| Message ID | 1457672078-17307-4-git-send-email-bharata@linux.vnet.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 11.03.2016 05:54, Bharata B Rao wrote: > From: Gu Zheng <guz.fnst@cn.fujitsu.com> > > In order to deal well with the kvm vcpus (which can not be removed without any > protection), we do not close KVM vcpu fd, just record and mark it as stopped > into a list, so that we can reuse it for the appending cpu hot-add request if > possible. It is also the approach that kvm guys suggested: > https://www.mail-archive.com/kvm@vger.kernel.org/msg102839.html > > Signed-off-by: Chen Fan <chen.fan.fnst@cn.fujitsu.com> > Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com> > Signed-off-by: Zhu Guihua <zhugh.fnst@cn.fujitsu.com> > Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com> > [- Explicit CPU_REMOVE() from qemu_kvm/tcg_destroy_vcpu() > isn't needed as it is done from cpu_exec_exit() > - Use iothread mutex instead of global mutex during > destroy > - Don't cleanup vCPU object from vCPU thread context > but leave it to the callers (device_add/device_del)] > --- > cpus.c | 39 +++++++++++++++++++++++++++++++++-- > include/qom/cpu.h | 10 +++++++++ > include/sysemu/kvm.h | 1 + > kvm-all.c | 57 +++++++++++++++++++++++++++++++++++++++++++++++++++- > kvm-stub.c | 5 +++++ > 5 files changed, 109 insertions(+), 3 deletions(-) Reviewed-by: Thomas Huth <thuth@redhat.com>
On Fri, Mar 11, 2016 at 10:24:32AM +0530, Bharata B Rao wrote: > From: Gu Zheng <guz.fnst@cn.fujitsu.com> > > In order to deal well with the kvm vcpus (which can not be removed without any > protection), we do not close KVM vcpu fd, just record and mark it as stopped > into a list, so that we can reuse it for the appending cpu hot-add request if > possible. It is also the approach that kvm guys suggested: > https://www.mail-archive.com/kvm@vger.kernel.org/msg102839.html > > Signed-off-by: Chen Fan <chen.fan.fnst@cn.fujitsu.com> > Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com> > Signed-off-by: Zhu Guihua <zhugh.fnst@cn.fujitsu.com> > Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com> > [- Explicit CPU_REMOVE() from qemu_kvm/tcg_destroy_vcpu() > isn't needed as it is done from cpu_exec_exit() > - Use iothread mutex instead of global mutex during > destroy > - Don't cleanup vCPU object from vCPU thread context > but leave it to the callers (device_add/device_del)] Reviewed-by: David Gibson <david@gibson.dropbear.id.au> > --- > cpus.c | 39 +++++++++++++++++++++++++++++++++-- > include/qom/cpu.h | 10 +++++++++ > include/sysemu/kvm.h | 1 + > kvm-all.c | 57 +++++++++++++++++++++++++++++++++++++++++++++++++++- > kvm-stub.c | 5 +++++ > 5 files changed, 109 insertions(+), 3 deletions(-) > > diff --git a/cpus.c b/cpus.c > index bc774e2..be0ac6a 100644 > --- a/cpus.c > +++ b/cpus.c > @@ -953,6 +953,18 @@ 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) > +{ > + if (kvm_destroy_vcpu(cpu) < 0) { > + error_report("kvm_destroy_vcpu failed"); > + exit(EXIT_FAILURE); > + } > +} > + > +static void qemu_tcg_destroy_vcpu(CPUState *cpu) > +{ > +} > + > static void flush_queued_work(CPUState *cpu) > { > struct qemu_work_item *wi; > @@ -1045,7 +1057,7 @@ static void *qemu_kvm_cpu_thread_fn(void *arg) > cpu->created = true; > qemu_cond_signal(&qemu_cpu_cond); > > - while (1) { > + do { > if (cpu_can_run(cpu)) { > r = kvm_cpu_exec(cpu); > if (r == EXCP_DEBUG) { > @@ -1053,8 +1065,10 @@ static void *qemu_kvm_cpu_thread_fn(void *arg) > } > } > qemu_kvm_wait_io_event(cpu); > - } > + } while (!cpu->unplug || cpu_can_run(cpu)); > > + qemu_kvm_destroy_vcpu(cpu); > + qemu_mutex_unlock_iothread(); > return NULL; > } > > @@ -1108,6 +1122,7 @@ static void tcg_exec_all(void); > static void *qemu_tcg_cpu_thread_fn(void *arg) > { > CPUState *cpu = arg; > + CPUState *remove_cpu = NULL; > > rcu_register_thread(); > > @@ -1145,6 +1160,16 @@ static void *qemu_tcg_cpu_thread_fn(void *arg) > } > } > qemu_tcg_wait_io_event(QTAILQ_FIRST(&cpus)); > + CPU_FOREACH(cpu) { > + if (cpu->unplug && !cpu_can_run(cpu)) { > + remove_cpu = cpu; > + break; > + } > + } > + if (remove_cpu) { > + qemu_tcg_destroy_vcpu(remove_cpu); > + remove_cpu = NULL; > + } > } > > return NULL; > @@ -1301,6 +1326,13 @@ void resume_all_vcpus(void) > } > } > > +void cpu_remove(CPUState *cpu) > +{ > + cpu->stop = true; > + cpu->unplug = true; > + qemu_cpu_kick(cpu); > +} > + > /* For temporary buffers for forming a name */ > #define VCPU_THREAD_NAME_SIZE 16 > > @@ -1517,6 +1549,9 @@ static void tcg_exec_all(void) > break; > } > } else if (cpu->stop || cpu->stopped) { > + if (cpu->unplug) { > + next_cpu = CPU_NEXT(cpu); > + } > break; > } > } > diff --git a/include/qom/cpu.h b/include/qom/cpu.h > index 7052eee..0720dd7 100644 > --- a/include/qom/cpu.h > +++ b/include/qom/cpu.h > @@ -237,6 +237,7 @@ struct kvm_run; > * @halted: Nonzero if the CPU is in suspended state. > * @stop: Indicates a pending stop request. > * @stopped: Indicates the CPU has been artificially stopped. > + * @unplug: Indicates a pending CPU unplug request. > * @crash_occurred: Indicates the OS reported a crash (panic) for this CPU > * @tcg_exit_req: Set to force TCG to stop executing linked TBs for this > * CPU and return to its top level loop. > @@ -289,6 +290,7 @@ struct CPUState { > bool created; > bool stop; > bool stopped; > + bool unplug; > bool crash_occurred; > bool exit_request; > uint32_t interrupt_request; > @@ -756,6 +758,14 @@ void cpu_exit(CPUState *cpu); > void cpu_resume(CPUState *cpu); > > /** > + * cpu_remove: > + * @cpu: The CPU to remove. > + * > + * Requests the CPU to be removed. > + */ > +void cpu_remove(CPUState *cpu); > + > +/** > * qemu_init_vcpu: > * @cpu: The vCPU to initialize. > * > diff --git a/include/sysemu/kvm.h b/include/sysemu/kvm.h > index 6695fa7..5d5b602 100644 > --- a/include/sysemu/kvm.h > +++ b/include/sysemu/kvm.h > @@ -216,6 +216,7 @@ 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 44c0464..35c0621 100644 > --- a/kvm-all.c > +++ b/kvm-all.c > @@ -61,6 +61,12 @@ > > #define KVM_MSI_HASHTAB_SIZE 256 > > +struct KVMParkedVcpu { > + unsigned long vcpu_id; > + int kvm_fd; > + QLIST_ENTRY(KVMParkedVcpu) node; > +}; > + > struct KVMState > { > AccelState parent_obj; > @@ -94,6 +100,7 @@ struct KVMState > QTAILQ_HEAD(msi_hashtab, KVMMSIRoute) msi_hashtab[KVM_MSI_HASHTAB_SIZE]; > #endif > KVMMemoryListener memory_listener; > + QLIST_HEAD(, KVMParkedVcpu) kvm_parked_vcpus; > }; > > KVMState *kvm_state; > @@ -237,6 +244,53 @@ static int kvm_set_user_memory_region(KVMMemoryListener *kml, KVMSlot *slot) > return kvm_vm_ioctl(s, KVM_SET_USER_MEMORY_REGION, &mem); > } > > +int kvm_destroy_vcpu(CPUState *cpu) > +{ > + KVMState *s = kvm_state; > + long mmap_size; > + struct KVMParkedVcpu *vcpu = NULL; > + 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; > + } > + > + vcpu = g_malloc0(sizeof(*vcpu)); > + vcpu->vcpu_id = kvm_arch_vcpu_id(cpu); > + vcpu->kvm_fd = cpu->kvm_fd; > + QLIST_INSERT_HEAD(&kvm_state->kvm_parked_vcpus, vcpu, node); > +err: > + return ret; > +} > + > +static int kvm_get_vcpu(KVMState *s, unsigned long vcpu_id) > +{ > + struct KVMParkedVcpu *cpu; > + > + QLIST_FOREACH(cpu, &s->kvm_parked_vcpus, node) { > + if (cpu->vcpu_id == vcpu_id) { > + int kvm_fd; > + > + QLIST_REMOVE(cpu, node); > + kvm_fd = cpu->kvm_fd; > + g_free(cpu); > + return kvm_fd; > + } > + } > + > + return kvm_vm_ioctl(s, KVM_CREATE_VCPU, (void *)vcpu_id); > +} > + > int kvm_init_vcpu(CPUState *cpu) > { > KVMState *s = kvm_state; > @@ -245,7 +299,7 @@ int kvm_init_vcpu(CPUState *cpu) > > DPRINTF("kvm_init_vcpu\n"); > > - ret = kvm_vm_ioctl(s, KVM_CREATE_VCPU, (void *)kvm_arch_vcpu_id(cpu)); > + ret = kvm_get_vcpu(s, kvm_arch_vcpu_id(cpu)); > if (ret < 0) { > DPRINTF("kvm_create_vcpu failed\n"); > goto err; > @@ -1495,6 +1549,7 @@ static int kvm_init(MachineState *ms) > #ifdef KVM_CAP_SET_GUEST_DEBUG > QTAILQ_INIT(&s->kvm_sw_breakpoints); > #endif > + QLIST_INIT(&s->kvm_parked_vcpus); > s->vmfd = -1; > s->fd = qemu_open("/dev/kvm", O_RDWR); > if (s->fd == -1) { > diff --git a/kvm-stub.c b/kvm-stub.c > index b962b24..61f9d5c 100644 > --- a/kvm-stub.c > +++ b/kvm-stub.c > @@ -33,6 +33,11 @@ bool kvm_allowed; > bool kvm_readonly_mem_allowed; > bool kvm_ioeventfd_any_length_allowed; > > +int kvm_destroy_vcpu(CPUState *cpu) > +{ > + return -ENOSYS; > +} > + > int kvm_init_vcpu(CPUState *cpu) > { > return -ENOSYS;
diff --git a/cpus.c b/cpus.c index bc774e2..be0ac6a 100644 --- a/cpus.c +++ b/cpus.c @@ -953,6 +953,18 @@ 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) +{ + if (kvm_destroy_vcpu(cpu) < 0) { + error_report("kvm_destroy_vcpu failed"); + exit(EXIT_FAILURE); + } +} + +static void qemu_tcg_destroy_vcpu(CPUState *cpu) +{ +} + static void flush_queued_work(CPUState *cpu) { struct qemu_work_item *wi; @@ -1045,7 +1057,7 @@ static void *qemu_kvm_cpu_thread_fn(void *arg) cpu->created = true; qemu_cond_signal(&qemu_cpu_cond); - while (1) { + do { if (cpu_can_run(cpu)) { r = kvm_cpu_exec(cpu); if (r == EXCP_DEBUG) { @@ -1053,8 +1065,10 @@ static void *qemu_kvm_cpu_thread_fn(void *arg) } } qemu_kvm_wait_io_event(cpu); - } + } while (!cpu->unplug || cpu_can_run(cpu)); + qemu_kvm_destroy_vcpu(cpu); + qemu_mutex_unlock_iothread(); return NULL; } @@ -1108,6 +1122,7 @@ static void tcg_exec_all(void); static void *qemu_tcg_cpu_thread_fn(void *arg) { CPUState *cpu = arg; + CPUState *remove_cpu = NULL; rcu_register_thread(); @@ -1145,6 +1160,16 @@ static void *qemu_tcg_cpu_thread_fn(void *arg) } } qemu_tcg_wait_io_event(QTAILQ_FIRST(&cpus)); + CPU_FOREACH(cpu) { + if (cpu->unplug && !cpu_can_run(cpu)) { + remove_cpu = cpu; + break; + } + } + if (remove_cpu) { + qemu_tcg_destroy_vcpu(remove_cpu); + remove_cpu = NULL; + } } return NULL; @@ -1301,6 +1326,13 @@ void resume_all_vcpus(void) } } +void cpu_remove(CPUState *cpu) +{ + cpu->stop = true; + cpu->unplug = true; + qemu_cpu_kick(cpu); +} + /* For temporary buffers for forming a name */ #define VCPU_THREAD_NAME_SIZE 16 @@ -1517,6 +1549,9 @@ static void tcg_exec_all(void) break; } } else if (cpu->stop || cpu->stopped) { + if (cpu->unplug) { + next_cpu = CPU_NEXT(cpu); + } break; } } diff --git a/include/qom/cpu.h b/include/qom/cpu.h index 