecture-support calls can fail. This could happen in the current code for situations where the modified device tree segment exceeds the buffer size provided by the guest via the call parameters. In these cases, QEMU will reset, allowing an opportunity to regenerate the device tree from scratch via boot-time handling. There are potentially other scenarios as well, not currently reachable in the current code, but possible in theory, such as cases where device-tree properties or nodes need to be removed. We currently don't handle either of these properly for option vector capabilities however. Instead of carrying the negotiated capability beyond the reset and creating the boot-time device tree accordingly, we start from scratch, generating the same boot-time device tree as we did prior to the CAS-generated and the same device tree updates as we did before. This could (in theory) cause us to get stuck in a reset loop. This hasn't been observed, but depending on the extensiveness of CAS-induced device tree updates in the future, could eventually become an issue. Address this by pulling capability-related device tree updates resulting from CAS calls into a common routine, spapr_dt_cas_updates(), and adding an sPAPROptionVector* parameter that allows us to test for newly-negotiated capabilities. We invoke it as follows: 1) When ibm,client-architecture-support gets called, we call spapr_dt_cas_updates() with the set of capabilities added since the previous call to ibm,client-architecture-support. For the initial boot, or a system reset generated by something other than the CAS call itself, this set will consist of *all* options supported both the platform and the guest. For calls to ibm,client-architecture-support immediately after a CAS-induced reset, we call spapr_dt_cas_updates() with only the set of capabilities added since the previous call, since the other capabilities will have already been addressed by the boot-time device-tree this time around. In the unlikely event that capabilities are *removed* since the previous CAS, we will generate a CAS-induced reset. In the unlikely event that we cannot fit the device-tree updates into the buffer provided by the guest, well generate a CAS-induced reset. 2) When a CAS update results in the need to reset the machine and include the updates in the boot-time device tree, we call the spapr_dt_cas_updates() using the full set of negotiated capabilities as part of the reset path. At initial boot, or after a reset generated by something other than the CAS call itself, this set will be empty, resulting in what should be the same boot-time device-tree as we generated prior to this patch. For CAS-induced reset, this routine will be called with the full set of capabilities negotiated by the platform/guest in the previous CAS call, which should result in CAS updates from previous call being accounted for in the initial boot-time device tree. Signed-off-by: Michael Roth Reviewed-by: David Gibson [dwg: Changed an int -> bool conversion to be more explicit] Signed-off-by: David Gibson --- hw/ppc/spapr.c | 40 ++++++++++++++++++++++++++++++++++------ hw/ppc/spapr_hcall.c | 22 ++++++++++++++++++---- 2 files changed, 52 insertions(+), 10 deletions(-) (limited to 'hw/ppc') diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c index 9300824..aa6a070 100644 --- a/hw/ppc/spapr.c +++ b/hw/ppc/spapr.c @@ -655,13 +655,28 @@ out: return ret; } +static int spapr_dt_cas_updates(sPAPRMachineState *spapr, void *fdt, + sPAPROptionVector *ov5_updates) +{ + sPAPRMachineClass *smc = SPAPR_MACHINE_GET_CLASS(spapr); + int ret = 0; + + /* Generate ibm,dynamic-reconfiguration-memory