From: Qemu-arm [mailto:qemu-arm-bounces+salil.mehta=huawei.com@nongnu.org] On Behalf Of Yanan Wang Sent: Sunday, May 16, 2021 11:29 AM To: Peter Maydell <peter.maydell@linaro.org>; Andrew Jones <drjones@redhat.com>; Michael S . Tsirkin <mst@redhat.com>; Igor Mammedov <imammedo@redhat.com>; Shannon Zhao <shannon.zhaosl@gmail.com>; Alistair Francis <alistair.francis@wdc.com>; David Gibson <david@gibson.dropbear.id.au>; qemu-devel@nongnu.org; qemu-arm@nongnu.org Cc: Song Bao Hua (Barry Song) <song.bao.hua@hisilicon.com>; zhukeqian <zhukeqian1@huawei.com>; yangyicong <yangyicong@huawei.com>; Zengtao (B) <prime.zeng@hisilicon.com>; Wanghaibin (D) <wanghaibin.wang@huawei.com>; yuzenghui <yuzenghui@huawei.com>; Paolo Bonzini <pbonzini@redhat.com>; Philippe Mathieu-Daudé <philmd@redhat.com> Subject: [RFC PATCH v3 6/9] hw/arm/virt-acpi-build: Use possible cpus in generation of MADT

When building ACPI tables regarding CPUs we should always build them for the number of possible CPUs, not the number of present CPUs. So we create gicc nodes in MADT for possible cpus and then ensure only the present CPUs are marked ENABLED. Furthermore, it also needed if we are going to support CPU hotplug in the future.

Hi Yanan, Yes, these changes are part of the QEMU patch-set I floated last year. Link: https://www.mail-archive.com/qemu-devel@nongnu.org/msg712018.html Perhaps I am missing something, but how this patch is related to the vcpu topology support? Thanks

Co-developed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Andrew Jones <drjones@redhat.com> Co-developed-by: Ying Fang <fangying1@huawei.com> Signed-off-by: Ying Fang <fangying1@huawei.com> Co-developed-by: Yanan Wang <wangyanan55@huawei.com> Signed-off-by: Yanan Wang <wangyanan55@huawei.com> --- hw/arm/virt-acpi-build.c | 29 +++++++++++++++++++++++++---- 1 file changed, 25 insertions(+), 4 deletions(-)

diff --git a/hw/arm/virt-acpi-build.c b/hw/arm/virt-acpi-build.c index a2d8e87616..4d64aeb865 100644 --- a/hw/arm/virt-acpi-build.c +++ b/hw/arm/virt-acpi-build.c @@ -481,6 +481,9 @@ build_madt(GArray *table_data, BIOSLinker *linker, VirtMachineState *vms) const int *irqmap = vms->irqmap; AcpiMadtGenericDistributor *gicd; AcpiMadtGenericMsiFrame *gic_msi; + MachineClass *mc = MACHINE_GET_CLASS(vms); + const CPUArchIdList *possible_cpus = mc->possible_cpu_arch_ids(MACHINE(vms)); + bool pmu; int i;

acpi_data_push(table_data, sizeof(AcpiMultipleApicTable)); @@ -491,11 +494,21 @@ build_madt(GArray *table_data, BIOSLinker *linker, VirtMachineState *vms) gicd->base_address = cpu_to_le64(memmap[VIRT_GIC_DIST].base); gicd->version = vms->gic_version;

- for (i = 0; i < MACHINE(vms)->smp.cpus; i++) { + for (i = 0; i < possible_cpus->len; i++) { AcpiMadtGenericCpuInterface *gicc = acpi_data_push(table_data, sizeof(*gicc)); ARMCPU *armcpu = ARM_CPU(qemu_get_cpu(i));

+ /* + * PMU should have been either implemented for all CPUs or not, + * so we only get information from the first CPU, which could + * represent the others. + */ + if (i == 0) { + pmu = arm_feature(&armcpu->env, ARM_FEATURE_PMU); + } + assert(!armcpu || arm_feature(&armcpu->env, ARM_FEATURE_PMU) == pmu); + gicc->type = ACPI_APIC_GENERIC_CPU_INTERFACE; gicc->length = sizeof(*gicc); if (vms->gic_version == 2) { @@ -504,11 +517,19 @@ build_madt(GArray *table_data, BIOSLinker *linker, VirtMachineState *vms) gicc->gicv_base_address = cpu_to_le64(memmap[VIRT_GIC_VCPU].base); } gicc->cpu_interface_number = cpu_to_le32(i); - gicc->arm_mpidr = cpu_to_le64(armcpu->mp_affinity); + gicc->arm_mpidr = cpu_to_le64(possible_cpus->cpus[i].arch_id); gicc->uid = cpu_to_le32(i); - gicc->flags = cpu_to_le32(ACPI_MADT_GICC_ENABLED);

- if (arm_feature(&armcpu->env, ARM_FEATURE_PMU)) { + /* + * ACPI spec says that LAPIC entry for non present CPU may be + * omitted from MADT or it must be marked as disabled. Here we + * choose to also keep the disabled ones in MADT. + */ + if (possible_cpus->cpus[i].cpu != NULL) { + gicc->flags = cpu_to_le32(ACPI_MADT_GICC_ENABLED); + } + + if (pmu) { gicc->performance_interrupt = cpu_to_le32(PPI(VIRTUAL_PMU_IRQ)); } if (vms->virt) { -- 2.19.1