7052eee..0720dd7 100644 --- a/include/qom/cpu.h +++ b/include/qom/cpu.h @@ -237,6 +237,7 @@ struct kvm_run; * @halted: Nonzero if the CPU is in suspended state. * @stop: Indicates a pending stop request. * @stopped: Indicates the CPU has been artificially stopped. + * @unplug: Indicates a pending CPU unplug request. * @crash_occurred: Indicates the OS reported a crash (panic) for this CPU * @tcg_exit_req: Set to force TCG to stop executing linked TBs for this * CPU and return to its top level loop. @@ -289,6 +290,7 @@ struct CPUState { bool created; bool stop; bool stopped; + bool unplug; bool crash_occurred; bool exit_request; uint32_t interrupt_request; @@ -756,6 +758,14 @@ void cpu_exit(CPUState *cpu); void cpu_resume(CPUState *cpu); /** + * cpu_remove: + * @cpu: The CPU to remove. + * + * Requests the CPU to be removed. + */ +void cpu_remove(CPUState *cpu); + +/** * qemu_init_vcpu: * @cpu: The vCPU to initialize. * diff --git a/include/sysemu/kvm.h b/include/sysemu/kvm.h index 6695fa7..5d5b602 100644 --- a/include/sysemu/kvm.h +++ b/include/sysemu/kvm.h @@ -216,6 +216,7 @@ 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 44c0464..35c0621 100644 --- a/kvm-all.c +++ b/kvm-all.c @@ -61,6 +61,12 @@ #define KVM_MSI_HASHTAB_SIZE 256 +struct KVMParkedVcpu { + unsigned long vcpu_id; + int kvm_fd; + QLIST_ENTRY(KVMParkedVcpu) node; +}; + struct KVMState { AccelState parent_obj; @@ -94,6 +100,7 @@ struct KVMState QTAILQ_HEAD(msi_hashtab, KVMMSIRoute) msi_hashtab[KVM_MSI_HASHTAB_SIZE]; #endif KVMMemoryListener memory_listener; + QLIST_HEAD(, KVMParkedVcpu) kvm_parked_vcpus; }; KVMState *kvm_state; @@ -237,6 +244,53 @@ static int kvm_set_user_memory_region(KVMMemoryListener *kml, KVMSlot *slot) return kvm_vm_ioctl(s, KVM_SET_USER_MEMORY_REGION, &mem); } +int kvm_destroy_vcpu(CPUState *cpu) +{ + KVMState *s = kvm_state; + long mmap_size; + struct KVMParkedVcpu *vcpu = NULL; + 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; + } + + vcpu = g_malloc0(sizeof(*vcpu)); + vcpu->vcpu_id = kvm_arch_vcpu_id(cpu); + vcpu->kvm_fd = cpu->kvm_fd; + QLIST_INSERT_HEAD(&kvm_state->kvm_parked_vcpus, vcpu, node); +err: + return ret; +} + +static int kvm_get_vcpu(KVMState *s, unsigned long vcpu_id) +{ + struct KVMParkedVcpu *cpu; + + QLIST_FOREACH(cpu, &s->kvm_parked_vcpus, node) { + if (cpu->vcpu_id == vcpu_id) { + int kvm_fd; + + QLIST_REMOVE(cpu, node); + kvm_fd = cpu->kvm_fd; + g_free(cpu); + return kvm_fd; + } + } + + return kvm_vm_ioctl(s, KVM_CREATE_VCPU, (void *)vcpu_id); +} + int kvm_init_vcpu(CPUState *cpu) { KVMState *s = kvm_state; @@ -245,7 +299,7 @@ int kvm_init_vcpu(CPUState *cpu) DPRINTF("kvm_init_vcpu\n"); - ret = kvm_vm_ioctl(s, KVM_CREATE_VCPU, (void *)kvm_arch_vcpu_id(cpu)); + ret = kvm_get_vcpu(s, kvm_arch_vcpu_id(cpu)); if (ret < 0) { DPRINTF("kvm_create_vcpu failed\n"); goto err; @@ -1495,6 +1549,7 @@ static int kvm_init(MachineState *ms) #ifdef KVM_CAP_SET_GUEST_DEBUG QTAILQ_INIT(&s->kvm_sw_breakpoints); #endif + QLIST_INIT(&s->kvm_parked_vcpus); s->vmfd = -1; s->fd = qemu_open("/dev/kvm", O_RDWR); if (s->fd == -1) { diff --git a/kvm-stub.c b/kvm-stub.c index b962b24..61f9d5c 100644 --- a/kvm-stub.c +++ b/kvm-stub.c @@ -33,6 +33,11 @@ bool kvm_allowed; bool kvm_readonly_mem_allowed; bool kvm_ioeventfd_any_length_allowed; +int kvm_destroy_vcpu(CPUState *cpu) +{ + return -ENOSYS; +} + int kvm_init_vcpu(CPUState *cpu) { return -ENOSYS;