node if required */ + if (spapr_ovec_test(ov5_updates, OV5_DRCONF_MEMORY)) { + g_assert(smc->dr_lmb_enabled); + ret = spapr_populate_drconf_memory(spapr, fdt); + } + + return ret; +} + int spapr_h_cas_compose_response(sPAPRMachineState *spapr, target_ulong addr, target_ulong size, - bool cpu_update) + bool cpu_update, + sPAPROptionVector *ov5_updates) { void *fdt, *fdt_skel; sPAPRDeviceTreeUpdateHeader hdr = { .version_id = 1 }; - sPAPRMachineClass *smc = SPAPR_MACHINE_GET_CLASS(qdev_get_machine()); size -= sizeof(hdr); @@ -680,10 +695,8 @@ int spapr_h_cas_compose_response(sPAPRMachineState *spapr, _FDT((spapr_fixup_cpu_dt(fdt, spapr))); } - /* Generate ibm,dynamic-reconfiguration-memory node if required */ - if (spapr_ovec_test(spapr->ov5_cas, OV5_DRCONF_MEMORY)) { - g_assert(smc->dr_lmb_enabled); - _FDT((spapr_populate_drconf_memory(spapr, fdt))); + if (spapr_dt_cas_updates(spapr, fdt, ov5_updates)) { + return -1; } /* Pack resulting tree */ @@ -972,6 +985,13 @@ static void *spapr_build_fdt(sPAPRMachineState *spapr, _FDT((fdt_add_mem_rsv(fdt, spapr->initrd_base, spapr->initrd_size))); } + /* ibm,client-architecture-support updates */ + ret = spapr_dt_cas_updates(spapr, fdt, spapr->ov5_cas); + if (ret < 0) { + error_report("couldn't setup CAS properties fdt"); + exit(1); + } + return fdt; } @@ -1137,6 +1157,13 @@ static void ppc_spapr_reset(void) rtas_addr = rtas_limit - RTAS_MAX_SIZE; fdt_addr = rtas_addr - FDT_MAX_SIZE; + /* if this reset wasn't generated by CAS, we should reset our + * negotiated options and start from scratch */ + if (!spapr->cas_reboot) { + spapr_ovec_cleanup(spapr->ov5_cas); + spapr->ov5_cas = spapr_ovec_new(); + } + fdt = spapr_build_fdt(spapr, rtas_addr, spapr->rtas_size); spapr_load_rtas(spapr, fdt, rtas_addr); @@ -1164,6 +1191,7 @@ static void ppc_spapr_reset(void) first_cpu->halted = 0; first_ppc_cpu->env.nip = SPAPR_ENTRY_POINT; + spapr->cas_reboot = false; } static void spapr_create_nvram(sPAPRMachineState *spapr) diff --git a/hw/ppc/spapr_hcall.c b/hw/ppc/spapr_hcall.c index f1d081b..7c46d46 100644 --- a/hw/ppc/spapr_hcall.c +++ b/hw/ppc/spapr_hcall.c @@ -950,7 +950,7 @@ static target_ulong h_client_architecture_support(PowerPCCPU *cpu_, unsigned compat_lvl = 0, cpu_version = 0; unsigned max_lvl = get_compat_level(cpu_->max_compat); int counter; - sPAPROptionVector *ov5_guest; + sPAPROptionVector *ov5_guest, *ov5_cas_old, *ov5_updates; /* Parse PVR list */ for (counter = 0; counter < 512; ++counter) { @@ -1013,13 +1013,27 @@ static target_ulong h_client_architecture_support(PowerPCCPU *cpu_, * of guest input. To model these properly we'd want some sort of mask, * but since they only currently apply to memory migration as defined * by LoPAPR 1.1, 14.5.4.8, which QEMU doesn't implement, we don't need - * to worry about this. + * to worry about this for now. */ + ov5_cas_old = spapr_ovec_clone(spapr->ov5_cas); + /* full range of negotiated ov5 capabilities */ spapr_ovec_intersect(spapr->ov5_cas, spapr->ov5, ov5_guest); spapr_ovec_cleanup(ov5_guest); + /* capabilities that have been added since CAS-generated guest reset. + * if capabilities have since been removed, generate another reset + */ + ov5_updates = spapr_ovec_new(); + spapr->cas_reboot = spapr_ovec_diff(ov5_updates, + ov5_cas_old, spapr->ov5_cas); + + if (!spapr->cas_reboot) { + spapr->cas_reboot = + (spapr_h_cas_compose_response(spapr, args[1], args[2], cpu_update, + ov5_updates) != 0); + } + spapr_ovec_cleanup(ov5_updates); - if (spapr_h_cas_compose_response(spapr, args[1], args[2], - cpu_update)) { + if (spapr->cas_reboot) { qemu_system_reset_request(); } -- cgit v1.1