| Message ID | 20210824122016.144364-4-wangyanan55@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | hw/arm/virt: Introduce cpu topology support | expand |
Hello Peter, Is the solution in this patch ok for you? Would appreciate if I can get some feedback. :) Thanks, Yanan . On 2021/8/24 20:20, Yanan Wang wrote: > From: Andrew Jones <drjones@redhat.com> > > Support device tree CPU topology descriptions. > > In accordance with the Devicetree Specification, the Linux Doc > "arm/cpus.yaml" requires that cpus and cpu nodes in the DT are > present. And we have already met the requirement by generating > /cpus/cpu@* nodes for members within ms->smp.cpus. Accordingly, > we should also create subnodes in cpu-map for the present cpus, > each of which relates to an unique cpu node. > > The Linux Doc "cpu/cpu-topology.txt" states that the hierarchy > of CPUs in a SMP system is defined through four entities and > they are socket/cluster/core/thread. It is also required that > a socket node's child nodes must be one or more cluster nodes. > Given that currently we are only provided with information of > socket/core/thread, we assume there is one cluster child node > in each socket node when creating cpu-map. > > Signed-off-by: Andrew Jones <drjones@redhat.com> > Co-developed-by: Yanan Wang <wangyanan55@huawei.com> > Signed-off-by: Yanan Wang <wangyanan55@huawei.com> > --- > hw/arm/virt.c | 70 +++++++++++++++++++++++++++++++++++++++++++-------- > 1 file changed, 60 insertions(+), 10 deletions(-) > > diff --git a/hw/arm/virt.c b/hw/arm/virt.c > index 82f2eba6bd..bdcf7435f0 100644 > --- a/hw/arm/virt.c > +++ b/hw/arm/virt.c > @@ -350,20 +350,21 @@ static void fdt_add_cpu_nodes(const VirtMachineState *vms) > int cpu; > int addr_cells = 1; > const MachineState *ms = MACHINE(vms); > + const VirtMachineClass *vmc = VIRT_MACHINE_GET_CLASS(vms); > int smp_cpus = ms->smp.cpus; > > /* > - * From Documentation/devicetree/bindings/arm/cpus.txt > - * On ARM v8 64-bit systems value should be set to 2, > - * that corresponds to the MPIDR_EL1 register size. > - * If MPIDR_EL1[63:32] value is equal to 0 on all CPUs > - * in the system, #address-cells can be set to 1, since > - * MPIDR_EL1[63:32] bits are not used for CPUs > - * identification. > + * See Linux Documentation/devicetree/bindings/arm/cpus.yaml > + * On ARM v8 64-bit systems value should be set to 2, > + * that corresponds to the MPIDR_EL1 register size. > + * If MPIDR_EL1[63:32] value is equal to 0 on all CPUs > + * in the system, #address-cells can be set to 1, since > + * MPIDR_EL1[63:32] bits are not used for CPUs > + * identification. > * > - * Here we actually don't know whether our system is 32- or 64-bit one. > - * The simplest way to go is to examine affinity IDs of all our CPUs. If > - * at least one of them has Aff3 populated, we set #address-cells to 2. > + * Here we actually don't know whether our system is 32- or 64-bit one. > + * The simplest way to go is to examine affinity IDs of all our CPUs. If > + * at least one of them has Aff3 populated, we set #address-cells to 2. > */ > for (cpu = 0; cpu < smp_cpus; cpu++) { > ARMCPU *armcpu = ARM_CPU(qemu_get_cpu(cpu)); > @@ -406,8 +407,57 @@ static void fdt_add_cpu_nodes(const VirtMachineState *vms) > ms->possible_cpus->cpus[cs->cpu_index].props.node_id); > } > > + if (!vmc->no_cpu_topology) { > + qemu_fdt_setprop_cell(ms->fdt, nodename, "phandle", > + qemu_fdt_alloc_phandle(ms->fdt)); > + } > + > g_free(nodename); > } > + > + if (!vmc->no_cpu_topology) { > + /* > + * Add vCPU topology description through fdt node cpu-map. > + * > + * See Linux Documentation/devicetree/bindings/cpu/cpu-topology.txt > + * In a SMP system, the hierarchy of CPUs can be defined through > + * four entities that are used to describe the layout of CPUs in > + * the system: socket/cluster/core/thread. > + * > + * A socket node represents the boundary of system physical package > + * and its child nodes must be one or more cluster nodes. A system > + * can contain several layers of clustering within a single physical > + * package and cluster nodes can be contained in parent cluster nodes. > + * > + * Given that cluster is not yet supported in the vCPU topology, > + * we currently generate one cluster node