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spapr: Render full FDT on ibm,client-architecture-support 

The ibm,client-architecture-support call is a way for the guest to
negotiate capabilities with a hypervisor. It is implemented as:
- the guest calls SLOF via client interface;
- SLOF calls QEMU (H_CAS hypercall) with an options vector from the guest;
- QEMU returns a device tree diff (which uses FDT format with
an additional header before it);
- SLOF walks through the partial diff tree and updates its internal tree
with the values from the diff.

This changes QEMU to simply re-render the entire tree and send it as
an update. SLOF can handle this already mostly, [1] is needed before this
can be applied. This stores the resulting tree in the spapr machine to have
the latest valid FDT copy possible (this should not matter much as
H_UPDATE_DT happens right after that but nevertheless).

The benefit is reduced code size as there is no need for another set of
DT rendering helpers such as spapr_fixup_cpu_dt().

The downside is that the updates are bigger now (as they include all
nodes and properties) but the difference on a '-smp 256,threads=1' system
before/after is 2.35s vs. 2.5s.

[1] https://patchwork.ozlabs.org/patch/1152915/

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
This commit is contained in:
Alexey Kardashevskiy 2019-09-02 15:41:16 +10:00 committed by David Gibson
parent c4ec08ab70
commit e68cd0cb5c
1 changed files with 9 additions and 79 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

88
hw/ppc/spapr.c
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@ -295,64 +295,6 @@ static void spapr_populate_pa_features(SpaprMachineState *spapr,
_FDT((fdt_setprop(fdt, offset, "ibm,pa-features", pa_features, pa_size)));
}
static int spapr_fixup_cpu_dt(void *fdt, SpaprMachineState *spapr)
{
MachineState *ms = MACHINE(spapr);
int ret = 0, offset, cpus_offset;
CPUState *cs;
char cpu_model[32];
uint32_t pft_size_prop[] = {0, cpu_to_be32(spapr->htab_shift)};
CPU_FOREACH(cs) {
PowerPCCPU *cpu = POWERPC_CPU(cs);
DeviceClass *dc = DEVICE_GET_CLASS(cs);
int index = spapr_get_vcpu_id(cpu);
int compat_smt = MIN(ms->smp.threads, ppc_compat_max_vthreads(cpu));
if (!spapr_is_thread0_in_vcore(spapr, cpu)) {
continue;
}
snprintf(cpu_model, 32, "%s@%x", dc->fw_name, index);
cpus_offset = fdt_path_offset(fdt, "/cpus");
if (cpus_offset < 0) {
cpus_offset = fdt_add_subnode(fdt, 0, "cpus");
if (cpus_offset < 0) {
return cpus_offset;
}
}
offset = fdt_subnode_offset(fdt, cpus_offset, cpu_model);
if (offset < 0) {
offset = fdt_add_subnode(fdt, cpus_offset, cpu_model);
if (offset < 0) {
return offset;
}
}
ret = fdt_setprop(fdt, offset, "ibm,pft-size",
pft_size_prop, sizeof(pft_size_prop));
if (ret < 0) {
return ret;
}
if (ms->numa_state->num_nodes > 1) {
ret = spapr_fixup_cpu_numa_dt(fdt, offset, cpu);
if (ret < 0) {
return ret;
}
}
ret = spapr_fixup_cpu_smt_dt(fdt, offset, cpu, compat_smt);
if (ret < 0) {
return ret;
}
spapr_populate_pa_features(spapr, cpu, fdt, offset);
}
return ret;
}
static hwaddr spapr_node0_size(MachineState *machine)
{
if (machine->numa_state->num_nodes) {
@ -983,11 +925,13 @@ static bool spapr_hotplugged_dev_before_cas(void)
return false;
}
static void *spapr_build_fdt(SpaprMachineState *spapr);
int spapr_h_cas_compose_response(SpaprMachineState *spapr,
target_ulong addr, target_ulong size,
SpaprOptionVector *ov5_updates)
{
void *fdt, *fdt_skel;
void *fdt;
SpaprDeviceTreeUpdateHeader hdr = { .version_id = 1 };
if (spapr_hotplugged_dev_before_cas()) {
@ -1003,25 +947,7 @@ int spapr_h_cas_compose_response(SpaprMachineState *spapr,
size -= sizeof(hdr);
/* Create skeleton */
fdt_skel = g_malloc0(size);
_FDT((fdt_create(fdt_skel, size)));
_FDT((fdt_finish_reservemap(fdt_skel)));
_FDT((fdt_begin_node(fdt_skel, "")));
_FDT((fdt_end_node(fdt_skel)));
_FDT((fdt_finish(fdt_skel)));
fdt = g_malloc0(size);
_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)) {
return -1;
}
/* Pack resulting tree */
fdt = spapr_build_fdt(spapr);
_FDT((fdt_pack(fdt)));
if (fdt_totalsize(fdt) + sizeof(hdr) > size) {
@ -1033,7 +959,11 @@ int spapr_h_cas_compose_response(SpaprMachineState *spapr,
cpu_physical_memory_write(addr, &hdr, sizeof(hdr));
cpu_physical_memory_write(addr + sizeof(hdr), fdt, fdt_totalsize(fdt));
trace_spapr_cas_continue(fdt_totalsize(fdt) + sizeof(hdr));
g_free(fdt);
g_free(spapr->fdt_blob);
spapr->fdt_size = fdt_totalsize(fdt);
spapr->fdt_initial_size = spapr->fdt_size;
spapr->fdt_blob = fdt;
return 0;
}