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Re: [Qemu-devel] [RFC][PATCH 2/6] cpus: release allocated vcpu objects a
From: |
Andreas Färber |
Subject: |
Re: [Qemu-devel] [RFC][PATCH 2/6] cpus: release allocated vcpu objects and exit vcpu thread |
Date: |
Thu, 29 Aug 2013 07:10:15 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130801 Thunderbird/17.0.8 |
Am 29.08.2013 04:09, schrieb Chen Fan:
> After ACPI get a signal to eject a vcpu, then it will notify
> the vcpu thread of needing to exit, before the vcpu exiting,
> will release the vcpu related objects.
>
> Signed-off-by: Chen Fan <address@hidden>
> ---
> cpus.c | 36 ++++++++++++++++++++++++++++++++++++
> hw/acpi/piix4.c | 16 ++++++++++++----
> include/qom/cpu.h | 9 +++++++++
> include/sysemu/kvm.h | 1 +
> kvm-all.c | 26 ++++++++++++++++++++++++++
> 5 files changed, 84 insertions(+), 4 deletions(-)
>
> diff --git a/cpus.c b/cpus.c
> index 70cc617..6b793cb 100644
> --- a/cpus.c
> +++ b/cpus.c
> @@ -697,6 +697,30 @@ void async_run_on_cpu(CPUState *cpu, void (*func)(void
> *data), void *data)
> qemu_cpu_kick(cpu);
> }
>
> +static void qemu_kvm_destroy_vcpu(CPUState *cpu)
> +{
> + CPUState *pcpu, *pcpu1;
> +
> + pcpu = first_cpu;
> + pcpu1 = NULL;
> +
> + while (pcpu) {
> + if (pcpu == cpu && pcpu1) {
> + pcpu1->next_cpu = cpu->next_cpu;
> + break;
> + }
> + pcpu1 = pcpu;
> + pcpu = pcpu->next_cpu;
> + }
No, no, no. :) I specifically posted the "QOM CPUState, part 12" series
early to avoid exactly such code appearing! Give me a few minutes to
apply that to qom-cpu and then please rebase your work on
git://github.com/afaerber/qemu-cpu.git qom-cpu
using QTAILQ macro and --subject-prefix="RFC qom-cpu v2" for the next
version of the series.
Also, why is this only in the KVM code path? Isn't this needed for TCG
as well?
> +
> + if (kvm_destroy_vcpu(cpu) < 0) {
> + fprintf(stderr, "kvm_destroy_vcpu failed.\n");
> + exit(1);
> + }
> +
> + qdev_free(DEVICE(X86_CPU(cpu)));
DEVICE(cpu) should be sufficient.
> +}
> +
> static void flush_queued_work(CPUState *cpu)
> {
> struct qemu_work_item *wi;
> @@ -788,6 +812,11 @@ static void *qemu_kvm_cpu_thread_fn(void *arg)
> }
> }
> qemu_kvm_wait_io_event(cpu);
> + if (cpu->exit && !cpu_can_run(cpu)) {
> + qemu_kvm_destroy_vcpu(cpu);
> + qemu_mutex_unlock(&qemu_global_mutex);
> + return NULL;
> + }
> }
>
> return NULL;
> @@ -1080,6 +1109,13 @@ static void qemu_dummy_start_vcpu(CPUState *cpu)
> }
> }
>
> +void qemu_down_vcpu(CPUState *cpu)
> +{
> + cpu->stop = true;
> + cpu->exit = true;
> + qemu_cpu_kick(cpu);
> +}
> +
> void qemu_init_vcpu(CPUState *cpu)
> {
> cpu->nr_cores = smp_cores;
> diff --git a/hw/acpi/piix4.c b/hw/acpi/piix4.c
> index 1aaa7a4..44bc809 100644
> --- a/hw/acpi/piix4.c
> +++ b/hw/acpi/piix4.c
> @@ -611,10 +611,18 @@ static const MemoryRegionOps piix4_pci_ops = {
> },
> };
>
> -static void acpi_piix_eject_vcpu(int64_t cpuid)
> +static void acpi_piix_eject_vcpu(PIIX4PMState *s, int64_t cpuid)
> {
> - /* TODO: eject a vcpu, release allocated vcpu and exit the vcpu pthread.
> */
> - PIIX4_DPRINTF("vcpu: %" PRIu64 " need to be ejected.\n", cpuid);
> + CPUStatus *cpus = &s->gpe_cpu;
> + CPUState *cs = NULL;
> +
> + cs = qemu_get_cpu(cpuid);
Are you sure this is correct as 0-based index? Igor?