within each socket node > + * by default. > + */ > + qemu_fdt_add_subnode(ms->fdt, "/cpus/cpu-map"); > + > + for (cpu = smp_cpus - 1; cpu >= 0; cpu--) { > + char *cpu_path = g_strdup_printf("/cpus/cpu@%d", cpu); > + char *map_path; > + > + if (ms->smp.threads > 1) { > + map_path = g_strdup_printf( > + "/cpus/cpu-map/socket%d/cluster0/core%d/thread%d", > + cpu / (ms->smp.cores * ms->smp.threads), > + (cpu / ms->smp.threads) % ms->smp.cores, > + cpu % ms->smp.threads); > + } else { > + map_path = g_strdup_printf( > + "/cpus/cpu-map/socket%d/cluster0/core%d", > + cpu / ms->smp.cores, > + cpu % ms->smp.cores); > + } > + qemu_fdt_add_path(ms->fdt, map_path); > + qemu_fdt_setprop_phandle(ms->fdt, map_path, "cpu", cpu_path); > + > + g_free(map_path); > + g_free(cpu_path); > + } > + } > } > > static void fdt_add_its_gic_node(VirtMachineState *vms)
diff --git a/hw/arm/virt.c b/hw/arm/virt.c index 82f2eba6bd..bdcf7435f0 100644 --- a/hw/arm/virt.c +++ b/hw/arm/virt.c @@ -350,20 +350,21 @@ static void fdt_add_cpu_nodes(const VirtMachineState *vms) int cpu; int addr_cells = 1; const MachineState *ms = MACHINE(vms); + const VirtMachineClass *vmc = VIRT_MACHINE_GET_CLASS(vms); int smp_cpus = ms->smp.cpus; /* - * From Documentation/devicetree/bindings/arm/cpus.txt - * On ARM v8 64-bit systems value should be set to 2, - * that corresponds to the MPIDR_EL1 register size. - * If MPIDR_EL1[63:32] value is equal to 0 on all CPUs - * in the system, #address-cells can be set to 1, since - * MPIDR_EL1[63:32] bits are not used for CPUs - * identification. + * See Linux Documentation/devicetree/bindings/arm/cpus.yaml + * On ARM v8 64-bit systems value should be set to 2, + * that corresponds to the MPIDR_EL1 register size. + * If MPIDR_EL1[63:32] value is equal to 0 on all CPUs + * in the system, #address-cells can be set to 1, since + * MPIDR_EL1[63:32] bits are not used for CPUs + * identification. * - * Here we actually don't know whether our system is 32- or 64-bit one. - * The simplest way to go is to examine affinity IDs of all our CPUs. If - * at least one of them has Aff3 populated, we set #address-cells to 2. + * Here we actually don't know whether our system is 32- or 64-bit one. + * The simplest way to go is to examine affinity IDs of all our CPUs. If + * at least one of them has Aff3 populated, we set #address-cells to 2. */ for (cpu = 0; cpu < smp_cpus; cpu++) { ARMCPU *armcpu = ARM_CPU(qemu_get_cpu(cpu)); @@ -406,8 +407,57 @@ static void fdt_add_cpu_nodes(const VirtMachineState *vms) ms->possible_cpus->cpus[cs->cpu_index].props.node_id); } + if (!vmc->no_cpu_topology) { + qemu_fdt_setprop_cell(ms->fdt, nodename, "phandle", + qemu_fdt_alloc_phandle(ms->fdt)); + } + g_free(nodename); } + + if (!vmc->no_cpu_topology) { + /* + * Add vCPU topology description through fdt node cpu-map. + * + * See Linux Documentation/devicetree/bindings/cpu/cpu-topology.txt + * In a SMP system, the hierarchy of CPUs can be defined through + * four entities that are used to describe the layout of CPUs in + * the system: socket/cluster/core/thread. + * + * A socket node represents the boundary of system physical package + * and its child nodes must be one or more cluster nodes. A system + * can contain several layers of clustering within a single physical + * package and cluster nodes can be contained in parent cluster nodes. + * + * Given that cluster is not yet supported in the vCPU topology, + * we currently generate one cluster node within each socket node + * by default. + */ + qemu_fdt_add_subnode(ms->fdt, "/cpus/cpu-map"); + + for (cpu = smp_cpus - 1; cpu >= 0; cpu--) { + char *cpu_path = g_strdup_printf("/cpus/cpu@%d", cpu); + char *map_path; + + if (ms->smp.threads > 1) { + map_path = g_strdup_printf( + "/cpus/cpu-map/socket%d/cluster0/core%d/thread%d", + cpu / (ms->smp.cores * ms->smp.threads), + (cpu / ms->smp.threads) % ms->smp.cores, + cpu % ms->smp.threads); + } else { + map_path = g_strdup_printf( + "/cpus/cpu-map/socket%d/cluster0/core%d", + cpu / ms->smp.cores, + cpu % ms->smp.cores); + } + qemu_fdt_add_path(ms->fdt, map_path); + qemu_fdt_setprop_phandle(ms->fdt, map_path, "cpu", cpu_path); + + g_free(map_path); + g_free(cpu_path); + } + } } static void fdt_add_its_gic_node(VirtMachineState *vms)