> + if (cs == NULL) {
> + return;
> + }
> +
> + cpus->old_sts[cpuid / 8] &= ~(1 << (cpuid % 8));
> + qemu_down_vcpu(cs);
> }
>
> static uint64_t cpu_status_read(void *opaque, hwaddr addr, unsigned int size)
> @@ -647,7 +655,7 @@ static void cpu_status_write(void *opaque, hwaddr addr,
> uint64_t data,
> }
>
> if (cpuid != 0) {
> - acpi_piix_eject_vcpu(cpuid);
> + acpi_piix_eject_vcpu(s, cpuid);
> }
> }
>
> diff --git a/include/qom/cpu.h b/include/qom/cpu.h
> index 3e49936..fa8ec8a 100644
> --- a/include/qom/cpu.h
> +++ b/include/qom/cpu.h
> @@ -180,6 +180,7 @@ struct CPUState {
> bool created;
> bool stop;
> bool stopped;
> + bool exit;
> volatile sig_atomic_t exit_request;
> volatile sig_atomic_t tcg_exit_req;
> uint32_t interrupt_request;
> @@ -489,6 +490,14 @@ void cpu_exit(CPUState *cpu);
> void cpu_resume(CPUState *cpu);
>
> /**
> + * qemu_down_vcpu:
> + * @cpu: The vCPU will to down.
> + *
> + * Down a vCPU.
> + */
> +void qemu_down_vcpu(CPUState *cpu);
The naming and documentation sounds wrong language-wise to me, but I am
not a native speaker either. Maybe "tear down" instead of "down"? Or
simply qemu_request_vcpu_removal() or something like that?
> +
> +/**
> * qemu_init_vcpu:
> * @cpu: The vCPU to initialize.
> *
> diff --git a/include/sysemu/kvm.h b/include/sysemu/kvm.h
> index de74411..fd85605 100644
> --- a/include/sysemu/kvm.h
> +++ b/include/sysemu/kvm.h
> @@ -158,6 +158,7 @@ int kvm_has_intx_set_mask(void);
>
> int kvm_init_vcpu(CPUState *cpu);
> int kvm_cpu_exec(CPUState *cpu);
> +int kvm_destroy_vcpu(CPUState *cpu);
>
> #ifdef NEED_CPU_H
>
> diff --git a/kvm-all.c b/kvm-all.c
> index 716860f..fda3601 100644
> --- a/kvm-all.c
> +++ b/kvm-all.c
> @@ -225,6 +225,32 @@ static void kvm_reset_vcpu(void *opaque)
> kvm_arch_reset_vcpu(cpu);
> }
>
> +int kvm_destroy_vcpu(CPUState *cpu)
> +{
> + KVMState *s = kvm_state;
> + long mmap_size;
> + int ret = 0;
> +
> + DPRINTF("kvm_destroy_vcpu\n");
> +
> + mmap_size = kvm_ioctl(s, KVM_GET_VCPU_MMAP_SIZE, 0);
> + if (mmap_size < 0) {
> + ret = mmap_size;
> + DPRINTF("KVM_GET_VCPU_MMAP_SIZE failed\n");
> + goto err;
> + }
> +
> + ret = munmap(cpu->kvm_run, mmap_size);
> + if (ret < 0) {
> + goto err;
> + }
> +
> + close(cpu->kvm_fd);
> +
> +err:
> + return ret;
> +}
I always assumed we'd need a new ioctl to inform the kernel about our
intent to remove a vCPU before doing such cleanups? CC'ing kvm list.
Regards,
Andreas
> +
> int kvm_init_vcpu(CPUState *cpu)
> {
> KVMState *s = kvm_state;
>
--
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- [Qemu-devel] [RFC][PATCH 0/6] i386: add cpu hot remove support, Chen Fan, 2013/08/28
- [Qemu-devel] [RFC][PATCH 2/6] cpus: release allocated vcpu objects and exit vcpu thread, Chen Fan, 2013/08/28
- Re: [Qemu-devel] [RFC][PATCH 2/6] cpus: release allocated vcpu objects and exit vcpu thread,
Andreas Färber <=
- [Qemu-devel] [RFC][PATCH 4/6] qmp: add 'cpu-del' command support, Chen Fan, 2013/08/28
- [Qemu-devel] [RFC][PATCH 3/6] qom cpu: rename variable 'cpu_added_notifier' to 'cpu_hotplug_notifier', Chen Fan, 2013/08/28
- [Qemu-devel] [RFC][PATCH 1/6] piix4: implement function 'cpu_status_write' for vcpu ejection, Chen Fan, 2013/08/28
- [Qemu-devel] [RFC][PATCH 5/6] qom cpu: add struct CPUNotifier for supporting PLUG and UNPLUG cpu notifier, Chen Fan, 2013/08/28
- [Qemu-devel] [RFC][PATCH 6/6] i386: implement cpu interface 'cpu_common_unrealizefn', Chen Fan, 2013/08/28